picked up a new welder today because a few friends need some things done and we would like to try to repair some holes in our project 87's fuel tank, plus I've been dying to try my hand at welding. We intend to do some serious flushing and rinsing of the tank before any welding begins and after were done we plan on maybe using a Kreem kit to line the inside of the tank to prevent rust (might do the Kreem, might not). Anyway, anyone have any helpful tips or advise? At my present welding skill level any tips would be greatly helpful.

Now off to Google, "how to weld"....lol

Edit; forgot to mention we will definately be doing some trials before hitting the tank...

[This message has been edited by weloveour86se (edited 11-24-2011).]

This might not help you, but I find it easier to solder the tank then weld it.

Kevin

My $0.02: DON'T WELD A FUEL TANK!!

I know I know it will 'probably be just fine' but we're all entitled to an opinion and that's mine. I'd look into every possible option before turning to welding and that includes buying a used one elsewhere. Soldering... Even looking into non-heat based sealing methods (putties etc.)

If you have not welded before starting on a fuel tank is not advised. Welding on thin metal like a tank is very tricky. You burn holes through very easy. You need to practice on some thin metal to get the voltage and feed set right. If your talking a mig welder it hard to not get pin holes also due to the low temp you have to use to prevent burn through.

quote Originally posted by Lambo nut: This might not help you, but I find it easier to solder the tank then weld it. Kevin

May I ask why you say this? You and the poster after yourself both say to solder it. Typical way for me to learn I guess, after the fact. Hey I'm dying to weld something anyway and we aren't expecting too much longevity out of the tank. I'm just trying to buy some time with the welds till I can set up to build a composite tank, but thats another thread...think Kevlar...

Even "dried out" liquid fuel can hide in the seams. That fuel will vaporize with welding heat. Those vapors are what will hurt you.

1. Tank tank to radiator repair shop and have the thing boiled out before trying to weld.
OR: 2. Hook up regulator and flood tank with inert gas after cleaning and drying tank at home.

I have repaired a tank with both methods. No. 2 is the most exciting. I flooded a very large tank in the bed of a pick up truck and started welding. The gas fumes coming out of the tank about put me out and the neck of the tank caught on fire. My friend who was watching got my attention and I flipped my hood up, saw the fire, and kept on welding. I was pretty sure it wasn't going to blow up. Good times.

JB weld would be safe

Arc welding on a fuel tank as a learning experience is doomed to failure I can tell you with no doubt. A gas welding rig using either brazing or silver will be much more likely to be successful. Solder with a large soldering copper is by far the easiest to patch up small holes. Good luck. Larry

quote Originally posted by weloveour86se: May I ask why you say this?

You sure may.
The metal on the tank is thin enough, and if you have a pin hole leak you can take a screwdriver to it and the hole will end up being the size of a dime at least. Trying to fill this hole back in with weld or patching gets to be tedious because the surrounding metal is still thinner then original. I have a Camaro that the tank had a pin hole in it from the strap area. I poked around to get to the good metal, about the size of a quarter. Flood tank with water three times, then hooked it up to my running 8N ford tractor tailpipe to try to dissipated any left over fumes. Cut me a pices of metal slightly larger then the hole, fluxed the heck out of it, soldered with small propane torch and is still good 6 years later. I would also advise against any of the putty fixes, these have always broke down over time for me. Might hold at first, but don't hold your breath.

Kevin

What type and brand of welder did you get? If you didn't buy yourself a quality brand name welder, do yourself a favor and take it back, spend a few $$ more and get a good one. I went the route of the cheapo HF welder and it was money wasted compared to the Hobart I have now.

I'll 2nd other opinions of don't weld the tank. Thin sheet metal like that, especially rusty will be a nightmare to weld. Big thumbs up for brazing.

Thanks everyone for the great advice. Spoke with a few union welders at the job site today and they all said brazing's the way to go. The holes in our tank would require a patch. The plan was, or is, to cut away the part around the filler tubes and make our own using similar gauge sheet metal. It would be necessary to add our own pieces of metal tubing for the filler lines. Then add our patch. Just have to figure the best way to add that patch.

Once we have the section cut out I think it may be easier to thouroughly flush the tank with dawn and warm water then repeat and repeat. Then we have a Kreem kit i bought for another project, using stage one of the kit will remove all traces of chemicals. Stage two of the kit etches the surface and removes stage ones chemicals. Perhaps we can get it clean enough to safely braze on???

Edit...typo

[This message has been edited by weloveour86se (edited 11-25-2011).]

Make sure your life insurance and health insurance premiums are paid up to date!

Seriously, repaired gas tanks don't usually last long. Not worth all the work.

Kurt

------------------
'86 GT 2.8 4spd, a very slow work in progress, but fun to drive

I welded my 88 tank (broke something with the feed and vent tubes when removing it.

I had no problems, it was really easy to weld the tank as well. I used stainless welding wire as well.

quote Originally posted by Lambo nut: This might not help you, but I find it easier to solder the tank then weld it. Kevin

quote Originally posted by weloveour86se: Spoke with a few union welders at the job site today and they all said brazing's the way to go. The holes in our tank would require a patch.

Brazing need more heat... Near welding heat. Can warp thin metal and cause cracking. Galvanize is Toxic! Galvanize hates weld/braze heat.
Most have good results with solder. Solder need far less heat and Fiero tank has plastic parts inside...
Use Self-tinning flux and Lead Pipe formula or straight lead.
Strip off Galvanize and other rust poof materials! Brass or solder needs to see base metals.
Using a patch? make sure you overlap the two pieces enough.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)

I fixed the tank on my 88 GT last summer. It had couple pin holes at the bottom near a rock chip. We poured water with cloth washing detergent twice and rinsed very well. Then used solder and put a tough epoxy on top just in case. If you have experience I'm sure you can weld it too. But since it is thin you got to be carefull. I see no reason why to scrap a good tank for just couple pin holes. If major rust then yes.

Over the years, I've patched a number of gas tanks quite successfully with regular Bondo. If as you say, you aren't looking for a long term fix, this will hold for many years. Prepare the surface properly.

Ok, i welded my tank with a mig welder and had no problems, here is what you have to do. Drop your tank and let the exhaust of a vehicle run in it for about 20 minutes. The carbon monoxide from the car will neutralize any of the fuel vapors that may be in the tank(assuming that the tank has been emptied of liquid gas) . Once you have welded the tank pour a bit of gas in it and slosh it around to soak up any moisture that the other vehicle may have run into it. Empty that gas out and re-install your tank, you are now finished.

You can weld a gas tank if you simply run your air compressor hose into the tank entire time your welding. especially if you have rinsed it.
The air flow will keep any fumes from building.