GuinnessGuy74 Posted December 8, 2008 Share Posted December 8, 2008 Ok. Finally have my table, hot box, and cloth rack finished for my Cozy. I am about to start a dream I have had for as far back as I can remember...it feels like Christmas has come early!! I did the practice layup (flat 6 layer BID piece) last night. I used the pressure bagging technique and I liked it!! When my layup cured, I weighed it and it came out to be 10.08 oz. A little light, but there are no dry areas that I can see. Here is my question: Is it possible to eliminate EVERY single air bubble? I squeegeed pretty aggrasively, but not enought to "see white" after the pass. When I hold this clear sheet up to light, I can see very, very tiny air bubbles scattered all over the place. When I put the sheet on a piece of foam it is very difficult to make out the air bubbles. I strong light helps, but even then I can only see a few. Am I being too picky? Or not squeegeeing enough? Thanks for all the input. Hoping to start the seatback tonight! Jim Quote Cozy MKIV #1565 (Chapter 6) Charlotte, NC Link to comment Share on other sites More sharing options...
TMann Posted December 8, 2008 Share Posted December 8, 2008 Re: Tiny Air Bubbles Did you vacuum bag this part? Quote T Mann - Loooong-EZ/20B Infinity R/G Chpts 18 Velocity/RG N951TM Mann's Airplane Factory We add rocket's to everything! 4, 5, 6, 7, 8. 9, 10, 14, 19, 20 Done Link to comment Share on other sites More sharing options...
GuinnessGuy74 Posted December 8, 2008 Author Share Posted December 8, 2008 TMann, Much to your displeasure, I did not vaccuum bag this part. Just used the plastic peel ply method, ala John Slade.... Jim Quote Cozy MKIV #1565 (Chapter 6) Charlotte, NC Link to comment Share on other sites More sharing options...
TMann Posted December 8, 2008 Share Posted December 8, 2008 Okay ..... you mentioned 'pressure bag' and I thought you might have mixed your terms. It could be micro that you are seeing. I have seen something like this vacuum bagging. I did switch to hardshelling and did not see it anymore. It's an extra step but you might give it a shot. Slurry the foam like normal then let it cure. Sand it and then procede with your steps. I use this technique for everything be it VB or not. Quote T Mann - Loooong-EZ/20B Infinity R/G Chpts 18 Velocity/RG N951TM Mann's Airplane Factory We add rocket's to everything! 4, 5, 6, 7, 8. 9, 10, 14, 19, 20 Done Link to comment Share on other sites More sharing options...
GuinnessGuy74 Posted December 8, 2008 Author Share Posted December 8, 2008 TMann, I didn't do this layup over foam. It was just a practice layup of 6 plies of BID, cut to 10 x 16. I mentioned the foam because the layup piece is clear (translucent?). When I hold it up to the light I can see the bubbles....very very very tiny ones. When I lay the cured piece on top of a piece of foam or table, it is very hard for me to see the bubbles. With a strong light I can pick out a few tiny ones, but nothing like just the laminate sheet by itself. Just wondering if this is normal for a piece of laminate to have these almost microscopic bubbles. To be honest, I didn't see them during the layup, so I have no idea if I could have avoided this, other than maybe more pressure on the squeegee, even though I thought I was pretty aggressive... Jim Quote Cozy MKIV #1565 (Chapter 6) Charlotte, NC Link to comment Share on other sites More sharing options...
TMann Posted December 8, 2008 Share Posted December 8, 2008 You're good. The only way to remove any more air is via vacuum bagging but the results you are quoting are fine. The criteria for what is acceptable are stated in chapter 3. Quote T Mann - Loooong-EZ/20B Infinity R/G Chpts 18 Velocity/RG N951TM Mann's Airplane Factory We add rocket's to everything! 4, 5, 6, 7, 8. 9, 10, 14, 19, 20 Done Link to comment Share on other sites More sharing options...
GuinnessGuy74 Posted December 8, 2008 Author Share Posted December 8, 2008 Thanks TMann. I appreciate the help! Jim Quote Cozy MKIV #1565 (Chapter 6) Charlotte, NC Link to comment Share on other sites More sharing options...
rickh Posted December 9, 2008 Share Posted December 9, 2008 ... Here is my question: Is it possible to eliminate EVERY single air bubble? ... Anything is possible I found if my epoxy and room (ambient) temps were warm, and I squeeged s l o w, I had fewer of the bubbles you mention. Whipping the epoxy into a froth by speed squeeging didn't help. Rick Quote Rick Hall; MK-IV plans #1477; cozy.zggtr.org Build status: 1-7, bits of 8-9, 10, 14 done! Working on engine/prop/avionics. Link to comment Share on other sites More sharing options...
GuinnessGuy74 Posted December 9, 2008 Author Share Posted December 9, 2008 Rick, You bring up a very good point! I did notice at one point that the epoxy I was moving around was sort of foamy. Almost a milky consitency. I take it I was TOO agressive! I think I will try the layup again, except maybe half the size to see if I can go s l o w and eliminate the air bubbles! Patience is a virtue. Thanks for all the advice. It is greatly appreciated... Jim Quote Cozy MKIV #1565 (Chapter 6) Charlotte, NC Link to comment Share on other sites More sharing options...
TMann Posted December 9, 2008 Share Posted December 9, 2008 I think I will try the layup again, ... ...... and use a hairdryer to warm the epoxy & glass as you work it. It will actually take less epoxy to wet out the fabric. Quote T Mann - Loooong-EZ/20B Infinity R/G Chpts 18 Velocity/RG N951TM Mann's Airplane Factory We add rocket's to everything! 4, 5, 6, 7, 8. 9, 10, 14, 19, 20 Done Link to comment Share on other sites More sharing options...
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