Hello all, long time, no see.

Been having a go at my first JABOD the past couple of days. Learning to start and manage a solid fuel fire without firestarters has been quite a humbling experience as i've only dabbled with propane before. This is more an exercise in attempting to achieve weld/white heat temperatures, which my diy gas forge wasn't able to reach. This will be using charcoal of course.

 

Images hopefully arrange in date order, can't seem to find a feature to spoiler them, apologies for the bombardment on your screens. Started off with a trench with a bick sized base. The next version was my most sucessful heat wise thus far; the one with the square profile, managed to get to a pretty bright orange with this one. I then tried forming a trench again, inspired by the famed JABODMKiii and others on here in a similar format. I then had a go making it more narrow in the hope that the smaller heat space would be more efficient, this didn't make much of a noticeable difference.

The square format was the most promising, bringing the stock to a bright orange, verging on yellow. I'm thinking the next layout could be like the square one, forming a lower fire box with a trench running across the top of it; In order to have a more defined area for the fire rather than chasing charcoal lumps up and down the trench as i've found has been a recurring issue when removing and replacing stock in the fire.

The air is supplied by a plunger matress pump, which is a 2l 1.bar 2000 cubic cm pump. I feel this may not be powerful enough based on the effort put into puming compared the results I got, or it could be the tuyre, which is 3/4". Or it could just be my fire management skills. All set ups have reached at least a dull cherry red.

 

Any tips/ideas for this next project are of course appreciated.

I think some of your issues may involve balancing delivering enough air/oxygen to the fire without blasting the light weight charcoal fuel out of the fire.  You might want to mash the tip of the tuyere down to spread the air flow or direct it to the side so that ot swirls around the fire area rather than blowing directly into the center or expand the tip of the tuyere to take a perforated end (similar to the bottom of a regular coal forge) so that it delivers more air but not at such a a high velocity or so concentrated.

Or, of course you could go to a heavier fuel such as coal or coke.

"By hammer and hand all arts do stand."

My first suggestion is legs for your box o'dirt. My back hurts just thinking about bending over that much.

Cheers for the tuyere idea George, i'll give it a try.

 

Don't worry N.S, Most of the back pain is coming from doing countless sets of 60 reps on the paddling-pool tier pump.

Rule number one of charcoal fires is KEEP YOUR FUEL DEEP. All of your setups (setsup?) here look too shallow to my eye (although I admit that may be a function of camera angle).

I'd also suggest moving your box into some shade for better judging of temps. You mentioned that the photos are from different days, in date order. The difference in colour for the same temperature of steel between the overcast-looking photos at the start and the bright sun in the later photos would be more significant than you think.

Welcome back to the dark side.

Like JHCC said make the fire deeper, at least 2 bricks high with dirt all around them. I would shorten up the fire pot, one brick on each side long ways and one on each end.

Remember that charcoal takes very little air compared to coal, coke so don't pump fast. We will get you  to welding temperature....promise.

I can’t control the wind. All I can do is adjust my sails. ~Semper Paratus~

In large part the box is too deep so you can't lay the stock deep enough without angling it downwards. Were it my forge I'd either cut the end boards down to maybe 2-3" higher than the bricks or as has been suggested stack another coarse of bricks on the trench.

If you're blowing charcoal around you are using WAY too much air. Charcoal likes a soft blast, slow down using the piston blower. 

Charcoal is a little tricky but it's just a matter of practice we ALL used too much blast when we were learning. Keep at it.

Frosty the Lucky.

To me it does not look like enough fuel. I use coal and my experience with charcoal is limited but i do know some smiths who do period reenactments. They use charcoal about the same way i use coal, a big pile with a fire in the middle and rake on new coal as needed. 

I've not played with charcoal much, but as I understand it as a "natural" material the quality can vary pretty widely.  Might be an issue for you as well.  Do be careful about using conventional red bricks for your forge.  Might not be an issue for charcoal, but I would be worried about spalling at higher temperatures.

Thank you for the input gents, it's a great help. Tried a deeper fire this morning, helped a good deal, also made the suggested cut outs on the outer boards to angle stock into the fire more easily. Dug out and shifted the box a to more shaded part of the garden, hope to try it out after work tomorrow. Also added a new, larger tuyere shown poking through in the third image, will see if it makes a difference.

Few more images; Deeper fire earlier today, an overview of the setup prior to move and an image of the newly set up JABOD.

Had another go this evening. Using the new, wider tuyere for the first time, along with a more generous helping of charcoal. Closest i've got yet. Think I may have even burned the (mild) steel for the first time. It's hardly a clean weld in that attempt, but I think it's done the job closer to the tip. Took approx 150 steady pumps to reach this result.

The piece with the wider end, despite having a broader surface area, didn't seem to catch the heat as well as the other. Reckon this is more to do with the angle it laid in the fire. The broadside of the faces were facing the tuyere rather than up-down, so the heat must've risen past it. Realised I was treating the tuyere as the source of heat for some reason with that one, derp.

 

Edging closer to the goal. May have a go at making something with this new setup soon. I certainly need a fire poker.

Looks like it was a little too close to the blast but not bad. Remember you don't want to pump hard, fast blast isn't a good thing. What are you using for flux?

Frosty The Lucky.

There is no flux save for ash collecting on the piece during the heating. It's mostly a product of brute force and ignorance. Was going rather steadier with the pump with more reps compared to previously, the tuyere change has probably helped with the result a fair bit too. Will make a note to go even slower on the pump next time.

Cheers again.

Ash from the fire is more likely to inhibit welding than help. 

What steps do you follow? If you have a clean carburizing fire you don't need flux. 

One important secret is no NOT hit the join hard, a heavy hammer is find just do NOT swing it hard. A firm solid tap with a 2lb. hammer sets welds nicely, then a couple more after a reheat and brushing will refine it well enough to forge. 

Giving it a hard smack can cause the pieces to bounce apart and commonly causes the join to shift in shear. Either tends to cause for a poor if any weld. 

Cheers back at ya. 

Frosty The Lucky.