newbie seeks advice: welding 24ga galvanized

I did a googlegroups search and came up empty.
I have the need to weld some 24 gauge galvanized steel.
I know that the fumes are toxic, and I should do it outside on a windy
day. Would a buzz box be the best bet for this task? I don't want to solder this much galv together.
I don't own any welder as of yet. Any suggestions are welcome. Feel free to post your response, or email me but watchout for the anti-spam in the return address.
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On Tue, 25 Nov 2003 15:48:34 -0500, Sam Shank

No chance with a buzzbox. MIG or spotweld. It's a little trickey even with MIG but it can be done with a little practice.
Another way that is real easy is to get a punch 'n flange (air operated or hand) for under $50 from HF. The air-operated one is very easy to use; just pull the trigger.
It makes about a 1/2" wide by about 1 metal thickness deep offset in one panel and punches holes in the other. I usually spaced the holes about 1" apart on autobody rust repair work, sticking in new panels.
Remove the galvanize with hydrochloric or muriatic acid -- about 2 bux a gallon at the lumberyard. The galvanize is usually so thin it only takes a few seconds. Then clamp the workpieces together, set the current and wirespeed on the small MIG by experimenting a bit, Hold the gun over the hole, shut your eyes, pull the trigger for an experimentally-determined small number of seconds (probably 1 to 3).
That fills the hole with weld metal, producing a "rosette" weld that works just as well as a spot weld, maybe better. You might have to grind the welds a bit but not much.
If the finished work is to be outside, smear some sealant in the overlappping lip to keep water out. The 3M stuff from autobody shops is excellent.
If you insist on a continous weld, it's a lot easier to put a bead on an assembly thus formed than it is to butt-weld 24-gage, though the latter definitely can be done with MIG and a fair amount of practice.
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Thanks for all the tips. Maybe with my budget I should go with mech fasteners.
I plan on making a dust collector for wood. Cosmetics aren't important (other than for pride's sake ;)
I don't think a cheapo spot welder would do the trick unless I make tabs down the cone and the cylinder and spot weld those? Would that work out, or should I use that special caulking and pop rivets?
Thanks for all the input.
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On Tue, 25 Nov 2003 15:48:34 -0500, Sam Shank
That's damned thin. An awful lot of that is going to be zinc, so (ignoring the fume hazard for a while) that makes it even worth for controlling the temperature.

Marginally. Do it outdoors and it's no big deal. 24 gauge is probably electro-galved rather than hot dip, and you can _taste_ the difference in coating thickness. As far as hazard goes for a small job, the electro stuff (pale grey coating, no visible crystals) might as well not be coated at all.

Not a hope. You could do it with MIG if you're fairly good with it, but it'll be an unpleasant fiddly sort of job.

I'd be looking at mechanical fasteners. What are you making anyway ?
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I get to do this more often than I'd like at work. 1st, lots of fresh air! If you manage to inhale a lot of the fumes you'll get sicker than a dog... Taking calcium tablets seems to help prevent this, or at least it works for me.
We use .030 wire, but I think something smaller (.023) would be even better. No chance of stick welding it, not easily or fast anway. The way I usually set the machine up is 1 or 2 steps colder than the chart inside reccomends. If you can do a vertical down it really seems to help keep the burn through's to a minimum also. But welds and outside corners seem to be about the worst for getting a decent looking weld, but it can be done. Alot of times what we do is turn .5" flange in that the other side will rest on (if it helps, most of what we weld is duct work). This extra material helps to pull some of the heat away (and add metal to the puddle), and also helps to keep things from warping too bad. Usually the best way to do it is very small stitch welds (about an inch long), but if you need to get this done asap, vertical down seems to be the fastest.
Aluminum colored paint also does a decent job of matching for touching up the welds.
-- Lynn "I have opposable thumbs, and I'm not scared to use em" Amick http://www.amickracing.com
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We used to weld a lot of duct work using dc reverse polarity and a carbon rod with everdower rod ,makes a nice smooth weld ...Drink a lot of milk when welding galv metal..Pat
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On Tue, 25 Nov 2003 22:08:07 -0800, "Lynn Amick"
......and in reply I say!:

Which brings me to a question.
Has anyone ever built themselves a fume extraction add-on for the actual MIG lead/handpiece?
I was wondering about having a go. Maybe a tube around the MIG lead (or a small one next to it), with a shield over the gun's nozzle. On the welder I would have a suction device (which has to be pretty powerful IMO, as it needs to get a fair bit of air back down the smallish tube available.
Or do I simply price one?
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Old Nick wrote:

That's not a good idea, you want the shield gas to stay around the weld.
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wrote something ......and in reply I say!:
I have to disagree. there are several manufactureres who make them. Obviously you don't want to sucjk the gas away too fast. That is the sort of design gotcha I am worried about. (Adjustable fan speed?)

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Old Nick wrote:

For some reason I got visions of a shop vac hose taped to the torch.
(embarrassed)
.....
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wrote something ......and in reply I say!:
No. Understandable. I knew what I was talking about because I had seen a picture. It only removes air to the point that I wonder whether a couple of PC fans would not do the trick at the other end.
Ah well...in the absence of other advice, I shall experiment ....<G>

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I've seen them before (I believe from hobart, but not sure). I think it pulls a very light vacuum, enough that the shielding gas isn't "too" disturbed. I doubt it would get every bit of the bad stuff, but maybe it'd help cut down the white floaties.
Like Mark said, you don't want to pull away the gas shield, but to be honest the puddle is so screwed up by burning out all the impurities, it's probably full of contaminates. This might not be true if the metal was thicker (since you could run the weld much hotter), but for sheetmetal, it likely isn't going to be a structural piece.
I would say not to worry about this if it's only an occasional thing, just be sure there's a breeze in the shop.
Interesting story (just bear with me, I'll shut up eventually lol). We had some 4"x4"x3/8" angle we were welding into protectors for some gutter (no idea why so heavy). Choice was to either buy galvanized metal, grind the galv off, weld, spray cold galv back on, or just weld with normal mild steel and send it off to get dipped in galv. Sure it would have been cheaper to send it off, but try being 23 and argueing with a know it all boss. I tried to weld it with out grinding off the galv, holly smokes (pun intended!). The plume of smoke would be so thick you couldn't see your hand holding the stinger (stick welding, fairly hot). And grinding the galv coating off, god what a PITA! More or less just smeared around on the metal, didn't really grind off. Ah, the fun days.
good luck with your project!
-- Lynn "I have opposable thumbs, and I'm not scared to use em" Amick http://www.amickracing.com
wrote something

air!
dog...
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On Thu, 27 Nov 2003 00:17:46 -0800, "Lynn Amick"
......and in reply I say!:

I have a photo of one in use. It's what impressed me. Thye differnce is amazing. I think they set it back a bit from the very workface, so it does not suck out the gas right away.

Trouble with a breeze in the shop is that you have to get it nicely set up so that it gets rid of the fumes, but gets nowhere near the work <G>
As for occasional. I weld a lot of scrapyard stuff. Weld...test...broken? OK. Must be exotic. Preheat. ..weld...test..broken? get out the stainless wire <G>
OR
Hmmm......galv eh? Smoke away!
I started to worry when I used some )bought at huge price) alloy metal, with quite a high Chrome content, among other things. Not nice.

snip of a lot of smoke <G>

Amazing stuff isn't it. I rmember having a discussion here about galv vs plastic coating. If you want tough, galv wins hands down! **************************************************** sorry remove ns from my header address to reply via email
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Old Nick wrote:

An old mag base with small piece of plate could work as a wind breaker.
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As far as I know the fumes have no long term toxicity.
If you have to weld it, you have to weld it. But I would be thinking pop rivets if at all possible. Maybe double back tape if it needs to be gas tight and does not need the ability to withstand high temps.
Dan

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On Tue, 25 Nov 2003 15:48:34 -0500, Sam Shank
......and in reply I say!:
Unless you want to spend at least a couple of months learning how to weld, use rivets.
Thin metal is a bitch. Galv thin metal is worse.
24 gauge is THIN.

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wrote something

You might try plug welding. You drill a hole in one piece of the sheet metal. You then clamp the pieces together. You weld the hole, using the second sheet as a backup. Works pretty good.
STeve
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On Tue, 25 Nov 2003 15:48:34 -0500, Sam Shank
......and in reply I say!:
Repost. More ideas.
Unless you want to spend at least a couple of months learning how to weld, use goop and rivets.
Thin metal is a bitch. Galv thin metal is worse. the Zinc makes it even thinner than it seems, and burns easily. This contaminates the weld, and also probably contributes to burn-through. This is not the project to start with. Very frustrating.
24 gauge is THIN.
With fumes, galv is not very nice. MIG does not like a breeze over the work. So you need a careful extraction system or a respirator.
You can try a piece of copper behind the work as a heatsink.
From your later posts, you are going to butt weld? They are about the toughest in thin steel.
then you need to paint the finished result at the welds.
Use goop and rivets. If you don't want to fold, use some sort of angle brackets, rivet each end to a sheet, then fillet goop the join inside. "Stitch and glue" metal work <G.

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Old Nick wrote:

Or grind off the zinc, what the hell, it's going to get burnt off anyway.
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