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Post by jirvin4505 on Feb 21, 2010 20:08:11 GMT 10
Waiting........
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Post by thevon on Feb 21, 2010 21:46:41 GMT 10
It looks great. Certainly takes a while and makes a big mess peeling off all the paper, epoxy and masking tape, so my girls enjoyed that bit. Then peeling off the mylars... the paint looks fantastic! Really like a moldie paint job. Since the photos I've trimmed off the excess from the trailing edge and sanded back the leading edge. There was quite a bit to take off some of the LE as one of the mylars had overlapped 2mm. It weighs 442grams. That's with a 2.4mm f/glass rod spar top and bottom and also all along the leading edge. Layup is 2 layers of the RE100H4 glass cloth, with a layer of 68gm Innegra between them. I put a 20mm strip of 200gm carbon cloth wrapped over the LE (ie wrapped over the glass rod LE and back onto the foam). One issue is that like Kevlar (altho perhaps not as bad?) the Innegra goes fluffy when sanded. So where I've sanded the LE back there's a slightly fluffy zone. Not sure what to do. One option would be to smear it with epoxy. Or polyester filler and sand back. But it's a minor issue - would fly well as is.
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Post by jirvin4505 on Feb 21, 2010 22:16:11 GMT 10
;D ;D ;D ;D ;D ;D ;D ;D >One issue is that like Kevlar (altho perhaps not as bad?) the Innegra goes fluffy when sanded. So where I've sanded the LE back there's a slightly fluffy zone. Not sure what to do. One option would be to smear it with epoxy. Or polyester filler and sand back. But it's a minor issue - would fly well as is. With kevlar on bagged wings I have acchieved a no fluff finish by wet sanding with sharp/fresh wet/dry (black) sandpaper 400 and finer. Detail finishing can also be done by rewetting with epxy and letting it cure (slow process) Since Avb doesn't do slow rubbing in foam friendly CA is much faster. Me... Wet sanding tends to work well enough. Welldone Avb
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Post by thevon on Feb 22, 2010 7:15:23 GMT 10
Thanks Jeff. I don't have any foam safe CA at the moment, but I believe the foam is well covered by epoxy (there's another glass layer beneath the Innegra) so I think I'll do a CA wipe.
I'm going to put it on my old Minij fuselage. It would be quick and easy to just have full span ailerons (like the old Minij) but I'd really like to have flaps so I will go the whole hog and do a 4 servo job. But with the Minij's fuselage I can put the flap servos in the fuse and the pushrods go out the back of the wing mount hump, so that will avoid having weak spots due to servo cutouts for flaps.
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Post by aussiejarred on Feb 22, 2010 10:48:53 GMT 10
wow man, cant wait to see the finished product!!!!!!
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zipper
> 50
Off The Edge Sailplanes
Posts: 88
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Post by zipper on Feb 23, 2010 8:29:21 GMT 10
What paper did you use Andrew? I use "oven bake" over the Mylar's because it doesn't stick to anything and then the bleed cloth over that . The hardest part of the hole bagging proses is NOT to take the Mylars of the wing, you should leave the mylars on for as long as possible, 7days is a minimum. If you take them off earlier the finish will look fantastic for about 2 days and then the cloth will start to bleed through giving a satin finish.
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Post by thevon on Feb 23, 2010 11:40:05 GMT 10
Glenn, Hey thanks, I will try the oven bake over the mylars. All we used was commercial-type paper towel on a roll, one layer laid over the top and bottom. The epoxy bleeds into it and sets. It doesn't stick, but since the epoxy bleeds back over the edges of the mylars too then sets hard, it takes some trimming off.
I only left the mylars on for 24 hours, then pressed the wing in the beds for another 24 hours. I'm aware of the problem of the weave showing through, and will let you know if/when it happens!
It does look impressive. It seems stiff - not as stiff as moldies with spars. But the torsional rigidity is amazing. I can't really get any twist into it by hand.
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Post by flyonline on Feb 23, 2010 15:21:45 GMT 10
I've had wax paper stick before, so I now wrap my wing/mylars in that cheap disposable plastic from bunnings then wrap that in paper towel breather. Any excess that bleeds doesn't stick to the plastic and can be poppled off once dry. A quick wax on the wax paper would probably work too.
If it's stiff now, it'll be even stiffer in a week or so!
Steve
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Post by thevon on Feb 23, 2010 18:34:53 GMT 10
Thanks Steve. The paper towel hasn't stuck to the Mylar at all - I have more trouble getting the masking tape off than anything else! When putting the mylars on and the mylars and my hands are contaminated with epoxy, the tape won't stick, which is a pain! But after 24 hours being squeezed at 18inches of vacuum, and the epoxy has set, that tape is darn hard to get off!
Has anyone tried other tapes that stick better than masking tape, for taping the top and bottom mylars together?
Yes I'm looking forward to seeing how much stiffer it is in a week. When I did some test patches with glass and Innegra, I did some comparative tests on them at 24 hours, but it was amazing how much harder and stiffer they got as time went on.
Now I'm thinking that I should make a mold from my old Minij fuse before I fit this wing to it and make a new tail, so I will have to work out how to do that! I will search RCG but Jeff, do you recommend any particular threads?
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Post by jirvin4505 on Feb 23, 2010 19:57:04 GMT 10
........ I will search RCG but Jeff, do you recommend any particular threads? Lots of good threads on rcg The latest I have seen is ;D ;D ;D big welcome to flyonline ;D ;D ;D ;D has some strong contributors www.rcgroups.com/forums/showthread.php?p=14418888basically anything by Adam Wyowindyworks is very professional and hard won experience. I would also look for some of Samotages well documented posts. The composite forum has a new mold thread every other month! Maybe a new thread Making molds - people..... There was some mold threads running on windsock a while back? cheers jeff PS If you have the time and aren't to busy you could probably save a lot of time and money by visiting some local well equiped sheds
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Post by flyonline on Feb 24, 2010 12:26:18 GMT 10
Thanks Steve. The paper towel hasn't stuck to the Mylar at all - I have more trouble getting the masking tape off than anything else! When putting the mylars on and the mylars and my hands are contaminated with epoxy, the tape won't stick, which is a pain! But after 24 hours being squeezed at 18inches of vacuum, and the epoxy has set, that tape is darn hard to get off! Has anyone tried other tapes that stick better than masking tape, for taping the top and bottom mylars together? Yes I'm looking forward to seeing how much stiffer it is in a week. When I did some test patches with glass and Innegra, I did some comparative tests on them at 24 hours, but it was amazing how much harder and stiffer they got as time went on. Now I'm thinking that I should make a mold from my old Minij fuse before I fit this wing to it and make a new tail, so I will have to work out how to do that! I will search RCG but Jeff, do you recommend any particular threads? Cheap electrical tape does the trick. Pulls of cured epoxy without leaving behind any sticky residue like every other tape I've tried. Sticks well to mylars too. Just get that nasty $2 pack of 6 rolls from the reject shop etc. Seems to stick better to the sticky mess too. Aww, shucks jeff Steve
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Post by cdsloper on Feb 25, 2010 5:54:50 GMT 10
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zipper
> 50
Off The Edge Sailplanes
Posts: 88
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Post by zipper on Feb 25, 2010 17:16:51 GMT 10
I've had wax paper stick before, Oven Bake is not wax paper, it is Teflon coated and just doesn't stick. I dont use tape on my Mylars, I take a little extra time when putting the wings in the bag to line them up with the cores.
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Post by thevon on Feb 26, 2010 15:31:19 GMT 10
Thanks Glenn. But maybe I'm missing something here - I haven't been worried about anything sticking to the mylar. The paper towel gets epoxy in it, but when it's set it peels off the mylar cleanly. Why do you need the Oven Bake?
Glenn, do you keep the vacuum on for the whole week?
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zipper
> 50
Off The Edge Sailplanes
Posts: 88
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Post by zipper on Feb 26, 2010 20:24:32 GMT 10
The oven bake keeps the epoxy off the paper towel and off the bag, also stops it sticking around the edges and it just makes it cleaner. Going by the pic of your girls ripping the paper towel off, it looks like you had some of the towel stick around the edges. If you use the oven bake, it will come off clean. I leave the vacuum on for 24 hours and leave the mylars on for at least 7 days.
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