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Old 10-09-2012, 09:08 PM   #70
therivermonster
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Joined: Sep 2010
Location: Tacoma, WA
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Quote:
Originally Posted by ebrabaek View Post
Before I start a project, I do a little testing first. In this case..... I knew the angles were pretty crazy for a non vacuum layup. So I first try to see if it is feasible to do this. I begin as such, so if it does not work... I don't have a lot of time in the piece....like foam extension, that all breaks away when I separate the two pieces. Second. ...I try to make a cast of the part needed to be worked, if possible and then save the original, so when I f%$# it up..... No harm done. That is what this cast would serve as.By now I could have made a print.,.... sand...buff....etc, and be done with it, but as there have been interest here, I am focusing not just on me, but on perhaps a future production, and as always it has to make sense financially. And when you step into the realm of vacuum bagging, there is another cost associated with it. Historically, that does not work in the favor of the small shop, as the pieces simply becomes too expensive for people to buy. That is why you have not seen me do any of those.... Plus it is a pain in the a$$, and you tend to disturb more than you help. I will try a few things today, and see what I come up with......
Look on the two aft corners, and the two forward center part of the beak.... see the pull off. Everything else is good. What happens.... mould making 101.....When you have a sharp 90 deg. corner, as the matrix cures, it creates a bit of heat. That heat is what is spiraling out of control as exothermic runaway when you have a pool of resin. Weather you set the piece out in the sun....or it created its own heat the polymeric composition changes. Like...... its tacky........ you add the sun..... now it re-flows again. That happens until the polymers have aligned and set. In that process the fabric...sort of can disturb itself, and that is where vacuum bagging can be helpful, as it holds the matrix in place....regardless of what goes on. Truthfully, I am surprised that it only pulled in the corners...... But I have done this more than once.... This piece would serve a few casts, before it would be in need of work, but I am not trying to copy a stock beak in Carbon Fiber.
I can see how vacuum bagging could be expensive for a small production shop, or even the hobbiest, and I can see how it could have its own learning curve - but, could you elaborate on why you feel that it could be or is difficult?

One aspect of bagging that is attractive to me is that it helps reduce BUBBLES!!!

Thanks, Earling!
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