decombs21

I inadvertantly glued the basswood top spar on to the ribs of my new project last night and forgot to position with the warp opposite of the bottom spar. Now I've got a 1/8 inch to 3/16 inch bow in the middle of the wing on the bottom.

Being new at this, do any of you have a sure fire method of fixing this?

Dave

JohnW

My Feedback: (6)

"do any of you have a sure fire method of fixing this" - yeah, redo it

A 1/8" error of that type may not be a super big deal, depending upon the plane size, type etc. Depending on glue used, you might be able to debond (CA) or cut out the spar and attach it properly without destroying the original parts. Sometimes you can shrink covering to reshape the wing. You can also reshape the wing somewhat if you add sheer webs, i.e. bend to shape and glue in webs. But ultimately, the best solution is to remove and reglue the spar.

Cheers.

2slow2matter

My Feedback: (1)

That's easily fixed with shear webbing. I wouldn't worry about it--just make sure you hold the wing flat on the table when you glue in the webbing, and all will be fine. Removing the spar will probably end up creating even more problems--especially for a newby. Even if the plans don't call for shear webbing, install them anyway. And remember, wood grain goes vertically on the shear webbing.

da Rock

If you're going to stick in shear webbing, dampen the inside of the warp with water a couple of times before gluing. Wood warps are partially from one side being dryer than the other. The dry side is the concave one when the moisture difference is the problem. But even when the warp is mostly from screwy grain, moistening the concave side will help the wood straighten, even if only temporarily.

It sounds like both your spars were warped in the same direction. Hey, you got a Hobie Hawk wing!!!

decombs21

I forgot about the sheer webbing and the plans do call for it. I'll give it a try and see what happens. I'll dampen the spars too.

Thanks, gents ...

Dave

decombs21

Just so you gentelmen know - and anyone else who might trip over this thread - I was able to fix that "bend" by adding the sheer webs.

I did do something a little differently though. I flipped the panel over and shimmed up the ends of the panel an 1/8" to counter the warp/bend. I then held the bend down while gluing on the sheer webs. I'm glad to report that it worked. However I did overdo it a little and got a reverse bend for my trouble. This was easily fixed by cutting off the 3 sheer webs at the wingtip end, removing the shims and regluing the sheer webs flat against the building board.

I now have a nice straight panel and will be much more careful on the next one.

Merry Christmas and Cheers!

Dave