Flue pipe material question: Galvaneel?

[elkdoc]

Anybody heard of "Galvaneel" steel. It's not galvanized, but similar in rust resistance. Will this stuff make me sick if I use it for a flue pipe and it gets hot?

I can't seem to find much info on it.

[oakwoodforge]

"Galvaneel" is just a newer hot dip coating process for zinc plating steel, involving a heat-treat process that chemicaly bonds the zinc to the steel. I beleive it is some what less dangerous than standard galvinized a high temps, its major industry benefit is that paint sticks well to it. Weater it makes you sick ??? Heavy-metal posioning is no joke, I wouldn't risk it. Plain black iron pipe or stainless will always be safer, but if you are using coal , you will be making sulfuric acid so black iron pipe will rust , if you dont want to deal with rust , Look at POR-15's Rust proof automotive exhaust manifold paint, It should hold up to the heat and sulfuric acid.
Hope this helps

[Glenn]

Galvanneal Steel is produced on a continuous hot-dipped galvanized steel line. As the steel emerges from the molten zinc bath all excess zinc is removed from the surface using heated air knives. From there the steel continues through an annealing furnace converting the zinc into a zinc-iron alloy coating (galvanneal). The coating is spangle free, dull grey in appearance and offers exceptional protection to corrosion as both the inside and the outside are properly protected. In addition Galvanneal Steel also provides an excellent surface for finish painting.

Galvanneal Steel is similar to other hot-dipped galvanized products with trade names such as Redi-Kote, Jal-Zinc, Zincgrip-Paintgrip, Wipecoat and Satincoat, all of which conform to ASTM A-525, A526 specifications with A25 (.25 ounces both sides) coating classification.

Source Baron Metal Industries


You may want to do a search on galvanized, galvaneel and galvalume also.

[Ed Thomas]

Judging from what happens to all the pipe I've used so far on my forges, I'd say it gets too hot for galvanized. The zinc always burned off pretty quickly. So I don't use that anymore just from the practical point... never mind the severe health hazard.

oakwoodforge: What temp does that stuff go up to? I've used hi-temp paint on my forge components, but it doesn't last long. I can't imagine it doing any better than what the black stovepipe comes with already.

I just installed 10" stainless pipe. It is outrageously expensive. I'm hoping it lasts a few years. The only place I could find it was McMaster Carr. I figure now that I hocked futures on my first 3 grandchildren to afford it, somebody will tell me where I can get it for 1/3 the price. Only the price of one grandchild, in other words. :|

[elkdoc]

Well crud...

Looks like I'm back to square one. I've called every place I can think of in the Knoxville, TN area and can't seem to find anything that's over 8" in diameter and not galvanized. The flue is all that's left to move into my shop and its been killing me for 2 months.

I do have the option of having some 12" pipe made up from 16 ga. cold-rolled sheets, but the labor and material combined will kill my budget. For the price, I'd be fine with black, snaplock stove pipe but I can't find the stuff big enough to vent my poor, small shop. :x

[yesteryearforge]

you can make your own pipe although I have not made any as small as 10 inches I have made pipe 16 inches.
used 16 gauge sheet metal / curl one end around and pop rivet then curl other end around and pop rivet then pop rivet along the seam
It is actually easier than it sounds but may help if you are bowlegged
best of all it requires no special tooling other than a hand pop rivet tool and you can get sheet metal up to 12 feet long fairly easy.
If this is a coal forge I doubt that the exaust stack would get hot enough to effect galvanized. Mine are painted steel and it doesnt get hot enogh to effect the paint but that is just my take on it / use your own judgement.

[oakwoodforge]

Ed Thomas,
The Permanent restoration product " factory Manifold grey paint " is a brush or spray-on paint that exceeds 1400 deg temp stability and is acid , salt water, chip and scratch resistant , so much so that you can Paint right over the old rust with very little surface prep. Not like regular manifold paint that re-rusts an a few weeks here in the humid state of Iowa!!! I sell Lots of it to restore old Dodge trucks , and we use it in our shop all the time. great stuff !! If you can't get large black stove pipe from your local Ace hardware or whatever check with: www.ventingpipe.com they arn't the cheapest but they have it. Also check with your local HVAC guys they might have a local supplier wharehouse that you never knew was there. Or they Might be able to make your pipe in their shop.

[oakwoodforge]

If you cut the "Crimped" end off 2 peices of 6" snap-lock an flip one 180deg. they will make a 12 " dual seam snap-lock pipe ( put several sheetmetal screws through each seam) , you just have to re-crimp the end and " massage" the pipe to get it nice and round ( this works better with 22 Gauge and lighter snap-lock pipe ) All you need is that 5 blade pipe crimping tool $ 20-25 bucks, a good investment if you are putting lots of pipe together otherwise you might be able to borrow one from a HVAC guy.

[Ed Thomas]

oakwoodforge: I used the normal off-the-shelf stuff from the hardware store. Both mixed in a spray gun, and straight spray can. It looks like they are really only good for 1000

[yesteryearforge]

Oh OK I must be dealing with imaginary heat

[Ed Thomas]

yesteryearforge: :mrgreen: Welllll.... you know what I mean. My forge has a 12" x 12" firepot which is fairly deep. Heating a 2" or larger bar can generate quite a lot, and in my case more than enough to blister paint and burn zinc off.

[Glenn]

Jerry Carroll suggested that I use heavy steel corrigated pipe as a smoke stack. 12" ran about $100 for 20 feet at the time.

Check the building codes in your area.

[bruce wilcock]

i made a flue in the sixties i cut 1/4 plate into strips and welded a square flue up ,it lasted till we took the shop down in 1990 to extend

[Glenn]

Bruce, I like the idea. Who said the flue had to be round? Why not square or rectangular ?

[HWooldridge]

A sheet of 4x8 galvanized sheet metal (26 ga?) makes a 12 inch square by 8 feet long. Gives you 22% more air capacity than 12 in round. It's also easy to flash, cut the hole, etc. I used one for many years until a storm wrecked the shop and ripped off the roof. I replaced it with 12 in round because that's what I had. A good chimney will dang near suck the iron right out of your hand... :wink:

In addition, I am also not going to recommend galvanized one way or the other BUT I am personally more worried about the other dangerous things in the shop like breathing coal dust, abrasive fines, CO fumes, active carbon from the acetylene torch, etc., etc., rather than whether the galv is cooking off. My stack gets too hot to touch with a bare hand but even in summer, it's never so hot that it sizzles water. Of course, my side draft collector box is out of black iron so the duct doesn't start until about 2 feet up and away from the fire.

[Ed Thomas]

Hollis: I don't have an objection to the galvanized stuff either as long as it is above where the zinc might burn off. Seems like once that happens, the remaining steel rusts through extra fast... probably because it's usually fairly thin gage stuff anyway. Of the two common stove pipes I've used, the black stuff seems to last a little longer than the galvanized, and I think they are nearly the same gage.

[urnesBeast]

I have a side draft to the same dimensions as Uri's.

BP1048 Side Draft Chimney | Blueprints 1000

The 12 stack is 15 foot tall, all galvanized. I figure this is already outside where the draft is going up and out. The inside side draft over the fire is stainless and is cool enough to touch, so I doubt my galvinized stack 3 foot away through the wall is going to be a problem because it is significantly cooler, outside and drafting up and out.

Do any of you think it will be a problem?

-doug

[Frosty]

Welcome aboard Doug, glad to have ya.

You should be just fine.

Before triple wall SS was the rule for wood stoves everyone used galvy and the only time you'd see it burned (chalky yellow over darkish ash gray) is when someone had either a runaway stove or stack fire. If you don't burn the galvy you won't get zinc oxide in the air.

I had galvy stove pipe in one place for nearly 10 years without burning any off.

If you'll click "User CP" at the top of the page and edit your profile to show your location it'll make it easier helping you. IFI is represented by more than 50 countries, so materials, tools nomenclature, fuels, etc. can vary quite a bit. It'll also help guys in your neighborhood let you know about get togethers, tool deals, lend you help, etc.

Frosty

[blksmth]

There are many blacksmith forges with a metal chimney which could be galvanized, painted, or not. Particularly with a side draft forge, the heat can be pretty intense where the fire enters the flue so, for that portion of the flue, some protection or different construction is desirable. Even on brick chimneys the bricks can deteriorate around the bottom of the opening. Usually the galvanizing or paint burns off, if galvanized or painted. When it is just plain steel it usually rusts through. There are many forges where bricks are used for the bottom 3 feet or so of the chimney. Above that any kind of pipe will work. Also, heavier iron around the opening would work and could be made removable if it need replacing.

A round chimney flue, of the same size, draws heat and smoke better than a square chimney. Nevertheless, I've seen plenty of square chimneys that work well. As was previously mentioned, it might be easier to fabricate a square chimney, although the round chimney suggestions sound easy also.