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Bodgy
20th Mar 2006, 03:47 PM
I am in the early stages of building a small forge and an anvil.

I like to use stuff that's lying around or has been disgarded, its part of the satisfaction.

For the forge, I am thinking about using the female end of an old terracotta sewer pipe, as the firepot. From what I can gather, these are usually a cast iron pot. Would the sewer pipe crack in the heat?

I have an old cast alum casserole pot. Would that suffice or is the melting temp of aly too low?

If the above are both impractical, then I can always buy a cast iron pot, but thats no fun.

For the 'bellows' I'll use my petrol blower. It has a throttle lock that engages at any speed so I should be able to get the correct airflow. No idea what that is, it'll be trial and error, mostly the latter I expect. The plastic blower tube will be a way from the heat. It'll go into a 6cm steel pipe with a gal steel cone into the firepot - made from left over dust collector reticulation.

Will probably look like a dogs breakfast, but it will work.

Incidentally anvil is being shaped from a 50cm length of railway track, mounted on a bed of 100x75 Oregan on a steel stand (made from an old gate)

Comments, advice and suggestions sought.

CameronPotter
20th Mar 2006, 04:54 PM
Ok...

The ceramic firepot isn't a good idea as it might be too brittle in my opinion. You don't want to stick in a lump of metal, bust the pot and get covered in hot coke...

I reckon the alu would melt FAR too easily.

That being said, you won't believe what my forge is...

I have an old Webber BBQ with the inside all covered in fireplace mortar. The inlet pipe is all steel plumbing (quite thick and strong) with a valve at the bottom to realease any garbage that comes down the pipe. Then this goes up into the base of the BBQ (which incidently is mounted on an old 44 gallon drum as I didn't trust the legs) and blows through an old brake disc with a grate over it to stop coke falling through.

This works an absolute treat and I have had this going so hot that I have melted bar stock VERY quickly.

Any questions? PM me.

Cam

Andy Mac
20th Mar 2006, 07:51 PM
Hi Bodgy,
The only thing I'd try for in cast iron is the grate, but I've worked with steel ones for years, and so ocassionally they need renewing. No dramas. My own forge has kiln brick and refactory cement over a plough disc but that just means you can't transport it! I've already had the bricks fall out.
Have a look at some old ones and many fireboxes are just sheet metal (steel) with no lining. In other words just go simple and have a bash. If you find a simple forge gets you excited move upwards, but I reckon you'll move off that rail iron anvil sooner!!:D I've still got mine, and I drag it out for small mobile jobs, but make a noise!!?:eek: An ear piercing ringing noise.
Anyway good luck with it, keep us posted, but there are plenty of plans on the Net...can't help right now (kids baths dishes drama) but I've got some sites bookmarked, like ABANA.

Cheers,

Wood Butcher
20th Mar 2006, 08:18 PM
I've seen quite a few forges made out of new plough blades. I had one that was over 6mm thick that would of been perfect but gave it to the above member to use. I bought it brand new for $5 at a scrap metal dealer.

Have a look at the AnvilFire website. It has some great advice especially in the FAQ section and lots of good links too.

In regards to the blower, You don't need huge amounts of air and I think that a petrol blower might be too much. What about using an air compressor? or find a heater fan from a car wrecker run off a battery?

Good Luck and look forward to some photos.

bsrlee
20th Mar 2006, 09:35 PM
Hhmmmm - hot things. I HAVE used a forge made out of wet dirt & an old fruit box - the sides were starting to char a bit after a day's use, and it sat on the ground so there was no where for stuff to drop to. Used 2 single bellows too, but it was for a 'demo' & you wouldn't want to do it regularly.

Too much blast does/can do a few bad things - one is that it tends to blow slag & clinker up thru' the fire & onto any surfaces you are trying to weld, resulting in a very frustrating experience & a lot of swearing, hot iron being thrown out the door etc. It can also cause cold spots in the fire, where the fuel has burnt away & the blast cools the metal faster than radiant heat can be absorbed.

Most small operators I have dealt with use an old vacuum cleaner (salvaged from roadside coucil cleanups) set in 'blow' mode, going thru' a box with a variable gate - one fellow had his set up so as one gate opened the other closed, one gate to the fire & the other pointed up the chimney to assist in drawing.

The same canny fellow convinced me of the benefits of a side blown forge with water cooling. The tuyere consisted of 2 pipes, the inner about 1", the outer about 4", with a plate welded to the fire end. On the 'back' end there is a large steel box with the 1" pipe going right thru' & the 4" pipe welded to the fire side. You could also make it with a thermal syphon, with 2 pipes coming from the water jacket, but it is theoretically possible to 'explode' the thing if the pipes get blocked, or just have boiling water everywhere. This setup has the advantage that the slag/clinker sets into a solid mass on coming in contact with the tuyere but it doesn't stick & can be lifted out easily in a lump - and you have hot water for washup at the end of the day:D

Schtoo
20th Mar 2006, 10:26 PM
Ally, no. Give it to me and I'll send it back as a blob. Only takes about 15 minutes to do that.

Terracotta, again no. Clay is good in a couple of circumstances. One, where it supports no weight and only acts as 'hotface'. Basically, you smear the clay on something else, like an iron pot. The other is where the clay is usually light in colour. Lighter the better. Usually (but not always) means that's it both strong and heat resistant. I have some Hong Kong kaolin here that is pure white, and it won't melt if it can get some air to it. Your sewer pipe, give it to me for about 45 minutes and I'll send that back as a blob too. ;)

Steel or cast iron will suffice. An old brake drum is great. Good shape, in various sizes and usually cheap. Won't melt it either (takes me about an hour actually, but I have nothing to keep it in!).

If you get stuck, some kind of form that will take a few kilos of steel and fuel and line it with an inch or two with plain old clay from the backyard. It's not perfect, but it should work very well. Just make sure you let it dry well, make the clay is fairly clean and get it hot slowly. Build a fire in it, make it burn for an hour or two then crank up some air slowly till the thing glows. By then the clay should be 'fired' and it won't give you too much trouble.

For mine, I am going to use a steel pot of some kind, and line it with some leftover cement I have here. Not everyday cement, alumina cement. It's the 'lower grade' stuff good for 1,500*C, or enough to melt iron without hurting the cement. Regular cement dies well below 1,000*C, and I have burned it out of a steel pipe before with no trouble.

For your blower, you don't need so much air. Too much will eat things up quickly. An old vac (;) ) or a cheap electric blower will work great. You do have to be able to control it, not only for how much air, but to also be able to turn it right off. You don't need lotsa heat all the time.

With the 'anvil', if it gets too noisy, wrap some chain around it. Should dampen a lot of the noise.

Google for 'brake drum forge' and you should find several simple designs that all work well and have features that are useful.

(BTW, I am serious about that ally pot. 15 minutes for a reasonably shaped blob, 5-10 for a random blob.)

Bodgy
20th Mar 2006, 10:45 PM
Thank you Gentlemen.

More research and visits to the wreckers required.

I think the petrol blower may be OK, as on tick over, there is very little air coimng thru. I can easily put a gate in the line, too.

What I want to achieve is a small, portable forge, as I doubt I'll use it that regularly, hence clay (due to the cracking) seems precluded.

I had hoped to pick up a plough disc, but it seems everyone has discovered that they make great BBQ plates.

The railway line is noisy, but when you test the 'rebound' it beats the Chinese cheapo cast versions hands down. PITA to shape the horn tho, forget the Hardy hole!

I'll post piccies when I complete the task(s).

CameronPotter
21st Mar 2006, 09:13 AM
Oh, I meant to say - you can use a hairdryer (with the element removed) as a blower - but I use a vacuum cleaner with a few holes drilled in the pipe to let air escape - otherwise it is too much.

As for anvil ring, try putting it on plasticene. You will not believe the difference this makes. I had a 200(ish) kg anvil that rang like a dinner bell. Put it on plasticene (after a LOT of grunting from me and my brother) and now it makes a plunk type noise.

HUGE difference.

Good luck

Cam

ps I should point out that the plasticene is not my idea, but from a book called the Artist Blacksmith. I didn't believe it until I tried it - and then I didn't believe how well it worked... (Thanks for the greenie though Schtoo - even if I was only passing on wisdom from another source. Ain't the web great!)