Middle band around trailer

[Jiggs]

I have a 1983 19 ft Scamp that I am repainting. I have stripped off the old paint and am getting ready to prime the trailer. Should the middle band ( I call it the belly band) which runs totally around the trailer be calked before priming and painting or can I leave it alone?

[Jon in AZ]

It is suggested to caulk the top to prevent water running behind the belly band, resulting in black streaks on the shell below. Leave the bottom uncaulked to and water that does get inside can drain. That’s how it comes from the factory.

[Ed Seattle]

Jon - if the caulk above the belly band is starting to show age, is the primary reason for redoing it cosmetic (i.e. black streaks) or is there a potential for water intrusion into the inside of the shell?

I'm not super familiar with the construction of what goes on behind the belly band on Scamps, curious if this has been discussed before and where to read up on it.

Has Scamp offered any advice on a preferred type of caulk for this job?

[Jon in AZ]

Mainly cosmetic, but…

The two halves are sealed on the inside with a strip of glass cloth to prevent leaks and strengthen the shell. However, the protruding mating lips hidden by the decorative belly band are not sealed from the outside. In my climate, water that seeps inside the belly band in winter will go through multiple freeze/thaw cycles, which could cause some separation of the joint over time due to expansion. I feel like it’s better to keep it out of that space.

Not sure about type of caulk, as I haven’t had to replace mine yet. It’s been discussed before, so if you type “Scamp belly band caulk” in the google search bar, you should be able to turn up some recommendations.

In general, avoid silicone-based caulks on the outer shell. They’re really hard to remove and leave behind residue that prevents other products from sticking.

[Engine2]

3M Urethane Seam Sealer #08368 White. I've used quite a few of the #08365 Beige over the years but only when I was going to paint over it. Doesn't turn black like some sealers and can be painted. Downside is you're looking at $30-$45 for a caulk tube.

[Jon in AZ]

Originally Posted by Engine2

3M Urethane Seam Sealer #08368 White. I've used quite a few of the #08365 Beige over the years but only when I was going to paint over it. Doesn't turn black like some sealers and can be painted. Downside is you're looking at $30-$45 for a caulk tube.

How is it to work with? Does it clean up with water, is it forgiving of mistakes, do you need to mask before applying,…?

[Engine2]

Fairly easy to work with and doesn't dry hard. I've used #08380 in the squeeze tube for 40+ years but 3M discontinued the squeeze tube 5 years ago. #08368 & #08365 is the same product in a caulk tube. It can be applied over bare metal, glass, fiberglass, plastic, painted surfaces. Can be painted in 30 minutes but I've pushed that. Cleanup with paint thinner or reducer, it's waterproof.

The big 3 automakers have been using it since the '70's where the roof attaches to the pillars.

Another use I found for it is my welding isn't as pretty as it used to be, still strong but not as steady. Run a light bead over the weld and smooth with my finger. Paint. Looks like a machine weld.

[Engine2]

https://www.3m.com/3M/en_US/p/dc/v000216590/

[Jon in AZ]

Thanks for the additional information, Jim. Many water-soluble caulks do become waterproof when cured. I'm not the most skillful with caulk, so with a spirit clean-up product, I'd definitely want to mask!

[mosquito13]

Look at 3Ms product 5200. There is a quik dry version. Widly used in the marine world. Cleans up with alcohol.

[ROBERT ONEILL]

Originally Posted by mosquito13

Look at 3Ms product 5200. There is a quik dry version. Wildly used in the marine world. Cleans up with alcohol.

Gin or Vodka? You said Wildly used so I thought that's what you meant or was way off base?

[mosquito13]

For a proffesor you should know when discussing alcohol in marine senerios it is always ruhm.

[Roy S]

I'm going to use 3M 4200, While 3M 5200 sealant results in permanent bonds, 3M 4200 has approximately half the strength, making it a good choice for applications where the bond may need to be broken in the future such as replacing hardware.