Sealant question (But not your normal caulking debate!)

[drodio]

I don't own an Airstream, but I'm coming over here in the hopes that the aluminum experts in this forum will have some great advice:

I own an Adrenalin Blast adventure trailer (here it is, in case you want to learn more about it: http://www.expeditionportal.com/foru...n-Francisco-CA )

The trailer swings open, clamshell style.

The floor has been leaking, which led to wood rot. I just tore out the vinyl flooring and the plywood underneath it to find the culprit. Looks like steel screws that have rusted and were letting water in (when the trailer is closed, this floor becomes the top of the trailer).

So now I'm down to bare aluminum + the steel screws. And I'm trying to figure out how best to seal everything back up.

And since the trailer floor is an aluminum tub, I'm thinking it might be a good idea to use some kind of pour-in sealant or even epoxy to really seal everything in well.

Here are the steps I've thought up so far -- but I'm 100% open to suggestions:

1) I was going to use POR 15 marine clean + metal primer to prime the screws and the aluminum around them, and then POR 15 the screws to stop the rust (these screws are permanently installed and will never need to be removed).

2) Then I was debating using some kind of caulk to caulk the screws where they meet the aluminum, as well as caulk the aluminum joint that runs down the middle of the floor.

3) And then I wanted to literally pour in some kind of sealant or epoxy (or something else entirely?) to a depth of about 2 inches. Something that would harden when it dries. (although it *could* stay semi-soft... we'll be walking on it so it just has to be durable)

4) Then I may or may not put vinyl flooring back down, depending on what I end up using in step #3.

I was thinking about using some kind of roof sealant for step 3. But I really have no idea what would be good. I'd love something that's not *too* heavy, as the roof pivots to become the floor... but the weight will probably be OK.

Anyone have any ideas on the steps above, especially what material to use in step #3?! MUCH appreciated.

Here are some pictures:

Here is the floor from an outside view:


Here's the floor from the inside:


Here's a closeup pic of the steel screws that have been rusting (I've since cleaned up the mess around them):

[Aerowood]

Have it sprayed with Rhino Liner or any other type of spray on bed liner. No need for the thickness you specified though, as it would be extremely heavy.

[Airtandem]

I agree with Aerowood, Rhino is a softer type, Lin-ex is hard rubber type, or Rustolem has a do it your self type put on with roller and brush. I'm more impressed with the Rhino and it comes in colors.

[Kemblkr]

The rust is galvanic corrosion from dissimilar metals. Sikaflex self leveling sealant is some tough stuff and it gets pretty damn hard. You would have to get that surface completely level and lay some barrier around the edges to the depth you want the sealant.

When you start poring this stuff it quickly levels itself out. You may want to rough up the aluminum surface with some 120 grit for extra grip. The self leveling stuff is designed for concrete gaps so I would get a small piece of aluminum and do a test on adhesion and durability prior to using it on your trailer.

You should predrill the aluminum hole slightly larger than the shank of the screw and use galvanized wafer head screws.

Apply some sealant to the hole so when you install the screw there is a film between the head of the screw and the aluminum. As an alternative you could cover the hole with electrical tape and then install the screw. This would leave the tape sandwiched between the screws and the aluminum. This will eliminate the current that causes the corrosion.

Just some ideas with no real practical trials but that is what I would try personally.


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[Bill M.]

Is there any chance of removing the rusty screws and replacing them with stainless steel screws and a gob of sealant?

[Kemblkr]

Also, if you seal the aluminum and the screw heads with a coating you should not have any corrosion. Corrosion requires atmosphere so if it sealed then it should eliminate corrosion, in theory.


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[twolanehwy]

Get a magnet and test metal as it looks like galvi to me.

[USAtraveler]

I agree with the last 3 posts. You want to use SS screws to eliminate the bi-metalic reaction. A magnet will not pick up SS, but will be attracted to nickel plated steel or galvanized screws.

[Barbieri]

If you say it's a tub why not put something like a hot water valve at the low point. Anything that increases the weight will also effect the castor and camber of the tires.

[rmatkovich]

There is a product called red guarde, sold at HD. We use it when we pour a cement shower base then tile over it. Check it out. It can B brushed on or rolled and turns to rubber.