tahoedirk wrote: ↑
Wed Feb 21, 2018 5:57 pm
These are all about 10 layers of 6oz, it seems like enough. I only clamp the edges. If one of these is a hit , I'm sure I can beef up and refine the mold further.
A seriously inexpensive and FAST way to beef-Up that mold, is to place
a cardboard retaining wall around the edges of the mold-half ; then
put a few inches of Hydrocal-30, or Ultracal-30 inside your dam. Sand
your glass mold , with 30 or 50-grit first ; and the plaster will stick just fine.
The plaster is about $25 for a 100Lb bag.
Anything Ya don't want the plaster to stick to ; just wax it first, (even the cardboard).
If Ya want to keep the mold ; place hemp fibers , or dry fiberglass
in the plaster , to keep it from cracking.
Alignment pins , are easily set in the plaster, ; and both those materials
i mentioned, have a WAY less expansion rate, than regular plaster, when
they are hydrogenated.
First thing you will notice when making a mold from scratch , using
this system ; Ya only need one or two layers of 6-oz glass now, instead of 10.
I use (2) layers of 3-oz plain weave.
It works Great for small parts like a hydrofoil wing ; larger parts
get a bit more complicated because of different expansion rates and such
but are easily over-come.