Today it's time to see how well the fay sealing method will be working for me. Yesterday I sealed and clecoed the stiffeners, fuel cap flange, and drain valve in place. Now it's time to see how much the sealant has cured and do some riveting.
I started with the drain valve flange. The sealant is still quite sticky and tacky, but definitely somewhat firm and rubbery. I pulled the clecos out and "wet riveted" the piece in place. Wet riveting means I apply a dab of fresh wet sealant into the dimple with a toothpick and smear it all around the dimple before inserting the rivet. This insures a layer of sealant around the rivet as it gets squeezed or hammered in place. When the rivets are set, another blob of sealant is applied inside the tank over each rivet bucktail, as you can see above, totally sealing off each rivet. The outside is shown below after cleaning it up. Nice flush rivets. Totally sealed. Looks good!
Next is the fuel cap flange. Here's a shot of it after riveting and sealing each rivet in place. You can also see the little clip that will hold the vent line.
And finally, the stiffeners. It's a tedious, time-consuming job, applying sealant to each and every rivet hole, inserting all the rivets, backriveting them over a steel plate, then putting a glob of sealant over each rivet inside, then cleaning everything up. Here is the result, several hours later. All the stiffeners are now riveted and sealed in place. All in all, I like the fay sealing method. Cleanup is much easier (especially all those clecoes!), and the whole process is less messy. You can pull out all the clecoes and the stiffeners stay in place while you insert the rivets. Any blobs of sealant left on the clecoes are rubbery and are easily pulled off, making cleanup much faster. The results are certainly very good. I think I will continue with it. Now this tank is ready for some ribs.