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  #16  
Old 10-26-2006, 06:12 PM
Lynn Erickson Lynn Erickson is offline
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Quote:
Originally Posted by argoldman View Post
Strange, Wayne, that the adhesion to a substrate would depend on the weight (for want of a better word) of the fabric. Fiberglass does not, itself want to bond to epoxy. It is treated with a chemical so that the bond can take place. If the glass has been exposed to moisture, this can be compromised. Is it possible that you got a batch of glass that either wasn't treated, was compromised before you got it, or became compromised in your shop?? Who was your suupplier?, what was your under glass preparation??

The Osprey aircraft uses 1.45 oz glass. Have these aircraft been experiencing delams??


Hopefully I will be sealing my Aerocanard strakes/tanks this weekend.
Its not the weight it is the thickness and the openness of the weave. the uni used in the rutan designs is very open and the amount of resin to glass is high. on the tapes with a close weave there is not as much resin and the cloth being very strong and can be seperated from the layer under it without much work. you are breaking the hardened resin one fiber at a time as you pull up on the fabric. the tapes used on the Osprey will do the same thing, try it, but they are not likely to do the under normal use as the load is in shear with all the fiber at once not a pulling up on the tape load. if you look at kit type construction after an accident you will see how easy it is to tear the tapes of the main structure.
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  #17  
Old 10-26-2006, 08:05 PM
argoldman argoldman is offline
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I beweave

Thanks
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  #18  
Old 10-26-2006, 10:23 PM
Wayne Hicks Wayne Hicks is offline
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The weave is very tight on the 2-ounce glass I used. Lynn nailed the explanation. Sorry I couldn't answer until now. I was out flying 3-ship formation around the course for this weekend's Great Pumpkin Air Race.
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  #19  
Old 10-26-2006, 11:33 PM
Ben Ben is offline
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For what it's worth, the KR community seams to have been using the fine deck cloth for a while. A search of their archives doesn't bring forward any delam problems (several/many planes are flying with it), but of course this is a subject that if one person reports a problem, all should pay attention.

See:
http://home.hiwaay.net/~langford/owings.html

http://www.maddyhome.com/krsrch/index.jsp
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  #20  
Old 10-27-2006, 12:06 AM
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My tech advisor used it 20 +- years ago and no problems, he wishes he had used it on the part of the wings that has the cracks
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  #21  
Old 10-27-2006, 09:51 AM
Wayne Hicks Wayne Hicks is offline
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For clarification, my 2-ounce cloth delam experience was with non-adhesion to dry MICRO, not to foam or fiberglass. But I did enjoy the link to the KR2 website. Interesting method of building wings. Those guys are a dedicated bunch, definitely.

(But please, don't ask my hangarmate about HIS 2-ounce cloth experience. He attempted to cover his highly modified cowls with this so-called 2-ounce "finishing cloth". It was finished alright. HE was FINISHED with it. The stuff didn't stick and he had to peel ALLLLLLLLLL of it off. He would discourage anyone from using this cloth for that purpose.)
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Last edited by Wayne Hicks : 10-27-2006 at 10:26 AM.
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  #22  
Old 10-27-2006, 03:36 PM
SteveWrightNZ SteveWrightNZ is offline
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my understanding of the final skim of micro was to fill the weave of the cloth - not to cover multiple sins of the builder. Clearly nothing adheres structurally to micro - nor was it meant to, so why not deck-cloth+peelply it first then micro... to fill the weave of the.. umm..

full disclosure: never done it - still studying

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  #23  
Old 10-27-2006, 08:04 PM
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+16th is not uncommon, sins or not, i would guess it is the norm
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  #24  
Old 10-28-2006, 12:14 AM
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Steve parkins Steve parkins is offline
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some have filled well over a 1/4" with mico with never a crack.
remember that boat resin is soft and will flex all day and all night and still hit a dock or two
most cracks are at the end of a run or a joint that is to close.
if you fill with hard glass at a window or a seam and dont prep most will tell you it will crack
you would be suprised at how thick are sin/s are
west is soft ,fill away.IMO
if you fill with 286, it is hard
i think most fill with 286 then cover with west(hard under soft will still crack) imo
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  #25  
Old 10-28-2006, 12:39 AM
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different fabrics have different uses. I made 2 layer flanges for the front edge of the tank and they worked perfectly. the cloth i have will take 1 dimensional bending, not compound bends, simple as that, weave is tight

In my fill i will cover thick micro where I expect movement or stresses, if this cloth will not do it, I'll get a looser weave for those areas.

Picking the correct material is very important.

For some like me, if it can go bad - it will
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Enjoy the build,njut av byggandet, godere il costruire, nyd bygningen, geniesse den Bau, apolafse tin kataskevi, disfrute la construcción, curta a construção, Pidä hauskaa rakentamisen parissa, bouw lekker,uživaj grade?inaslajdaites postroikoi, geniet die bou
dust

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  #26  
Old 10-30-2006, 06:32 AM
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karoliina karoliina is offline
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Gliders are constructed so that there is first the structural unidirectional cloths on top of the foam core and then a 110 g / m^2 cloth which is partially sanded away. I did a repair to a glider wing on a composite course last weekend this way and I did not need any micro to get it smooth without damage to the cloth under this final top layer finishing cloth. The amount of sanding was quite reasonable and it started to feel like finishing the Cozy can be done without spending time like forever. All resin used was MGS L285. The difference in glider wing though is that after the salvageable finishing cloth, a layer of gelcoat is applied before paint. In case of Cozy the gelcoat is unnecessary as in the glider it is only there under the paint because of the original molded composite method (and this was a repair to a wing constructed that way).
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