Tank bung help!!! Mig welds suck..

[pipehack]

I have an old BSA gas tank that I'm working on . I had to get a weld in bung so I can move the pet **** for clearence issues. My welds either burned though or globed up so bad that I had to grind them down. It looks terrible. Couldn't get any settings right and really don't have any scrap to practice on. I have a home depot auto darkening helmet from lincoln and it seems too dark. I was using a Lincoln 180c with .023 wire and 75/25 gas @25cfm. I'm very discouraged and just about had it. Can't give up because I have too much money in all this. You know what I mean?

[pipehack]

Seriously??/ Why was the word petcock altered?

[zapster]

Seriously??/ Why was the word petcock altered?

Looks like you typed it as 2 words in the orig post....

pet ****...

See?
Yet petcock is OK...

...zap!

[fortyonethirty]

I'd suggest that you just keep welding until there are nothing but high spots and then grind it smooth. Welding different thickness with mig has never turned out very pretty for me.

Also, a flap disk with 80 grit should make grinding a lot easier.

Also also, putting the bung down flush with surface might make it easier to blend.

[PapaLion]

Is the tank stainless by chance? that might explain the difficulty. Try a magnet on it, and see maybe.

Zap> petcock> ok for her to say I guess?:)

[pipehack]

Not stainless. Mounting it flush could be done. This bung has a step on it so it sits in the hole.
this is the one..
http://www.autometer.com/cat_accessoriesdetail.aspx?vid=63

[pistolnoon]

I take it tig wasn't an option.Try on something similiar before the bung, switch back to .024 and use less fill and slow it all down abit to give yourself time to move around otherwise you endup making 3 or 4 welds connected.I've had trouble around round obects.You may wish to take a torch and reflow the weld otherwise leave it alone.

[dave powelson]

Be prepared for some leaks from all that goobering you're doing with the MIG.
The more grinding/welding, the more stress into that tank's skin.

Every start and stop is a potential or real leak point,
plus you apparently have no idea of just 'what' you need to be seeing
with the puddle/what to do/how to do it.

Down the road, you might consider swallowing some pride, getting
another bung and taking the repair to a tigger, who has competent
experience in seal tight welding....or a cracker jack migger.

[Jay O]

You might be better off starting over and either spend some time practicing that exact weld or have someone else do it. Since you have your money already spent might take the time and get it done right. In general I do find it a little humorous that people assume that welds on thinner metals like roll cages, intakes/exhaust and fuel tanks/cells are going to be easy but do require a bit of skill.

[pipehack]

I'm cutting it out... Already made a patch panel. Yes... it will be tig'ed. A little disappointing to say the least.

[PapaLion]

You'll like the result, My bud who TIG welds for a lot of local bikes has some talent and you'd be proud of the results. ? I re-read the first post.... U have an old BSA, kool... might you step back a little and show us the WHOLE keen bike in a few pics?:)
enjoy

[pipehack]

You'll like the result, My bud who TIG welds for a lot of local bikes has some talent and you'd be proud of the results. ? I re-read the first post.... U have an old BSA, kool... might you step back a little and show us the WHOLE keen bike in a few pics?:)
enjoy

Actually it a 73 Triumph engine in a 72 triumph frame with 72 forks and whell. The rear is off a Suzuki the tank is an old BSA. I've had it for about 5 years and used to have a set of Harley fatbobs on it. That wasn't working for me. Needed something different.

[Black Wolf]

I took a quick look at the original product you used - We call them Port Flanges or Tank Flanges up here...

After you have the proper sized hole, so that the shouldered portion passes through, and the rest sits flat on the surface, ONE PASS is all you need to seal that up.

I installed a very similiar Stamped Steel Port Flange onto a Diesel tank last week...

I used a PowerMIg 350MP, .035" ER70S-6 wire, and 18.5Volts & 225 IPM or thereabouts.

I do understand that those settings will be of little help to you, but I will have a look on my Lincoln SP170-T, and see if I can give you something more "In the Ballpark" for the machine that you are using.

You never listed your settings, but if you are "Burning Through" you either have to turn the Voltage DOWN, the Wire Feed UP, or Move FASTER...

[PapaLion]

Kool, sumthin' besides a V-twin... coming along nicely.

[Donald Branscom]

Kool, sumthin' besides a V-twin... coming along nicely.

That tank bung should have been TIG welded. End of story.

A 110 v wire feed in the hands of an expert might have worked.

I sure wish they WOULD make motorcycle gas tanks out of stainless. But that has its problems too because of the way stainless corrodes.

Something different OK..
http://i47.tinypic.com/drcua8.jpg
http://i47.tinypic.com/sbmw4x.jpg
Hand built frame Honda V4 Vf1000R engine.

[pipehack]

I like it!

[DougAustinTX]

[QUOTE=Donald Branscom;396328]That tank bung should have been TIG welded. End of story.

A 110 v wire feed in the hands of an expert might have worked.

I sure wish they WOULD make motorcycle gas tanks out of stainless. But that has its problems too because of the way stainless corrodes.


Donald:
I was a little surprised to read the part of your message that said stainless gas tanks corrode. I have never seen corrosion on a stainless gas tank. Are you referring to some specific application that causes corrosion? I'm not trying to be a smart*ss, just wondering if I have been missing something.
Doug

[gordon stephenson]

Am I wrong in thinking that the original tank would have had brazed petcock fittings,I think thats what I would have used as the preferred method.

[Oldtimer]

Or you could have just brazed it on. Old tech, still works great, low cost.
Nice bike.

[William McCormick Jr]

Believe it or not, Stainless steel will corrode, when you subject it to water, and other contaminants in gasoline. I believe in most cases it will outlast steel several times over. But after fifty years under the right conditions it could spring a leak.

If you did not use backup gas for welds on stainless, and then clean the welds, it could leak as quick as steel.

Stainless is downright funny metal.

Where steel will turn to rust and put up a fight. Stainless steel will allow what looks like worm holes to carry contaminants deep into parts.

Now Chrome Molly lasted a very long time in some Marine applications. I believe it was the Cobia boat company that used Chrome Molly for its sidewall gas tank. The boat was supposed to have flotation in the floors so it was unsinkable. So they put the gas tank in the sidwall of the boat. It held up very well even in salt water.

Republic Steel and Republic Aircraft first invented that stuff from what I know about it. I believe it was labeled and sold as Electrunight steel.

Sincerely,


William McCormick

[Donald Branscom]

I recently welded in a gas tank bung with a 110v Miller wire feed.

Set at 3 and 4.5 for .024 solid wire and 75/25 gas ...Tack first on two sides. Let cool.
Then fully weld. No problem- keep moving.
Tank top was 14 ga.

[goinssr]

May want to back off on your gas flow too. I only run 20 cfh with .035 wire with no problems. With that low of a heat setting and that small of wire 25 cfh sounds a bit breezy.

[pipehack]

It's been a while since I've seen this thread. Working on the bike here and there. I sent the tank out not too long ago so I should be getting it back soon. A couple of things holding up a couple of things and so on. Sometime I think I should have just started all over. Next build ......

[yorkiepap]

Hey p-h,
I do 6-10 tanks a year for a fellow a few miles down the road who builds custom choppers. This year he brought in a couple aluminum tanks that had broken mounting lugs to be re-welded back on. Said the vibration played real he11 on the aluminun tank lugs & he was switching over to steel. A couple weeks later, he brought over (4) new steel ones he fabbed & needed the petcock fittings welded in. I told him because of the thinness of the tanks, the best route was to silver-solder them in. I did one while he was there to show him how easy it was & superb sealing with it. He liked it & said that was how he wanted them done from now on. Worked great for both us. You may want to consider sil-sol.

Denny

[Horseshoe182]

Is that your board track racer in the avatar pipehack?, lets see the pic,s. I like the silver solder idea, nice gentle heat for a very old tank. IMO, mig is to arressive, and a gentler approuch is needed for old stuff. Tig with S,Steel filler is my next option. Very old steel can get contaminated, and that it needs to be ground down to good flesh metal in order to get a good weld run down, And you don,t have the steel thickness for that. You should set up the mig for any welding, on some scarp and not the job!

cheers mick