Advice Needed: Sealing '65 Hollow A-Frame Ends

[KristinS]

We just finished painting the frame of our '65 Overlander in preparation for a new subfloor, and as I was painting I noticed that water has been getting into our trailer through the open ends of the a-frame under the coupler. The beams are hollow and open to the elements where they meet under the coupler (our trailer wiring ran through one of them).

I'm guessing that while towing in the rain or just parked in wet weather as ours has been, water can get inside of them and flow into the belly of the trailer. This seems like a huge design flaw, and could undermine all our hard work to keep water, rodents and insects out of there.

The question is, can we seal these ends up somehow, and do we seal just the outside ends at the coupler, or both ends? Does the interior of the beam need to breathe, or will that plus any moisture trapped in the belly promote more rust?

What's the best way to seal it? We didn't want to take the coupler off but we can if we have to weld. Would spray foam work well enough if we reapplied it periodically?

I know that Colin and others who have the space and equipment typically pour rust inhibitor into the hollow a-frames and rotisserie the frame so the inside is well coated. We couldn't do this since we were limited to a shell-on restoration. I painted as far into each end as I could reach, but will just have to hope that not letting more water in will halt any futher rust. We want the trailer to last us 10+ years of full-timing, so we're trying to do everything right the first time.

Thanks in advance for any help! We've been doing well so far with finding help here, but some things like this are way out of our area of expertise!

[Protagonist]

Rather than sealing the frame, wouldn't it be better to drill small drain holes instead, so the water can run out before it gets to your trailer's belly pan?

Drill the drain holes close to where the frame meets the trailer skin, so the frame drains when tilted up (through the drain holes) or tilted down (through the open front end of the frame). Then, when the trailer is in storage, instead of completely leveling it, store it with the front end tilted slightly down, just enough to ensure that any water that gets into the frame drains away from the trailer's belly pan, not toward it.

If you're worried about weakening the frame where you drill the drain holes, you can weld thick washers to the bottom of the frame where you intend to drill (fillet weld, all around, inside and outside the washer) as a doubler plate, then drill through the hole in the washer.

[KristinS]

That's an idea, thanks for the suggestion. I guess I'm as worried about water getting in the a-frame at all as I am about it making it to the belly pan, though? If we keep letting it in there and can't paint the steel to resist rust, won't it keep rusting, even with somewhere to drain?

Maybe we could put some chassis paint on a wadded up rag wrapped around a paint stirrer or something and try to get a coating on at least part of it, but it'll never be as good as really coating the inside.

We're full-timing in our trailer someday, so it'll never be covered or in storage. I just worry about that constant exposure to the elements, bugs and rodents.

Not saying it's not what we'll have to do, but I don't want to drill holes and seal up my trailer belly without exploring all my options first!

[reinergirl]

This is what Colin did to cap mine...post 91

http://www.airforums.com/forums/f109...-78136-10.html

[KristinS]

Thanks, reinergirl! I thought about calling him and asking but I feel bad harassing him too much and only being able to buy a couple axles in return. I sure wish we lived closer to him and could have him do it!

I wonder if metal caps could just be put on with Vulkem instead of welding. We don't have welding skills or equipment and I really didn't want to have to remove our coupler just to seal those up. We'd have to re-seal them periodically, but it sure would save us a lot of time and money. Hmm.

[Seymour1971]

Have you considered expanding foam. This is what I used. Working well at keeping water and pests out.

[KristinS]

Seymour - We did consider that, actually. I was wondering how well it would hold up and I'm glad to hear you had success. What type did you use, just the stuff in a can from the hardware stores?

[Argosy Heir]

I am in the process of my Argosy renovation and was also concerned about rust inside the frame channel. I drilled a 3/16 hole at the end of the frame to let out any water. After allowing it to dry after flushing out the voids, I applied this Eastwood product. Seemed to be the only solution available. Hope this helps.

http://www.eastwood.com/internal-fra...ay-nozzle.html

[alumascoupe]

I had a carpenter Ant infestation (they were doing a great job of removing wet/rotten wood ! ) I sprayed all my tires with insecticide and found they were climbing the Jack then using the open ends of the frame as a Super Highway into the belly pan and subsequently the whole trailer, plug those holes even if you do drill some drain holes, I also found a completely mummified chipmunk (minus the linen strips of course !) that I'm fairly sure entered the trailer through the frame holes. Depending where you live, all kinds of stuff can get in there.

[KristinS]

Thanks, Argosy Heir! That's exactly what I was looking for since I couldn't get paint inside there. I think we'll end up sealing the frame with spray foam or metal caps, but I'd like to apply something like that to try to encapsulate the rust first.

Alumascoupe - Thanks for the tip! When we opened our belly we found a ton of infestations as well. I recently worked for a pest control chemicals company, and we carried a stainless steel mesh with very tiny holes that's used in foundations of homes to prevent termites from entering around floor penetrations. It's called TermiMesh. We're going to use it over as many holes in the frame and belly as we can. It should give us a lot more protection than the sad excuse for a pest screen that was over our refrigerator floor vent before--you could fit your pinkie finger in the gaps!

We're also going to treat our subfloor with a liquid product called PenaShield before installing it. It's a borate-based, natural wood preservative, fungicide and insecticide. It kills and prevents termites and carpenter ants and offers years of residual protection. It may be overkill, but if we're going to be living in this trailer for a long time I want to take every precaution we can!

[polarlyse]

Just a suggestion from a different direction. In the automobile restoration world they use spray products for rust prevention. There is a catalogue company named Eastwood that will carry all these products. Look for one with a long extension wand that you can reach down into those exposed frame members and give a good spray. Water will get down into these voids, you can bet on that, but letting the air flow freely will also dry them out. I would not advise trying to seal them up and block the air flow. Prevent the corrosion and let it evaporate.

PS: If you have carpenter ants you have other issues, specifically leaks. Correct the issues then evict the ants.

Good luck whichever route you choose.

[KristinS]

Thanks, Roger! That's a great solution, I'm going to pick some up and try it.

Ordinarily I wouldn't seal the ends either, but unlike a car frame that's separated from the interior, these hollow beams start under the coupler and terminate inside the belly of the trailer, directly under the floor. I'm worried that water draining under the plywood subfloor will rot it from underneath, and that it will also be a great entry point for insects and rodents to spread into our bellypan and make their way into the trailer through plumbing openings and such. I could seal just the end of it in the belly, but then I still worry about bugs and rodents nesting in the beams and causing us issues when we hitch up. I don't really want to deal with a nest of stinging insects deep in our trailer tongue!

[Silverflames]

I have been kicking around the same idea. I think I will be making caps out of aluminan flashing, and then riteving them over the ends with SS rivets. Adding in Spray Foam would be a good idea.

[polarlyse]

I'm having difficulty picturing this. I thought that the frame rails ran front to rear. I didn't think that they would dead end in an opening into the belly pan. Now that you mention this and I think about it, yes I guess they could / should be sealed. But I still go with the thought of spraying some moisture inhibitor down there first. We all know that moisture will get in there. Either directly or by condensation so putting a layer of something could only help. In a perfect world there's all sorts of stuff that could / should have been done during fabrication that would work nicely. Butttttt....... . Now we need to work with what we got. Someday I would like to open up the belly of ours and see what's down there. Sooner would be best since I know it's had an easy life with indoor storage until now. Maybe one of these days I will take on that project. But not right now.

Good luck with whichever route you take with yours.

[Colin H]

Originally Posted by KristinS

Thanks, reinergirl! I thought about calling him and asking but I feel bad harassing him too much and only being able to buy a couple axles in return. I sure wish we lived closer to him and could have him do it!

I wonder if metal caps could just be put on with Vulkem instead of welding. We don't have welding skills or equipment and I really didn't want to have to remove our coupler just to seal those up. We'd have to re-seal them periodically, but it sure would save us a lot of time and money. Hmm.

I have also tacked 1/16" steel caps on the ends of the rails without having to remove the coupler. Then just seal up the remaining gaps with vulkem. Shelly's Overlander has a "C" channel frame that is "boxed" from under the front floor area & up to the front of the "A" frame. The rear of the "boxing" is open so it can breath. The main goal is to stop water from getting in the front of the A frame, along with any sort of vermin.
You should also create a full rear crossmember & weld it completely to the frame rails. This should stop vermin from entering from the rear. The next spot is to seal the wheel wells really well & make sure your dump valve protrusion is as tight as possible. Perhaps vulkem that gap too.
Have fun,
Colin

[KristinS]

Thanks, Colin! I think we'll be doing exactly what you recommended, and probably spray some rust encapsulating paint in first if we can find the one with the long applicator that others recommended.

I figured it needed to breathe, so we'll leave it open under the floor but seal it under the coupler. I'll do insect mesh on the interior end too, just to be safe.

You should have bumper stickers or shirts made that say "When in doubt, Vulkem". It would be a great inside joke for Airstreamers.

For now I sadly have to wait for her to thaw. We had our first "big" snowstorm in Knoxville in several years. Last weekend it was 70 degrees and we were painting the frame! Looks like I'm painting plaques and doing fiberglass repair this weekend.

[RestoWarrior]

Originally Posted by Silverflames

I have been kicking around the same idea. I think I will be making caps out of aluminan flashing, and then riteving them over the ends with SS rivets. Adding in Spray Foam would be a good idea.

Spray foam holds moisture. Would be better to just seal in the patch piece. ??

[Colin H]

Originally Posted by RestoWarrior

Spray foam holds moisture. Would be better to just seal in the patch piece. ??

In 1968, Airstream used spray foam under the floor, & it was a nightmare. The floors rotted & the frame rails in the area of rot were typically very rusty. The foam holds the water against the underside of the floor.
We removed the floor from one trailer, & after my staff pulled up the first panel, they came running out of the door. There was an infestation of carpenter ants living on the foam & munching away on the plywood. We have seen a lot of "treasures" in bellypans, but this time the underside of the floor was "boiling" with ants.
On another trailer we discovered a hollowed out cave that was likely a squirrel nest, or perhaps rats, we're not sure.
Moral, spray foam has it's uses, but applying it near steel or wood in an Airstream is a "no no"
Thanks,
Colin

[Wabbiteer]

So it was factory foam? I was invited to see a project nearby where he'd found the rear half of the frame of a '68 either disappeared or hideously maimed - rust covered foam w/ no/low metal remaining. Seeing an older gentleman near tears sure made an impression...

[Colin H]

[QUOTE=Wabbiteer;1250811]So it was factory foam?



yup.
Colin