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How to repair rust pin hole and cracks in floor?

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Re: How to repair rust pin hole and cracks in floo

All good inputs, and they could be difficult to implement.
At least 2 if not more of the seat track nut area's are not in an area clear of obstructions to allow easy welding on the underneath side.
The frame is very close to the rear outside ones, so depending on where the crack propagates from and to would determine if you can even weld the patch all the way around. If one is going to weld or braze to repair for a small crack, this could be done by using a steel washer. A corresponding washer may be needed under each of the other bolts holes to maintain the seat being level. But the ease of the repair is greatly facilitated.
Other areas of pin holes run into the same problem in regards to welding on the underneath of the floor pans.
You also run into the problem of burning off any paint or coating or even having undercoat catch a fire on the bottom side when welding from the top side. You would need to clean and re-coat those area's with something or they will be prime candidates for rust and starting the problem all over again. This could put a treatment such as POR15 and glass as the best method. At least until the day the body is removed.
FWIW
 
Re: How to repair rust pin hole and cracks in floo

Forgot to mention but for a crack to stop cracking, drill a small hole at both ends. Whether or not you use weld or resin, you'll need to do this.
 
Re: How to repair rust pin hole and cracks in floo

PeterK said:
Forgot to mention but for a crack to stop cracking, drill a small hole at both ends. Whether or not you use weld or resin, you'll need to do this.
Click to expand...
I don't know squat about welding but I like Peter's idea.
I think I might try the glass idea for my situation. I want to get this thing on the road after being cooped up the the shop for 10 years. Glass the floors and drive for a couple of years to stock away the capital for the body off.
 
Re: How to repair rust pin hole and cracks in floo

Thanks everyone! You totally sold me on the POR-15 and glass, given the relatively good condition of the floor.

Picked up some POR-15 for the chassis as well, since the reviews here have been so good. Then chassis black top coat since the POR-15 is not UV stable and gets chalky with UV exposure. Also going to POR-15 the block with silver POR-15, and then go over it with their aluminum-colored top coat for engines. Should look nice!

--> Can anyone confirm POR-15 works well on the block?

I will attempt to weld the small cracks at the rear seat mount. Thanks for the tip of drilling a hole at either end of the crack--I've done that in glass but wasn't sure if it applied in metal. Still leery of blowing through the metal, but there is a metal plate welded directly below the cracks, so might be OK on this one. Ugh--need to practice before I touch it!

--> Any of you in Davis, CA, or Sacramento and know how to weld thin metal? I'll buy you a beer if you come by and show me how it's done! (that is, weld it for me, and I can be practicing in the corner on and old garbage can...)
 
Re: How to repair rust pin hole and cracks in floo

I painted a block with POR glossy black and it looked very good and no problems with the heat.
Mix the stuff well but don't shake the cans, stir it until it's even. It spreads easily and levels itself so if you're careful it looks sprayed on.
I didn't prep the block well, wiped the oil/dirt off as best I could and painted, it stuck anyway so you shouldn't have any problems.
Good luck and I agree about welding the stress crack, I wouldn't paint/glass that area.
 
Re: How to repair rust pin hole and cracks in floo

Quick update:

- I got a MIG welder (flux core) at Harbor Freight for $120, practiced on some 22ga sheet, then welded the cracks in the floor around the rear seat mounting points. Just welded from above. Very tricky for a novice welder to weld that thin metal, but there was effectively some metal backing with the small piece of sheet to which the nut is welded. I did blow through on part of the crack beyond that metal backing, but managed to fix it pretty easily with a very small patch (5mm by 5mm or so). Overall, could not be happier with the repair, and excuse to get a welder for future repairs!

- Since there is only one pin hole in the floor, I decided to use POR Putty (epoxy putty) to fill the rust pits in the floor instead of fiberglass. I just don't need that much reinforcement, and the putty should look better. Going out to try that now... I'll post results.

Thanks!
 
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