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Charles dP

Coal Forge WIP

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Hi there. I was tempted to put this in WIP but decided it should live here :D. I am building my first forge and, after having considered cannibalising my barbecue and other things, finally decided to scratch build. Any comments are greatly appreciated but please forgive my welds as I have no real experience (before yesterday that is).

I decided to make the forge 1m wide, 50cm across and about 95cm high using a frame of 4mm thick 40mm equal angle mild steel and a table of 4mm sheet. The table slots into the frame so that I can replace it if I need to. The fire bowl is 12cm (5") deep cast iron pot from eBay.

First I cut the sections for the top frame and welded them together

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School boy error though, I welded the inside as well. Can't seem to get these ground down so I decided to use that frame as my support.

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I welded a second frame, this time leaving the inside alone

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Next I cut the four legs. I welded the 45' off cuts I had laying around onto the bottoms to give a bit more surface area to the feet. Sorry I thought I took a photo of the welded feet but can't seem to find it.

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Next I lay two legs parallel with the table frame on the end at 90' to the legs. These were then tack welded to hold in place an d further welded after rechecking. The odd looking thing in there is a welders magnet end-on.

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Once this was done, I placed the second frame 24" down from the top one and facing the other way. Again a lot of measuring, tacking, some choice words and finally welding.

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Voila. All I had to do now was slot in the table sheet, position the pot, mark and grind. You can just about see the feet weld on the far side.

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Sinking the pot enough took ages and the lowest I could get it to go is the handle thickness. Today I plan to get some bolts to hold it to the table (via the handles) and work on the blower assembly  I have a 480w bouncy castle blower (again eBay) and some free 5cm stainless steel tubing. I also plan to (eventually) put a side draft chimney on as well as raise the 'right' to stop my coal falling off  I have also yet to cut the grooves for working with larger pieces.

Unfortunately, this being England, it is now raining quite a bit and this may not progress until next time I'm now working on a dry day :mellow:

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Unfortunately I've managed to delete the original thread (don't ask). Basically Alan came to my rescue and told me the cast iron pot is too thin. Karim was kind enough to post some photos of his forge and may be so kind again...?

I did a bit of searching and managed to find someone to make a firepot for me (I could only get steel sheet in 1m x 2m lengths which cost more than getting Dave at Glendale Forge (Great Dunmow, Essex) to make me one. Dave is also happy to make more and even alter the spec if anyone needs a pot.

Edited by Charles du Preez

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This week I managed to make support bars for the table courtesy of Karim. They were welded on today.

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In the background you can see the table with the larger hole cut in for the new firepot which I picked up this morning :D

And here it is:

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The firepot is 10mm thick. Alan suggested this as a minimum  12mm or 15mm would have been better (correct me if I'm wrong please Alan). The vertical depth of the pot is 6". The top of the pot measures 12" wide and 10" across and the base is 5" square.

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The finished forge. Both the table and the pot only rest in place. Apparently I've been photobombed by my Springer.

 

 

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Of course, also today I fired her up. I am using a 480w bouncy castle blower that is waaaay overpowered. I had to make a hole half the size of the 4" pipe to let some air out. I'll be ordering a router speed controller tonight. Is the firepot supposed to glow red?

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Here's the forge with the blower on

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and my my first project. I am making tongs, but as I don't have any, I am using either end of a piece of mild steel and working towards the middle. At the end I will saw the piece down the middle to then join the two pieces up.

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Nice job on the tongs so far!  And no, the pot should not be glowing, that shows either way too much air or an obstruction in the fire diverting the blast onto the side.  Either a clinker or the fire packed too tight can do that.  But I suspect just too much air by a factor of twenty based on the flame height.  

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Yeah as Alan said you're running that thing at close to the heat of the sun! Air speed control is essential unless you fancy a puddle of metal every time you fire it up. Looking good though otherwise!

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Cool pictures and yes weee to much air ;)

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I suppose that's why I can see the level of coke actively dropping in the firepot :D

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Go with minimal air and work your way up. You'll be surprised how little it take to keep a fire at forging heat.

You might want to kick in the turbo when you need to get thicker stuff up to welding heat, but a breeze will do on something as thin as a blade.

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Thanks Don

My router speed control should be here on Friday but I'm hoping for Thursday as I have the day off. I'll crank it way down once it's going and take it from there.

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Fantastic work on the coal forge

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Thanks Rob

The router speed controller showed up and it works great. The forge has become a bit of a heavy beast to lug around the garden so today I attached some wheelbarrow wheels. I found a small offcut of I beam at a steel merchant which I welded on to hold the blower.

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The plan is to use some round tube to weld a 50cm U-shaped handle/tong-rack to the side opposite the wheels.

I forged the tongs a bit more and decided to separate the halves. As they are not quite evenly forged (yet), I used the centre of gravity to decide where to cut them. Just a plain hacksaw as I don't have hardies yet. This weekend I am hoping to complete the tongs.

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Well, I have made my first tongs. Learned a lot. Drilled the second hole squiff compared to the first, so they are a bit off-centre and will get sawn even. Riveted with some thin-ish rod that I upset the end on before cutting the section I needed. It was quite difficult and now I understand why it is called "upsetting" :D.

Thank you to all those who helped and advised. Another couple of tongs and I'll be ready to tackle a knife. I still seem to be getting the firepot too hot (a dull red now). Any ideas on why this is? I have the blower cranked way down. I am using Forge Breeze coke (for farriers). I think I just need to learn better fire control.

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The tongs look good!  As for the fire, probably still too much air.  That said, coke burns hotter than coal, so it may just be something to live with.  

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Thanks Alan.

What would make a good alternative blower? I heard that hair dryers have a tendency to burn out as they are not meant for prolonged use. Also they are noisy; my controlled blower is only a whisper. I kept reading about squirrel cage blowers but don't really know where you find them. Also, what kind of power are you looking for (evidently 480w is a bit o.p.).

Thanks.

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Something that moves around 150 cubic feet per minute / ~4 cubic meters/minute is about right at full blast.  These are little blowers.  In the US we rate motors in horsepower, but maybe 1/8 hp or 60 watts should be more than enough.  With the coke you're using you should only get maybe 15 cm of flame off the top at full blast.

Your current blower would be great for a smelting furnace, though!

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Great. I'll keep it for when I get to that part of the to-do list. I'll start keeping an eye out for a different blower ITM. The router controller they sent was the wrong one and rated to 1600w (about 3x the blower power). Is this a problem? It seems to work okay but sounds like it is struggling when I turn it go very low revs.

Thanks

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Thanks Karim. I noticed that is 2000w rated so unless your blower is meant for blowing up life-sized bouncy castles, my router should be fine. I hope to get some forge time on Thursday again so will see if I can get that turned any lower without the wheel stopping. I think I should probably also put some graduations on the face as it only has 3 large sections labelled low, medium and high

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Its Chinese cheapo crap so i went for safe, goes from almost 0 to max speed - that i use to clean up the firepot by blasting all remains out.

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I started out with a stripped down push vacuum cleaner, adapted the orifice where the bag went to accept a pipe, and put a cheap dimmer switch on it (the knob type for residential lights... 2 or 3 bucks). It would run from a hum to blowing the coke out of the pot. It was still running when I quit using it.

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Thanks Don. Good idea. What was the noise like on that cranked down? I've got to be a bit mindful of the neighbours. We are on good terms and I'd like to keep it that way.

Karim, what is the power rating on your blower?

Thanks.

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I use a bouncy castle blower on my forge. I have a small collection of bouncy castle blowers, actually, and they are not all made equal.

The one I use is the crappiest, weakest, and looks most like a kosher forge blower.

If I may add, modulating blast via blower motor speed is very inefficient. Much better to fit a slide valve on your forge, which allows you to turn the blast from completely ON to completely OFF and back again in seconds. I have been down the dimmer type route and it is not up to snuff. 

 

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1 hour ago, Charles du Preez said:

Thanks Don. Good idea. What was the noise like on that cranked down? I've got to be a bit mindful of the neighbours. We are on good terms and I'd like to keep it that way.

Karim, what is the power rating on your blower?

250W ratio 1/4 seems safe w Chinese stuff.

 

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