spot weld a new floor in a '69 GMC? and a few welding Q's

[thejed72]

This is my first post so be gentle...

I did a search on others replacing, so I get the basics of all involved, but I still have a few questions.


My floor is SHOT. I have a place down the road selling complete floors for cheaper than a few of the venders, and better yet, there's no shipping on it. I'm thinking of just cutting out the whole thing and starting fresh. The edges are rotted 6-8" inside the doors, and what's good is pitted and rough underneath. No through rust in the center, but the floor/cab supports are rusted out on the outer edges, cab corners and rockers are gone. Kick panels are rotted at the bottom 1-2" both sides, and the driver's is a little rotted a little into the firewall, but not much. The cab has more rot that can be patched, and we'd like to keep this cab. Plus, we're East Coasters, so I can't imagine in central PA finding much better. My question is this, when you guys are replacing entire floors are you just plug welding, welding or ??? I have access to a spot welder and my welding skills are minimal., but willing to learn. I know these things were all spot welded originally so... Advice. I know things like the kick panels will need welding and the firewall, but can the majority of it be spot welded in? Also, any cheap welding suggestions? I know it's harder, but can you arc weld this stuff in? Planning on doing the floors, rockers, cab corners, kick panels, and a few minor patches.

BTW, '69 GMC short step half ton with a sixer.

Sorry for the long post.

[Shyguy]

Don't think an arc welder would work. My son uses a wire feed welder with the flux in the center.

He spot welds stuff in then goes back and fills in between the spot welds. It is done this way to prevent warping. I am sure others that have done a lot of welding will chime in.

I have heard of people buying welders at Harbor Frieght, but I bought mine at Northern Tool.

Replacing the whole floor is a great idea, my son ended up replacing most of the floor in the truck he restored for his wife on piece at a time. It was pretty time consuming, but came out ok.

[gcburdic]

first off thejed.... to the boards....

check out this build....they replaced the floor and the firewall.....http://67-72chevytrucks.com/vboard/s...d.php?t=317665

[Sinister]

MIG welder with .023 wire and C25 Argon/CO2 mix would be your best bet. Tiny tack welds spaced apart then you gradually fill them in until the whole panel is welded in.

[haysonj]

I bought a Lincoln Mig and used the 035 flux core wire with no gas. I used an old tail gate and taught myself to weld then replaced the rockers and one cab corner. I paid $800 for the welder and then sold it for $500 when I was done so it only cost me $300 plus parts to fix my cab. I also boxed part of my frame and welded the patch with a fuel door into the bedside. the Lincoln welder is much more user friendly and I found it fairly easy to learn with. Like Sinister said I put a spot every 2 inches and then kept going back until it was all filled in.

[thejed72]

Thanks for the welcome and the advice. I'll keep everyone posted on the project as it progresses.

[GASoline71]

Originally Posted by Sinister

MIG welder with .023 wire and C25 Argon/CO2 mix would be your best bet. Tiny tack welds spaced apart then you gradually fill them in until the whole panel is welded in.

Yep... I do it with .025 wire as well.

Gary

[Rooster's 67]

you will probably want to use GMAW(Gas Metal Arc Welding) which is commonly refered to as MIG (or MAG the other subtype of GMAW) using .023-.025 solid wire with C25 Argon/CO2 bimix gas. using self-shielding fluxcore wire wont require a welder capable of using gas(cheaper inital welder investment) but will require chipping and brushing of the slag produced. using solidwire and shielding gas produces a cleaner weld bead.
good luck.

[stsalvage]

first off I take my hat off to any one doing the floor in one of them trucks.Major respect.One last thing Make sure you weld bars in to keep the cab from flexing.Cus if you don't you will have a floor that will go ever which way but loose.I love that movie with Clint Eastwood too bad you can't find another truck cab in a barn

[Ron 586]

First Welcome to the site. Now go to the projects thread and you can learn a lot about what to do and not to do. Don't rush, take time to do it right the first time