Hrs: 8

Fuel tank stringers

First round of tank sealant session was riveting the stringers to the skin.

I did not deburr the holes with the rotating deburring bit but used a file, sandpaper and SkotchBrite to remove the burs and scuffing the area that will be covered by the tank sealant.
Reason why I didn’t want to use the rotating deburring bit is to avoid a small countersink that could increase the risk of a leak.
Next I used Acetone to clean the area, only wiping in one directing and drying the wet area with a second wipe and a new paper towel.
To protect the rest of the skins I used some painters tape:

Also the rivets need a shower in Acetone so they are absolutely clean, before using them I rub them dry with a paper towel:

I found some info on VAF that there are 4 seals to make:

Safety first: my workshop has a big fan that ensured sufficient ventilation when working with Acetone and tank sealant and I used eye protection and nitrile gloves!

Proseal ready to be mixed, 50 strokes, not too fast (to prevent heating up the sealant) and a 90 degrees rotation with every stroke, I used the drill bit adapter to make this easier:

Next I covered the skin with sealant, pushed the stringer in and removed it again and then smeared the sealant on the skin and stringer so that there was a 100% cover of sealant. Then I put the stringer back and first inserted rivets in every other hole. I put a bit sealant on the rivets before inserting them. Next I inserted clecos in every remaining holes:

Inside view:

I modified the sealant gun nozzle so that it’s just a bit bigger than rivet tail, squeezed a bit sealant out, insert it over the rivet tail and retract the gun while making rotating movements:

Right 2 rivets are done, left to go:

Gravity helps when the skin is laying flat on the workbench.

Next I removed the painters tape and cleaned a bit with Acetone, looking good:

I also cleaned the outside with a paper tower and Acetone (not soaked!):

Tip: clean the clecos with Acetone while the sealant is still wet!

Up until now my experience is that working with tank sealant isn’t too bad.