Smallish rust holes in floors - patch or other? Discuss

[N'om'ad]

OK, so I have finally got my floor up. Generally sound up front with surface rust from soaked ply but the rear is, as usual, worse. I have a couple of small perforations and am wondering whether it's really worth the time/effort/expense of patching them with steel, given that there could be places where it's almost through all over.
I'm planning to XPS insulate the floor, glued down with PL urethane adhesive and wondering about, along with the seat bolt holes, simply sealing off all with a ring/blob of adhesive as I lay the insulation. Another, better, thought is to put a patch of Blueskin or similar over the worst bits to ensure a watertight seal.
At the end of the day, this thing isn't a museum piece or gonna last forever, and just has to provide me somewhere to live for a few years, then maybe someone else for a few years after that.
I'm all for doing a good, proper job but this one, despite the fact that everyone does it, seems questionable. The floor would be plenty solid enough, and watertight, without patching, for years to come.

 

[thrifty1]

Pics? I did extensive rust repairs on my floor but at minimum treat with a converter then paint. I tried different methods and overall to fill the smaller holes a dab of lexel sealant worked best.

 

[N'om'ad]

No pics sorry.. They're kinda standard rusty holes.. At worst, the metal is garbage for about an inch or two square.. and one strip along the back of one wheel well about a 8"-12" long, and about an inch wide..

 

[N'om'ad]

I should add that I still intend to convert rust, prime and paint as normal, not just stick insulation down onto an untouched floor

 

[thrifty1]

I’m in the fix it first boat. At minimum cut out the bad spots, marine grade epoxy new metal in, then seam seal the overlap. No tools required and 100 times better than leaving holes. In my opinion that is

 

[N'om'ad]

That's definitely more appealing a suggestion than welding in.. 'seam seal'?

 

[thrifty1]

https://m.autozone.com/sandpaper-an...ey-dynatron-auto-seam-sealer-caulk/167027_0_0
I used this for the bigger gaps after I welded.

 

[N'om'ad]

Right on.. thanks fella

 

[N'om'ad]

Could I ask why 'marine grade' over regular epoxy - it's not like it's submerged..

 

[thrifty1]

Because I like to overdo things[emoji854]. But really water has an opportunity(even condensation) to make it up under your flooring. You said you’ll be using XPS to mitigate moisture absorption, but if you use an epoxy that’s not moisture protected then that will be the weak point.. blah blah...[emoji6]

 

[N'om'ad]

Aha.. and ha ha!.. I was kinda thinking that the seam sealer would have things covered in case of partial epoxy failure.. in fact I wondered about simply seam-sealed patch panels riveted to floor but that's a fair amount more work with drilling, etc huh?..

 

[thrifty1]

I’ve seen people do just that with success (so far). But we live in a very humid climate, (and have two young kids), so I always plan for the “what if the kid spills his milk in the corner and it gets trapped... etc”

 

[N'om'ad]

Well, that was a slightly disappointingly limited discussion..

 

[EastCoastCB]

https://m.autozone.com/sandpaper-an...ey-dynatron-auto-seam-sealer-caulk/167027_0_0
I used this for the bigger gaps after I welded.

Good stuff- I use it myself.

 

[N'om'ad]

Still not done with this..

What about forgetting epoxy and just using urethane seam sealer/adhesive like this?:

PRO FORM - Products

Given that it's all going to be squashed together under a floor buildup and stuff on top of that I'm not sure I see the need for epoxy. Urethane adhesive has gotta be up to the job of sealing and holding patch plates surely? The stuff sticks like crazy..

 

[Mark_In_MA]

I would use the seam sealer on top of the patches because the floor will move and flex. The steel floor is really just an underlayment/weather protecting layer for the plywood above. Just with all the shakes/rattling/vibrations of driving down the road, I'd rather be SURE the holes are sealed.

I'd rather know that the couple thousand dollars I'm spending on the interior (and just having a weather-sealed rig in general) is as protected as it could be. For a few extra hours and $50 of sealant, knowing it won't leak is worth it to me. I'll trade the overkill for the peace of mind.

 

[N'om'ad]

I agree but I don't understand your suggestion - you'd run a bead along the edge of the patch?

To be clear, I'm suggesting using JUST seam sealer/adhesive - an 'all-in-one' product - to glue down AND seal the patch. A patch that would overlap the hole by at least an inch or two, meaning that there would be an inch or two of adhesive/seam sealer all around any hole and I'd make sure there was enough applied that it was squeezing out of all edges all around so a perimeter bead wouldn't be required.

I can't see that that would be any less solid than a welded patch and, even if it was, would easily last the 10-20 years (absolute max) that I want out of it

 

[thrifty1]

I think it would be fine, only limitation is the degradation of the product you use. 1 year or 10? I would recommend lexel if you go that route. Just make sure it had dried completely because it will eat foam if not cured. It’s sticky as hell but best on the market I’ve found for sealant and flex.

 

[N'om'ad]

The stuff I linked to is an automotive product so I feel assured that it would be suitable and durable.

From the web blurb:

"Recommended for large gap filling and where additional flexibility is required. Use on seams and joints that have a lot of mechanical stress, shock and vibration. Durable and UV resistant"

Sounds like it was designed for the job..

 

[Ninjakitty]

The small.holes should be fine with a patch like you suggested with just seam sealer. Just weigh it down a bit when you place it. The wheel well, you may want some rivets or screws in there, just depends on how bad it is.