Tiny Bubbles In Silmar 249 Polyester Resin

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#1

Hi,

I did a CF overlay on my gas cap. I used Silmar 249 clear resin and mixed it slowly and poured it slowly to avoid bubbles.

The part came out very good after sanding. The only problem is that I noticed there are some tiny bubbles trapped in the resin.

I bought a propane torch because I heard the CO2 from it pops the bubbles…I have to try this tommorrow…

Is there a better way to remove the bubbles…or use epoxy resin? I have seen lots of pics when people lay up CF with epoxy
there is no bubbbles…

Can anyone recommend a good crystal clear expoxy resin?

Cheers,
Roy

#2

i get 1000 times more bubbles with epoxy! i used silmar this time and the oly parts that had bubbles are the completely flat parts,not sure why though,im guessing a little heat might pop them out.

#3

…but while they are in the liquid state and not after they are cure!

It seems with myself, get longer work time epoxy and mix it way ahead of time to allow the bubbles to come to the top and pop.

Or has anyone tried to vacuum degass the epoxy resin mixture? I was going to experiment with it but we ran out of time before the class was closed.:frowning: Moving all my classroom stuff sucks!

#4

I degass (my epoxy). I use a length of 4 inch drainage pipe with a solvent weld screw cap on the end and a fitting screwed in for the vac line. I also added a bit of clear acrylic so you can see what goes on in the chamber.

#5

have any more pics of that set up?

I get bubbles in my parts but its mostly trapped air in the cloth and some tiny air leaks in my bagging.

Ill get rid of them somehow.

#6

Today I made up two samples with Silmar 249 resin.

This time I mixed the resin more slowly than my previous trials and poured the resin on the CF from a higher position, allowing a long thin stream of resin to flow down onto the part.

I also waved a hair dryer over the liquid resin and It worked. I had no bubbles…

I will try it again on a much larger piece and work out a procedure to get consistent results.

Cheers,
Roy

#7

Would using vacuum bagging or infusing the part eliminate the air bubbles?

#8

No I only infuse and I still get some bubbles…its more an art than a science at that point.