What Should I seal this floorpan with?

[Supercharged111]

If this is a plow truck, you're doing an excellent job. Most of the plow trucks around here don't even have floor pans... or rockers.... or wheel arches... or bed rails.

I do see the small hole now that you pointed it out. I'd fill it with short strand fiberglass filler. U-Pol Fibral Lite is my favorite one but there are other good ones out there.

Rktpwrd might have a better suggestion but this is how I'd handle it.

That's after the Eastwood Encapsulator and paint go down I assume.

Passenger side is looking better too. I think I need to cut the seam sealer back a smidge farther to the right to make sure I get both ends. Amazon says the Eastwood stuff will take until 16-18 May which I can do, just don't want to. I'll call the local paint shop tomorrow and see what they have in stock. They were closed when I went poking around earlier.

 

[Supercharged111]

Once it is black and dry, just shoot over it. No rinsing is necessary; at least I have personally never bothered and have used the stuff as my go to rust assassin for several decades.



Nick

I found it was pretty gooey and sticky without rinsing, how about you?

Also, check this out. I didn't think today did anything on the driver's side. It always looks all doom and gloom when it's wet.

Yesterday.

Today.

I did it for shjts and giggles, passenger side and finding the leak was really today's goal. Windshield is water tight, the HVAC box not so much. And the radio antenna grommet was just flopping around in the vicinity. Those all correlated with the dirt trails on the firewall, so I feel OK about getting the carpet back in once I'm finished treating the passenger side rust and sealing/painting. And plugging those damn holes in the floor. Best guess on the driver's side is snowy wet feet soaking the carpet and it never drying. There's no evidence of the firewall leaching any moisture inside and the bottom was all white from what I recall.

 

[Rktpwrd]

@Rktpwrd might have a better suggestion but this is how I'd handle it.

You don’t want to ask my suggestion, he won’t like my answer:

😅😅😅

All joking aside, I agree with joesregalproject , short strand fibreglass filler would probably be fine, so long as it’s applied correctly, and to clean, dry steel. Not over gooey stuff, and not over top of paint. Get the treated areas as clean, dry and rock hard as possible. Then profile the surface with an aggressive grit like 36 or coarser, then apply the filler. Because it has a hole that’s also exposed from underneath, that area will have to be made 100% water tight as well or else the filler will just absorb moisture from underneath.

If that happens, you’ll not only be back to square one, but the next time it comes back it’ll be worse because the filler will have absorbed the moisture and held it over a larger area. (The size of the filler you put on).

 

[Supercharged111]

How should I water tight that hole? I was under the impression that the fiberglass was gonna do that.

 

[Rktpwrd]

How should I water tight that hole? I was under the impression that the fiberglass was gonna do that.

My go-to, in case you haven’t already noticed in all my bodywork posts, is always epoxy primer. Once cured, it’s waterproof and non porous like regular primer-surfacers. Then, your choice of paint, followed by a generous coating of undercoat or oil coating, whatever you prefer, should give it a fighting chance.

Bare fibreglass, filler or otherwise, is still porous. It’ll wick up whatever moisture it’s exposed to.

 

[Supercharged111]

My go-to, in case you haven’t already noticed in all my bodywork posts, is always epoxy primer. Once cured, it’s waterproof and non porous like regular primer-surfacers. Then, your choice of paint, followed by a generous coating of undercoat or oil coating, whatever you prefer, should give it a fighting chance.

Bare fibreglass, filler or otherwise, is still porous. It’ll wick up whatever moisture it’s exposed to.

If I throw down an epoxy primer, that hole is still gonna be there to expose the fiberglass to the elements. That's where I'm lost as I thought the fiberglass was to cover the hole, but if it's porous then like you say it'll just wick up the moisture and start the process all over again. Unless I'm supposed to fiberglass the bottom and not the top (derr)?

 

[Rktpwrd]

If I throw down an epoxy primer, that hole is still gonna be there to expose the fiberglass to the elements. That's where I'm lost as I thought the fiberglass was to cover the hole, but if it's porous then like you say it'll just wick up the moisture and start the process all over again. Unless I'm supposed to fiberglass the bottom and not the top (derr)?

Bare metal - short strand fibreglass filler (both sides) - epoxy primer (both sides) - paint (both sides) - undercoating underneath.

 

[Supercharged111]

Bare metal - short strand fibreglass filler (both sides) - epoxy primer (both sides) - paint (both sides) - undercoating underneath.

How thick should I smear it on for this application and how far past the hole should I go?

 

[CopperNick]

The goo just means that the stuff has done its job and due to being generous with the appplication you have some excess left over. Wipe it off and let the panel dry some more.

As far as the holes go, I'm on the Miller side of the bar, literally, 'cause my own rig is a Miller. Not knocking glass because I have used the stuff but found I had to bury it in multiple layers of resin in order to gain some level of waterproofing and then still had to lay on the primer and paint. On balance it is up to you as to how you want to proceed, with time, labor, and cost being some of the factors to consider.



Nick

 

[Supercharged111]

I priced out the filler and primer today and I don't think I want to sink over $100 into this floor, so looking to borrow a cordless angle grinder to lop out a piece from a willing donor at the pull and pay tomorrow. Then get a flange tool which I'll have forever. I don't trust myself to butt weld it together, I think know I'd blow through a lot.