Help from some smiths on here? -- myArmoury.com

Peter Messent · Posted: Sun 14 Apr, 2013 2:43 pm Post subject: Help from some smiths on here?

Howdy folks,
I built a new forge & (ghetto) anvil today. The forge is constructed of bricks, with a shallow (about 5") hole in the ground to hold the charcoal - just about the only advantage to having my back yard made of sand. The air supply is a small shop vac connected to a metal pipe leading into the coal pan. The forge has one rectangular opening on the front about 4x6" for the workpiece and one triangular opening on the top about 6" on the side to let some heat out.

Well, I was banging on a piece of rebar just to see how they were working out (very well, at first) and then threw it back into the coals and turned the blower on. I check back about 30 seconds later and where the beginnings of a knife blade was, a weird, flat looking cauliflower was now! In that space of time, the heat of the workpiece had risen, by my reckoning, about a thousand degrees, and was beginning to melt.

This isn't my first time forging, but it is the first time I've had this problem - I usually get a little under forging temp, rather than over. Can anybody tell me what variable may need to change to keep the temperature at a workable level? Should I open up the top more or restrict the airflow coming in? Less fuel? Is it normal for a forge to burn over-hot and I just need to pay more attention? Should I just cut off the blower completely once it's up to temp until it starts to cool down?

Thanks,
Pete

Michael Pikula · Industry Professional

Hi Peter,

Sounds like you got the steel too hot, and it was starting to burn.

I would recommend getting an air source that puts out much less air, and noise, than a shop vac. If you are looking for cheap, I you could even go with a hairdryer, which happened to be my first air source for the first forge that I built. Also when dealing with solid fuel forges you always want to be paying attention and checking the temp of your work piece since it is very easy to overheat, and this is part of the normal learning curve.

Best of luck!
Michael

Peter Messent · Posted: Sun 14 Apr, 2013 3:42 pm Post subject:

Thank you! I was using a hairdryer for my old ground forge, but thought the shop vac would be a good step up - that'll teach me I guess Big Grin

I'll try again using the hairdrier and see how that works.

Thanks,
Pete

Tim Harris · Industry Professional

I find keeping the airflow minimal until a bit of a rev up is needed works best for me.

Until I got sorted with a decent blower with air control, the hairdryer was my choice as well.

Mark Moore · Posted: Mon 15 Apr, 2013 8:34 pm Post subject:

Battery powered inflatable swimming pool blower-upper thingy. Works great as an air source ......McM

Peter Messent · Posted: Thu 18 Apr, 2013 7:14 pm Post subject:

Thanks Tim and Mark - I just built a Tim Lively-style forge for the time being, and once the clay is dry I will try using the hairdrier. I've bounced between numerous designs over the last few days, building underground and above ground to try and find what works best. Forging temp is easy to achieve, but I'm finding it very difficult to reach welding temp - where I want it, at least. I did manage to get a nice big puddle of barbeque grill (the holes were too large, coals fell through and had enough air to get way too hot), but just can't seem to get the welding heat where I actually want it! Hopefully I will have more luck with the Lively forge, as I've been making knives for a while and feel like moving on up to axes.

Thanks,
Pete