prepping gas tank for cutting/welding
 

im about to cut open my tank to weld in a sump cup and convert to intank efi pump. curious what methods you guys have used to prevent explosions and death? ive already washed my tank 3x with soap and water, i cant smell gas in it anymore but im still concerned. has anyone tried the dry ice co2 trick? i know i can use argon but was kinda looking for alternatives.

this is kind of dangerous!
I heard of pumping in Car exhaust to create C02 s that the tank won't explode.I do not know if it works though.
I worked with a guy that attempted a FIX..he was sent 30 feet back in the air and got 2 months off work.it exploded n his face and he is lucky to be alive..but he had no "brain"..lol,,so no pain..(you could hit that guy with a hammer and he wouldn't flinch!)

On a gas tank or two that I have welded in the past for rust repair/patches, I filled them with water first; to just below the repair area. If your working on the bottom of the tank, just turn it so the work area is on top, then fill with water and weld.

Legal Disclaimer: I'm not responsible in any way, shape, or form if you still manage to blow yourself up.

When I did mine I washed it out with water and marine clean (a por15 product) 3 times, let it sit in the sun to dry quite a while (several days) and then washed it out again just to make sure. I did another tank a few years later using the same method and had no issues both times.

I should also mention though, that in both cases, the tanks had been out of the car for several months and were empty that whole time, so they were pretty well aired out.

If in doubt, wash it a few more times, but I'm sure you'll be fine if you can't smell anything. I'll admit though, both times when I started my first cut i was shielding my face lol. Once the first sparks hit and you don't have a fire you're pretty much good to go....

im using a similar industrial cleaner to clean the tank, has anyone heard of using dry ice to create co2 inside the tank? im thinking of filling it with water and throwing some dry ice in there when i make the cut.

I've welded dozens of gas tanks, and I'm a certified welder. It's not that dangerous if done properly. You've washed it out three times. Now go turn the hose on and let it flush out for about 6 hours. Then go to town. Any residual vapor that you cannot smell wont be enough to cause anything to happen. Don't cap any holes on the tank, and make sure the pick up is out. Cut with a cutoff wheel.


And be sure to pressure check and spray with soapy water after you're done welding to ensure no leaks.

Pay somebody else to do it. :icon_tup:

Don't bother, just flush it out for a while like Twilightoptics said and you'll be fine.

I have always rinsed well, flushed with soapy water, rinsed again, and started cutting.


Isaac

HELL NO! haha, no one else will ever put their hands on my car or any part of it.

thanks for all the ideas guys! im just being over cautious just in case. I will start cutting tonight!

well im not dead or injured so i must have done something right! thanks for all the info guys.

I have welded gas/fuel tanks in 3 different ways.

1) filled tank full of the same fuel/gas that was in it. If you do it this you have to have it compleatly full, as in no air. The fumes are what ignight not the fluid.

2) empty tank fill with water compleatly.

3) run exaust fumes in the tank from another automobile.

A philosophy I generally follow, but there are some things it makes no sense to do or tool up for myself.

Machining brake rotors, for one example. Most press-work I will pay to have done. Hot-tanking, some plating, end-housing lapping, stuff like that gets farmed out for practical reasons.

Welding, as I currently don't have welding equipment, is on that list. & I'm explosion adverse, having been blown up once.

Glad it worked out for ya, though. :nod:

^DD you really need to get a welder. You do such meticulous work I'd love to see what you'd come up with if you could weld lol

highnitro12187 - glad it worked out for you!

Why not just use a gsl=se tank?

because he wants an in tank setup. an external SE pump with the SE tank would be just fine i'm sure, but maybe he's going for a different approach.

SE tanks are getting hard to find for one, and with them you still have a external pump.

Modding the tank to use an in-tank setup from an FC makes it nice and simple (and quiet too)

I can weld... or at least I used to be able to.

I took three semesters of metalworking in a very-well-equipped metal shop in high school. Learned milling & lathework, forging, aluminum sand-casting, gas, mig, tig, & arc welding. Made some cool projects, including a gyroscope and a working model airplane engine.

Granted, it was a long while ago...seeing as I graduated HS the same year my -7 was built. :egrin:

plus getting a gsl-se tank is more expensive than modding the stock tank, its actually pretty easy to mod it and i feel its better in the long run. plus i get to make a custom sump cup to suit my needs.

could you post a few pics for reference?

I bought a SE parts car. Good luck finding a tank in good shape for a reasonable price. This one needs to be boiled and coated which will cost more than modding the tank I have which I know is clean. Also, the pickup is nasty and I don't even know if it's what it's supposed to look like. I used the steam cleaner at work as best I could and the tank still rattles with varnish and crap.

Anyone have a link to a decent write up on making the FC setup work? I've always preferred an in-tank setup anyways.

There are several write-ups around, I did it a little differently, click on my FB build and there are some pretty good pics of an fc slosh cup/pump hanger in an FB tank.

Isaac

Love your pictures and details! I'm seriously thinking about building an adapter plate like that and run MS on my 12a. I have all the parts and a TII s4 and s5 manifold! Looks like if you can weld the FC pickup is the way to go.

here is my first prototype sump cup, im going to test it with sloshing water a bit and either rock it or redesign.

http://i295.photobucket.com/albums/m...d/P7080197.jpg

http://i295.photobucket.com/albums/m...d/P7080198.jpg