February 3, 2021
The more I worked with the Pro-seal the less I hated it. I still hate the stuff but much less now than when I started. I have some tips that may make it easier for the next guy.
It cannot be overstated, Make sure that you are prepared before you mix up the batch. Have all the rivets cleaned and laying out, have all the tools that you are going to need handy and make absolutly sure that you have fabricated all the parts that you need. I kept wanting to forget about the little vent line clip that rivets to the fuel filler and the small piece to cover the tooling hole on the outboard rib.
There is no way that you can have too many rubber gloves. This stuff sticks to everything it touches you don't want it on your hands. I went through over 150 gloves during the construction of both tanks.
MEK works well to cut the stuff before it is cured. Make sure you wear a good respirator while using MEK and make sure the area is well ventilated. You don't want to kill any brain cells while you are building this thing do you?
I discovered one night after the second tanks baffle went in that Pro-seal will cure while completely submreged in MEK. I had to be somewhere that night and could not clean all the clecoes that I used to put in the baffle so I dunked them in MEK and left. The next day the Pro-seal had cured. Luckily it is not all that difficult to get off the clecoes but there are a lot of them so it was a real pain. The moral of the story is to make sure that you have plenty of time to finish the contruction job AND the cleanup. Also remember that it always takes longer than you think.
I got good results mixing the Pro-seal with my little homemade 10:1 balance that I built. See it here.
On the first tank I took a lot of time putting just the right amount of Pro-seal in just the right places and then fretting over how bad it looked when I was finished and wasted a lot of time trying to be conservative and perfect. And like a good little manual reader I put the little fillets on every rib/skin joint. Not only was this agrivating but it wasted a lot of time. On the second tank I just smeared a bunch of the stuff in there and riveted, then I removed the excess with my trusty popcicle stick (Oh yeah you can't have too many of those either). You have to be a little careful and make sure that you squeeze out the excess a little before you start to rivet so that you don't get any bulges from too much pro-seal but I got much better results from this method than trying to be picky. It looked better it took less time and oh yeah, the second tank didn't leak the first time I tested it. The first tank didn't leak the second time I tested it. :-(
You don't have to like the black nightmare but don't be afraid of it either, just because people like me don't care for the stuff it is not a difficult process it is just not necessarily a fun one, but then neither is deburring wing ribs.
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