BlueMax3

My Feedback: (1)

Any of you veterans out there want to share any tips for epoying wing halves? I plan to use 30 min two part epoxy. How do you do it and get a good solid bond without a lot of mess?

Thanks,

Travis

Combat Addict

Ok, first of all get some paper towels handy. If there are any servos or torque rods, it makes it more interesting. Line up any joiners(rods or whatever). Then coat one whole side with epoxy. Hold the wing vertically so the flat horizontal surface has epoxy. Now slap em together! Epoxy should Ooze out! Now use the paper towels to wipe up the epoxy. Tear the paper towels into small pieces 3x3 inches. Wipe these once or twice to clean off epoxy per rag. Then stay with the wing, make sure it is square. Check on it every minute until the epoxy cures to make sure none extra oozes out.
Good luck

Kaos Rulz

Travis,

I do about the same as Combat Addict, however, I use 3 inch wide masking tape to help control the ooz of the epoxy out the bottom side. After dry fitting the two halves to satisfaction, I then tape the bottom side of one wing panel, leaving half the width of the tape ready to accept the other wing half. Place the epoxy on the non-taped wing half, join the two, clamp together, then insure the masking tape is sticking tightly to both halves. Once dry, the tape can be peeled off. A light sanding to the wing joint might be in order.

Intruder38

If I'm joining covered wing halves (like in ARFs) I apply strips of painter's light-tack masking tape (blue in color) right up to the edge of the joining ribs, all the way around. Then apply your epoxy as in preceding posts. Apply regular masking tape across the joints at frequent intervals to hold the joint tight and check the alignment frequently while the epoxy sets. When set is complete, peel up the tape and you're done; no muss, no fuss.

Combat Addict

Good point about the tape. That works well. Forgot that. oops.
Ive also used regular scotch tape, but sometimes the epoxy bonds to that.

Bama

My Feedback: (18)

I do it like Intruder said. Put tape right up to the edge on both halves, glue like everyone has said, clean off the excess with paper towels sprayed with alcohol, then put tape on to hold it together. I sometimes use a squeeze type clamp (looks like an overgrown clothes pin) on the trailing edge to keep them aligned.
Alan

J_R

Keep in mind that the bonding of the two halves adds very little to the strength of the wing. The alignment of the halves IS important. The strength is in the brace. If the brace does not fit tight and is sloppy, consider making a new one with thicker plywood. Getting epoxy into the box is the major concern. Get something like a machinest's rule and "paint" the sides of the box and the brace. If the fit is sloppy, you will not get a good bond, no matter how much epoxy you put in the box. I usually epoxy in one side of the wing brace and box and let it set, checking the aligment. Then, after it is set I mate the wings and proceed, epoxying the center sections and the other half of the box.

Epoxy is water solubable until it has set up. That means you can clean it up using water if you get where it does not belong. I use rubbing alcohol because it cuts the epoxy even better. Don't flood the area with either. Put it on the paper towels. Only make one pass with the paper towel and throw it away.

The alignment of the wing halves is important. Once you have the epoxy on and cleaned up, putting plastic electrical tape on the bottom works well. Then put in down flat. Jig the wing up so that any dihedrial is correct. Wipe the top off again and let it set. This should all be ready before you start.

Don't try to use anything less than 30 minute expoxy, it won't give you enough time to do all the checking you need to.

Putting fiberglass or tape around the finished joint makes the wing considerably stronger. Stripping back some of the covering may be necessary if you are going to glass it. You can use either epoxy or resin. Remove all the excess with wadded up toilet paper. The excess epoxy or resin add nothing to the strength of the glass. Of you don't remove the excess, your in for a lot of sanding. Do not sand into the glass, just the surface. The epoxy or resin IN the glass adds the strength. You may have to get more covering to recover the area you strip. Be careful not to cut the wood. If you use fiberglass resin, or polyester resin, rahter than epoxy resin, be aware that it has a wax in it that comes to the surface and will have to be sanded off before recovering. Epoxy resin does not have this problem, but is harder to sand.

Keep rubbing alcohol handy. If you get epoxy on your fingers, wipe them off with it right away and don't spread it all over the wing.

Before the epoxy sets, look for finger prints, globs of epoxy and clean them off with the alcohol. Once it sets, it is too late.

Make sure you have everything ready before you start.

JR

the troll

Also if it is an ARF use the bags that the wing panels come in to protect the panels from errant epoxy by taping the bags in place near the joint. Of course the technique can be used on built up models too but you will have to supply the bag.

Combat Addict

I think you can also use rubbing alchol to thin epoxy.

J_R

Using rubbing alcohol to thin epoxy is not a good idea. The idea is that the alcohol should evaproate before the epoxy sets. Rubbing alcohol has 30% water in it, which does not evaporate quickly. The other 70% is isopropyl alcohol, which can be used in it's pure form. Ethyl alcohol (denatured alcohol) also works to thin epoxy, as does MEK and several other things.

JR

hookedonrc

I do one additional thing that has helped me. Do most of what is said above using the epoxy, paper towels, alcohol to swab up the extra epoxy. Now...I do one other thing for keeping pressure on the wing halves to get a good seal and keep the alignment in place. If the wing has two mounting dowes on the leading edge, take 2 or more rubber bands and tighten them around the 2 dowels causing the wing halves to press together. Also, if the wing has 2 mounting bolt holes in the trailing edge, I take 2 dowels the size of the bolt holes, and put rubber bands on the top side and the bottom side. This will also pull the edges together to keep pressure on the two halves. Make absolutely sure that the two halves are lined up properly. This will allow you to concentrate on the oozing epoxy.

TLH101

My Feedback: (90)

I have found that a piece of wire or bamboo skewer works really well for a spreader, especially inside the box for the joiner. You can just roll the epoxy inyo place with it, and get all way down in the box. It also works on the rib faces as well.

higheronnitro

One more tip to add to the list
Gently warm the mixed epoxy using girlfriends/wifes hairdryer helps reduce the viscosity and improves the glue penetration for a really good bond. PS avoid getting glue on girlfriends/wifes hairdryer !!!
BR Steve

_WIT_

Excellent words of wisdom above. One thing I'd add, is to mix more epoxy than you think you need. It isn't that expensive, and you don't want to be measuring out a second batch while the first is hardening up unattended.