My homemade forge, getting too hot?

[Handmade Matt]

I bolted an old wok on top of a steel bucket, then fitted a pipe to the bottom of the bucket that goes off to my girlfriends hair dryer. I've built it just to use for making knives, annealing and heat treating.

I got a good bed of fiercely burning charcoal.

I then put in an old farriers rasp that I was intending to anneal, to work it into a knife.

When I took it out it had bent into a slight curve.
Is it becasue I got it too hot and sagged under it's own weight?

Secondly, has anyone used a set up like this to hammer steel into shapes? Fire steels, curved knives, simple things like that?

 

[JohnC]

I could believe it... I did this to a knife I was making, the metal burnt off. The other blade developed an intresting pattern that indicated the surface was starting to melt.
The charcoal and the forced air got it all up to a very high temp..

 

[Handmade Matt]

That must have been disappointing to pull that out of the coals! Blimey, bless ya.

I've had some interesting patterns on my last blade from the heat, I quite liked it actually, it gave it a rustic Ork like handmade feel.

The hair dryer has two speeds and I had it on maximum the whole time. I also didn't turn the rasp over at all which would have been helpful I guess. It's such a great learning curve all this!

 

[robin wood]

charcoal with a blower will get plenty hot enough to burn all the carbon out of your steel. Fire management is just part of the learning curve. Kepp pulling the blade out and sliding it back in so you can check the heat. If it comes out looking like a sparkler you got too hot, have burnt the carbon and best start again with a new piece.
Second piece of advice, a hair drier costs less than £10 in Argos, any man that uses his girlfriends hair drier to power the forge has to be on borrowed time.

 

[lannyman8]

it could just be the shape of the bucket/wock and the way you put the steel into the fire.

you need to put it in flat if you can (as in, horizontal to the bottom of the forge) with the thin edge down this will stop it bowing so much, the more time it spends in the forge the more chance it will bow or melt

also if the heat is all in one area that spot may well melt while the areas near to it might not get hot enough to even do that, the area around the "air hole" is the hotest due to the forced air, a better method is to have a steel pipe with holes drilled allong the length, this gives a more even heated area more suitable for making blades.

when you aneal you only realy need to heat the metal to a cherry red / dark orange, i dont dother with holding it for as long as possible, it does not realy make a differance once heated to that temperature anyway.

as for your bucket forge working for smithing, yep, nay probs, just watch you dont get stuff to hot, or again it will melt...

for the forced air try getting another hair dryer, the mrs will kill you when it burns out... or get an airbed footpump, its what i use, reason 1, it needs no power as where i forge there is none and reason 2, you have more control over the fire and it keeps the fuel cost down due to the lack air in between hammerings...

just my thoughts and i am by no means an exspert, i just bash a bit...

hope this helps...

chris.

 

[JohnC]

If it comes out looking like a sparkler you got too hot, have burnt the carbon and best start again with a new piece.

Yep, thats it exactly, it was sparking, but I was concentrating on the other blade (too many irons in the fire!) and only checking the magnetic/non-magnetic state... I had read somewhere about checking/heating in the shade or in a darker area so the colours are more apparant..

 

[Everything Mac]

A slight bending is nothing to worry about. - you can just hammer it back in to shape

But as has been mentioned - if it comes out looking like a sparkler then you have well and ruined it. - You can cut a decent chunk of it off and use it for fire steels but it will be useless as a knife.

I learned that lesson a few years ago, which is why I use a gas forge for HT now. (Jojo did a how to thread - it's one of those) I spent several weeks working on the blade - you can imagine my rage when it came out with the tip missing

When doing HT in a coal forge make sure you have constant control of the blade and try to keep it moving about so you get a good even heat. (Hot spots create differing hardness - thus weak spots IMO)

Pics would be nice!

Best of luck
Andy