Forge air supply question, for blacksmithing forge

>>1147309
>adjustable valve
yes

>>1147309
I imagine that's greatly simplified, but it's gonna be a pain starting an air pump underground. An adjustable valve is just gonna put more stress on the pump, just get a cheap triac PWM that works at the pump's rated wattage/current. And that better not be PVC pipe. You might want to make the air come out more dispersed around the pit, both so that fuel doesn't get down the holes and so you can get air to the fuel all around the pit and not just in the centre. I'd also make it so you can inject a liquid/gaseous fuel into the airflow and have the thing run off that, pretty sure it's more economical than charcoal, but don't quote me on that. More economical than both is to get some nichrome wire and make the furnace electric, of course it can't go above it's melting point, which is a cosy 1400°C. You'll also need some sort of lid to stop the heat from getting out. But it will need a hole in the lid so the right amount of heat can get out if you do have a blower.
https://youtu.be/Cte_LSYflAE

Fine tune the air with a inlet damper you mong

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>>1147309
How I would do it.

Lot's of details missing OP
We need to know how big the forge, the piping, the pump, the intended temperature and what types of metals you plan to work with.

>>1147991
Also, do you really intend of building this in a pit? I would user fire bricks to construct something above ground

>>1147991
>>1147992
>>1147975
>>1147911
>>1147312
>>1147311
Sorry for the lack of detail all and thank you for the responses. The forge will be above ground in the basin of an old sink held up on a frame with the pipework underneath the frame.

On my original question. I have realised that I can attach a potentiometer across the on/off switch. Varying the resistance on this should allow me to increase and decrease the air flow.

If anyone is interested I will be posting a picture of the forge so far in 22 hours time.

>>1148097
>potentiometer
Please don't, those things are insulated to like 12 volts, have a bunch of stray capacitance, and can only handle much less than an Amp of current, maybe a couple if you're lucky. They waste a bunch of power and heat up, and chances are you're going to electrocute yourself.

The only HV pot I found has a max power rating of 8W, so if your air pump pulls any more than 0.07A, you're going to blow it up. Also it's $250.

DO THIS INSTEAD:
https://en.wikipedia.org/wiki/Pulse-width_modulation

https://www.aliexpress.com/item/4000W-220V-AC-SCR-Voltage-Regulator-Dimmer-Electric-Motor-Speed-Controller-HT119/32709179019.html

>>1148097
what pump/fan are you using?

If he doesn't read the thread in another 11 hours and completes the thing using a teensy potentiometer as a "speed controller", I'm gonna laugh when he burns it to pieces. If he doesn't post at all I'm gonna assume he killed himself touching a badly insulated potentiometer shaft.

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>>1148182
>>1148191
>>1148443
Don't worry about the pump, it is a small battery power device so the potentiometer should be fine, haven't had a chance to test it yet what with work and such.

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Here is the set up as it looks so far.

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>>1148627

>>1148627
Nice cock

Why bother with Electronic speed control? Just make a simple sliding air gate and be done. Also be sure to fill that sink almost to the edge with Fire cement, a firepot that is too deep sucks big time

>>1149619
Thanks, I have fire cement on the way to me.

>>1149442

It's a big black cock with a juicy red ... head.

>>1149619

Heh, can 100% verify. Have a forge back at home from my beginning days and man it sucks. Big time. Problem is it gets extremly hot at the pit, but not hot enough to make big sections of steel hot. Also it fills up with ash. A lot.

>>1148626
>>1148182
op listen to this man pulse width modulation is the way to go.

also you are going to want a bigger blower, that tiny little "air pump" will do next to nothing in a forge unless it pumps something like 50 cfm minimum, recommended sources are, car ac fans, bathroom exhaust fans, basically any large centrifugal fan.

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>>1151085
I'll try the little pump and if that doesn't work I will have to make some kind of bellows. Your suggestions are good but I do not have a electricity supply in or near my barn.

>>1147309
Get bellows, your normal pump you have, and maybe an air compressor. Now you have three different air sources and two of them can be moved around.

BTW OP that is a pretty advanced build.

>>1148182
Nothing that you said about potentiometers is correct.

>>1147309
I built one of these with a blow dryer and used homemade coal. I was shocked at how quickly and evenly it heated and worked.

>>1151276
i'm all for making things work but a centrifugal blower will work wonders for you rather than that pump. btw how will you get power to the pump if you can't get power to a proper blower?

best idea get ive had today, get a busted car fan and attach a hand crank, maybe a set of bike gears or something.

>>1151356
The pump is battery powered.

I know a place were I might be able to find an engine fan. Also if I can find a small fly wheel I think to would work well with the blower.

>>1147309
http://blacksmithingtutorials.com/brake-drum-forge/