how much weight when sheeting a foam wing?
10-20-2006, 08:38 PM
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how much weight when sheeting a foam wing?
I'm preparing to sheet a 500 square inch wing panel using 1/16th inch balsa sheeting and west systems laminating epoxy. Will 200 lbs be enough weight for proper adhesion?
10-20-2006, 09:44 PM
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RE: how much weight when sheeting a foam wing?
Transfered over from another thread that is now deleted. JW, please don't start multiple threads on the same topic. Just keep it all in one.
ORIGINAL: jwblackout
I'm preparing to sheet a 500 sq in wing panel with 1/16th in balsa and west systems laminating epoxy. I'm looking for ANY information as to minimum, maximum, optimum weight per sq in when sandwiching my cores, skins, epoxy, saddles. Please help.[
]
I'm preparing to sheet a 500 sq in wing panel with 1/16th in balsa and west systems laminating epoxy. I'm looking for ANY information as to minimum, maximum, optimum weight per sq in when sandwiching my cores, skins, epoxy, saddles. Please help.[
]
10-20-2006, 10:02 PM
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RE: how much weight when sheeting a foam wing?
Bruce,
I'm sorry. I'm out of the loop when it comes to online etiquette. Hard to believe in the 21st century, but true. It won't happen again. Just looking for answers.
I'm sorry. I'm out of the loop when it comes to online etiquette. Hard to believe in the 21st century, but true. It won't happen again. Just looking for answers.
10-21-2006, 01:03 AM
#4
RE: how much weight when sheeting a foam wing?
200lb should be good with epoxy, more will not hurt the core if you want to hoist it onto the table. Make sure your building board/table is strong enough to carry that weight without sagging, once the wing is sheeted it will NOT come back straight. The bible for sheeting wings:
http://www.mackrc.net/patternwings2/index.htm
Mark
http://www.mackrc.net/patternwings2/index.htm
Mark
10-21-2006, 02:33 AM
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RE: how much weight when sheeting a foam wing?
Mark,
Thanks for the reply and great link! The wing is for a Dick Hanson designed excess. His plans say a minimum of 1/4 lb per square inch is needed for bonding, so I doubled that. I got nervous when I saw how much pressure could be applied via vacuum bag method as I don't have the resources for a setup just now. I just want to make sure that this wing won't blow apart.
Thanks for the reply and great link! The wing is for a Dick Hanson designed excess. His plans say a minimum of 1/4 lb per square inch is needed for bonding, so I doubled that. I got nervous when I saw how much pressure could be applied via vacuum bag method as I don't have the resources for a setup just now. I just want to make sure that this wing won't blow apart.
10-21-2006, 11:18 PM
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RE: how much weight when sheeting a foam wing?
No sweat, I know it's a newbie thing 
Just thought I'd point it out while joining the threads together for you.
What are you using to glue the sheeting down? There's no need to squish the heck out of the cores. You only need enough to hold the wood firmly in contact with the core. that may well be just a couple of ounces per sq foot or a few ounces of vacuum if you elect to go with a vacuum bag system.
I modified a simple aquarium pump to work as a vacuum pump a few years back. It was enough to crush the beads in the regular white styrofoam when bagging on some epoxy coated fiberglass or newsprint. I had to add an old engine needle valve as a vacuum leak to tone down the vacuum to just a couple of ounces per sq inch to avoid the problem. Doing this with balsa sheeting may well work just as nicely for you. The only problem is that you need to use epoxy for the glue since an air dry glue won't dry in a vacuum bag. BUt then I suspect it'll have problems with all that sand on top of it as well.
Just thought I'd point it out while joining the threads together for you.What are you using to glue the sheeting down? There's no need to squish the heck out of the cores. You only need enough to hold the wood firmly in contact with the core. that may well be just a couple of ounces per sq foot or a few ounces of vacuum if you elect to go with a vacuum bag system.
I modified a simple aquarium pump to work as a vacuum pump a few years back. It was enough to crush the beads in the regular white styrofoam when bagging on some epoxy coated fiberglass or newsprint. I had to add an old engine needle valve as a vacuum leak to tone down the vacuum to just a couple of ounces per sq inch to avoid the problem. Doing this with balsa sheeting may well work just as nicely for you. The only problem is that you need to use epoxy for the glue since an air dry glue won't dry in a vacuum bag. BUt then I suspect it'll have problems with all that sand on top of it as well.
10-22-2006, 10:02 AM
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RE: how much weight when sheeting a foam wing?
BMatthews,
The adhesive I'm using is West Systems Laminating Epoxy. So far, I've sheeted the flying surfaces for the rear and the stuff was great to work with.
The adhesive I'm using is West Systems Laminating Epoxy. So far, I've sheeted the flying surfaces for the rear and the stuff was great to work with.
