Rust temp fix until I can repair properly?

[JoshT]

**EDIT 2: Apparently edit 1 wasn't clarification enough. This rust is on the back floor pan of the CAB, not on the tank.**

So started working on my 68 last weekend. First order of business was pulling the gas tank to clean it out in preparation for installing EFI and getting it running. Well found a rust hole (about 2"x3" guestimating) and a bunch of surface I wasn't expecting and am not prepared to fix properly at this time.

*EDIT 1: The rust is on the cab floor under the tank, not on the tank itself.*

I know that the only way to properly fix the rust is to cut out the cancer and weld in new metal. Don't have the skill with a welder to tackle this yet and, even if I did, getting the truck running and road worthy is a higher priority. That said I want to do something to slow the spread and hopefully stop the hole from growing until I have the time and skills to fix it properly. Here's what I'm thinking:

1) Wire brush and grind rust and small area around rust to bare metal
2) Apply rust converter to neutralize what rust I'm unable to remove
3) Prime and paint area to protect it
4) Apply foil tape over hole to close it up

Then reinstall tank and try to forget about it until I can make a more permanent repair.

Actually got a couple of other small holes on the cab that will get the same treatment up near the front of the passenger door. Those are probably where I'll start with the repairs. They are small holes and not much in the way of surface rust around them, so should be easy to learn on.

[sargentrs]

A whole new in cab tank is only $200. Less if you go the Mustang swap to the rear frame rails. I wouldn't bother "fixing" a tank. If there's one spot rusted through, there's another waiting to. You can

[DuckRyder]

If the rust is in the tank agree with sargeantrs.

If on the other hand its the cab floor (or some other part of the truck body) then your scheme should work. If the area is flat, you could also make a sandwich out of some sheet steel and fusor.

[Jacksdad]

Yep - a new or good used gas tank is the way I would go. If it's an in cab tank, you don't want to run the risk of it leaking. Quite apart from the fire risk, the smell would make driving a real chore.

[JoshT]

No, no, the tank is great for its age. This is on the cab floor under the tank, meant to clarify that in the OP. Guess I forgot, will fix that now.

If the tank had rust holes, I'd be replacing/relocating it. Tank was just cudded up from sitting for 12 years with half a tank of old gas, so I removed it to clean. Aside from the crud it's amazingly solid, not even any pin holes. I knew the cab had small amounts of rust, but I thought the floor was solid from crawling around underneath it. Just found this surprise when I got the tank out.

[JoshT]

If the area is flat, you could also make a sandwich out of some sheet steel and fusor.

I considered something like that, but the area isn't quite flat enough. I've got access to some thick foil tape with very good adhesive thanks to my job. It'll conform better to floor shape and come off easier when it's time to make a proper repair.

[Ranchero50]

Replace it. A good side impact that disables you will probably cause the tank to rupture and you'll end up a dead crispy critter because you were too cheap to fix it now.

Not a good return on your investment.

[Jacksdad]

I know I'm going to sound like a broken record, but now is a good time to learn to weld. An old truck with rust issues will empty your bank account of more cash than a cheap MIG welding set up if you're paying someone else to fix it.
There is rarely just one rust hole. You just haven't found the rest yet.

[JoshT]

Replace it. A good side impact that disables you will probably cause the tank to rupture and you'll end up a dead crispy critter because you were too cheap to fix it now.

It's on the cab under the tank, not on the tank. I may not work on cars for a living, but I do work on aircraft for a living. I have a brain, I know how to use it. If tank was bad in any way it would be getting replaced now, I would not be fixing it.

Please people, take the time to read before replying rather than jumping to a conclusion. I mean come on I even put it in bold text to make it stand out.

[JoshT]

I know I'm going to sound like a broken record, but now is a good time to learn to weld. An old truck with rust issues will empty your bank account of more cash than a cheap MIG welding set up if you're paying someone else to fix it.
There is rarely just one rust hole. You just haven't found the rest yet.

No, now is the time to get the truck roadworthy. It's been parked for 12 years and still hasn't moved or started since I started working on it. That means at a minimum getting it to run (EFI system ordered), getting it to stop (most components purchased for front disc conversion), getting new tires and a new windshield installed. With the truck roadworthy I will be able to drive to buy a replacement bed, hood, or inner fender that are too far gone to repair. With a running driving truck I'll be able to go buy a good donor body if I deem this one too far gone.

There isn't just one rust hole. There are lots of rust holes and I know where most all of them are. First thing I did when decided I was going to start fixing it up was to crawl all over and look for rust and other stuff that obviously needed fixing. The hood is gone, the bed is gone, and I'll be better off replacing the passenger inner fender than trying to repair it.

Compared to the rest of the truck the cab is relatively rust free. There are two rust holes near the passenger door and this one under the gas tank. I knew about the two near the door. The one under the gas tank was a surprise because it was hidden by the tank from inside and by the channel that runs side to side underneath the cab between the rear cab mounts.

I'm not paying someone to do anything other than possibly the paint. Money isn't the issue. I have had access to access to MIG welders my entire life, I've just never needed to weld. I will learn to weld and repair these holes myself, but it won't happen until after other things on the truck are sorted. Even then I don't have a place inside to work, so it won't happen when the heat index is above 100 like it has been all week which means October-November at soonest.

The only pictures of the two smaller holes in the cab. I've since cleaned up the inside a lot, but didn't have my camera to take better pics. Didn't get pics of the hole under the tank yet. The one on the cowl panel does not extend into the floor pan. Want to get it treated to stop it from progressing there until I can get to fixing it.

[Ranchero50]

Replace it. A good side impact that disables you will probably cause the tank to rupture and you'll end up a dead crispy critter because you were too cheap to fix it now.

It's on the cab under the tank, not on the tank. I may not work on cars for a living, but I do work on aircraft for a living. I have a brain, I know how to use it. If tank was bad in any way it would be getting replaced now, I would not be fixing it.

Please people, take the time to read before replying rather than jumping to a conclusion. I mean come on I even put it in bold text to make it stand out.

Come on man, have a little faith in humanity. I saw your original edit after posting mine, figured mine was more fun thinking you were going to JB weld the tank back together.

Per the floor, if you have full exhaust I'd just leave it alone until you are ready to repair it. If anything, strip the carpet and boat plugs out and pressure wash the whole thing. Wire brush the loose rust and crud and then hit it with some cheap spray paint. No bondo, no rust converter junk, just leave it alone so you have less stuff to remove or burn through.

If you'r an AC guy, bang the panels out and buzz them in. Personally I take a torch across the floor to flash melt any thin rusty crap back to weldable stock.

[sargentrs]

Sorry, I thought the tank was bad. Just the floor under it? What you said to start with is fine till you you can get around to welding in a patch.

[DuckRyder]

As I’m sure you know the key to slowing down rust is to keep air and water from reaching it.

Some might argue if you are going to use rust converter only remove the flaking stuff so there is something to convert.

That seems an odd spot for rust on the top side of the cab crossmember, have you determined what caused it?

[JoshT]

Come on man, have a little faith in humanity. I saw your original edit after posting mine, figured mine was more fun thinking you were going to JB weld the tank back together.

Just a little frustrated. Thought I was clearer in the original version of first post. Then I thought I made it clearer with edit and next post. Then very next post is someone else thinking that I was talking about patching the tank.

That was made even worse buy the guy at O'Reilly's yesterday. Was considering using a liner/sealer inside the tank. Website showed that they carry Red-kote so I was checking if the store by work carried it, when I didn't see it on the shelf I asked the guy at the register. He suggested the same that thing that you thought I was asking about, except he was suggesting Bondo instead of JB weld. I left the other stuff I was going to get on the counter and left ASAP.

I might consider JB on some hard to find tanks for small pin holes, but only after a thorough cleaning and until I could source a replacement. No pin holes on this one though and new tanks are too easy to get.

If anything, strip the carpet and boat plugs out and pressure wash the whole thing. Wire brush the loose rust and crud and then hit it with some cheap spray paint.

I can see how it looks like carpet in those pics, but it's vinyl and surprisingly intact. What looks like carpet is just the amount of dirt and crap that was on the floor when Dad parked the truck 12 years ago. The boat plug is gone and floor had been well cleaned. Have considered pulling the seat and floor tomorrow to get better access to rusted areas and treat any surface rust trying to form on the floor pans under the vinyl. Just depends on weather and when my EFI kit is ready to be picked up.

If you'r an AC guy, bang the panels out and buzz them in. Personally I take a torch across the floor to flash melt any thin rusty crap back to weldable stock.

I am an AC guy, but unfortunately it's Depot level maintenance on fighter aircraft and I'm on the mechanical side of the operation not the structural/sheet metal side. I can cut, bend and rivet, but we don't bang out panels or weld on this airframe. Mostly flat panels and simple curves. Cracks in skins get stopped drilled and doublers installed, cracks in structural areas gets the structure replaced.

[sargentrs]

I would also suggest going on the underside with a piece of scrap metal or flashing, coated or painted, put a bead of RTV around it and screw it to the bottom with some sheet metal screws or panel bond adhesive. That would keep road water from getting inside.