Tiny Bubbles-Tiny Bubbles How I hate Tiny Bubbles Help

R

RHankins

Joined
Jul 14, 2007
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190
Trying my hand at MyKarta and still getting Tiny Bubbles in the Epoxy.
What should I do?
 
I've never made mykarta but I've laid up fiberglass for r/c sailplanes and stuff. Are you getting complete wetting on the fabric and are you using enough pressure during the forming and curing?

Really pushing the epoxy into the fabric helped me when I was doing glasswork.
 
i dont know how your making it or what epoxy your usign but i press into the box a little wait and watch the bubbles to flow then press some more (more bubbles ) i do this a few times while i have usable pot life

i find keeping the epoxy cool as long as i can really helps then when i press and i dont see any/or few bubbles i fire up the heater and start the reaction
hope this helps
 
Thanks guys
Use a steel form (Bread Pan) with a steel plate cut to fit inside for compression.
Have a Vacuum pump but not sure at what point to pull the vacuum during the process. After layup, while pressing, when clamped?

Butch what you do makes sense, by allowing the bubles to squeeze out slowly. I'll bet that gets a better wetout.

Using a local supplier for my epoxy so not sure who the manufacturer is exactly. He buys in bulk and sells smaller quantities. It cures tough as nails though and passes the "Whack With a Hammer" test:D
Any tips and tricks would be appreciated.
 
Butch is "the expert" but I'll toss in a few tricks too from working with fiberglass on canoes, cars, etc.

- Don't "whip" the epoxy when you mix it. Try and stir it without folding or creating bubbles.
- Wet it out. If you're not making a mess, it's not wet enough ;)
- In areas where I've built up fiberglass, I'll actually soak the weave or tape in the pot until it's good and wet and then apply it to the surface. Maybe soak your layers longer before stacking?
- I'd apply the vaccum after layup AND during the press/clamping until cured if possible.

my $.02
 
heres one for you what kind of fabric are you using and if its new are you washing the sizing out of before you use it

sizing is great for when your folding and stitching but will stop some of the wet out from happening

also some fabric just does not seem to wet out well i like high cotton % in my stuff

and no im far from a pro at this as i still have a good deal of waste epoxy while i get great blocks for using i bet i still press out a pint glass of resin as i gett better i still have to remember that different weaves and fabric blends "take in" more resin per yard cut
 
here is a shot of a block i skimmed of a 3/4 slab and cleaned up the clean "face is 6x10 inch
 

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Try to stay with 100% Cotton for fabrics, however looking at carbon fiber as well.
The twill weaves seem to do well. Do wash them first to get out the sizing. So at least one of my steps is correct.
 
In general when vacuum debubbling plastics, ans this is probably no different, pull as close to 29 inches of vacuum as you can without boiling out your solvents right after you are done mixing, then bring it back to STP (standard temperature and pressure) then wet your material, pull and release vacuum again to assure penetration, put your material in it's final configuration and pull and release vacuum again, probably a little excessive, but then I have a reputation for overkill, that way you have debubbled your mix, you have ensured penetration, and lastly you have debubbled your assembly.
Actually if you have laundered your cloth you may want to pull 29 1/2 inches on the dry cloth for several minutes before assembly to boil off any residual moisture, perfume solvents, if there is synthetics in your fabric unbonded plasticixers etc.

I haven't made mycarta yet but did spend a little bit of time playing with plastics for what little it's worth.

-page
 
:D good on my bad skin
all free soap and extra rinse on everything do
nothing wrong with over kill on clean and prep
 
Cool stuff....Butcher Block That is a wild and cool pattern you did....

Bob,I take it you got the new shop building were you can grind?

Bruce
 
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