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first gas tank rib

Adam W

Well Known Member
wow riveted and sealed my first rib in the left tank what a lousy job i did
my rivets are sitting higher than id like. they appear tight and i believe sealant is everywhere it should be.
any tips on a better riveting job the stiffeners and fuel filler were easier with back riveting but also not as good as all my previous rivetting
im using a mushroom set with a rubber ring compressor down to 45lbs
ill take any advice
thanks in advance
 
Proud rivet

wow riveted and sealed my first rib in the left tank what a lousy job i did
my rivets are sitting higher than id like. they appear tight and i believe sealant is everywhere it should be.
any tips on a better riveting job the stiffeners and fuel filler were easier with back riveting but also not as good as all my previous rivetting
im using a mushroom set with a rubber ring compressor down to 45lbs
ill take any advice
thanks in advance

It may be the proseal but you mentioned the others are flush.
Try heavy packing tape over the rivet to hold it down then feather the trigger for a few taps to partially set. Every gun is different but 45 psi seems kinda high for a #3. Just my $.02.
 
I take it that your setting the rivets "wet" rather than waiting a day for the proseal to set up? The tank dies help, but at the end of the day I found riveting the tank very challenging. The tank dies help so that you can get a little proseal under the rivet head and not have them sit proud, but I found the tradeoff is that the rivets like to "tip" or "tilt" a little more than usual. I found that I had to drill out and re-set more rivets than I really wanted. It seems extra care is needed holding the bucking bar just right. (Keeping the bar clean with a wipe between each rivet set helped) Btw...Not the most fun drilling out rivets in proseal!

Hang in there...keep the faith and try your best. Get the dies it will help.

You may be of the fortunate few who feel that riveting in proseal is easy. I myself wasn't that fortunate. I found it a bit of an art.
 
Take the rubber ring off your rivet set. Better yet, get a swivel flush set like this one: https://smile.amazon.com/gp/product/B005VR9256/
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It'll really cut down on smileys elsewhere in the build, too.

Rivets are going to sit just a bit higher on the tanks. I would keep working wet and not do the "set up before riveting" method because you'll get better clampup between the parts.

It's messy and there's not much a way around it. Though if I were to do it over I'd mask off the ribs and skins before applying sealant.
 
thanks

thanks to all
i am setting them while wet didnt know there was an option
i cleaned the bar every few rivets ill change to every rivet. i will also try the tape as though im back rivetting

ive heard people refer to a tool called a rivet shaver. is this a way to fix the rivets that sit a bit proud?
 
ive heard people refer to a tool called a rivet shaver. is this a way to fix the rivets that sit a bit proud?
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Yes you can use a rivit shaver and I bought one of them for the very same reason. At the end of the day I did not use it and after primer and paint the rivits are not noticeable any more than anywhere else on the wing
 
Or contrary to all of the advice so far...
You could do what I have done on all of the tanks I have built over the years 20 - 30 or so, but have lost count) and scoop the sealant out of the dimple before inserting the rivet. I have never had a leak at a rivet.

No rivets sitting high
No reduction in joint integrity from a coating of rubber like material between the rivet head and the material you are attaching.

Think about it.... you apply sealant to the rib. It gets placed against the skin which applies a layer between the rib and skin. You set a rivet which pulls the rib and skin even tighter together causing the trapped sealant to squeeze around the rivet even tighter.
 
good advice

the packing tape was a great help
and the idea of removing the proseal from the dimple makes alot of sense

thanks to all again
did a couple more ribs and its improved but not as good as id like getting there
 
Scott McDaniels, I am about to start working on my tanks on an RV-7. Since you said that the sealant squeezes out during this process would you recommend a very thin layer to start? And based on your comment of scooping out the sealant, a very thin coating inside the dimple, is that correct? Then I'll come back afterward and add a fillet to the rib/skin joints. My wife is a cake decorator, I may enlist her for this job. :) Thanks, Ryan
 
Scott McDaniels, I am about to start working on my tanks on an RV-7. Since you said that the sealant squeezes out during this process would you recommend a very thin layer to start? And based on your comment of scooping out the sealant, a very thin coating inside the dimple, is that correct? Then I'll come back afterward and add a fillet to the rib/skin joints. My wife is a cake decorator, I may enlist her for this job. :) Thanks, Ryan

The way I install a rib....

Apply sealant to the entire rib flange (I squeeze if from a bag, cake decorator style)

Use a craft stick to get the entire flange coated.

Scrap the flange in two passes with a tilted craft stick so as to leave the sealant with a peak shape that is about 1/16" thick down the center (over the top of the rivet holes) and tappers out to nothing along each edge of the flange.

Insert the rib (starting near the center first so that you can always spread the skins apart for each successive rib as you work towards the ends).

Cleco in place

Use narrow strips of scrap paper to scoop sealant out of each dimple before you insert a rivet.

Rivet from the leading edge towards the back of the tank on each rib. I always use a hand squeezer on the aft most 1 or 2 rivets because there is no stiffness to the rib and it is difficult to get the rivets to sit flush using a gun.

Finish by forming a nice fillet in the squeezed out sealant along the perimeter of the entire rib flange on both edges.
 
And doublecheck to be sure you're not pushing on the bucking bar against the gun. That's a common mistake of people shooting rivets and it ends up pushing the rivet back.

A light pressure on the bar against the rivet...shoot...the bucking bar lifts slightly and then your pressure brings back...slowly forming the shop head.

This is 100% technique. The Van's instructions on what to do w.r.t. ProSeal etc are just fine.

Also remember the old George Orndorf video -- people still have George's videos, right? "If you look at it and say, 'this probably isn't going leak', it probably will. If you look at it and say 'it's not going to leak,' it won't.". His fuel tank videos were incredibly helpful to me when building my tanks.

Also, make a huge mess. It's good for you.
 
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Do people dimple or countersink the spanwise rivet line that attaches the skin to the rear baffle? I used dimples on the ribs and stiffeners but I counter sunk the skin at the baffle joint. I used a squeezer and all the rivets ended up proud and the skin was distorted upwards at each rivet. Very discouraging after all that work. I tried shooting a few with the rivet gun at they came out worse. I had counter sunk just a tiny bit too deep hoping that would compensate for the sealant. Didn?t work. Should I dimple the skin along the baffle on the next tank?
 
Dimple or countersink

Do people dimple or countersink the spanwise rivet line that attaches the skin to the rear baffle? I used dimples on the ribs and stiffeners but I counter sunk the skin at the baffle joint. I used a squeezer and all the rivets ended up proud and the skin was distorted upwards at each rivet. Very discouraging after all that work. I tried shooting a few with the rivet gun at they came out worse. I had counter sunk just a tiny bit too deep hoping that would compensate for the sealant. Didn’t work. Should I dimple the skin along the baffle on the next tank?

Both. I've seen it done both ways. Countersink the skin allows the baffle to slide in clean.
I did it that way and had a few rivets sit proud. I discovered the odd rivet needed a tiny bit more removed from the mated holes to sit flush. A turn or two with a debur tool was sufficient. I also used few fat rivets to hold the baffle skin alignment. Clekos were allowing the baffle to move a tiny bit. I'm a little OCD and it bothered me.
 
the packing tape was a great help
and the idea of removing the proseal from the dimple makes alot of sense

thanks to all again
did a couple more ribs and its improved but not as good as id like getting there

I learned to use rivet tape on all my flush rivets, regardless of orientation. This keeps the rivet from popping up with the first strike.
 
Dimpled

Both. I've seen it done both ways. Countersink the skin allows the baffle to slide in clean.
I did it that way and had a few rivets sit proud. I discovered the odd rivet needed a tiny bit more removed from the mated holes to sit flush. A turn or two with a debur tool was sufficient. I also used few fat rivets to hold the baffle skin alignment. Clekos were allowing the baffle to move a tiny bit. I'm a little OCD and it bothered me.

I dimpled the rear baffle holes and the rear baffle kind of snapped in place. I think i might have hit a few with a countersink as i was setting the rivets
 
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