Perfect master mold

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#1

How can one go about creating a mold like this?

[ame=“http://www.youtube.com/watch?v=1ssRTWF0nt0”]YouTube - resin infusion[/ame]

I always thought about taking any mold here, making a thick fiberglass part with a full flange, not trimming the flange, and using that as the upper portion of the mold. The idea would be then to take that new part , add on a rubber gasket to the edges, and then tap in holes for the vacuum and resin lines. The idea would be to turn a mold which would require a vacuum bag for compression, into a double sided mold where you would achieve perfect vacuum in a matter of seconds.

I basically would like to be able to reuse the same bag, (or in this case a molded back form) to be able to 1. Save money in the long run on materials, and 2. save time on setup.

In this case with this violin mold, I see they put resin grooves so that way they do not have to use flow media. That then would save on the cost and time of purchasing / adding flow media as well.

Any ideas?

#2

I love the idea!!! It’s like…VARTM heavy! (vs RTM lite…heehee)
The channels do not replace media, but there is no reason why the plastic mold top could not have those smaller flow channels in it as well.
I like the idea of using the rubber seal and a solid plastic mold half…taking the best of all worlds.
Talljohn, this is your goal… MAKE IT :slight_smile:

#3

No, you!

Haha, I guess I have to give it a try now haha. I’ll have to think of some ideas and then post back tonight :).

#4

I’m guessing if you have enough money/materials, you can make a vacuum forming mold, then make the top layer (obviously making the master mold with the channels/material thickness changes), then add the rubber and stuff later. Might be a good idea to try. Master mold. Vacuum form one half. Add a layer of wax/clay, vacuum form the other half!

#5

Where can I purchase thin layers of wax? I was thinking of just spraying on PVA, twenty coats of latex paint, then gel coat / fiberglass, pull the top, (back) mold off, and then peal off all the latex. By doing that I’ll have a pretty decent spacing in between molds so that way it fits over all the carbon fiber.

#6

Mcmaster has sheet wax.

http://www.mcmaster.com/#prototyping-materials/=bv69tl

#7

The infusion channels built in is cool.

This reminds me of a vacuum table with a reusable flexible membrane that vacuums down onto the mold.

Kinda like what Torr Technologies can make. Torr also sells a rubber that can be heat shaped.

#8

you get wax from Freeman supply

#9

Thanks for the wax info guys! That will work well for bigger molds and then for smaller molds with more detail I’ll try my latex idea.

So far the idea is…

Layup the mold very precisely with sheet wax. The wax should equal the thickness of the carbon fiber that will be going into the mold to create the laminate. then take silicone tubing (the kind that will be used to infuse that particular mold) place it strategically over the wax, then use clay to fill in the negative gaps. Add gel coat, fiberglass, and finished. The cavities left by the tubing should work in place of the flow media. My only concern is, 1. How much extra resin would I be wasting, and 2. will it be very difficult to remove from the part and or mold once cured? Should I just stick with the flow media netting?

Also, what do you guys think would work to smoothen out the wax for a nice back side surface? Or should I do some body work on the finished mold and then spray with duratec primer?

This actually seems like a very easy thing to do.

#10

I was also thinking of just using that smooth-on sprayable vacuum bagging material, but its very expensive and seems like it would not last as long as a two part fiberglass mold?