Having trouble welding wood burner

[gordon stephenson]

I'm in the process of making my first gas bottle wood burner, and despite grinding welding area bright it's welding like pure crap,Loads of spatter and even a little white fur and fume just like galv,and does to want to form a nice weld bead at all,sometimes start an arc and the wire immediately burns back to the tip,Thought maybe the Kemppi 190 had gone bad on me, but tried on mild steel and runs excellent as usual, this has me a little (a lot) puzzled as everything should be OK,ground bright,argon flow OK,welder settings checked, not draughty,
Do you think the galv will have penetrated the metal to a certain extent and needs more grinding, Just that in all the threads i"v read on making gas bottle wood burners nobody has mentioned difficulty in welding
Thanks Gordon.

 

[Drains]

Not aluminium is it Gordon? I've never see galv on a gas bottle (nor ally, TBH).

Jammy - I thought it was going to be a joke thread...

 

[gordon stephenson]

Deffinitely not aluminium, nice sparks when grinding, cuts nice with 0.8mm disc and plasma worked fine as well.Just does not want to mig,I wonder if they made any bottles aluminised like the coating on some exhausts

 

[Dobcrosslion]

I had a similar issue with a calor bottle that I chopped up to make a bbq. I was gas welding some hinges on, and the fumes were murder. ( this was after cleaning all the paint off ) So I got a flap disc on the old grinder and had at it. Sure enough, there was a thin coating on the bottle, under a very thick coating of paint.

 

[Jammy James]

sorry i didnt read the type of shielding gas used and flow.

 

[knoba]

I had exactly the same trouble with a burner I made, Gordon. There were sometimes blues, greens and whites in the weld arc. The arc was more "flarey" too. The freshly cut surfaces, of the off-cuts would not rust after being left outside for months. The metal felt soft when grinding & cutting.

The burner was used "a lot" and never took a coat of uht paint properly (it just shrugged it off). I used a m/s 1/4" top plate & starter motor casing (for the flue elbow), they rusted like mad!

http://www.mig-welding.co.uk/forum/showthread.php?p=84346#post84346

On a plus note, it never leaked, fell apart, corroded or rusted, even when red hot!

 

[gordon stephenson]

Hello. Knoba.
Sounds exactly like the same problem, very "flarey" and quite often mig crackle/sizzle changed to just a hiss,Hope this is a one off as I was planning on making a couple more.I'm going to try grinding the metal even more before(attempted) welding resumes.
Would be grateful if somebody knows how best to overcome my problem.

 

[knoba]

I was not overly happy with any of the welds on the bottle metal. I got lovely beads on the m/s parts. The stainless flue... well, that's another story.

Take the metal to a scrap yard (that has a hand-held x-ray fluorescence spectrometer)?

Try another bottle?

 

[shenion]

Sounds like the metal may have lead in it. Lead can be used to help the metal machine or form. Acts like a lubricant.

Makes it hard to weld. I have used some 12L14 metal in the lathe as it machines nicely but does not weld well. Arc works better on this type of metal.

 

[gavuk]

I've found the bottles have a good coating of galv,grind it more Gordon,think I used a grinding disc rather than a flap disk

 

[knoba]

Funny you say that, shenion. When I think back to how the metal felt, when being cut by hand & filed, that's the one alloying metal it most reminded me of. It would have machined beautifully.

nb. I had 3 blue bottles to choose from (for my burner build). The other two had elongated holes in the bottom pedestal ring. The one I choose had round holes in it. Don't know if that's significant...

 

[Shox Dr]

Built a Blast pot out of one a while back, the galv is very thick. Try grinding it more

 

[the snooper]

as gavuk states it will be galv all you have to do is give it a good clean with a grinding disc to remove the galv i had no problem at all

 

[gordon stephenson]

Thanks guys, will hit it some more with a 40grit flap disk and try again,

 

[the snooper]

dont bother with the flap disc they just arnt upto the job use a grinding disc then if you want a better look tidy it up afterwards with a flap disc

 

[gavuk]

I agree with Snoop,not the right job for a flap disc,try a grinding disc

 

[gordon stephenson]

Hi, Guys,
Thanks for the response, It did turn out to be galvanised, quite a thick coating and the base metal was very pitted and zinc embedded in every one. Almost like millions of deep little pores.Never seen anything like it.
What is it that effects the arc so much with tiny mounts of zinc stuck in the pores?
Thanks again, Gordon.

 

[shenion]

The zinc melts at a low temperature. When you weld over it, it boils violently and vaporizes because of the high heat of welding.

 

[gordon stephenson]

I,v never seen such deeply pitted metal galvanised before,

 

[Drains]

Might it have been heavily shot blasted before galving?