American Coach: Basement Rust Repair

[Meames1]

Originally Posted by Maik

Meames1; you answered some of the questions i was thinking to ask you. One answer seams strange; is the way the floor is attached to the uprights/ walls. Tek 5 screws? I did see them on my coach with the floor hanging down, but would have thought they would have bolted the steel in the heavy areas. It seems that the two areas of concern with these coaches is the back wet bay and the forward propane tank bay.

I know I should keep into consideration the time it took to fail from new. But I still do wonder?

No bolts with nuts at all in the basement floor to uprights. Only the self-tapping tek screws. Although, I did double the amount of mine, 6" on center vs the 12" on center A/C used. Primarily because I used 410 stainless steel tek screws vs the original steel and they have a lower shear strength.

[degkop]

Great work!! What gauge steel tubing did you use? Ordering my steel this week to start work on the battery bay (starting small - rest of the basement is just as bad as yours was!!) and just want to be sure. PO replaced a bunch of it with angle iron and C channel, so I am flying blind until I get it all ripped out. Would prefer to have materials on hand before I get too far along.

[Meames1]

Originally Posted by degkop

Great work!! What gauge steel tubing did you use? Ordering my steel this week to start work on the battery bay (starting small - rest of the basement is just as bad as yours was!!) and just want to be sure. PO replaced a bunch of it with angle iron and C channel, so I am flying blind until I get it all ripped out. Would prefer to have materials on hand before I get too far along.

I used all 16 gauge tubing. The original tube was 18 gauge, but my supplier carried the 16 gauge and I think the added weight of the heavier tubing is negligible. Good Luck !

[degkop]

Thank you! Order is placed and looking for a stainless supplier now. Amazing how costly that stuff is.

[degkop]

Meames1, starting work on my battery bay and have come across something that I figured I would ask someone who has done it right. My chassis battery support appears to be welded to the bottom of the floor. Thinking this is a redo done by PO vs. original design. Do you have any photos or notes from your rebuild that would clarify the design intent?

[Meames1]

Originally Posted by degkop

Meames1, starting work on my battery bay and have come across something that I figured I would ask someone who has done it right. My chassis battery support appears to be welded to the bottom of the floor. Thinking this is a redo done by PO vs. original design. Do you have any photos or notes from your rebuild that would clarify the design intent?Attachment 316306
Attachment 316307

You are correct. Someone has welded that, the factory design bolts through the floor through one of the floor frame members.
If you go back to post #98 you'll see the two holes already drilled in the new battery floor frame. Also there is a picture of it bolted in.

[Drewfab]

Originally Posted by degkop

Meames1, starting work on my battery bay and have come across something that I figured I would ask someone who has done it right. My chassis battery support appears to be welded to the bottom of the floor. Thinking this is a redo done by PO vs. original design. Do you have any photos or notes from your rebuild that would clarify the design intent?Attachment 316306
Attachment 316307

I have also done the complete basement replacement similar to Meames1, just never got around to doing a build thread. I did it in all aluminum. I have all my pics in on drop box, send me a PM with your email and I can share them with you. I completely designed the bottom of the RV in 3D CAD and CNC cut all the tubing. If you need any drawings let me know

[degkop]

Wanted to toss out a question to you guys who have repaired their basements over the years. Did you ever consider ABS or some other non-metallic material for the bottom coating? If the aluminum/steel wasn’t a great idea because of the corrosion, rather that going aluminum/aluminum like Drewfab or steel/stainless like Meames1, would steel/abs be as effective as the original if I went with a thick enough abs?

[Dav L]

Originally Posted by degkop

Wanted to toss out a question to you guys who have repaired their basements over the years. Did you ever consider ABS or some other non-metallic material for the bottom coating? If the aluminum/steel wasn’t a great idea because of the corrosion, rather that going aluminum/aluminum like Drewfab or steel/stainless like Meames1, would steel/abs be as effective as the original if I went with a thick enough abs?

I would use the FRP board laminated to plywood. FRP to the bottom side.
I would not use plastic on it's own. The plywood doesn't drop with long term weight applied in hot weather, you can hold a screw in plywood, easy to buy, cheaper, etc. The Plywood also acts to dampen any rock impact damage.

[Drewfab]

Originally Posted by degkop

Wanted to toss out a question to you guys who have repaired their basements over the years. Did you ever consider ABS or some other non-metallic material for the bottom coating? If the aluminum/steel wasn’t a great idea because of the corrosion, rather that going aluminum/aluminum like Drewfab or steel/stainless like Meames1, would steel/abs be as effective as the original if I went with a thick enough abs?

Hard to say. Not sure I'd use plywood/FRP board as mentioned above, the plywood would trap moisture and ply/FRB would be heavy.

I used FRP on the topside of the floor and walls of the inner bulkheads and thats what the original seemed to be.

I used .030 or so aluminum on the bottom. I think some sort of plastic would be a good alternative. I used .060 ABS to make inner fenders, it worked well for that but can be brittle when you bend or drill it. I would worry that it could crack or split if you used it on the underside. A stronger plastic like UHMW or something could work well, just not sure about bonding it to the metal structure and foam insulation.

[degkop]

Bonding the plastic to the steel and being able to support the weight from above was/is my main concern. Drew’s comment about cold/brittleness also has me thinking about thermal expansion of dissimilar materials. I am leaning back to stainless (reluctantly) and rivets.

[Meames1]

Originally Posted by degkop

Bonding the plastic to the steel and being able to support the weight from above was/is my main concern. Drew’s comment about cold/brittleness also has me thinking about thermal expansion of dissimilar materials. I am leaning back to stainless (reluctantly) and rivets.

IMO, stainless is the best option. Drewfab will have no problem with the aluminum he used as he also used aluminum framing. But, for steel I'd stick with S/S. Finally, the original poor design of .010 aluminum sheet glued (vacuum-bonded) to unpainted steel lasts 20-30 years....so, pick your poison.
The other problem is the original panel assembly being vacuum-bonded as a modular unit has better strength than building the panel piece-by-piece and gluing it together. I believe you would want the added strength of a metal bottom more than plastic would allow.

Edit: By the way adding any kind of break to the SS will really help stiffen it if you have the ability or know someone with the equipment. I wrapped my SS around the tubing at the perimeter which really helped stiffen it and hold position better then just relying on the rivets. In hindsight, the only thing I wish I did different was to make the channel I broke in the panels thick enough to also encapsulate the FRP panels at the perimeter. Anyway, rambling now...

[degkop]

Originally Posted by Meames1

IMO, stainless is the best option. Drewfab will have no problem with the aluminum he used as he also used aluminum framing. But, for steel I'd stick with S/S. Finally, the original poor design of .010 aluminum sheet glued (vacuum-bonded) to unpainted steel lasts 20-30 years....so, pick your poison.
The other problem is the original panel assembly being vacuum-bonded as a modular unit has better strength than building the panel piece-by-piece and gluing it together. I believe you would want the added strength of a metal bottom more than plastic would allow.

Edit: By the way adding any kind of break to the SS will really help stiffen it if you have the ability or know someone with the equipment. I wrapped my SS around the tubing at the perimeter which really helped stiffen it and hold position better then just relying on the rivets. In hindsight, the only thing I wish I did different was to make the channel I broke in the panels thick enough to also encapsulate the FRP panels at the perimeter. Anyway, rambling now...

I have been researching homemade brakes and looking at tool rental places to mimic what you did. I trust that by wrapping it around the edges, you didn’t have any problems with the SS thickness pushing out the sides/ends. And by “encapsulate the FRP panels”, you mean that the SS would wrap over top of the FRP? I presume that would reverse your construction process - FRP, insulation, then stainless? I am almost there anyway, as I was intending to wrap the ice and water shield around the steel frame under the stainless, which would require the SS to go on last.

All of this waterproofing makes me want to make everything perforated so it just drains out and dries.

[Meames1]

Originally Posted by degkop

And by “encapsulate the FRP panels”, you mean that the SS would wrap over top of the FRP? I presume that would reverse your construction process - FRP, insulation, then stainless?

Yes, but this is just a picky thing that once I was done I wished I had done. What I did do was add a S/S angle 1/2"x1/2" to go over the FRP edge pop-riveted in place. This way you cannot catch the end of the FRP while loading stuff in the compartments. Actually the pop rivets of these angles are covered by the door frames anyway so they are not even seen.