Proseal tubes
Ian,
The tubes of proseal sold by Vans are filled with both resin and activator at the factory. The two components are mixed with a plunger that is part of the package.
I ordered one of these when I did my rudder. It worked, but after doing my tanks with the plainly packaged quart and a handfull of 60 cc medical syrings from the local farm store, I can recommend that you NOT go the route of the Semco gun.
The prepackaged proseal will ultimately cost you 5 to 10 times (due to package cost and wasted proseal) what the plain can of proseal will cost.
MEK or Laquer thinner disolves the stuff. The semco packages don't do anything to avoid getting it all over the place while wet rivetting, so your gonna get messy anyway. In my opinion, the semco ain't worth it for this small RV task.
If I was laying beads on a production line, it would be a different story.