dmlandrum

Home blacksmithing
« on: December 17, 2008, 07:06:05 AM »
Okay, speaking of activities which are good exercise:

I got hooked on blacksmithing at a friend's place in Colorado Springs. He had a cool old coal forge with a hand-cranked blower, and we used to make all sorts of things with whatever was handy.

So here I am in Michigan with no room for a forge, but I was checking out some of the torches at places like Lowe's and Home Depot and I got to thinking, "couldn't I use one of those to spot-heat cold-rolled stock before whacking it with a hammer?"

So I thought I'd ask here. I'll try this for myself, but any ideas are welcome. I need to find the nearest harbor freight to get an anvil and some hammers, I suppose.
Darren Landrum

Be comforted that in the face of all aridity and disillusionment
And despite the changing fortunes of time,
There is always a big future in computer maintenance.


shabtek

Re: Home blacksmithing
« Reply #1 on: December 17, 2008, 07:40:55 AM »
 :o

"really fine players do not use stomp boxes or master volume, they match the amp to the room and turn it up to 11.  Stevie Ray, BB King, Albert King, Duane Allman, Dicky Betts, Louis Armstrong"
   -CJ

sodderboy

Re: Home blacksmithing
« Reply #2 on: December 17, 2008, 07:56:12 AM »
I don't think that those weekend warrior torches will work effectively.  They can sweat a pipe or burn the garage down, I mean burn the paint off the garage, but they do not work well for annealing larger silver work like bowls.  And you need even more power.  And it will take 2 tanks to make an iron bracelet.
There is a reason why they use a forge and not solely a direct flame.  You can check for acetylene torches that will give you more umpf and a larger tank.
Find a local craft school and use their gear, under their supervision, to explore your interest.  The cost of the classes will be less than the gear, and you will learn directly instead of trial by error.  Grave consequences to "error" in blacksmithing!
Mike

PRR

Re: Home blacksmithing
« Reply #3 on: December 17, 2008, 02:15:18 PM »
> no room for a forge

A farrier's portable forge is the size of an end-table. The forge does NOT generally set the size of the room; it is bench and anvil and tool space, room to swing red-hot bars without risk of burning your helper, odds and ends of scrap and projects, and room to breathe.

My father and I did some alloy casting with a heavy cast-iron hibachi and Kingsford charcoal. An hour of that did not melt a few ounces of aluminum, so he added a vacuum cleaner set to blow. Nearly set the house on fire, burned a full pot of charcoal in a couple minutes, but the aluminum did flow, sorta. The iron laddle did not soften. Conclusion: to work iron you will need a denser and maybe cheaper fuel than fluffy picnic charcoal, and a deeper bed of it than a hibachi.

I'm not gonna do the math now, but a plumber's propane torch is like 3,000BTU, a horseshoe forge should peak over 30,000BTU.

Big difference between melting solder, melting aluminum, and just softening iron. Solder is 700 and iron is 1400-2800? Heat losses rise exponentially with temps above 400.

Big difference between an ounce of pipe and a pound of iron.

Any piece of metal thicker than thinwall pipe or hotter than solder draws the heat out faster than a torch can put it in. Part of the point of the large coal bed in a forge is to keep a long length of stock hot, so the end can be brought up HOT. Another point is the fairly low air velocity; a propane torch blows-away a lot of the heat it makes.

I've bent 2"x0.125" Aluminum with a propane torch. I've failed to bend 1.25" iron pipe with a welding torch; oxy/acetylene can make a hot molten spot but not a large soft spot. Well, not with the tips and hoses an auto mechanic uses for modern car work.

My aluminum bending actually failed. The high temperature causes rapid oxidation of the metal and it fell apart. A key trick in hot iron work is controlling the oxygen (and carbon!) content of the gases around the iron. Most heating is done with slack blower, the iron deep in the middle, an oxygen-poor (and carbon-rich) atmosphere. Oxy/acetylene has such control, and a welder picks a balance for the work being done. Plumber's propane torches have no control.

Good iron-work also limits Hydrogen, because it makes iron brittle; a reason to avoid hydrocarbon fuels. I suppose that's not too important until you get to building bigger stuff. But hydrocarbons also cost more. Bad for the metal, bad for the profit; the only point is low start-up cost due to simple burner.

Metal-working is almost all about Cost Of Energy. Red dirt is almost free at the pit. Cooking the metallic scum off the dirt takes a LOT of heat. Re-heating the raw iron to adjust its carbon is more heat, reshaping pig into slab or rails or casting is a lot of heat. OK, you can get all this cheap, with scrap-iron at ~~~$100/ton. But softening an old boiler-stay into a goth earring is a LOT of heat input.

Unless you get lucky, a pound of propane is $3, which is like gasoline at $20/gallon. 20 pounds hobby-grade coal is $15, and the price goes way down from there. Yes, you can get prope cheaper in big jars. It is still a very costly fuel.

But WTH. A $5 torch is only $30. You can probably soften paperclips. You may be able to forge a few 0.75"x0.1" strap iron cabinet braces before the tank runs dry.
« Last Edit: December 17, 2008, 02:27:45 PM by PRR »

dmlandrum

Re: Home blacksmithing
« Reply #4 on: December 17, 2008, 03:29:38 PM »
Wow...

Well, I have space outside to set up and swing a hammer. The issue really is with having a large forge taking up space in part of the backyard. So I was hoping to find a smaller option that can be put away at the end of the day.
Darren Landrum

Be comforted that in the face of all aridity and disillusionment
And despite the changing fortunes of time,
There is always a big future in computer maintenance.

beatpoet

Re: Home blacksmithing
« Reply #5 on: December 17, 2008, 05:30:26 PM »
I think it depends on what you are doing with the forge.

look up : "one brick forge"

for small stock like pocketknives and carving knives I just use a mapp torch and a couple of fire bricks. The mapp will even get hot enough for quenching for up to 4-5" blades if the heat is conserved properly. Mapp runs about 5000 degrees which is plenty, so the object is to conserve the heat and flame.

To conserve heat, I use the top hole of a 8x12 cinder block with a fire brick covering most of the rear of it. Sit that up on a table (or work sitting on a concrete pad like I do) and aim that torch in that hole, aiming at the sides of the brick to reflect the flame at the rear of the piece as you cover the front. The round of the cinder block hole carries the flame very nicely to the rear of the piece. Make sure the block is dry, moisture will crack it as you heat it.

You can use flame reflection off of an anvil to sumultaneously heat both sides of the quick and dirty small stuff. Hell, I've used the side of my vice to not only create a good bend but also to reflect flame.

For bigger stuff I was thinking a small oxy/acetylene setup from Menards.

No, my neighbors did not like the column of coal smoke coming from my backyard, so I use the forge sparingly. I also burn it much hotter and use wood chips.
« Last Edit: December 17, 2008, 05:36:02 PM by beatpoet »

Gus

Re: Home blacksmithing
« Reply #6 on: December 17, 2008, 06:46:01 PM »

PRR

Re: Home blacksmithing
« Reply #7 on: December 17, 2008, 07:32:36 PM »
http://www.anvilfire.com/index.php?bodyName=/21centbs/forges/microfrg.htm

1/4" (6mm) round bar to forging heat  ... this is about the limit of the work that can be done with one of these.
 
« Last Edit: December 17, 2008, 07:34:13 PM by PRR »

sodderboy

Re: Home blacksmithing
« Reply #8 on: December 17, 2008, 07:32:57 PM »
Thats why I recommend a crafts course or two first.  Bang on someone else's stuff, and experience their skill and love for the art.  They have courses to try and pay for their  outlay!  Its like anything- they want you to buy GEAR, and once you buy it, you have to buy MORE, and by then, you have gone on to something else and toss the silly forge and anvil on top of the frickin' kite-surfing junk on top of the pile under the scuba sh*te under the dead bonsai tree.
I work with silver and stones as a hobby in a local museum, and am glad that there is no gear in or around my house- dust, mess, equipment, money, ventilation, time- too much of some, not enough of the rest.

30,000 BTU- an SL9072J is more than halfway towards working a horseshoe, if you can re-direct and concentrate all the heat (5000W= 17KBTU) generated!  I sense a possible symbiosis re-kindling two dead industries.  No AC needed either, hmmmmmmmmm. . .
Mike
PS: Anyone in this guild will be happy to help http://www.miblacksmith.org/.  There might be someone close?
« Last Edit: December 19, 2008, 07:59:29 AM by sodderboy »

Mbira

Re: Home blacksmithing
« Reply #9 on: December 21, 2008, 05:14:29 PM »
What are you wanting to make?  I use up to 3/8" thick cold-rolled steel on a railroad rail without heat.  You create plenty of heat just by hammering.  Guess it depends on what you are making and the effect you are going for.  Sometimes I throw the stock in a bonfire just to soften it up a bit before working on it.

Joel Laviolette

Rattletree   |  https://www.rattletree.com
The Rattletree School of Marimba | https://www.learnmarimba.com


NewYorkDave

Re: Home blacksmithing
« Reply #10 on: December 22, 2008, 11:48:20 AM »
Here's another vote for signing up for "shop class." When I was a boy, I took a metal shop class that included some blacksmithing work and it was a lot of fun. I remember forging my own set of cold chisels.

Johan

Re: Home blacksmithing
« Reply #11 on: December 22, 2008, 12:02:24 PM »
Here's another vote for signing up for "shop class."

+1..
..you might find out quite soon that this was not for you, or that the anvil you bought might not be what you need. taking a few classes might point you in the right direction about what you need, before you buy it ( it's not much, only has to be right)  a 4 pound hammer might not be the thing for knocking out mideveal jewelery. a one pounder not for doorhinges..
..you also need heat if you're going to do some serious shaping of the material..or it will crack and split
here in sweden there is a saying.."the devil takes one "coldsmith" every seven day's..."
and also, obiously. " strike while the iron is hot"
here is something I did last week..

..it started out as a piece of metal about 12X45x200mm and took several hours...
johan

NewYorkDave

Re: Home blacksmithing
« Reply #12 on: December 22, 2008, 12:32:35 PM »
Beautiful work, Johan!

Mbira

Re: Home blacksmithing
« Reply #13 on: December 22, 2008, 01:33:32 PM »
Quote
"the devil takes one "coldsmith" every seven day's..."

 :D
That has to be one of the weirdest sayings ever...
Joel Laviolette

Rattletree   |  https://www.rattletree.com
The Rattletree School of Marimba | https://www.learnmarimba.com

dmlandrum

Re: Home blacksmithing
« Reply #14 on: December 22, 2008, 03:39:02 PM »
I should reiterate that I did spend a number of weekends one summer doing blacksmithing over at a friend's place a few years back. I really enjoyed it, and have been really jonesin' to get back into it. I'll have to dig through boxes to see if I can find any of the things that I made. One was a cubicle wall hook for a coat. It wasn't perfect, but it was mine.

My friend had a pretty nice and big coal forge with a hand-cranked blower. It worked a treat, but I don't need anything that big.
Darren Landrum

Be comforted that in the face of all aridity and disillusionment
And despite the changing fortunes of time,
There is always a big future in computer maintenance.

JohnRoberts

Re: Home blacksmithing
« Reply #15 on: December 22, 2008, 04:02:38 PM »
We had a coal forge on the back of our high school metal shop and even did some basic aluminum casting with simple compacted dirt molds.

Of course every year one wise guy would slip a golf ball into the fire just before the end of the period so it would explode in the next class... :-[ I suspect modern golf balls might take that up a notch... Don't do this at home.

JR
Don't only half-ass tune your drums. Visit https://circularscience.com to hear what properly "cleared" drums sound like.


 

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