Great Video: Casting a Part With Polyurethane | Part 2
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- čas přidán 15. 07. 2024
- Welcome to Part 2 of BJB's Mold and Part Making Video Series! Using simple methods developed over decades in Casting, Rapid Prototyping, Movies, DIY & much more... learn how to cast high quality Polyurethane parts in the silicone mold made in Part 1 of this series. BJB is the industry's preferred resource for "Taking the Mystery Out of Materials".
Part 1 Video here: • Great Video: How to ma...
Company Website - www.bjbenterprises.com/
Phone - 714-734-8450 (USA)
For 40 years, BJB Enterprises, Inc., an ISO 9001:2008 Company, has been in the business of formulating and supplying quality liquid resin systems to a vast array of industries and with a myriad of applications in mind!
BJB offers a complete line-up of Castable Polyurethanes, Epoxy Systems, Silicone Casting Rubbers, Polyurethane Foam Systems, Aliphatic Water Clear Urethanes, Sprayable Polyurethanes, Pigments and Release.
www.bjbenterprises.com/
0:00 Introduction
1:56 Exothermic Reacts/heats faster with increased mass.
2:12 Temperature Affects Work-Time
2:45 High Viscosity = Thick
2:50 Viscosity Centipoise (CPS)
5:22 "Paintable" Mold Release
5:25 E302 Rocket Release
5:49 Silicone Oils can transfer to the part.
6:00 Mold Release can Limpart a texture.
6:16 E236 Urethane Release
6:23 Don't flood the surface!
6:31 Don't spray release in casting area!
6:41 Allow a few minutes before closing mold.
6:59 The mold is clamped between two boards to close seam line.
7:51 Vent Risers & Fill Funnel create reservoirs to account for material shrinkage.
8:31 Rolled Funnel
8:45 Smaller Cross Section • Increased Head Pressure
8:54 Paper can cause moisture contamination!
9:24 Dispense Equipment
10:12 9-Min Work Time 1000 CPS
11:07 2% X 100g = 2g 6821 Cherry Red Pigment
11:15 Don't mix 3 components together at once!
12:04 Double Mixing
14:04 Heat promotes quicker demold
14:29 Pressure does not force air out of the mold.
14:43 40-80 psi common pressures - Věda a technologie
One of the best videos on the topic I've seen so far, informative and concise. Thank you!
Thank you. I watched some non-professional videos before and the difference and quality you achieve here is enormous. You speak at a good pace so we have time to actually listen w/o need of going back so often. I also appreciated the science on it, because to achieve quality one has to consider the properties of different materials.
"A hatchet? A gun? Nah, I'll just use the screwdriver..." XD
Thanks for the informative videos. They put the Smooth-On product videos to shame. Such professionalism makes me inclined to choose your company as my source for RTV and Polyurethane materials.
So you found our subtle bit of humor in that video. Glad you got it! Thanks for the compliments, we are doing our best to provide good info and teach useful techniques for successfully working with casting materials.
@@bjbenterprises AWESOME little Easter Egg!!
exellent video. Excellent technical coverage, excellent comentator, clear speach, easy to understand. Bravo !!
Thank you very much for the feedback!
This videos are a pleasure to watch.Thank you.
This video was so helpful thank you so much!!
Brilliant series of two tutorials, thnx so much!
Mark Schuurman fantastic, thanks for the feedback. Be sure to check out our advanced mold making tutorials as well: czcams.com/video/C7uMkBzOMaM/video.html
This was great!
Great instructional videos!
great video, very clear and well done
Sure I learned many things about casting and molds.
It's good job you do the test and videos .
Very instructional video. Now i just need to build my cast and figure out what material is best for a snow sled.
Fantastic information, both part 1 and 2 videos.
Thank you for the feedback!
Fantastic information, both part 1 and 2 videos.
Great Vid! I just started at a urethane supply company and need to understand the process. Very informative. Well done
Thank you for your comment!
exellent video
Thanks for the excellent videos. Really good to see so much attention to detail and passion for quality. Makes me confident that you care about your products, too. I have an idea to do some prototyping of ultra high precision electronics, where I would make a Silicone mold to accurately 'pot' small irregularly shaped circuit boards. Time for some more research on your website ...
Our materials are fantastic for this type of application. We have many customers who pot electronics for wildlife research in harsh environments and do exactly what you mention. Give us a call or drop us an email and we will be happy to help!
This is one of the better intro videos for casting I have seen. The only step that I think was missing is using a vacuum chamber after the mold has been filled with material. This can help dislodge any small bubbles that tend to form around troublespots. Vent tubes are not always sufficient. Under vacuum material will flow backward through the fill and vent tubes. It shouldn't make too much of a mess if your tubes are long enough and assuming you had not trapped any huge bubbles. I make the material to flow back and forth a few times by cracking the vent petcock while the pump is running. Follow this with curing under pressure and you should have no bubbles or voids. Note that if your mold itself has any bubbles or voids then curing under pressure will distort the mold. You don't want any bubbles, not even the tiny, almost invisible ones. The mold will shrivel while under pressure.
Hi Noah, thank you for your comment. We do have many production customers that use vacuum assist in their casting process but it's a much smaller percentage of people in comparison to those simply using a pressure chamber after pouring in degassed polyurethane. The problem many people encounter is that if they pull too much vacuum on a mold filled with urethane, it will degass and boil again, causing additional bubbles and the material will overflow out the mold. We will typically recommend no more than 10-15" hg of vacuum applied to prevent that. Also, few people have a vacuum chamber big enough to place larger molds under vacuum, so proper placement of vents and the fill port helps with filling a mold and reducing trapped air. What equipment and level of vacuum are you typically using in your process? The potential cost of equipment (vacuum pumps/chambers, pressure pots, etc) is a concern for newcomers to molding and casting. We've found teaching proper techniques of vent placement and mold posturing for general purpose parts can reduce the need for additional equipment required for molds that are not set up properly. Once again, thanks for bringing up another valuable option for the casting process. If you have any reference videos or tutorials, let us know!
Yes, actually, that's a good point. Some resins will generate new gas while under vacuum, so that would just make things worse. Is it just polyurethane that does this? It must actually be causing the resin to break down. If the resin were just boiling due to a high vapor pressure then you would expect that gas to condense back into liquid when you release vacuum. Perhaps there is some hysteresis that leaves some bubbles behind. Perhaps irrelevant for this our purposes...
And you're also correct about the amount of vacuum I use. Now that I think about it, when I do this I don't pull a full vacuum. I open and close the petcock to release and then pull vacuum in order to rock the resin back and forth in the mold. If there are any bubbles stuck in the resin it's pretty obvious because you can see the resin flow back out of the fill and vent holes. When I release the vacuum the resin gets pulled back into the mold. When the resin doesn't move much after a few cycles then I know I've gotten rid of any bubbles trapped in the mold.
I work mostly with small molds. Almost have fit into a 10 gallon (abut 40 Liters) chamber.
I am a little upset that the Luger was not used as improvised scissors..
Hi Mr , can we make car lamps with your resine .
The resine has the same property than the polycarbonate ( used for the car lamps specially the transparent parts )? resistance to high temperature of the light in the car lamps like leds etc ...
whats the code of the clear resine to buy it , and finally have you a shop in europ ?
thank you
Thanks. I wish somebody could make these machines affordable for DIY use.
Which machines are you referring to? We have many DIY customers using our materials to make their parts.
can you explain mass production with your machines?
thanks
Thanks for the video!
I really wish there was a cheap system for degassing / pressurizing (pressure tank + vacuum chamber in one and a cheap vacuum pump)
Dejay Rezme Hi Dejay. Define cheap? While an industrial vacuum system can be an investment, there are some reasonable systems available on the internet if you do some searching around. You might Amazon or ebay for some chamber/pump combos. For pressure tanks, many people use paint pressure pots that are widely available and reasonable in cost. They are certified for pressure and have the appropriate safety valves to make pressure casting a safe process. Once again, it is an investment to purchase tools and equipment, but the quality of the parts produced is increased exponentially and is a sound investment if you plan to continue using the molding/casting process. Regards. - BJB
BJBEnterprises I mean dirt cheap ;)
Yeah I guess it simply needs a bit of investment like any hobby. I've seen an air compressor / vacuum pump for < $100 but not sure if they are any good. I guess it's better than nothing in any case.
Shouldn't those designs for paint pressure pots be theoretically be strong enough for vacuum as well? I guess you do need a window to see / control the bubbles. But other than that it looks really simple. A pot, a thick transparent lid, a seal and clamps for the pressure.
Could you mod a pressure cooker for this?
Anyway, thanks for your answer!
You can use a pressure pot as a dual purpose vessel if you built an acrylic lid with gasket and pull vacuum. We use 1" thick acrylic to resist the forces of vacuum pulling down. I would also mention that the vacuum pump required to effectively remove air from mixed materials is quite high. You need a pump that can pull a minimum of 5-6 CFM down to 28-29" of mercury. If you try to use a weak pump, the bubbles will not even budge and it's a waste of time. To get some ideas if you are on a budget, look at something similar to these: www.amazon.com/s/ref=nb_sb_ss_i_3_10?url=search-alias%3Dtools&field-keywords=vacuum%20chamber%20kit&sprefix=vacuum+cha%2Ctools%2C381
Thank you very much for the info!
So more than 141.584 liter per minute and at least -982 mbar. Well I'll keep a lookout on ebay. But if I get into this I at least want to have some dual use. Pressure / vacuum pot and also use it as an air compressor for airbrush / painting stuff. And maybe sandblasting (I'm just trying to rationalize why I need to spend money for a new hobby haha)
would like to know how many microns of vacuum would be required.
Thanks for the comedy 😂😅
Looking forward to make my own Bionicle with this
So long as you perfect your maniacal laugh to complete the character! :) Let us know if you have any material or mold making questions in the process...
I'd really like to mold PLA or ABS, do you have any tips ? Thanks for your attention !
@@_Xantras_ PLA and ABS is a thermoplastic, not a thermoset material so you can't mold them in a silicone mold like this. It would only be 3D printed or injection molded.
Hi BJB Enterprise, your 2 videos are very informative and I'm excited to try on doing it. I have some questions tho regarding BJB's products, first how about food grade molds? second, do you ship internationally? Thankyou! looking forward to hear from your respond.
Joseph Shalom Hi Joseph, we do not certify materials for food grade applications. This is not a liability BJB chooses to accept and processing 2-component materials to qualify for food grade is a critical process. Our Customer Service is very capable of shipping BJB products Internationally. We sell our products all around the world! The best thing to do is contact us through our Website: www.bjbenterprises.com
Thank you for another well presented, fantastically informative video! Is it feasible to cast accurate threads into parts not requiring significant post processing, using silicone molds? What is the curing temp of polyurethanes? Eg, would the temperature created during the curing period prohibit the use of threaded wax inserts - then heated for a faster cure and the removal of threaded inserts?
Hi Karl. Molding threads into castings is very common. Threaded rod with mold release applied is very common and also threaded metal inserts (brass or stainless). I am not familiar with anyone using wax inserts for this process unless a very specific geometry or thread configuration was needed. Although exotherm temps of curing polyurethane is mass dependent (more mass=more heat), we typically see exotherm temperatures in the 150-220F (65-105C) range.
I want to make a plastic canopy with a little tint for my model airplane. I don't have a mold for it and the manufacturer is out of business. What I need to do please? I'm in southern California inland empire area.
Great video. Do you sell DVD's on your videos. I am a Newbie and learning more everyday by trial and error.
Hi Richard. Currently we do not have the videos on DVD. You can view all of the BJB videos in our CZcams page individually or by Playlist. czcams.com/users/BJBEnterprises
Great video. I was thinking of making my own phone case but after looking at your video it seems like I would need a professional vacuum. Could these techniques be accomplish by someone who doesn't own a vacuum and no experience?
yes. a vacuum gives the best quality but there are other methods that are basically free you can look up to remove air
in Vietnam where I'm can't buy it.
What materials are used in molding case and how to do it?
Hi ...Great video!! I have quick question. Several people now a days are using pretty large vacuum chambers to pour and degas urethane simultaneously making sure it also reaches all spots into the mould. It eliminates the need of degassing separately and pouring separately. Is it the most effective way of casting?
That technique is called vacuum casting and it has been a very popular method used in the rapid prototyping industry over several decades. It does work well for producing complex parts or if the system you're using is very moisture sensitive. The big issue with it is that you need an expensive piece of equipment and specialized consumables like the mixing paddles. If you are in a production setting and the company can afford to invest into equipment, then it is a good method to produce urethane parts. If you are a smaller shop, or an individual making small quantities, mixing the material by hand and pulling vacuum separately in a vacuum chamber is effective and easy. Setting up the mold with proper vents like our video can eliminate many of the issues with trapped air, or you can use a pressure tank to help with small air bubbles trapped in a mold.
hi , nice video , i have a question about vacuum pump , how many cfm vacuum pum i need to extract all the bubbles? thank you :)
+Lucia Galvez Gallego If you watch the video around 12:40 we list a lot of information about the vacuum required. Typically we recommend a minimum of 5-6 CFM with a high vacuum pump.
10:55 - someone needs to watch that guy. looks like he was deciding which weapon to use against his co-workers. Any man that chooses scissors over a hatchet has some serious issues.
Anguinus Vir don't know why Americans like to criticize. Only thing they are good at
D-MMA hey moron, Americans like to criticize other people and other countries, that's the truth and u know it hurts you moron
haha made my day :P
@Parveen Sharma Dude it was a joke .... You are Indian ... Criticizing Americans for Criticizing other countries... while you criticize a person who is not even Criticizing anything & probably isn't even American... I'm an Indian Living in the Americas and people like you make us look bad ... Worldwide... Grow the Fuck Up !
lol right? The guy in the background seems intentional, but I'm not sure what the intention was. Maybe they were just having fun.
Great video. Thanks for all of the information. I am trying put a rubber coating on a round, heavy ball. What kind of material should I use? I am looking for the consistency and feel of a racquetball or handball. I hope that makes sense. Thank you advance for your time.
+Thumber Pasta The approach to applying a coating to the ball would depend on how
smooth you need the surface and how consistent you need the coating. If
you are simply trying to add a tough layer around the ball, you could
look at brushing or spraying an elastomeric coating. If you need more
precision, you might need to look at casting an over-mold in a closed
mold to control thickness and surface quality. Without defining those
parameters, it's hard to say what will work best. Of note, a
racquetball Durometer would likely come in around 60-70 Shore A.
+BJBEnterprises Thanks for your reply and valuable information. I do have to have a perfectly symmetrical ball and a smooth surface. I am not good with the lingo, but here is my best try at describing my setup. Because of poor graphics, let us assume that the inside square below is my ball sitting on 3 small cone shapes that are the same material as what I am going to cast. These small cones will be sitting on the other mold. The space between the 2 squares will be 1/8 inches. When I pour the casting in the mold and it hardens, I should have a perfect round cover sealed over my ball (with the cones becoming part of the ball). I HOPE it does. Does this sound like a good plan? What material would you recommend using, if we thought 60-70 Shore A was a good hardness? I wish I could talk to you or someone from your Company. I will look you up tomorrow. I am going to have to order materials. Thanks again for your time, I do appreciate it. Sorry for the bad graphics. I hope you can make sense of it.
Liquid
________( )_______
l __________ l
l l ball l l
l l_________l l
l \/ \/ l
-------------------------------
+Thumber Pasta Of course it moved a little bit when I hit the reply button. It is good this whole "internet" thing is just a fad. Lol
I'm trying to make a halo costume what casting material would I use to make a solid piece, basically I want it to have the impact and abrasion resistance of high end knee pads, anything I can buy off the shelf or internet is a plus
buzz lightyear buzz lightyear You will be looking for something in the "Semi-Rigid" class of materials, probably in the 50D-60D range. This has been used on many movie armor-style suits. Feel free to contact us direct to get some
cured samples of material or technical help. Thanks for your interest in BJB materials. info@bjbenterprises.com bjbenterprises.com/index.php/polyurethanes/castable/semi-rigid/all-purpose/
Hi I need a resin or urethane to case some action figure accessories. Something rigid, but flexible enough to bend without breaking. Anything that you might suggest?
We have a few products that fit into that category. You might check out our TC874. It is easy to pigment and has a nice mix of toughness, flex, while still being failry rigid: bjbenterprises.com/index.php/tc-874-a-b/
Hi i have a fast setting PU resin and am having trouble degassing within the pot time. Would degassing part a and b before mixing help to remove any trapped air?? Thanks again for your videos, definitely the most informative and detailed on youtube!
Oddly enough, this does help to a certain degree, especially if you have mixed pigment into one side already. When you are pulling that much vacuum on a liquid, you are also pulling microscopic air and moisture out. Make sure you are using a good plastic mixing container as well. Paper cups will increase the amount of air bubbles while under vacuum. You might also want to take a look at your vacuum pump/chamber set up and make sure you are using the largest and shortest air hose possible between pump and chamber. You may also want to fill up some of the empty volume in the chamber with scrap silicone bricks if you have too much space in there.
awesome thanks for the advice!
hey where can i buy that preasure pot and i need some boolet proof poly carbonate from lexan the best on. which one should i buy
That particular pressure pot is a custom-made piece of equipment we purchased second hand. You can buy similar sized systems from R3 Manufacturing: www.r3mfg.com/
Is poleurethane rigid?
can i just port a vacuum line from my car engine, they pull high vacuum at idle or under load?
Not likely. The vacuum required to effectively de-gas silicone and cast urethane is fairly high but you also need high CFM to do it in a timely fashion. This means you need at least 28-29" of Hg and 5-6 CFM at a minimum. Often times we hear customers are trying to use single stage pumps that can only reach 26" of Hg and they struggle to pop the bubbles that rise to the surface. If you are living at higher than normal altitudes, this compounds the problem even worse. Having a good vacuum pump opens your options to using a much wider variety of material systems and not just hobby grade materials that sacrifice mold life and material properties in an effort to make vacuum unnecessary.
Is there any casting material that gives a flexible plastic. For example, if you were to make a coffee cup lid, what would you use?
Yes, we have a huge variety of materials from extremely flexible, hard/rigid, and everything in between. Contact us through our website and we would be happy to send you some cured samples to evaluate. -BJB
Great thanks.
I want to ask, what is the material that creates the product, The formula to mix it,, Thanks you so much!
Hello, the list of items used are in the description. The material being cast in the mold is our TC-870FR polyurethane. We have a huge variety of casting materials available on our website: www.bjbenterprises.com
why when we use pressure to get rid of bubbles we won't have explosion of these compressed bubbles in case of product tearing after it's cured and finished ? excellent info by the way
With flexible materials, compressed bubbles can return and distort the parts. We have seen this many times. With rigid material, the bubbles can't rebound like that because the material is hard. Pressure is best used in conjunction with material that has been vacuum degassed, and the pressure forces the liquid material into the fine detail of the mold where bubbles may become trapped. Good question!
Hi,what type of resin is hardest to be used on ball bearing housings,thanks
That sounds like a question that needs more than a CZcams response. Best to email your project needs to our technical staff: info@bjbenterprises.com
Thank you. Great videos. I'd like to know more about the materials, durometers. I need something that is flexible but hard or firm to touch and push on. The part needs to flex hundreds of times and needs strength to be pulled on Hard. Maximum thickness needs to be 1/16 inch thick. 20 inches long. 5 inches wide. Would this be a nylon? Or please tell me, I'm all ears.
***** Hi Richard, you might want to have a look at our Durometer Video: czcams.com/video/Q6jn223_1Mw/video.html
Also, feel free to call or email our Tech Dept. to find the material you need. We would be happy to answer your questions: info@bjbenterprises.com 714-734-8450
Could this foam or any other type of foam be used to cast armour and be durable for stunts?
***** To clarify, the systems shown here are not polyurethane foam. These systems are non-foaming castable polyurethanes you can cast into a mold. We do have another video that explains foams and processing. czcams.com/video/_O_vd_I_ojI/video.html
To answer your question: Yes, we have many customers who build foam swords, weapons, costumes, and armor for Cosplay, LARPing, and Halloween characters. Contact us through our website or email info@bjbenterprises.com to get cured samples of our foam. -BJB
I keep hearing urethane rubber is hard to paint, do you have any insight on that?
Yes, we have solutions for that. We offer a couple of Flexible Paint systems; SC-92 and SC-89. bjbenterprises.com/index.php/polyurethanes/coatings/
Plus, we have an adhesion promoter called TC-89 that increases the bond even further. For many years these have been used on theme park character heads, special effects, costumes, prototypes, flexible foam, and much more. One thing to also be aware of is the type of mold release you've used in making urethane parts. You'll want to avoid silicone-oil based mold releases if possible and opt for a "paintable" mold release like our E302 Rocket Release. Please call us if you have additional tech questions. We are happy to help. 714-734-8450
BJBEnterprises Thanks, you guys are tops
I have been looking at this as a solution for a costume dilemma I've been having I need to fashion two identical small accessories.
However they'd need to be gold, which pigment would be the best to replicate the correct colour?
You may need to look into cold-metal urethane casting using gold powder pigments. See our distributor BITY mold supply for a good tutorial on this subject: czcams.com/video/9OFteD7iKLI/video.html
What information would you give me to make a cast that is kinda bumpy has holes bcs I wana make a mold,for my tech deck,penny. Board and you guys look like realm experience at what you do
If a part has an irregular shape or geometry, you can also use a bed of modeling clay (like non-sulpher based plastalina or similar) to define the first half of the mold. This is also a common method for making two part molds. The clay would plug any through-holes in the pattern.
Thank you so much
Please why the mixture A and B boiling when covered do you place it on heater?
No, this is vacuum pulling air bubbles out. No heat is used.
Where can I find the clear tube like part that you connect to the vacuum pump to de-gas the resin material?
+Wakeman Edwards Hi, if you are referring to the large glass bell jar we place the material container into, you can find these through many lab supply companies. They are somewhat expensive and most people will use a chamber with clear acrylic lid instead. The bell jar we used in the video is great for video purposes to see the action happening inside. For a better visual of a typical vacuum chamber, see our video on BJB's industrial vacuum cart system. czcams.com/video/_srHYTiRCB4/video.html
That's a lot of help....thanks!
Can I use a stainless steel two part mold to poor your material in? and if so, will I need a release for it?
Yes, you can use metal molds but you need to use mold release. Cast polyurethane has very strong adhesive properties, so on metal molds we recommend to first apply 2-3 coats of a mold release wax followed by a light spray of urethane mold release. We have a video here showing choosing a mold release: czcams.com/video/kNtkwKo0-VU/video.html
Hi, very good! What material do you use to do the cap/hat?
George Freitas the original pattern was 3D printed on an Objet. The cast part is made with our high impact, fire resistant TC-870FR polyurethane with Red pigment added. Links are in the description.
@@bjbenterprises the link does not show the description or the value of the material.
George Freitas bjbenterprises.com/index.php/tc-870-a-b/
I need to know, does degassing strengthen a part?
Good question. Yes, it does in some ways. If you're eliminating bubbles form a casting material, then you are removing stress-risers or weak points by removing that air.
i wanna ask for ur help, i have a flight stick joystick for Fligh Sims which is for right handed... and i wish to make it left handed... how can I invert the handle?
There isn't a way to do that with mold making and casting. You would need to 3D scan the original, reverse the model in the computer, then print, and then make a new mold.
Would this be a good (preferred) method for making vehicles, such as school buses and RV's (trailers and/or motor homes)? If not, what would be? Thanks!
If you are referring to making small model vehicles, yes it would. You can create much better detail with less obvious marks on the part by adding strategic vents and fill ports vs crude mold making techniques.
Yes, HO scale school buses. What can be used for the windows?
You could cast the entire thing from a clear resin and then paint the rest, but this is more of an engineering question than materials since there are so many different ways to approach this task.
How would u make the shape or mold??? I want to make replacement interior pieces for my car and also custom parts, thanks.
An old video, and still good info. However I see a few channels using those old scales with weights on them (not sure what it's called, other than 'old' scale). Any reason why those are used vs digital that would easily show a number, vs messing around with some weights to measure. A few drawbacks with digital would be 1) needs batteries, 2) can most easily brake. I'm messing with plastics and silicone on a hobby basis, doing mixing based on volume, which I know is the least accurate method, just wondering how that stands up to that old scale that seems to have some room for inaccuracy too.
It just happened to be that we used those in our sample lab at the time. We have digital scales all over our facility, including some highly sensitive scales that measure to the thousandth of a gram. The Beam Scales are quick if you are use to them, but certainly digital scales are more universally used and easy to read. We have since gone to show digital scales in our videos since it can be confusing or intimidating to folks new to mold making and casting. Thanks for the comment!
so the Luger wasn't needed in this process?
Fortunately, no.
How could I cast a skateboard wheel. It needs to be a hard rubber. Is there anyway I could do that?
Yes and no. You can certainly cast durable wheels from what we term "room temperature urethane" for a number of applications. BJB produces some of the best room-temp processed elastomers that are also easy to cast. However, production skateboard wheels are typically cast in a process called "hot-pour urethane" in which the polymer is processed at temperatures approaching 200F/94C. The chemical make-up in hot pour urethanes does not work at room temperature; it needs heat to lower the viscosity from a gel/solid state (making it pourable) and it also needs the heat to act as a catalytic/cross-linking agent. You will achieve higher physical properties like rebound, tear strength, and abrasion resistance over room-temperature urethanes. We have had many customers (like Shark Wheel) use our urethane systems to prototype and produce short run urethane wheels for sporting applications like skateboards and robotics as well. If you have a unique or specific application requirement, please feel free to email us at info@bjbenterprises.com and we'll be happy to help you out either way. Regards - BJB
Do you have a clear UV resistant product? I'm looking to make the top half of a sealed outdoor electronic module that needs light to get in for the solar panel.
Yes, our rigid Water Clear polyurethanes are UV resistant and perfect for this application. You can see our video on making an auto tail light lens to learn more, or contact us for product info: czcams.com/video/WME8R2-Ot8E/video.html
714-734-8450 info@bjbenterprises.com
@@bjbenterprises Thank you! That looks perfect! But what is the actual UV stability for full-time outdoors..? I know a lot of _epoxies_ claim UV stability but it doesn't last more than a few months. And obviously in the case of classic cars, you keep them inside and drive them once in a while, so it takes a month of sundays to actually get much accumulated UV.
For year around exposure to the sky in say California or Texas, what would you expect the usable lifetime in years to be? (90% transmissive for the solar panel, and it needs to not get brittle and crack/shatter if a bird lands on it.)
Are we talking about a few months? 5 years, 10 years?
Thanks!
@@fromjesse Our Water Clear polyurethanes have been used for several decades in a variety of harsh UV environments. Automotive aftermarket parts, outdoor art, and theme park attractions to name a few. We are talking years, not months.
@@bjbenterprises Thank you!
The pieces that you cast. Are they pretty strong? I would like to cast flanges but is not sure about the strength of it.
+Hakasauars The polyurethane parts cast are indded strong, and high performance. We try to formulate these systems to simulate a lot of injection molded plastics like ABS, Polypropylene, and Polycarbonate. So to answer another way, they are not considered brittle or weak unless you are using the entirely wrong plastic for a given part.
BJBEnterprises Thanks for the info. Is there a way to cast cylinders without the cores being solid? I need to make an adapter for a bicycle frame tube
+Hakasauars Yes, you would simply need to mold a part with the desired wall thickness and the hollow portion of the part would be filled with silicone as you pour the mold. Seeing a picture of the part would help to guide you the rest of the way but that's the simplistic explanation above. Check out our other video on casting a part from a 3D printed model. czcams.com/video/b_KMWhJyYLE/video.html
BJBEnterprises Thanks
+BJBEnterprises How would this product respond, in use with fiberglass instead of using a typical fibreglass resin??
Why my silicone blue rubber always sticker in the mold ?It's made of steel cromed ball very shiny and with no porosite. My rubber silicone can have bad quality?
Silicone can be tacky for several reasons: You used the wrong spray mold release, you didn't mix the silicone long enough (or used the wrong mixing utensil), you were not accurate on the mix ratio (use a scale, not your eyes), when using a platinum silicone you cast against something that the silicone didn't like (latex, sulfur clay, unclean metal oils, tin silicone, certain urethane elastomers, other natural rubbers, etc), or it is very cold and you need to wait longer for cure (or add some heat). It's also possible you used poor quality silicone material or very old material.
does polyurethane 50 d have good resistance to handle scratches? I want to make a mini rc car body, maybe you can provide a good shore solution for a mini rc car body
Yes, materials in the 50-60 Shore D hardness range have very high abrasion and impact resistance. We have several options on our website: www.bjbmaterials.com
@@bjbenterprises aha, thank you.😃😃😀. I will go to see. Nice nice.
Sir , I bought Isocyanate & Polyol from Amazon India. I live in India. It's forming foam. It's not forming any solid gum . I was trying to make skateboard bushings.what Can be done with that solution?
Did you buy polyurethane foam? Or, did you mix the material and there are too many bubbles? There is not enough information about the material and the way you processed for us to help. You should ask the manufacture of your material as well.
@@bjbenterprises I bought two separate liquids.Dark - Polyol & Light - Isocyanate. When I mixed , It foamed. I don't know which type of Isocyanate & Polyol I should buy to make skateboard bushing gum . Kindly help me.
can we buy this product on ace hardware? or other dept store in Indonesia?
Our products are not sold in hardware stores. They are available for purchase on our website and certain distributors worldwide. Keep in mind these are intended for Industrial use and are not intended for a general consumer. Knowledge of the process and materials is essential for success and safe use. Thank you for your interest in BJB products.
How many parts can typically be made on a mold before it degrades beyond use? I understand many things come into play so use the fireman hat, how many hats would you expect to get from the tool in this video?
thanks
+Wayne Kinne A simple part like this with minimal undercuts may net you roughly 25-30 parts. You would likely see wear in the helmet badge area where silicone is under stress from pulling out parts from the undercut. Parts without an undercut like that may net 30-50+ parts. These are very generalized numbers but if you demold the parts in the proper time (don't allow them to sit too long in the mold) and use a proper mold release, you will see the best performance. Also, casting one type of material, as oppose to switching materials around, will also help achieve maximum use. Great question!
+BJBEnterprises It looks like 200 parts in your adds, what is up with that? I am looking at an ABS type of hardness.
+Wayne Kinne I'm not sure where you are pulling that information from. There are cases in which you may see 100+ parts out of a mold, but in the industries that quote custom molds and parts they will often place a conservative estimate of tool life in numbers similar to above or simply cast multiple tools. There are many variables to mold life which affect this number so giving a blanket statement it is better to error on the conservative side rather than over-promise on something that could be misleading. If you are referring to the cost effectiveness of silicone tools compared to mass production, then it's still a viable way to produce hundreds of parts. For ABS-like parts, you would look at products like our TC-808, TC-803, or TC-890 series.
+BJBEnterprises Ya opps, I am mixing up my google searches, sorry. It is 3D printed tools that are claiming 200 parts, my bad.
Can you give me a better idea on how to choose? TC-808, TC-803, TC-890? What are the differences? What are the benefit of each. Which Silicone to use as mold? Which mold release?
My final product will float in water, need to withstand freezing temperatures as well as 70 F temps. And be durable.
Thank you,
Wayne
Hi Wayne, lots of info to answer there. For polyurethane selection, you would consider the size of the part and the working time you need to mix A&B and get it poured into to the mold. Some folks can work with 2 minutes, some need 5. Will you degass in a vacuum chamber first or go into a pressure pot? Are you just mixing and pouring? How many bubbles are acceptable to you then? For silicone, do you have lots of undercuts or is the piece simple in geometry? You want to use the stiffest silicone you can get away with for best mold life and part tolerances. A good place to start is a 40-45 Shore A like our TC-5041. It's best to call our helpful Tech department and we can sort through this stuff in a matter of a 5-minute conversation. 714-734-8450 Wayne Kinne
13:57 how much time to wait 38 degree?
The time would depend on the size and thickness of the mold. Silicone is very insulating, so it takes time for it to heat up, but when it is warmed up it retains heat very well for some time. For a mold this size, we would say 30-60 minutes should be sufficient.
I'd like to see part one, but how to find it???
Here you go: czcams.com/video/iRj6xzNx7P4/video.html
can we cast 200°C hot plastic in that silicone mold?
We would not recommend that. Temps are too high for a silicone mold to last like that.
its a brilliant video.
We are casting transparent polyurethane in an aluminium profile which is open on the casting end. We degass the polyurethane and make it entirely bubble free and pour it into the aluminium profile . The gel time for our polyurethane is about 30 minutes. So post degass and mixing we still have about 10 minutes left .
After pouring it into the profile the bubbles start forming again and again and again. its quite depressing to see bubbles in the profile. kindly help us out with a solution. We let the Polyurethane cure at room temperature for 24 hours.Kindly help us out with a solution. Thanks
+lakhan agarwal Hello, it's possible that there is moisture/water contaminating your polyurethane. When PU comes into contact with moisture, it forms CO2 and makes bubbles. The moisture could come from mixing in a paper cup or using wood mixing sticks. Another possibility is that there is still microscopic air in the polyurethane after mixing (not enough vacuum strength during degassing) and the heat/exotherm is causing the small bubbles to grow and turn into larger bubbles you can now visibly see. You can email us pictures of your parts and mold to help us understand the issues better: info@bjbenterprises.com
Thank you for your interest in BJB!
can i use it to make a slush cast for a mask?
+Charly Welter You can certainly use silicone molds and casting polyurethane for slush molds, but this 2-piece mold is designed for a complete fill. You might want to look at our other video to see something more suitable for slush casting: czcams.com/video/yOOdNyJjhD8/video.html
+BJBEnterprises i try to make a mask that is robust and hard like a car tire, but i need that it is slush cast compatible but i cant find it anywere can you help me?
+Charly Welter To make a slush-cast part, you will want something that will gel quickly. You can build thicker layers with additional material. You might want to look at something like our FP-60 or FP-70. A car tire is approximately 60 Shore A hardness so a 60-70A polyurethane is something to consider: bjbenterprises.com/index.php/fp-60-a-b/ bjbenterprises.com/index.php/fp-70-a-b/
i need that german gun
How to casting plastic boards more strong plz upload
We are not sure what that means, sorry.
@@bjbenterpriseshow casting plastic boards
@@vickysekar7232 plastic board for what? Skateboard, cutting board, snowboard....?
valo
Do you have distributor in Vietnam?
No but we ship products worldwide.
@@bjbenterprises could you please send me the quotation for 10kg via email: hungdinh@qualiserv.com.vn. CIF Noi Bai Air port and Exw?
Can you support me to choose wish BJB Polyurethane material i can use for mechanical part that can holds impacts and heat resistant
Thank you in advance
Yes of course. It is best to send material questions to our technical team. They help customers choose products for specific applications so you can get the correct material the first time. info@bjbenterprises.com
Using TC-804 on its own, no problem, works great, no air bubbles at all. Adding pigment, I end up with lots of tiny air bubbles. I make sure my two parts with pigment are bubble free before mixing, mix in a separate cup, then degas for at least 2 minutes. Bubbles seem to form during pouring even though I'm very careful. Is that a problem anybody else has? Is there a known cause, am I overlooking something, is there a solution? Thanks!
Precision: I'm mixing a total of 280g of TC-804 for that casting.
I have not heard of that specific issue but bubbles can form many ways. Moisture is the most common reason which could come from the pigment, paper mixing cup, wood stir stick, and etc. The best way to help you would be to have you go over your situation and variables with our experienced Technical Team. Send an email with details to info@bjbenterprises.com or just call 714-734-8450 for the quickest resolution. Thank you for reaching out!
@@bjbenterprises Thank you for the quick answer, working on all these conditions, mostly moisture. I always use plastic mixing cups but I have been using wood stirs, switching to metal and plastic now. Just placed an order for the longer worktime TC-806 system.
Incredible video i hope to follow this process so can you provide me cap 3d file to me then i will follow your process by purchasing your products
hello, what do you mean by privide a cap 3d file?
It means plastic casting cad
@@caloriecoin_ceo7847 We do not offer CAD services. Do you have a design of the part you need? We can look at the design to help understand the part, but we do not design parts for customers. We sell the molding and casting materials only, but we can help you understand the process.
@@bjbenterprises on this video, you made small plastic cap.so i need plastic cap cad file.
also I hope excaltly to follow your process to make it. so plz teach me materials you sell. I hope to buy them
77f is not room temperature. The median is around 68f.
For scientific work, room temperature is taken to be about 20 to 25 degrees Celsius (68-77 F) with an average of 23 °C (about 73.4 F). Most material manufactures use approx 25 C as a general standard to determine pot life and cure for their formulated systems. Regardless of temp used, the important thing is that data sheets use a consistent number to act as a comparative among different materials.
Hehe watch it 11 minutes in, in the background in the left hand side.
+dnelms2 - that's funny as hell. Totally didn't see that.
Great, but its very slow process. The same part can be injection molded in metal mold probably 1000 times at the same time that you mold one here. Polyurethane better and very effective for small quantities.
True, but most parts that are created using this process are never intended to be produced in those numbers or are a functional prototype to prove the concept before investing in injection molded tooling. This process is called Bridge Manufacturing, designed to "bridge" the gap between 3D Printed prototypes and full scale injection molding. In some cases like medical enclosures and/or specialty products, the numbers produced in a year may only be in the dozens or several hundred. If it is in a prototyping stage, making drastic changes to design geometry would cost much more in metal tooling vs casting a new silicone mold. Understanding where these processes produce a cost benefit is critical in any product design and many of our end users use all forms to help bring their customers' ideas to market.
Ahhh is polyurethane use to create those kind of squishies toy ?
Many of the squishy foam toys are made with self skinning polyurethane foam. This video shows non-foaming castable polyurethane which is similar in properties to injection molded parts. Polyurethane is a very diverse chemistry and we have a huge variety of materials to make different types of parts. Thanks for the comment.
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Why not pour the mold in a vacuum. Then there won't be any chance of bubbles!
That is a technique called vacuum casting and it has been used for a couple decades in product development. However, you need special equipment to do the mixing and pouring of polyurethane into the mold while under vacuum. Some people will fill a mold and place it into a vacuum chamber but if not done properly, the material will bubble/boil and spill out of the mold causing the loss of casting material.