Proseal vs Tape for Trailing Edges

[czechsix]

Vans originally recommended using Proseal on the riveted trailing edges, and now the plans recommend double sided tape. The tape seems attractive (less messy and no long wait for Proseal to cure), but I saw on someone's blog that they had tried the tape and did not like the results...there was some separation between the TE skins and the wedge between the rivets, so he went back to using Proseal. For those of you who have used tape, are you happy with the results?

Also, one RV-10 builder recommended breaking the edge (putting a slight bend just like you do where there are lap joints on the wings and fuselage) of the TE skins to help ensure they lie flush to the wedge when they are riveted. The plans don't mention doing this. Has anyone tried it?

Thanks,

[gfb]

I have tried both tape and proseal. My experience is similar to what you suggest, tape is easier but the finish is not nearly as nice. I finished the rest with proseal and will likely drill out and re-do the tape with proseal also.

Once you get the hang of it, proseal is really not a big deal, I just try not to get any in my beard...

[Tom023]

I just finished my flaps and have one aileron setting up right now and one to go and I went the proseal and slight edge break. I am pretty pleased with how tight the skins are and how straight the edges are coming out but I don't think there is a guarantee of gapless skins. The three I have done have some minor separation (1/64", 1/32" worst case) in a few places due to either excess proseal, a slight stretch in the skin while making the edge break, or combination of the two. The aileron skins are .016, the flaps skins I think are a tad thicker, but unless you are extremely careful breaking the edge with a roller tool you can easily stretch it a tiny bit which I think leads to a slight pucker or lifting between rivets.

[rvbuilder2002]

The change was made to using the tape for all of the reasons already mentioned (mess, cure wait time, etc.), but one additional one is difficulty in characterizing "thin coating of tank sealant".
Thin to one person is not the same amount to another.

Use of a very thin coating is important from a strength aspect as well as aesthetics. If it is too thick, the cured but still compressible sealant will compress which results in indentations at each rivet and in severe cases, puckering between the rivets.

If those considerations are kept in mind, sealant is still fully acceptable.

[czechsix]

Originally Posted by rvbuilder2002

The change was made to using the tape for all of the reasons already mentioned (mess, cure wait time, etc.), but one additional one is difficulty in characterizing "thin coating of tank sealant".
Thin to one person is not the same amount to another.

Use of a very thin coating is important from a strength aspect as well as aesthetics. If it is too thick, the cured but still compressible sealant will compress which results in indentations at each rivet and in severe cases, puckering between the rivets.

If those considerations are kept in mind, sealant is still fully acceptable.

Do you find it easier to put the thin coat of sealant down on the skins or on the wedge? The skins have dimples in them which would make it a challenge to lay down a thin, even layer of sealant, so it seems easier to coat the wedge...but methinks more sealant is going to end up down inside the lightening holes and countersunk holes in the wedge than on the mating surface. I can definitely see how the sealant approach could result in added weight to the trailing edge which is the worst place to add weight to a control surface...

[jeffw@sc47]

I used the tape on all of the tail feather trailing edges. Two layers on each of the skin-to-wedge contact surfaces. Another 14 builder recommended that I use three layers, as they did, but two worked fine for me. I did not break the trailing edges. All the trailing edges came out nice and straight. I'm happy with all the results.

I did as much as I could to keep the rudder and elevators as straight as I possibly could with wide, flat, and straight boards, and weights while everything was setting up - all on top of a very solid and flat table.

My guess is that two layers of tape is twice as much adhesive as one layer; 3 layers, 3 times..

[czechsix]

Originally Posted by jeffw@sc47

I used the tape on all of the tail feather trailing edges. Two layers on each of the skin-to-wedge contact surfaces. Another 14 builder recommended that I use three layers, as they did, but two worked fine for me. I did not break the trailing edges. All the trailing edges came out nice and straight. I'm happy with all the results.

I did as much as I could to keep the rudder and elevators as straight as I possibly could with wide, flat, and straight boards, and weights while everything was setting up - all on top of a very solid and flat table.

What is the rationale for using two or three layers of tape instead of only one?

[gen1313]

As a first time builder and starting with the empenage kit I was faced with trailing edges early in the build. I used the tape method as instructed.

After reading posts about rudder twist and crooked trailing edges I was nervous but I was very pleased with the results. All my trailing edges are done now with consistent results. The tape probably gives a slightly thicker edge but I felt that the straightness was the major consideration - and I didn't have to play with ProSeal

[Kyle Boatright]

I did a set of flaps using the wedges and proseal. I was pleased with the results. I'd purchased the tape, but had concerns about the possibility of parts initially lining up incorrectly and the tape making it difficult to reposition them.

Either way, I suggest it is one of those "Just do it" parts of the build where most of us overthink it instead of just hammering out airplane parts.

[HeliCooper]

To those going the proseal route I found using a small trim paint roller worked great for putting on a thin layer on the wedge. Just get a cheap throw away one and use it directly on the plastic roller without the cloth roller on it.