Need help making a plug: How to create thickness uniformly?

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#1

So I’ve been wondering on some plug making techniques… Most of my stuff is done by infusion and the thickness of the part is negligible for them to fit perfectly. Now, I was thinking, if I had something I could make a direct mold out of BUT the part needed to be like 1/4"-1/2" thick, how would you do it?

For sake of an example, Lets say I had a bowl that I wanted to use as the plug to make the mold from, BUT the part I wanted to pull out from the mold needed to be 1/4"-1/2" thick what is the fastest and more accurate way?

This is all I could think of…
Option 1: Lay up FG in the bowl, and sand/bondo til 1/4"-1/2" thick.
Downfall, laborious, and likeness it will not be uniformly even

Option 2: Try to Vacuum for a piece of plastic to the bowl using a 1/4"-1/2" sheet of poly polypropylene (or laminating several layers to create the thickness I want to achieve

Option 3:…?

#2

Build it up with sheet wax.

http://www.mcmaster.com/#sheet-metal/=12c8hlq

#3

Just keep on laying up more glass cloth, this will keep the thickness uniform.

#4

I would be infusing that in one go. Pre-preg is also good for uniform thickness, but debulking every 2-3 layers is a pain.

1/4" thick would be 32 layers of 200 gram fabric, and 1/2" would be 64 layers of 200gsm fabric. Obviously that’s a lot of layers to do, so use heavier fabrics if you want to make the layup quicker. 10 or 20 layers of 660gsm fabric is very quick and easy.

#5

Industry standard is calibrated wax. Google Freeman Supply.

#6

I’m somewhat confused by what the OP is trying to do… Are you making the plug or the mould or the finished part? You seem to use each term interchangeably, so I’m not entirely sure.

Roger’s post has also made me unsure what you are trying to achieve. Are you trying to simulate part thickness, or do you need to make something that is solid and hard and your specified thickness?

#7

You are right, it is a bit confusing. I was reading consistent thickness and my mind went directly to offset for a counter mold. Now that I’ve reread it, I’m not so sure either.

Mui, you want to clarify a bit?