4.2 Hours -
Time to break out the tank sealant (aka, black death)!
First thing I did today was scuff the rivet lines on the inside of the right tank skin as well as the stiffeners. Once this was done, I meticulously cleaned everything with MEK. According to the instructions, the surface must be perfectly clean in order to ensure a good bond with the sealant. Unfortunately, this means I had to wear gloves the entire work session once the parts were cleaned.
Next, I started setting up to back-rivet and seal the stiffeners to the skin. I soaked some rivets in MEK to clean them (by the way, don’t do this in a plastic cup, the MEK will dissolve the cup…ask me how I know!), and pulled out a kitchen scale for weighing out sealant components. I also made sure that I had MEK within arms reach as well as a lot of rags and paper towels to clean up any messes.
Everything, including the rivets, has to be throughly cleaned with MEK prior to using tank sealant.
At this point, I also placed some electrical tape around the tank drain area. This tape will be pulled up once the flange is riveted, and it will ensure that water has a clear path to the drain…no sealant blocking it.
I taped this pattern onto the tank drain area to ensure that no sealant would block the path to the drain.
Once the rivet gun and back rivet plate were set-up, it was time to start. I weighed out 30 grams of the base component and 3 grams of the activator into a plastic cup and mixed it with a popsicle stick. This stuff is thick, but it mixes together well after a minute or two of stirring.
After the sealant was mixed, I spread a thin layer on the mating surface of two stiffeners, set the stiffeners in place and back-riveted them to the skin. After riveting, I used a popsicle stick to make a fillet of sealant, between the stiffener and the skin, all the way around the stiffener. I repeated this process, two stiffeners at a time, until all the stiffener were riveted. Then, I dabbed some sealant on the shop head of each rivet in order to encapsulate it.
The stiffener rivets will be back-riveted, so I taped them into place.
The right tank sitffeners are all riveted and sealed...not too messy.
A close-up of one of the stiffeners after riveting and sealing.
I thought about stopping here for the day, but I changed my mind, and decided to rivet the drain and fuel cap flanges today as well. Just like the stiffeners, these also had to have the mating surfaces coated with sealant before being riveted. The drain flange was easy since all the rivets could be reached with my squeezer. However, the fuel cap flange was a bit more of a challenge…mainly because I decided to rivet it with a flush set in my gun, only to realize on the very last rivet that I could have back-riveted it to the skin. However, I was pretty happy that I remembered to rivet the vent line clip on using one of the rivets for the fuel cap flange.
After all the rivets were set in both flanges, I dabbed more sealant on the shop heads. The last thing I did was a little clean-up. I really didn’t make that much of a mess, but I cleaned any sealant off my tools and also cleaned the outside of the tank skin where any sealant oozed out of the rivet holes. During my next work session, I’ll start riveting and sealing the tank ribs.
After sealing the rivets, I pulled the tape up. Water should have no problem making its way to the drain.
The outside of the tank drain after riveting.
I surprised myself by remembering to rivet the vent line clip on with the fuel cap flange!
The outside of the fuel cap flange after riveting and a little cleanup.
