sig king kobra wings
 

I am building a sig king kobra. I am almost done and ready to cover. I sheeted the wings and used a contact cement to join the sheeting and foam. Well, I took my plane I was so proud of over to a friends to show him. Not thinking, I left the wing in my car and went to work the next day. Well...it got hot and the foam expanded just a little. Enough to break the sheeting free from the foam in the middle of the wing in a couple places. any ideas on how to get those spots to glue back down? I have installed retracts, thus I have spent countless hours on the wing and I am not too excited about starting over. I was toying around with the idea of a syrenge full of glue with a needle....but figure I better look for some experience first.

Thanks,
Mike

sig king kobra wings
 

I would use Z-poxy finishing resin and micro-balloons. Mix some Z-poxy then add micro-balloons untill you have a thick mixture. Then trowel on and force into the cracks. Wipe off the excess with a putty knife or old credit card. Let dry overnight and sand smooth. Easy to work with and will be an invisable repair. Enjoy the plane it is AWESOME. Wish I had retracts on mine. Also beware of the elevator throw. do your initial flight using sig's rec. throws and you will have no probs. Use to much elevator and it will high speed snap. One of my favorite planes...enjoy !!
good luck
Brian

Wing sheeting problem.
 

Get some balsa the same thickness as your sheeting. Glue it to a piece of foam from your wing's cores (what was left when they cut the wing from the block of foam. Get your covering iron. Experiment with the heat setting. You want it to be just below the point that it will melt the foam. Once you have determined this. Re-iron the sheeting down to the foam. Heat a small section, then apply pressure until it has cooled. I have used method this in the past and it works. Just be careful not to melt the foam under the balsa by staying in one spot too long. You'd better check for warps induced by the heat. If it's warped, then Sig sells the wing kit separate. Good luck.

sig king kobra wings
 

Throw it away! Its trash now!......Just kidding. Try Probond, that is what the guys use on 40% planes with foam wings. That glue expands as it is drying, so I would suggest shooting some in with a needle, and putting a LOT of weight on it overnight, that should take care of it.
....Or tell your work to make a new wing for you since they caused it to get messed up. LOL
Again just kidding, or am I?

sig king kobra wings
 

Well...I finally tried putting about 50 pounds of weight on the wings. Seemed like it worked, but 2 days later...I had bubbles again. So, realizing I have nothing to lose...I decided to make a cut in the middle of a bubble and try putting glue in and re-lay the sheeting back down. Once again...looked perfect for a day, but then it just bubbled somewhere else. So...I ordered a new wing. After I ordered the new wing, it dawned on me that heat was causing it to bubble. SO I took my heat gun and heated the entire wing. I was able to easily peel the sheeting back off. It had a couple dings in it where some of the glue was still stuck. I bought some more sheeting and asked the hobby shop manager what kind of glue he recommends. He sold me some stuff called "Southern's Sorgham." I re sheeting the wing and it looks perfect. THat glue was awesome. Thanks for everyones help!

Mike

sig king kobra wings
 

I've heard that glue is pretty good. I used the Elmer's Probond Polyurethane mentioned earilier in this thread - it worked great and I could probably stand on the wing, it is so strong.
I think the only thing I would worry about now is the fact that you can't get all of the old glue off, and heat may again make the sheeting come loose.
I am putting retracts in mine as well and know how much time is involved. I am covering mine now and have probably a few more weeks to complete everything (only can work for an hour or two in the evenings), and the fact it is cold here and I need to paint some of the trim and can't til it warms up.
I had a Kougar back 20 years ago and loved the plane and can't wait to fly this thing!!
By the way, I am using an O.S. 91 4-stroke in mine. It took some time to get it to fit, and fortunately I only needed to extend the front of the cowl out 3/8".

sig king kobra wings
 

I don't want to discourage you, but exactly the same kind of trouble hapened to me some time ago on a sig kougar.
I tried everithing to save the wing without good result.

now I use sig core bond for my foam sheeting job and I don't have troubles anymore

sig king kobra wings
 

Yep, Core-Bond is great stuff....similar to the Southern Sorghum.