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What RTV to use on TE of elevators?

dwollen89

Well Known Member
I'm folding the trailing edges on my RV7A elevators. Section 5.7 says to place a wad of RTV where the stiffeners overlap. I'm assuming you squirt a wad about the size of a piece of gum on the TE end of the stiffeners so they both contact the silicone? Also, what type of RTV have others used? Anything special about it or just standard blue RTV silicone?
 
I tend to stay away from stuff with silicone in it wherever possible. I seem to remember learning about 100 years ago that some versions of may be corrosive to aluminum, but don't quote me on that.

For sure, it will cause paint to not stick well. I realize that you don't paint the inside of the elevators, but all it takes is one oopsie with a wet finger the outside of the skin for you to cause a lot of hassle for yourself on down the road.

Out of an abundance of caution I used a dollop of pro-seal at the end of those stringers. just a little bit to tie them together, say about the size of a small wad of chewing gum.

You're going to have to get friendly with pro-seal sooner or later anyway, and if you've never used it, this is an easy non critical application to learn on.
 
Pro seal to the rescue..., might as well get used to it now.
RTV-3145 is also a great product if you don't want to mess with proseal
 
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Say no to RTV…

Use 3M VHB tape. Works very well at keeping the TE with no clean up or paint adhering issues. Just lay in the tape on one half, put the skins together, rivet…done.

For reference, is also the recommended method in the RV-10 KAI and described in drawing 9.
 
Use 3M VHB tape. Works very well at keeping the TE with no clean up or paint adhering issues. Just lay in the tape on one half, put the skins together, rivet…done.

For reference, is also the recommended method in the RV-10 KAI and described in drawing 9.

RV7 elevators are folded, not riveted, the question was about joining the stiffeners as recommended, not the TE.
 
That's my fault on the thread title...I was in a hurry and probably could have worded it better. I was referring to the RTV used on the ends of the elevator stiffeners prior to closing things up.

I'm thinking of getting the proseal instead of using the RTV. Looks like Vans sells a 3.5 oz bottle of flamemaster. Does anyone know if a standard caulk gun will work with the convenience bottle they sell? I'd think you could grind down the plunger on a standard gun to fit if it's too big.

Aircraft Spruce also sells a Chemseal B2 Tank Sealant for a little cheaper. I'm assuming this is the same type of stuff as proseal.
 
I have used Permatex Ultra Black on several builds for this purpose. It is a neutral cure, sensor safe and non corrosive. It has incredibly good adhesion and cures to a hardness very close to pro seal. I use the aerosol can type dispenser, easy to get it where you want it. I also use this for sealing baffles it works great.
 
That's my fault on the thread title...I was in a hurry and probably could have worded it better. I was referring to the RTV used on the ends of the elevator stiffeners prior to closing things up.

I'm thinking of getting the proseal instead of using the RTV. Looks like Vans sells a 3.5 oz bottle of flamemaster. Does anyone know if a standard caulk gun will work with the convenience bottle they sell? I'd think you could grind down the plunger on a standard gun to fit if it's too big.

Aircraft Spruce also sells a Chemseal B2 Tank Sealant for a little cheaper. I'm assuming this is the same type of stuff as proseal.

I used the copper permatex RTV. Worked great, is not corrosive and available on the zon of ama. It was recommended by several people and a&p ia is good with it.

https://www.amazon.com/Permatex-81878-Maximum-Temperature-Silicone/dp/B0002UEOPA/ref=sr_1_2°Crid=AXW9GBWQKHPM&keywords=permatex+ultra+copper&qid=1646244957&sprefix=permatex+ultra+copper%2Caps%2C60&sr=8-2?th=1&psc=1
 
This goes back 40 years in RV construction. This keeps the upper and lower skin from vibrating and flexing right at the end of the stiffener (flange riveted against skin). Cracks form. The sealant keeps it stable.

Long ago it was discovered very careful work you can get the stiffener flange closer to the radius of the trailing edge. Closer means right where radius starts. The issue of cracks forming right where flange stops typically happens when people leave a long space from end of stiffener to trailing edge radius, leaving skin unsupported. The goop was a fix to large gaps of unsupported skin.

Silicon can be used if you prime the surface. Silicon is acidic and will etch aluminum and this can lead to corrosion. As long as do good surface prep (etch, alodine) and prime silicon is good.

Yes pro seal will work. I do not use any glob of any goop, I just make sure the stiffener is right up to the radius. You have to relive the stiffener free flange so it does not touch the opposite side of skin. Allow some room for movement.

Prime and use RTV or use Pro seal. Do not recommend chewing gum. Ha ha.
 
This goes back 40 years in RV construction. This keeps the upper and lower skin from vibrating and flexing right at the end of the stiffener (flange riveted against skin). Cracks form. The sealant keeps it stable.

Long ago it was discovered very careful work you can get the stiffener flange closer to the radius of the trailing edge. Closer means right where radius starts. The issue of cracks forming right where flange stops typically happens when people leave a long space from end of stiffener to trailing edge radius, leaving skin unsupported. The goop was a fix to large gaps of unsupported skin.

Silicon can be used if you prime the surface. Silicon is acidic and will etch aluminum and this can lead to corrosion. As long as do good surface prep (etch, alodine) and prime silicon is good.

Yes pro seal will work. I do not use any glob of any goop, I just make sure the stiffener is right up to the radius. You have to relive the stiffener free flange so it does not touch the opposite side of skin. Allow some room for movement.

Prime and use RTV or use Pro seal. Do not recommend chewing gum. Ha ha.

SiliconE...

Specifically Acetoxysilane-based RTV which releases acetic acid (aka Vinegar) during the curing process.
 
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