hi guys,just wanna make sure im thinking along the right lines here,im thinking that the discouleration and 3 million bubbles in the picture are caused by either
1-gelcoat too thick
2-bubbles in the mixing tub before application
3-not enough vacuum
4- all of tha above!
whats your best guess and any tips 
explain the process you used to make it.
Hand layup in the mold I take it?
hand layed into a female mold using a poly gelcoat,3 layers of twill and poly resin and vacuum bagged for 3o mins until resin set,
Did you let the gelcoat semi cure before laying up? Did you use heat to pop the bubbles in the gelcoat?
yes the gelcoatwas nearly dry,just slightly tacky and no i didnt use any heat,the rest of the part id totally bubble free…
so whats the verdict ?? :?
Without actually seeing it on hand is it hard to say exactly, but it looks like a combination of things to me. First, it looks like subsurface air bubbles trapped between the first carbon layer and the gel coat maybe the result of insufficient vacuum or vacuum bag lock on the edge of the mold. Second, there also seems like a resin rich area in the corner where the fabric did not fully compress against the side and resin accumulated between it and the gel coat. As far as the sub surface bubbles, I have had this happen to me on occasion with vacuum bagging. Once Evan showed me the light and I came down from the mountain converting to infusion, I have not seen this again. Now an alternative is to not put down the gel coat in the first place. This would then eliminate the bubble trapping issue and still use vacuum bagging. I hate vacuum bagging anyway especially with poly products and all the stink, not to mention additional exposure. Once the part has finished curing, you would the spray down a top coat (either an auto clear or a product like Duratek Top Coat) to achieve the glossy, finished look. Many paths to the same destination.
hey Kyanktan, your sayin that you dont use gelcoats in the mold for infusion? or not gel coating a complex mold were you can’t get into!
Do you guys find that with or without the gel coat would affect anything when infusion? (difficulty, speed,)?
I go either way (and don’t read to much into that :shock: ) and it just depends on what I am trying to get from the piece. Not sure what you meant by "not gel coating a complex mold were you can’t get into! ". For example, one of the pieces that Evan and I did that I had posted a pic of was a 3 gauge pod that we infused without any gel coat in the mold first. I put down a top coat once it was removed from the mold, but I really did not have to as we used UV stable epoxy and the finish was smooth.
It almost sounds like you are saying that you are using gel coat to facilitate your mold release???. To me, having to spray down the gel coat is just another step that adds to the overall time. If I don’t have to, I won’t.
right,looking at the part in bright sunlight reveals tiny bubbles all over th epart,i am convinced these are iin the gelcoat and were bubbles in the gelcaot in the mixing tub before i even brushed it on the part,obviously when i let the gelcoat tack up then the vac pump is never gonna pull them out as they are within the curedish resin.
i think i need to find a way of eliminating the air bubbles in the mixing and applying process so whats the best way to do this,i dont have spray gear.i was advised by evan not to heat it as it would cause problems with localised curing or is this the only way? what about vacuuming the resin in the tub somehow???
When you mix your gell coat… Maybe put the gell into a vacuum jar and de-gas it before you use it if you are getting that many bubbles in the mix.