I'm building an Ultra Sport .40 and I'm to the part of the wing build where I am supposed to cover the wing joint with fiberglass cloth. I've never done this and from what I can gather its a VERY important part of the wing building process - I don't want to fudge it up.

The manual says to tack it down with 3M 77 spray and then run lines of thin CA over it until its saturated.

The little I've been able to find on these forums/internet says to use fiberglass resin or epoxy. I have lots of epoxy and was leaning towards doing that. However, I've seen some people say to thin it with denatured alcohol and some say don't. Also when I do it do I need to do the entire thing at once? Or can I do the top part, let it dry, then come back and do the bottom?

Also, if you could post up how you do it with what you find to be the easiest and best method, and any tips/tricks, it would be greatly appreciated! Thanks!

Ca would work, but it is messy, smelly, and will bubble and be rough. 30 Minute epoxy is the way to go. Lay your cloth on the bottom first, no need to tack it. Static electricity should hold it down fine. Mix a batch of epoxy, and smooth it onto the surface. No thinning required, and not recommended. If it seems too thick, grab your heat gun and heat it a little, then spread. You only need enough epoxy to fill the weave of the glass, so scrape off all that extra before it cures. Try to get as smooth a surface as you can. Once the bottom is cured, do the top the same way.

There are many ways to glass a center section and
trying to discribe how it's done so someone can
understand the process can be a difficult task.

Try to find someone in your club who is a decent builder
and ask them to show you how they do it. Chances are
they might even help you.


Good luck,
Roby

I agree with dead eye. Its pretty straight foreward, you'll do fine.....Gene

I've done many wings with both the epoxy method and the CA method, they both work. I tend to use epoxy since it doesn't make all those pesky fumes.

30 minute epoxy will work, thinned epoxy will work even better. But the best is 20 minute finish cure. It's made for glassing, doesn't need thinning and it sands easier.

Yes you can let one side cure before doing the other side. Gets way too messy if you don't.

Dave

How about posting a link to the brand and type you prefer ? I am certain the newbies would find it useful. I would as well.

Bob

Here is the method I have used for many years and never a failure. I apply masking tape to the wing just outside of where the wing tape will end. This is just to protect the rest of the wing from glue and provide a line to guide the application of the wing tape. Next I brush the area where the wing tape will go with thinned Tightbond. The idea here is just to seal the wood. After this drys then a light sanding just to remove the rough wood due to the sealing process. Clean the area with a tac cloth or other method that you use before painting. Cut the wing tape for one side of the wing. Starting at the leading edge of the wing brush on some Tightbond Glue and then lay the wing tape over the glue and press down into the glue. You have to work fast here or the glue will begin to set up and create one big mess. Continue this process until one side of the wing is finished. Let dry and then proceed to other side and repeat the process. After this drys then brush on a thinned coat of glue and let this dry. Sand lightly when dry. Repeat until cloth is completely filled with glue. Tkes me about three coats.
Hope this helps

Counterpoint.

Skip it.

Terry in LP

Any finish cure epoxy or finishing resin is fine. I usually use the Bob Smith 20 minute finish cure that the local hobby shops carry with the hobby shop name on it http://www.amainhobbies.com/product_info.php/products_id/37088/n/Bob-Smith-Industries-FINISH-CURE-20-Minute-Epoxy-(13oz). I use it because it's convenient. I'm sure the Great Planes Finishing Resin http://www3.towerhobbies.com/cgi-bin...?&I=LXK304&P=7 is also a fine product.

If you're only doing one wing center section, thinning some 30 minute epoxy 50% with alcohol works fine too. I do a lot of building so I keep finishing resin on hand.

Dave

Some fiberglass notably some stuff I recently got from Tower doen't soak through well. Might have to put some epoxy down before the glass is applied and then again on top. Try this link to get an idea of how it can be done.
http://www.theflyingknights.com/phpB....php?f=3&t=137

.

Thanks for all the tips guys!! I really appreciate it, they helped a lot. I think I'm going to go with the 30 min epoxy, since I have a ton of the stuff.

All I use is polyester resin. I don't like Epoxy. Probably because it's popular.

Charles

Well, got it done with the 30 min epoxy, and it went very well. Did one side last night, and the other this afternoon. At first the epoxy just stayed on top of the fiberglass, but after about 5 minutes it started seeping in and after ~10 minutes everything was golden and it did exactly as it should.

And now (hopefully!!) i have an uber strong wing joint. Thanks agin.

30 minute or slower epoxy is the way to go. Do NOT thin it with anything, just put on as thin a coat as you can then heat gently with a heat gun. The heated epoxy will instantly flow out through the weave. Now, get a roll of Saran Wrap (that plastic wrap used in the kitchen make sure it is Saran, not a look alike) and cover the entire area with it. You can now smooth it out with your hands and set it aside to cure. After it is cured, you remove the Saran wrap and you have an absolutely smooth surface, perfect fairing at the edges and no sanding required.

Nuts!! Wish I had known about the saran wrap trick. I did try and "squee-gee" the excess away, but I bet using the Saran wrap would have helped, too. Especially with minimizing or eliminating the need for sanding.

And I didn't thin it with anything, and didn't need to use the heat gun - it got fully saturated on its own. I was nervous about using the heat gun anyways, as I was worried that I'd get it too hot and the rxn would speed up and it would set before I had it exactly where I wanted it.

saran works well but polyester dress lining or peel ply (same thing) works better. there is a build thread by experimental aviator (a king kobra) where he glasses the entire plane and uses peel ply to eliminate a lot of sanding. i've used it and it works very well.

I spray the area to be covered with that 3M contact cement first. That will hold the fiberglass in place while you epoxy it

I have never fiberglassed a wing center section and I always thought from reading the forums that you have to use a resin like "West Systems" resin or some other equivalent resin. This is the first time that I have heard using 30 minute regular epoxy. Well that is certainly good news since I always have 30 minute epoxy handy..........and I have yet to buy any finish resin or equivalent. I have done minor repairs to car plastic parts with used airbag cloth and epoxy and it turns out to be very strong. This is very, very good news for me...............the 30 minute epoxy application part.
Thanks
larry

A few guys at my field use polyurethane. a few coats fill the weave nicely and is self leveling. Brush on a coat, apply the glas, wait 30 mins. apply and reapply as necessary to fill the weave. I saw one guy do his wing and fuse using silk and polyurethane instead of dope. Looked great!

Some good tips in this thread and here's another.Use a bolt roller as you can use far less resin..it's the weakest part by far and it's heavy.