I'll take on a couple....
> I'm trying to make an all Carbon all flying stabilizer mount like Mark
Drella's: When you build a part like the V shaped support,
>
> 1)Do you have to mold it to final dimensions, or can you trim the part to
dimension after it cures?
Sure you can trim it, but you'll have to do more surface prep than if you
mold to final size. Taking some off the edges is not that hard, but be
aware of severing long fibers and significantly weakening things...
> 2)If you can trim it to final dimensions, does the vibration of
some thing like a dremel tool cause delamination or weakness?
Make sure the rotation of the cutter is tangent along the edge, not across
it. If you hold a thin sheet flat and position the dremel tool
horizontally, you will get vibration like an instrument reed which can be
damaging. If you hold the tool vertically, the stock will not vibrate and
will be much safer.
> 3)After my part comes out of my simple mold can I
> add the reenforcing tow as a second step?
Yes (see #4)
> 4)If I am molding in multiple steps what precautions should I take to
insure that I get a good bond in the secondary steps?
Using epoxy, be sure to either pile layers upon one another only a few hours
apart or clean the surfaces thoroughly between coats. Curing epoxy will put
an "amine blush" on the surface which won't allow the next layer to properly
grip the preceding. Wash with warm soapy water. You can lightly sand, but
only after you clean off the blush.
Using polyester resin, you will need to know what type you are using.
Laminating resin will not fully cure, but can be recoated w/o much prep.
Finishing resin has a wax disolved in it that makes an air-proof layer
allowing full curing. If you use this, be sure to let the resin cure, then
wash w/ something that will strip the wax (acetone, etc), then sand.
> 5)What do you use for mold release? Where do you get it?
PVA (get the spray cartidges), mold wax. You can experiment w/ others, just
consider how much your mold is worth. Look in autoparts shops, plastics
shops or marine shops.
> 6)If I don't need a perfect finish can a use a cheaper/easier to get mold
release like Parafin wax or car wax, vaseline? ?????
You can always try. Again, do a cost/benefit analysis. Is it worth the
risk of ruining a mold that took 50hrs to make for a $10 jar of wax? Or do
a cheaper experiment on something that won't be missed.
Hope this helps...
Tony Rogers
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