Epoxied the Trailing Edge -- Now I'm Worried

Finally epoxied the rudder trailing edge, a job I've been dreading since I bought the kit. Wish I felt better about it. She's good and straight cleco'd in place to the angle, but I hope I just didn't epoxy all my cleco's and the angle to the rudder! I boelubed the surface of the angle and each cleco, plus cleaned out each hole and any excess epoxy I could see, but man I've got a bad feeling about this!

Anybody else have a problem with this when everything set up? Also, how did you clean the hardened epoxy off the rudder? I assume a deburring tool will clean out the holes if needed. Never thought I'd feel more comfortable riveting than gluing, but I can drill out a bad rivet.

Guess I just don't like having to let things set 24 to 36 hours before I can see what I've got!

Epoxy vs ProSeal

SD,
I haven't heard of anyone using epoxy for this. I used ProSeal, and I'm curious to know why you went with epoxy rather than ProSeal? The objective is to hold things together firmly enough to allow the actual riveting, not to act as a permanent adhesive. The proseal, while being the chemists version of baby poop, can still be cleaned out of the clecos.

Yep, Van's said I could use epoxy, and I've read others here who have used T88, so that's what I used. Opted out of using the proseal because of the low shelf life.

Checked everything this morning and the cleco's I tested came right out, so assume that is a good sign. I'll let it set some more and check it again this evening.

I used West Systems epoxy with flocked cotton for this job. I did not use ProSeal because I didn't have to per the plans, and because it is expensive.

Stalldog said:

Yep, Van's said I could use epoxy, and I've read others here who have used T88, so that's what I used. Opted out of using the proseal because of the low shelf life.

Checked everything this morning and the cleco's I tested came right out, so assume that is a good sign. I'll let it set some more and check it again this evening.

Click to expand...

Find something else to worry about, the angle and clecoes will come loose just fine.

Thanks, Sam. Wings are being delivered next month, so I'm sure I'll find something else to fret about.

Epoxy does not adhere well to aluminum unless you give it a lot of 'tooth' and are really fanatic about keeping things clean. So the clamping angles will let go readily. Clecos are usually the opposite of clean as well, and epoxy is generally brittle enough that if any oozes into the cleco it still won't hold it. I used clecos for fiberglass work such as gluing the upper cowl inlet ramps in place or the blisters for my wingtip lights, with no problem.

Trailing edge

I used epoxy 7 years ago...everything looks fine. I called Van's too, said it was OK. As Van's always say's, just build it.

heat gun and a plastic scraper

it's easy to get any additional residue or gloop off. Just heat it up a bit and pop it off with a plastic scraper.

Stalldog said:

Finally epoxied the rudder trailing edge, a job I've been dreading since I bought the kit. Wish I felt better about it. She's good and straight cleco'd in place to the angle, but I hope I just didn't epoxy all my cleco's and the angle to the rudder! I boelubed the surface of the angle and each cleco, plus cleaned out each hole and any excess epoxy I could see, but man I've got a bad feeling about this!

Anybody else have a problem with this when everything set up? Also, how did you clean the hardened epoxy off the rudder? I assume a deburring tool will clean out the holes if needed. Never thought I'd feel more comfortable riveting than gluing, but I can drill out a bad rivet.

Guess I just don't like having to let things set 24 to 36 hours before I can see what I've got!

Click to expand...

I used it... Worked fine. Build on.

Well, the good news and bad news

Okay, I took out he cleco's this evening. Cleco's came out fairly easily. A few were a little stubborn, but no big deal. Then I tried to remove the rudder from the angle -- it was stuck. I carefully inspected it without going any further to see what was going on, and it was so tight I couldn't see between the angle and rudder. So, fortunately I had an angle that was about a foot longer than the rudder, which gave me something to grip, so I grabbed the open end and began twisting carefully and slowly. Finally, the angle popped loose, but not without exerting a fair amount of torsion. I was afraid when it broke loose that it had also broken the rudder skins apart, but that didn't happen, and the rudder appears to not have been damaged by the problem.

I was a bit surprised that the angle stuck as badly as I had feared since I had applied Boelube to the angle. I must have slathered on too much epoxy, but there's no guidance for something like this, so I did what I thought was right.

The good news is that I have a VERY straight rudder trailing edge. I haven't riveted yet, and plan to let it set for another 24 hours before doing that, but based on what I'm seeing and have read posted by others, I doubt riveting will cause a problem. That T88 epoxy seems to be some pretty tough stuff.

This may not have happened with the proseal, but I chose the epoxy route, and in the end it turned out okay. I'm just glad I had a long enough angle to help me twist it off the trailing edge. The thought of having to try to pry the angle off the rudder was not very appealing.

Also, cleaning out the dimples was actually easy, even though they had a fair amount of epoxy oozed out into them. At first I carefully used a #21 drill bit with my hand to clean out the dimples, and that worked very well. But then I grabbed the battery powered screwdriver with the deburring tool and it made quick work of cleaning out the dimples. I spot checked some rivets after the clean up and they fit just fine with no debris holding them out of place.

Hope this helps those that come behind me.

epoxy

Stalldog,
I used proseal and wish I had used epoxy. I am just more comfortable with epoxy and used it for years. I was to generous with the proseal and my edge isn't as "clean" as I would like it. I am going to use a light weight fiberglass tape folded over the edge and filled to hide the edge and rivets completely.

I know filling the rivets is not very popular around here, but wow, does the rest of my rudder look great!

Rockwood, not sure I understand why you would do that with the fiberglass tape. Did the proseal cause your rivets to stand up proud of the dimples? Personally I think that neat line of rivets looks pretty good.

I just like the looks

The edge of the rudder looks fine as it is and the proseal did not keep the rivets from looking great. Between the rivets, I may have a bit too much proseal, but not to a level that would be noticeable to anyone but me. I will put the tape over the edge and smooth it out with a combo of epoxy, fairing agents, and glazing compound. So far what I have done looks great.

I come from a boat building background - everything from hand built kayaks, canoes, sail boats, and restoring Chris Craft run-a-bouts. I like a glass smooth finish. I have seen some beautiful RV's with amazing rivet work, but there is still some dimpling on surfaces like the wings, stabilizers, and rudder. I am in the process of filling them so I get a flat, smooth, surface to paint.

Im not trying to cover up anything, just make the finish I want on my plane. Some informed me that if I was getting judged at OSH, it would be a deduction - something I don't give a rats a$$ about.

Im not trying to convince or even care if anyone else does the same thing. It is my plane and the way I want it to look is what makes the difference.

I guess my point was epoxy is a fine product to use on the rudder and other edges. After using both, I think the epoxy is easier - but maybe with more experience, I would be able to use both well. The advantage of epoxy is if applied correctly, it will never come off, much harder than the aluminum itself, can be sanded, and covers well with paint. It also does a great job of filling in rivet dimples.

I understand, my friend, and I'm sure it will look great. Maybe even faster! In the end the epoxy worked fine for me, as you suggest, but it did give me a scare. I doubt the proseal hardens like epoxy!

Please proceed with caution

Rockwood,

You mentioned that you used a lot of proseal and now you would like to add fiberglass tape to cover the rivets. I would check with vans first, but all that weight that far back from the hinge point, from my understanding, could cause the rudder to be out of balance....... Unless you plan on adding more weight to counterbalance your fiberglass installation.

You could have put an adjustable wrench on the free leg of your angle and piped it off no problem.

Regular cheap turtle wax works good for making sure clecos and the like don't get stuck....goop it on....

Rockwood,

Just seconding with a reply to have you reconsider your plan about your rudder trailing edge. Training edge shape in flight controls at the speeds RVs are capable of, is very important. It's a little involved, but if will affect the amount of pressure required for a given hinge moment, and might also adversely affect a flutter speed. I wouldn't be too cavalier about modifying it.

Rivets are cool....exquisite in a riveted metal structure.

Take care,
Brad

filling rivets and smooth rudder trailing edge

After looking at quite a few photos of other rudder assemblies, I don't think I used any more than others did. The total amount I used would easily fit into 1/2 of an egg shell - and much of it squeezed out.

I ended up not using tape on the trailing edge of the rudder. It didn't need it after I filled and sanded. I did fill all the rivets with a thin coat of light weight filler. I filled the HS and VS too. I carefully weighed each piece and none gained over 2.5 ounces, total gain for the 4 parts was just under 8 ounces after sanding and cleaning the dust off. I am sure I will save that much weight when I prime the parts because the surface is smoother and the primer will not build up in depressions.

If 2.5 ounces added overall on the entire rudder will make it flutter, then I bought the wrong kit. Most everyone else that used proseal or epoxy on the trailing edge did too since it is much easier to gain or lose that much just by the quantity used.

I will be filling the rivets on my wings when I build them too - at least the tops. I did notice when I saw the RV-1 that the wing rivets were filled. I like the look of a smooth wing and rudder.

I am not trying to convince anyone that they should do it too, it is just what I am doing. I have many years of experience with epoxy and fiberglass and I am bright enough to understand how adding too much weight in one location on a control surface could cause problems. I have not done that and filling the rivets and smoothing out the trailing edge does not unbalance the rudder. A smooth surface has better airflow.

Rockwood, just curious, I took the EAA composite class this past weekend, which was my first experience with fiberglass. So, if you fill the rivets, how do you smooth them out? Do you just take scotchbrite or sandpaper to the aluminum surface???

Stalldog said:

Rockwood, just curious, I took the EAA composite class this past weekend, which was my first experience with fiberglass. So, if you fill the rivets, how do you smooth them out? Do you just take scotchbrite or sandpaper to the aluminum surface???

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I may have not been accurate saying filled. Even back riveting, you get a little depression that shows up as a small impression when the light hits it. Using a mushroom rivet driver, it can be more noticeable. I wanted a glass surface like the Glasair wings I help build years ago.

What I did was scuff the AL surface with sandpaper. Then cleaned it with acetone. I used a lightweight auto body filler over some of the rivet depressions. I used an old hotel card key to spread it over the depressions. The largest was about the size of a quarter and less than the thickness of the card key. After it dries, I hand sand with a block with 320 to smooth everything out. If you have done LOTS of sanding, you can use your hand or sponge sandpaper. If it needs another coat, do it now. Then I use 600 lightly, then 1200 to fair everything out. Very little actual filler remains and you have a very smooth surface. If it is a deeper fill, I would use West Systems epoxy. Im sure other epoxy is as good, I just have used WS for years on everything from wood Chris Craft boats to the full size replica of the B2 bomber that was used in the movie - Broken Arrow. The epoxy is great, but it is very hard and difficult to sand - but will be there forever.

I guess more accurate would be filling the depressions along the rivet lines since they are flush rivets. Im not sure how the guys building the 12's fill their rivets. I could not get the few pulled rivets on the round part of the rudder smooth. I tried on a practice piece and it just didn't look good so I didn't try on the rudder bend.

In my opinion, the HS, VS, and rudder, came out great. They are very smooth and very little weight was added. It is how I want them to look and I enjoy doing the glass work.