Welding a Tank

[bigbadwolf]

Hey All,
The Short: What gage or thickness steel is the gas tank? It's an 83 GS650G.

The Long:

I'm doing a bit of work on a gas tank and am getting ready to remove the bracket that holds on the emblems on my 83 GS650. I like that slick un-gunked up look. I may have to weld the holes shut and was wondering what the thickness of the tank walls are so i can get the settings right on my welder. Is it possible to remove that emblem holder w/out damaging the rest of the tank? I am planning on sealing it later anyway. TIA, DAn

[oldgrumpy]

material tank thickness,,,

hi i,ve got a 1980 gs1000e,,, the material thickness is 3/4 of a mm.....no wonder they suffer from pin holes ,,,,if you are goung to fix itget a good sheet metal worker and TIG, hope this helps you regards oldgrumpy

[Hammered]

its the metric equivilet to about 16ga on the sides but the bottom is heavier. Id say 14ga. Heres the pics of the one Im "redoing".

[1_v8_merc]

What kind of welder?

If it's a small hole, you could get away with using a tiny buzz box.

If you're just using a run-of-the-mill 120v welder, I would use Gas, so you don't burn threw.
If all you have is Flux, set your voltage as low as possible, and increase your wire speed, that way you just Blip or Tack over the hole.


But like I said....depends on what ya got.

Since it's just sheet metal, you can even get away with a propane torch and some filler-metal.

[Tarbash 27]

use a mig with gas with like .023 and just get tiny tacks so you wont blow through. Dont waste your time with the .035 fluxcore. It will make a mess and you will get a bunch of porosity in your tacks and will still leak.

You can try to tig it, but you may be putting to much heat into it.

[bigbadwolf]

Yup, I've got a gasless mig welder I was going to use. Guess I'll just use a propane torch and some lead. That should seal up the holes enough for the coating to do the rest. Thanks for the input fellas.

[bigbadwolf]

How I did it...

Hey all, Well, I bit the bullet and decided to use the welder after all. I hadn't taken the brackets for the emblems off yet and decided to try a different tact from ripping them off. I used my angle grinder to very gingerly cut thru them as close to their mounting point as possible till I could snap them fairly easily, leaving as much metal still intact where its welded in. Unfortunately I decided to try drilling them out first and punched holes in two of the mounting points which needed to be filled.

I have a Craftsman gasless mig welder w/ wire speed controls and a max/min setting for voltage. I bought it I think about 10 years ago and it's still going strong. The recommended setting on the cover of the welder called for minimum voltage and a #4 for wire speed if that means anything to anyone. I started with a couple of small tacks at the weakest part to 1) test the strenth of the metal at the weakest point and 2)make sure the setting was appropriate. It worked pretty well. I went over it once, ground it down and filled in the rest. I repeated about 3x's until I was as satisfied as I could be. I think that the little pin hole that you see in the one pic isn't one that penetrates to the gas tank but we'll see for sure when i go to coat the tank in the next few days. Here are some pics. Sorry they aren't in order. Flame or praise at will.









In terms of removing paint, I'll never used one of those wheels on a drill again. It was messy and time consuming and I didn't really care for the results too much. I think I'll use chemical means next time.
I hope this helps some one in the future!

[chuck hahn]

Now if you have a set of torches, flux over the welds and slop on some silver solder to seal any micro cracks in the welds..youll be glad you did. Also the tank will obviously need coated and that too will help be sure it is 100% sealed peffectly.

[bigbadwolf]

10-4 chuck! Thanks for the tip! I have propane and a map/oxy torch but no acetalyne set up. I'll try plumbing solder. That should do the trick, no?

[chuck hahn]

Doubt if youll achieve enough overall heat..but maybe with the MAPP gas..if it doesnt stick it wont hurt anything. The acetylene will for sure get it right. I did a 750 tank about 4 years ago and i had to flow some silver solder over the patch to seal the micro cracks. Maybe a buddy at a radiator shop could solder over the welds?? In any case, its best to be sure than be sorry later and have the gas eat thru the new paint from the inside out!!!

Plumbing solder will get down in there and seal things. Once youir done, fill the tank with water and let it set a while on a new piece of cardboard. If it leaks the water will stain the cardboard. drain and dry the inside by blowing air in it with the exhaust side of a shop vac for a while.

[bigbadwolf]

Mapp/oxy worked great but we'll know more tomorrow. I've also heard that hair dryers work wonders for drying out tanks. Thanks again for everyone's help. More to come in the exhaust section! Lol

[bigbadwolf]

It was interesting using the mapp/oxy set up. It started to melt the weld slightly and at that point I added in the plumbing solder. It made an alloy of sorts that I thought was kinda cool. But the added bonus is that it's water tight. Next step is sealing. I'd bought the kreem stuf but everyone here seems to dislike it. I was trying to get my bike up for this weekend but since that won't likely happen I'm going to return it and get the POR stuff that seems to be prefered. I"ll post more about that process here when I get to it. One question that I do have is what do you all use to seal up the filler, sender unit and pet cock holes? Steel, plexy, rtv? I tried searching but this appears to be common knowledge that I'm just lacking LOL. Thanks again everyone!

[chuck hahn]

I took a old furnace air duct and made metal plates to cover mine..a good bead of permatex to seal it and thats about it. Once you remove the plates, the permatex will scrape off and you can put it all back together.

[mighty13d]

umm... All you needed to do was remove the emblems and smooth everything over with body filler.......... Seems like you enjoy making headaches for yourself?? I don't mean to be insulting but I almost decided to do that with mine and just filling over them is easiest. You wouldn't have even needed to reseal the tank.


Also, I did have a pinhole in one of my tanks and I welded it. As mentioned before... microcracks in the weld suck. I completely forgot to seal the tank and after about a week it started to seep and ruined my paint I so painstakingly put on.

And don't forget to grind PRIOR to welding too. It looks a little like the area was rust beside the weld and probably in your weld. You do not want to weld over any contaminates on something like a tank, rust especially.

[bigbadwolf]

umm... All you needed to do was remove the emblems and smooth everything over with body filler.......... Seems like you enjoy making headaches for yourself?? I don't mean to be insulting but I almost decided to do that with mine and just filling over them is easiest. You wouldn't have even needed to reseal the tank.


Also, I did have a pinhole in one of my tanks and I welded it. As mentioned before... microcracks in the weld suck. I completely forgot to seal the tank and after about a week it started to seep and ruined my paint I so painstakingly put on.

And don't forget to grind PRIOR to welding too. It looks a little like the area was rust beside the weld and probably in your weld. You do not want to weld over any contaminates on something like a tank, rust especially.

Hey mighty,
As far as the emblem mounts, I was worried that vibration (or what ever) might cause the bodywork over top vibrate off/crack/break etc and about it possibly not lining up. dunno, by eye, it just didn't look like it would be nice and level (not that it matters, being that my skills aren't that great anywayLOL).

As far as the micro cracks etc, I guess I'll just hope for the best. Gonna (maybe) try to seal it this week. Thanks again for the tip.