Wash tub forge question

M

mad bodhi

Joined
Nov 7, 2004
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I'm going to be making a wash tub forge like the one on Tim Lively's site but most of the tubs of suitable size and shape that I have seen are galvanised.Seeing that sticking galvanised in a forge is bad juju should I keep hunting or does it not matter because the clay refractory takes most of the heat?
 
I'm not sure, but I've got a piece of galvanized pipe I'll be making into a new gas forge and I plan on laying in on a wood slab pile that I'll be burning and see if that won't burn the galvanized off.

For the forge type your talking about I'd probably say it is OK, but galvanized fumes have killed more than one persion, including I believe Paw Paw Wilson? A very experianced metal worker/blacksmith.
 
i built one like that, with a galvanized tub. the mortar on the inside keeps the heat and direct flames away, its never been close to burning off. the sides are often cool enough to touch. so go for it buddy! they make great blade forges. mine is for sale if youre anywhere near sacramento CA. good luck.
 
L.K.Smithy said:
i built one like that, with a galvanized tub. the mortar on the inside keeps the heat and direct flames away, its never been close to burning off. the sides are often cool enough to touch. so go for it buddy! they make great blade forges. mine is for sale if youre anywhere near sacramento CA. good luck.
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how do those work? I'm just sitting here thinking about forge stuff... in davis.... if you want to chat off thread I'm at sietchtabr at gmail dot com
 
Was cruising shopfloortalk forums and found that you can strip the zinc with muriatic acid (found at any pool supply or hardware store) then neutralize with water and sodium bicarbonate AKA baking soda.Maybe it will never get hot enough for the galvanized to be an issue but better safe than sorry.Zinc fumes are nasty stuff and can kill you.You'll have to paint it to protect it after stripping the zinc of course but this is my plan of attack.
 
I built a bucket forge using Tim's design. I lined the bucket with refractory cement, thickly.

The metal of the bucket only gets hot when I shut off the blower and leave blades in it to cool under the coals. Even so, it never gets hot enough to vaporize the galvanization.

I forge outdoors, so even if it did I doubt it would be a problem.

Andy
 
I picked up Lou's the other week and have fired it twice. He had used it extensively prior to that. No problems with the galvanizing at all. The hottest I've gotten during an anneal at the end of running it for 2 hours was "3 second touch" hot.
 
mad bodhi said:
Was cruising shopfloortalk forums and found that you can strip the zinc with muriatic acid (found at any pool supply or hardware store) then neutralize with water and sodium bicarbonate AKA baking soda.Maybe it will never get hot enough for the galvanized to be an issue but better safe than sorry.Zinc fumes are nasty stuff and can kill you.You'll have to paint it to protect it after stripping the zinc of course but this is my plan of attack.
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Speaking of nasty fumes, muriatic acid (hydrochloric acid) and galvanization (zinc) make hydrogen gas!
 
where's the sulfur coming from? there is none in HCL (hydrochloric acid) nor is there any I am aware of in the metallic zinc of the galvanisation. Am I missing something?

-Page
 
Never I repeat Never take a chance with getting galvanized steel hot. The fumes will make you very sick at the least if not KILL YOU!!!

If you want to make an inexpensive forge get an old metal wheel barrow body (you can find these in garage sales or even at the dump for little or nothing) and then line it with the refractory clay the same way you would with the wash tub.

You are taking a big chance with the galvanized. All it takes for you to be exposed to the fumes is a slight breakdown in the clay and then the metal will start getting hot. It is not a chance I would be willing to take.
 
Robert Mayo said:
That would be hydrogen sulfide gas and it will kill you a lot quicker.:eek:
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I'm also missing where the sulfur is coming from. I had assumed galvanization was pretty much entirely zinc. Hydrogen sulfide is indeed deadly, my concern was more of death by explosion.
 
seriously guys, i know the danger. i have heard the stories first hand of what it does to you. and being well aware of the danger, i worked with it in the open air, and always checked the whole setup for overheating between heats. even at its hottest the outside was nowhere near releasing any kind of fumes. the thing had a good 4 inches of steel reinforced fireplace mortar between fire and galvanized steel. i think its just a matter of being aware of what could happen and proceeding to pound steel with caution. lets get ahold of Tim Lively and see what he thinks :) and muriatic acid would be a big mess stripping that much material. i use it regularly for washers and bolts with no problems, but anything bigger like a piece of stock a few feet long, in a pvc pipe with muriatic acid, makes allot of nasty fumes, its burned my eyes, lungs etc, just from a tiny whiff in my face. also, its no good for hydrogen. i had better luck making that with drain cleaner and aluminum foil balls. dont ask why, cause i wont say on the internet :) (big boom). muriatic acid mixed with some degreased steel wool and allowed to dissolve (with good ventilation) makes a really cool wood stain that gets darker over time, i like that allot. fun to play with.
-Lou
 
You're under the assumption that everyone who builds these forges will have sufficient refractory to keep the zinc from burning off. The thickness and even materials used will vary greatly.Using the muriatic acid and neutralizing with baking soda is a one time thing that can be approached with proper safety in mind.If you go without stripping,then maybe your'e refractory develops a crack that allows the zinc to burn off or any number of other things could change.I personally prefer to deal with something one time under controlled circumstances rather than hope Murphy doesn't get bored one day and decide to smoke me.
 
not to be argumentative, but assuming the refractory is sufficient to insulate the galv, wouldnt a crack (not a fissure, but the hairline crack that could develop from expansion etc.) be small enough that heat wouldnt be transfered? it just seems that if you kept an eye on the heat, there are far more hazards in the shop to worry about before the outside chance of a catastrophic washtub failure. on a side note, arent steel studs in house construction galvanized? seems like fumes from a fire would be alot more dangerous...
-Lou
 
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