Making a plastic mold
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Forum Name: Fiberglass, Fabrication, and Interiors
Forum Discription: Fiberglass Kick Panels, Subwoofer Enclosures, Plexiglas, Fabrics, Materials, Finishes, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=57899
Printed Date: April 29, 2024 at 8:52 AM
Topic: Making a plastic mold
Posted By: chump
Subject: Making a plastic mold
Date Posted: June 17, 2005 at 1:10 PM
Hey guys, I was wondering if any of you might be able to point me in the right direction as to my next project. I would like to make a plastic mold out of an existing shape that I already have which is aluminum. I am planning on taping it, applying a release agent, and then duplicating the shape out of plastic. Basically the same way you would do it with fiberglass resin. The question I have is regarding the materials I need. Is ther such a thing as polyurethane or ABS plastic that you can brush onto a surface that would cure and get hard? What I am creating needs to be very rigid and also needs to resist heat and cold which I am sure polyurethane and ABS plastic should be able to handle. Do any of you know of such a product and maybe a website that sells it? I would appreciate any info you might have. Thanks.
Replies:
Posted By: abovestock
Date Posted: June 17, 2005 at 3:03 PM
How big is the part in question. Probably use fiberglass for the project(but that is my response for everything). Some pictures would help a lot to know what kind of mold to build, and material to build it out of.
Posted By: oonikfraleyoo
Date Posted: June 17, 2005 at 7:24 PM
Check this out------------- Nik
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Posted By: chump
Date Posted: June 17, 2005 at 8:20 PM
oonikfraleyoo: Thanks for the info, I will check out Polytek to see if they have what I need. I cannot make it out of fiberglass since it will be going in my engine bay.
Posted By: oonikfraleyoo
Date Posted: June 17, 2005 at 9:12 PM
If you decide to go that route, let me know how it turns out. I've been wanting to give that process a shot as it looks like one could do amazing things with it. Alas, I'm lazy and that is alot of work. ------------- Nik
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Posted By: chump
Date Posted: June 17, 2005 at 11:44 PM
Just incase you are curious, I am making an air intake tube for my engine.
Posted By: oonikfraleyoo
Date Posted: June 17, 2005 at 11:51 PM
hmm..sounds doable. Why are you not using the metal one? Weight reduction? ------------- Nik
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Posted By: chump
Date Posted: June 18, 2005 at 7:38 PM
It's long story, heh. But basically I want to use a short ram system and make a box around it so that it does not suck in hot air from the engine bay. The reason I am not using the metal one is because the way the filter is angled on the end of the pipe will make it impossible to make the box around it. So I will be making my own custom tube that angles in a better way.
Posted By: adambeazley
Date Posted: June 28, 2005 at 11:53 PM
Have you ever thought about Carbon Fiber?
The process os almost Identical to fiber glass however you can get high temperature resins and hardeners so that you can place these pieces in the engine bay and not worry about deformation. If you find a plastic you can mold around that shape chances are it will deform under the high temps in the engine.
anyway just a thought.
Posted By: 97blackrodeo
Date Posted: June 29, 2005 at 10:44 AM
coming from a family of plastic injection molders, i can say injection molding is ur friend on this one. making something of this caliber would be very difficult with a "brush on" material. as some others mentioned, carbon fiber might be ur best option.
Posted By: adambeazley
Date Posted: June 30, 2005 at 12:15 AM
yea I agree, I mean injection molding would be great but the startup capital of a project like that is pretty expensive. However if your planning on making quite a few of these things (1000's) then the investment might be worth it to you in the long run. Also if you planning on doing a big run like that I dont think an Aluminum mold is the way to go.
Go carbon fiber, if you producing a smaller number. Just get a small box with some heat lamps in it to cure the resin/hardner(8 hours usually). release and wax your mold and you could easily pump out one per day per mold. If you want a good finish you can try using a vaccume settup and a layer of fiber glass.
Posted By: chump
Date Posted: July 02, 2005 at 12:13 AM
I do not know much about working with carbon fiber. Is it almost like working with fiberglass resin? Where do I purchase the materials to create a carbon fiber mold. Also, can carbon fiber be painted?
Posted By: oonikfraleyoo
Date Posted: July 02, 2005 at 7:45 PM
Working with carbon is almost exactly like fiberglass. It can be painted and I think select products has everything you need. ------------- Nik
Jeeputer Progress
[|||||||||||-] 90%
Check it out.
Posted By: adambeazley
Date Posted: July 02, 2005 at 11:40 PM
The process of fiber glassing and carbon fiber are very similar depending on the aplication and finish you want to get. You can check out this site to learn about it: https://www.fibreglast.com/showproducts-category-Epoxy%20Resins-5.html
You can definently paint and bondo carbon fiber. And as far as making a mold you can actually make a mold from the carbon fiber as well. If you go to any local marine boat shop and buy some gel coat. Now I am assuming you have a plug (a positive mokup of the finished product), so if you have a plug preferably made from some type of metal then you can brush on a few layers of gell coat cooking the plug and gellcoat for about 15-30 minutes between coats. Then you can begin to layer the carbon fiber over the gellcoat until you have a good 7 to 10 layers to ensure that its a stong mold. Dont forget to wax the plug with some sort of mold release wax. I could give you alot more specific instructions on how to go about fabricating the mold but without being able to see the product I cant really tell you the best way to layer and press the mold. In other words it makes a difference if the final product will be hollow, solid, heat resistant,etc..
What I have told you so far can be applied to the piece as well. you can wax and release the mold you just made and coat the sides with gellcoat and then fill with carbon fiber (sheets or tows) depending on the application. Tows are long strands of carbon fiber which look like shoe laces and you run them through a resin/hardner mixture and fill your mold. Keep in mind that the tows have their strength along their length, unlike the woven carbon fiber sheets which have strength in both directions. There really is a whole scien behind carbon fiber fabrication, but if you are familiar with fiber glass fabrication then I would say that you can use the same techniques.
I hope this helps,
Adam
PS: if you need some specific direction or answers related directly to you product you can PM me.
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