Galvanized or Satin Coating Sheet Metal TIG

Wolvie · Mon Jun 27, 2011 6:01 pm

I everyone. I am new on that fantastic site. I have searched the site but can not find infos on welding that kind of steel. It is named Satin Coating Steel.
I have 1/16 steel sheets, forming drawers. I am trying to Tig weld the sides (overlap & corner styles). I use 11 scfm Argon, number 4-5 cup, 1/16 Cerium electrode and (for now!!!#$%#$%$%$#$) 65 amps. I tried to clean the surfaces with a grinding disk (brand new). But the steel has a tendency to <<burn>> if not melted, making dropplets or bubbles, exploding on the tip of the electrode, etc. Full nightmare. Itried with and without 1/16 mild steel & 1/16 ss rods. I was able at some point to <<tack weld>> but i think that the steel is to thick. Should I use an acid ?

Just don t know what to do anymore. I have a Miller Diversion 180

Help help help. it is for my work.

cheers

Hugo

ogorir · Mon Jun 27, 2011 9:21 pm

if it's galvanized, you'll want to grind back the galvanizing at least 1/2" from your weld areas, if not a full inch. you'll see a noticeable color change when you grind through the zinc. make sure you clean both sides of the sheet, too. also, 16ga (1/16", 0.063") should be fine around 65A, but I'd use a 3/32" electrode for 16ga. it's starting to act more like plate and less like sheet at that thickness, which seems to be harder on tungstens.

Mon Jun 27, 2011 9:26 pm

Yeah, that sounds like zinc contamination to me. Are you getting purple at your arc? TIG is really sensitive to zinc residue in the joint.

A magnet will tell you if the base metal is carbon steel or not.

One of the better ways I've found to remove zinc coatings is with a cutting torch with an oxidizing flame. Keep your distance; you don't need the steel glowing. The zinc will turn to zinc oxide, a white powder. Clean it up with a wire wheel or flap-disk, then hit it with a neutral flame and look for that purple color. If it's gone, you should be clean. If not, lather, rinse, repeat.

If the flame screws up the base metal, you've got some non-ferrous alloy and may be better off brazing or silver-soldering.

Steve

Wolvie · Tue Jun 28, 2011 11:42 am

I thank you both for the info. As soon as I can, I will try both tricks. But none of you have talked about the rods I should use. Or should I only try to melt it down with nothing? I have some gas lenses to...

best regards

Wolvie · Tue Jun 28, 2011 11:43 am

I forgot yes i have purple at my arc...

Tue Jun 28, 2011 3:31 pm

The purple is almost a dead giveaway for galvanizing, so you should be dealing with mild steel. If the magnet test confirms this, I'd use an E70 series rod (mild steel). If that's what you have in the 1/16 size, that should be fine.

Just to cover all the bases, the machine should be set to DC, electrode negative (positive ground). A common shop prank is to swap someone's polarity and see how long it takes him to figure it out.

On light gauge metals, I use a cooling block behind the joint (aluminum, copper, or brass), especially in corner joints. This keeps you from blowing through, overheating and dripping out, and reduces "sugaring" on the back side of the weld.

Steve

Wolvie · Tue Jun 28, 2011 5:59 pm

Great info! So I suppose that I will let go the TIG for my old standard rod machine. Will it need as much cleaning or can I go direct (I know; not the best but faster...). If I understand well, i should buy 1/16 E7018. Can you confirm?

Cheers.

Tue Jun 28, 2011 7:53 pm

16 ga. can be welded with stick (and 7018 1/16 would be the rod of choice), but I find it difficult. Personally, I'd go with TIG.

I was referring to 1/16 TIG rod, such as e70s-02 or e70s-06. You weren't using a rod meant for gas-welding were you? That'll give you trouble.

If you're comfortable with stick, though, there's no harm in trying. You'll still want to clean the metal, but it won't have to be spotless.

The polarity recommendation I gave was for TIG; To stick weld it, of course you'll want DCEP (negative ground).

Do you have access to scraps of the same material for some trial and error/practice?

Steve

Wolvie · Wed Jun 29, 2011 7:40 am

My bad.

I was lost; naturally it was a rod for TIG. Sorry #$%$#@ ! My beast is a Diversion 180 (Miller) so I can't change the polarity.
Last night, I tried 6013; nightmare... Than decided to go with a 1/8 E7018 (i know, just to fat a rod but the only one I had!). Well... it was one of the best result for now; with no cleaning at all (but will clean in the future; the results will be better). So I'll try with 1/8 E7018 today. From the TIG point of view, I tried the spot-weld technic ( 180 A, full throttle); superb results, the best but... to thick. Can not past through the second layer. Saddly. Yes bnow I have scraps... the piece I screwed up!!!!!

Best regards and thanks again for helping. Really appreciate.

Wed Jun 29, 2011 1:25 pm

Ah.

The Diversion 180 in DC mode has the correct polarity already, so disregard my comments about DCEN.

I assume you have another machine for stick welding. (If you're clamping a 7018 in your TIG collet body, your polarity will be wrong, though it'll still weld.)

Glad to hear you're getting better results.

Steve

Wolvie · Thu Jun 30, 2011 7:33 am

Yup. A Miller Thunderbolt XL 225/150 . Love it. Would appreciate a better dial/indicator for having a more precise indication of the amperage but, still love it. I bought some SODEL 31 (1/16) for the galvanized. I will let you know!

Thanks again!

TheExpert · Wed Nov 30, 2011 2:03 am

Satin coat steel is a very light galvanized coating. I don't know how they do it, but I doubt it is dipped. It is probably sprayed on hot.

Ultralow787 · Wed Nov 30, 2011 7:32 pm

Satin coat is nice stuff if you want to paint it afterwards. It paints much better than normal galvanized sheet metal.