Floor pan help.

[Evan Dutch]

Today I got a chance to start working on my rear floors in my 1972 dart today. After I cut the majority of the rear drivers floorpan out I noticed the section of floor underneath it. I plan to get the old paint and surface rust off of the pan underneath it. What do I coat it with to prevent the rust from coming back? I also will still need to weld the new pan in, so I am a little weary of coating it with something I don't want to weld over. Thanks.

 

[GeorgeH]

It really looks like you're going to need some patching on the lower before you put the floor down. I spot blasted the lowers part you're talking about in mine , treated with Ospho, then epoxy primed. Drill/ prep the floor pan, lay it in and use a spot drill bit in holes you put in the pan to clean the lower panels. It's a blind area once assembled so you want to minimize bare metal as best as you can. One other suggestion, You don't need to drill slam through, you're only drilling to to remove the upper panel, You're making a bunch of holes that are unnecessary on the inner rockers and such.

 

[dukeboy440]

Today I got a chance to start working on my rear floors in my 1972 dart today. After I cut the majority of the rear drivers floorpan out I noticed the section of floor underneath it. I plan to get the old paint and surface rust off of the pan underneath it. What do I coat it with to prevent the rust from coming back? I also will still need to weld the new pan in, so I am a little weary of coating it with something I don't want to weld over. Thanks.

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I wouldn't waste time costing it, cut that out and replace it, then coat it or at least spray it with an epoxy primer

 

[Evan Dutch]

I bought the amd full front as well as both rear sections, I'd like to put the rear pans in first since the front floor overlaps the rear. Not a fan of having and empty space in between two pieces of metal. Bad things can happen.

 

[Evan Dutch]

It really looks like you're going to need some patching on the lower before you put the floor down. I spot blasted the lowers part you're talking about in mine , treated with Ospho, then epoxy primed. Drill/ prep the floor pan, lay it in and use a spot drill bit in holes you put in the pan to clean the lower panels. It's a blind area once assembled so you want to minimize bare metal as best as you can. One other suggestion, You don't need to drill slam through, you're only drilling to to remove the upper panel, You're making a bunch of holes that are unnecessary on the inner rockers and such.

Yeah, the hole in the rear of the rocker was by mistake. The closest hole on the inner rocker is a piece of metal folded back. There's not really a hole there. Just looks that way.

 

[kiss]

I've seen floor pans way worse than that. You'll be alright. Get as much of the rust off as you can, clean it with something like alcohol or acetone, and coat it with POR-15.
You can then topcoat it if you want but I didn't bother. I used POR-15 on my floor pans over 10 years ago. Still going strong. I filled some small holes by using JB weld and the head of a nail. Grind off the rest of the nail after the JB weld hardens. If you have access to a quality welder that would be a superior option.

 

[Evan Dutch]

I've seen floor pans way worse than that. You'll be alright. Get as much of the rust off as you can, clean it with something like alcohol or acetone, and coat it with POR-15.
You can then topcoat it if you want but I didn't bother. I used POR-15 on my floor pans over 10 years ago. Still going strong. I filled some small holes by using JB weld and the head of a nail. Grind off the rest of the nail after the JB weld hardens. If you have access to a quality welder that would be a superior option.

I've got myself a quality welder. Por15 on the lower section of floor and then weld the new pans in over that?

 

[Evan Dutch]

Anyone have any experience with weld thru primer?