delete

 

the car exhaust with a pipe to the tank works, ive done it many times

 

up

 

i'm in for learning this process too.

 

Filling the tank with car exhaust works great...Just plumb it in and weld. That's how we do sumps on stock vehicle gas tanks.

 

Exhaust does the trick.

 

so you are running the exhaust in there as you weld, kinda like a purge setup?

 

I've never had a problem, but it scares the **** out of me every time i strike the first arc on a tank. lol I've done the exhaust thing, but i was also told by a wise old man to flush the tank with Joy dishwashing soap. I usually do that and let water run through it with the soap for about 20 min. I have no idea if it's overkill, but i haven't blown myself up yet.

 

^ what if the car back-fires?

I've been told to use baking soda with the dish washing detergent.

 

I fill the tank with co2 usually, never thought of using the cars exhaust. Going to do that next time. By the way, washing a tank out with soap and water doesnt work. A guy my dad knows did that, went to weld the crack in the tank shut...well...lets just say gas tanks turn into grenades and send shrapnel out when they explode. Hes not as pretty as he once was.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GTibunny16v &raquo;</TD></TR><TR><TD CLASS="quote"> Hes not as pretty as he once was. </TD></TR></TABLE>

lol oh s&$t you are good... not everyone can make a horrendous accident sound funny.

GTibunny16v

 

Just water should work fine, fill it up with water and then weld it.

 

i have a 15 gal cell.
i welded a 10an bung to it like 5 min after draining it from being totally full.
all i did was drain it, flush it with water, the run a strong shop vac through the fill port. the return and vent worked to circulate air in. i also tossed a match in there to make sure it wasnt volitle...hahaha.

im still hot

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by weiRtech &raquo;</TD></TR><TR><TD CLASS="quote">so you are running the exhaust in there as you weld, kinda like a purge setup?</TD></TR></TABLE>

Yeah...Plumb it in, let it fill to displace the oxygen, and keep the car running as you weld. Keep enough of an opening so the exhaust can escape as well so it circulates.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Flashmn &raquo;</TD></TR><TR><TD CLASS="quote">Just water should work fine, fill it up with water and then weld it.
</TD></TR></TABLE>
are you just saying this or have you done it?

please post up real advice that anyone has done because others can and will find this useful to avoid accidents.

 

fill it with water, dump the water out and then weld it. It's the easiest, fastest and most reliable way to purge it of all fumes.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ManBearPig4silly &raquo;</TD></TR><TR><TD CLASS="quote">fill it with water, dump the water out and then weld it. It's the easiest, fastest and most reliable way to purge it of all fumes.

</TD></TR></TABLE>

There ya go, that is all you need to do.

Can't believe some of you guys are actually filling the tanks with exhaust

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ManBearPig4silly &raquo;</TD></TR><TR><TD CLASS="quote">fill it with water, dump the water out and then weld it. It's the easiest, fastest and most reliable way to purge it of all fumes.

</TD></TR></TABLE>

This does not work. Residual gasoline will not necessary be washed out with the water and you still have an explosion hazard. Plus if your tank is steel, the water moisture will cause the inner surface of your welds to rust immediately (hot metal is extremely susceptible to corrosion - think about how quickly exhaust systems rust). Water will also messy up an AL weld - you will have a much more difficult time getting a clean weld with moisture present.

The best solution is definitely purging the tank with welding gas (argon, co2, or whatever) prior to welding. To make sure you have enough inert gas in the tank, light a match or lighter and dip it into the fill cap - if it goes out you're safe to weld.

The car exhaust idea seems like a good poor-mans solution which accomplishes the same thing as above. It seems like more effort then just holding your torch with the gas flowing in the tank for a min or two though.

I ruined a handful of tanks with the water-method suggested, don't make the same mistake.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dave@passenger &raquo;</TD></TR><TR><TD CLASS="quote">

There ya go, that is all you need to do.

Can't believe some of you guys are actually filling the tanks with exhaust </TD></TR></TABLE>

Douche

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Fiero &raquo;</TD></TR><TR><TD CLASS="quote">

This does not work. Residual gasoline will not necessary be washed out with the water and you still have an explosion hazard. Plus if your tank is steel, the water moisture will cause the inner surface of your welds to rust immediately (hot metal is extremely susceptible to corrosion - think about how quickly exhaust systems rust). Water will also messy up an AL weld - you will have a much more difficult time getting a clean weld with moisture present.

The best solution is definitely purging the tank with welding gas (argon, co2, or whatever) prior to welding. To make sure you have enough inert gas in the tank, light a match or lighter and dip it into the fill cap - if it goes out you're safe to weld.

The car exhaust idea seems like a good poor-mans solution which accomplishes the same thing as above. It seems like more effort then just holding your torch with the gas flowing in the tank for a min or two though.

I ruined a handful of tanks with the water-method suggested, don't make the same mistake.

Douche </TD></TR></TABLE>

Actually it does work, I've done it several times. Emptying the tank and than washing it out with water will in fact get all the flamable gas out of it. After you are done the welding cool the tank down and rinse it with diesel or gas a couple of times to get water out and you are good to go.

No need to call names pumpkin

 

DO NOT PUT WATER IN YOUR GAS TANK!!!!!

It will rust out...and you'll have fuel filters being clogged etc. IMO..don't fill it with water. Even if the tank is sloshed...it may start to rush.

If you tank is aluminum... go for it....if its plastic...well you cant be welding it with a tig torch then can you?

 

I have welded on just about every kind of tank that you can put gas in.And on small deals i stick a vacuum cleaner in the biggest hole and let it suck out all the fumes.But on bigger stuff like 5 gals and up i purge it with argon.Also if there is a hole into the tank where you are welding anything but argon wil contaminate the weld.
And i was watching Mythbusters and they tried everything they could do to get a car gas tank to explode and no dice.They even had an a/f meter so they could control the tank to be the best a/f to blow up..And it just lit on fire.And maybe a little WHOOOF but that was it.
I have only heard horror stories of tanks blowing up but have never seen the after math of one.
I do have a funny storie though...I worked at a boat shop called Future marine.And we built stuff for high dollar ski race boats .Anyway i built bad *** trailer for a 21' boat with a 200 gallon alum. gas tank that was shaped like a wing.that was on four legs above the boat for quick filling. Well after a while it got a small leak right in the middle where a baffle worked a crack .I drained it and washed it out with engine cleaner and water real good and purged it with argon for about half an hour before i started welding on it.Anyway here is the funny part ..Everybody at the shop was scared to death it was gonna blow up so i told everyone to go out front of the shop.When everybody was out front I lit off an acet. bomb in a half gal milk carton that was loud as a mother [freak]ker.And man did they shiit .LOL

 

LOL that is hilarious.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by -RedneckDave- &raquo;</TD></TR><TR><TD CLASS="quote">LOL that is hilarious.</TD></TR></TABLE>

+1, I'm gonna have to try that some time.

 

I've used water and never had a problem on fuel lines or tanks. :shrugs: Learned the trick from a coworker who welded on tanks of some sort. Can't remember what they held but it was explosive.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Flashmn &raquo;</TD></TR><TR><TD CLASS="quote">Just water should work fine, fill it up with water and then weld it.
</TD></TR></TABLE>

Thats what I do with no cap on the tank.
There is also a product out there that claims to clean the tanks good enough for welding but I dont remember the name.
I let the tanks air out and self dry then just fill with water