Riveting Fuel Tanks

[dwollen89]

Just looking to see what others do. I'm riveting my second fuel tank together and its super fun...lol. I'm having some issues with the rivets clubbing over, namely on the top of the tank skin. I just riveted together the right leading edge and had zero issues. It's only on the tanks for some reason. I consider myself to be pretty good at riveting, but I just can't get good consistent results.

I'm wondering if it's the pro seal on the shop side of the rivet causing the bucking bar to slide. Or, possibly just that there is a little gap between the skin and the rib because of the pro seal allowing misalignment. Not sure, but it's getting frustrating.

Anyone have any similar experiences or advice?

 

[wcalvert]

Pro seal is a great lubricant before it cures! I found it helpful to have a solvent soaked rag nearby to wipe the bucking bar after each rivet. It's a pain but produces a much nicer result.

 

[Robin8er]

It sounds like you are not bucking the rivet at a 90 degree angle. One method I used that helps is hold the bucking bar in such a way that you fill the gap between the bucking bar and the tank skin with your finger/thumb tip to allow to to feel if the bucking bar is at a 90 degree angle to the skin. Be careful, you will most certainly pinch your finger tips with the bucking bar as you rivet. If you go slow you will have good control over it. It will take a bit of practice, but I’ve found that works well for making sure you are holding the bucking bar perpendicular to the rivet.

 

[wirejock]

Proseal

Pro seal is a great lubricant before it cures! I found it helpful to have a solvent soaked rag nearby to wipe the bucking bar after each rivet. It's a pain but produces a much nicer result.

That was my thought as well. I don't recall problems but it sure was a slippery mess. I cut a bunch of blue shop paper towels into small squares. That way each was used once or twice by folding it then tossed. That stuff goes everywhere.

 

[DanH]

I'm having some issues with the rivets clubbing over, namely on the top of the tank skin. I just riveted together the right leading edge and had zero issues. It's only on the tanks for some reason.

Did you dimple with tank dies?

 

[dwollen89]

Did you dimple with tank dies?

No, I just used the standard cleaveland dimple die.

 

[DanH]

Good for you.

Usual culprits are too long, too wobbly, bar not 90 to the rivet, or slippage.

The lubed slippage aspect raises a curiosity question. Usually we keep our bars polished. Anyone ever bead-blasted or sandblasted the face of a bucking bar?

 

[skelrad]

I had the same problem as well. With the proseal on the rivet, I just couldn't get what I thought were acceptable rivet heads. I'm sure most of this just comes down to experience, but that was my reality. For the first rib I went the route of wiping off each rivet after I stuck it through the goo. That works, but was messy and time consuming. I ultimately switched over to the method of letting the proseal cure for a day, and the results were night and day different. Not only were the rivets much, much better, but it took the stress level down 100 notches. Worries about the parts not pulling together enough with the clecos while the proseal dried were unfounded (cleco in every single hole, plus I also used tape and straps to make sure everything was as snug as possible). Pulling the clecos out after a day or so pulls out the glob of proseal in the hole, so the rivet goes in clean. A good mound of proseal over each rivet head and good sealing of the rib/skin interface made for no leaks. I did rivet the back baffle with wet proseal, not dried, mostly because that area was easy to use the squeezer.

https://vansairforce.net/community/showthread.php?t=7602

 

[dwollen89]

Thanks for the replies!

I just got done with another session. I riveted two more ribs in. It went much better than yesterday. A couple things I did were to wipe the shop end of the rivet and the bucking bar before setting each rivet. I also switched to my swivel set after the first few rivets were done at the curved edges. Still not perfect, but much better. I have one more rib to go and then I can squeeze the end ribs and the baffle. Then tanks are DONE!

Dan you bring up an interesting point. I was having problems with my squeezer tipping rivets. I spoke to Mike from Cleaveland Tools while at Oshkosh. He told me to rub my rivet sets on the concrete to rough them up and help avoid the slippage. I also wonder if that would be a good idea to try on the bucking bar.

 

[dwollen89]

I had the same problem as well. With the proseal on the rivet, I just couldn't get what I thought were acceptable rivet heads. I'm sure most of this just comes down to experience, but that was my reality. For the first rib I went the route of wiping off each rivet after I stuck it through the goo. That works, but was messy and time consuming. I ultimately switched over to the method of letting the proseal cure for a day, and the results were night and day different. Not only were the rivets much, much better, but it took the stress level down 100 notches. Worries about the parts not pulling together enough with the clecos while the proseal dried were unfounded (cleco in every single hole, plus I also used tape and straps to make sure everything was as snug as possible). Pulling the clecos out after a day or so pulls out the glob of proseal in the hole, so the rivet goes in clean. A good mound of proseal over each rivet head and good sealing of the rib/skin interface made for no leaks. I did rivet the back baffle with wet proseal, not dried, mostly because that area was easy to use the squeezer.

https://vansairforce.net/community/showthread.php?t=7602

Were you still able to do the fillets the next day? Or did you fillet everything prior to letting it sit overnight?

 

[skelrad]

Were you still able to do the fillets the next day? Or did you fillet everything prior to letting it sit overnight?

For most areas, even with just clecos holding it all together, there was enough squeeze out to know that the rivet holes were surrounded with proseal, so I filleted it right away just to make it a easier to deal with after it was a little more cured. Once it was cured and riveted, I looked for any areas where it hadn't squeezed out as much as I'd like and hit those areas with a little more proseal. I subscribed to the advice Scott gave on the Van's instructional Youtube video and didn't go overboard on the proseal.

I didn't have any leaks doing it this way. The one leak I did have was in one of the corners of the rear baffle, which I riveted wet. Sounds like that's a common area, so pay attention there. Thankfully those corners are pretty easy to get proseal into after the fact to fix.

 

[mountainride]

I made a video showing how I did my tanks. This is slightly different because the end rib is squeezed but controlling the proseal is the same. I wipe the tool after every rivet to prevent spreading proseal everywhere. I also wipe the proseal that was pushed through the hole with a popsicle stick before bringing another tool into the mix. The video is a quick 2 minutes but shows a lot of the techniques from the Vans Aircraft video by Scott, a must watch before fuel tanks.



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