I don’t get any pin holes any more, I just infusion 2 parts earlier this week without one single pin hole or voids anywhere.
I use CCP IVEX C400, viscosity 110 cps with a 42 min gel time.
^ What’s your process if you don’t mind me asking?
Since I’m fed up with pin holes, I gave up in prevention and just post gel coat and clear because it also does add a much higher quality finish. Win win :).
If you got pin holes air is coming in from somewhere.
^ I think my air has been coming from within the mold. Not sure how it stays there. But my theory is…
Say my mold is 5 inches wide and 20 inches long. I adhere the infusion hose about 1/6th into the length of the mold. When resin enters the mold from the hose it instead of flowing directly one way, it flows two ways. One way towards the vacuum, and the other way away from the vacuum towards the back of the mold. I believe that pushes the air from that sector of the mold away from the pump and pushes it towards the very end of the mold where the sealant tape is and it stays there. Once I clamp the hose the air that was trapped in the mold by the flowing resin, tries to push its way toward the vacuum?
Next time I’ll be holding vacuum for at least 10 min before I infuse. I usually turn the vacuum on, check for leaks, mix resin, and infuse with out any breaks in between steps.
What I do now to fill pin holes is just flood on the clear coat, wet sand with 220, clear coat again, wet sand with 400, then 800, clear coat again, then wet sand with 1500 and polish. I do it so many times to give a perfect mirror like finish. But it just takes way too long :(.
I guess you are still not spraying gel coat in your molds, leak free system and gel coat for me and totally no pin holes.
I should probably get back to using gel coat… Slows down production, but I guess saves me the hassle of everything else.