NguyenHoang

Yeah exploding crucibles was my main concern. The graphite crucible was heated slowly to remove any moisture, the little homemade ingot mould was twice fired and then slow heated as well. The forge (A JABOD) was converted to a 'furnace' with just an opening at the front and the rest surrounded by fire brick, just to keep the heat in and to stop anything from flying out (mainly charcoal, for what ever reason the charcoal I bought likes to violently explode). It was fun regardless, I am just curious about the weird steel copper baby that I created, I have no Idea what happened there.

Hey, hope everyone enjoys this little story of me getting mentally destroyed by copper I thought it would be fun to try melt down some copper to use for fittings for some knives. Using a charcoal forge, turned more into a furnace, I placed some stripped copper wire in a graphite crucible, aaaaannnnnnd…. the crucible either shattered or just completely eroded before the copper got hot enough (I warmed up the crucible slowly over 20-30 minutes to avoid temperature shock). Copper 1, me 0 tossed the copper into the forge to see what would happen, it melted and I got some rough looking copper. I took the crucible, cut off the base, ground down the sides so that the base and the crucible sat flush, and covered it in high temp refractory mortar. Placed the copper in it once it cured and hit it directly with a propane torch, aaaaaaannnnd… nothing. It probably needed something more insulating. Copper 2, me 0. placed it in the forge again. It survived longer than the new graphite crucible. However the graphite completely eroded within 30 minutes without the copper melting. With no surface to hold onto, the refractory didn’t look too safe to use so I binned it. Copper 3, me 0. I took a steel pipe. Forged the ends shut and then folded it up to create a little steel crucible. Aaaaaannnnnndd…. the copper refused to melt… until the steel melted and formed some abomination of steel/copper . The break in the steel was at the bottom yet somehow the copper traveled all the way up the pipe? Copper 4, me 0. Not willing to be defeated but with nothing else to use, I took my homemade ceramic ingot mould, copper inside and left it in the forge. Aaaaaannnnd…. it actually worked this time (kind of). The ingot had large pores in it rendering it unusable so I threw it back in aaaaannnnnddd… yep the mould cracked before the copper melted this time. so I made a little bowl from some mild steel, placed the copper it in and watched and waited for the copper melted and yep you guessed it… The bowl nearly melted completely, save for a few pieces, taking the copper with it. I don’t know if I just looked away at the wrong time but I swear the copper only melted when the steel started to melt. I am now inclined to believe the melting point of copper > tungsten (joking of course!)

I learnt my lesson after ruining a nice piece of 1075 just by smashing it with a hammer (my first post on here was about that ). Next chance I get I’ll try reduce the diameter of the pipe on the forge side.

I didn't think of that to be honest! (only a few weeks in so far so my brain doesn't think like a blacksmith.... yet)\ I'll give it a go with the spare 25mm pipe that I have and see if I can reduce the opening to 3/4inch / 19mm

Unfortunately I don’t have any smaller diameter pipe on hand at the moment I have changed the tuyere positioning to the side now and have made it more of a trench and it seems to be a lot better now, the fire spreads out much more evenly and longer than before.

Hey so I gave it and other crack before making any big changes. All I did was make the length of hose shorter, push the tuyere in through the firebrick by about half an inch and moved the side walls in so it was a little more narrow. It was better but still encountered the same problem from before where the fire or hot part was only confined to the front half. I stacked charcoal up to the top as well

Frazer I'm not too sure why I switched the Tuyere, in the last configuration that I had (coming in from the side) the entire base of the brick was glowing so I will likely go back to that design. I did have a lot of charcoal in there (nearly reaching the top the entire length of the brick. I was going crazy with the hand crank blower trying to make the fire longer so I burnt through quite a bit. I was thinking of creating a trench by cutting the fire brick diagonally (like a miter cut). I definitely want to remove the back brick so I have more room. I was thinking of cutting the back fire brick either in half or cutting it in 3rds and using a 1/3 piece of the brick as a back wall just to hold the sand back. If I do this, I can push the two side bricks back and If I cut the side bricks diagonally, I can use the cut off pieces to extend the trench. I hope what I'm saying makes sense with this horrible paint diagram. I would use the offcuts (coloured in red) from the two side bricks to extend the trench and maybe add the offcuts from the back firebrick(coloured in yellow) to prop up against the front wall to protect the wood from the heat. The Tuyere will come in from the side (haven't decided which side yet, the blower might block it on the left side and the blower will be a pain to move so the pipe will likely go over the blower kind of like in the picture and the hose will wrap back to connect or I'll place it on the other side and use a longer hose. Glenn The pipe is 25mm or approximately 1inch in diameter and 17cm / 6.6inches in length. I will definitely raise the Tuyere a little bit higher, having it on the bottom didn't work too well as the hottest part of the fire was located just in front of the Tuyere quite deep down. My goal is to put the Tuyere on the side and raise it slightly (and potentially angle it down a bit as was mentioned earlier).

Hey, little update here I decided to go with a JABOD design and so far I like it a lot. It’s filled with sand and small charcoal bits instead of dirt. It’s a lot smaller than most JABOD’s out there as I really wanted the portability to move it around the backyard. The hand cranked fan also works great and I attached it to the side of the box so it all moves as one unit. I honestly don’t know if this will work but I attached a copper/aluminium heat sink from spare laptop parts to the pipe tuyere at the back of the box to hopefully keep it cooler so the hose doesn’t melt. I ran it for about 1 and a half hours and the heat sink got plenty hot but I really don’t know how useful or effective it is. the only problem that I have into now is the fire is basically limited to a small area near the tuyere. I have the tuyere sitting basically flush with the firebrick as frosty suggested but I also made it so the tuyere is basically on the floor. I tried my best to get the fire to extend further out but it refused to get any bigger than that. Any recommendations on how to get the fire to be more elongated? I tried heating up some steel to test but it only reliably heats up about an inch. Sorry for so many questions everyone but I really appreciate all the help you guys have given me

I'm glad I was wearing the respirator then! (hope it did its job). Threw the piece away and all the charcoal that was in the forge with it just incase.

Ah I see, I fired it up and boy it was significantly stronger than my original forge, the whole base was basically alight. I was able to take it apart as others have suggested in this thread, a JABOD would be much better! But I'll keep that in mind pnut, I'll see if I can put the tuyere basically touching the floor in my next build

Apologies for the super late reply Thomas, I made another thread and completely forgot about this one. I definitely will work with some mild steel before attempting to work with the more expensive knife steels. Before I put the piece away, I did try alternating between the edge and the flat of the steel, so hit the edge once, flip and hit the flat, repeat until I needed to reheat. It definitely helped prevent the edge folding like it did when I first did it but the middle of the bar was so thin it just kept warping. I had to google what hammer and anvil dressing were haha. My anvil when I made this post was a very large, flat gate hinge screwed to a log, I now have a small 10kg (22lb) anvil that does have some somewhat sharp edges (it also has no way of securing it to a sturdy surface so that's a problem). The hammer (3lb) doesn't seem to have any sharp edges as far as I can tell. Both the anvil and hammer I have are in the two photos below Unfortunately I'm in month 2 of a 3 month lockdown so going out and finding metal to work with is tricky. I basically flipped our shed inside out finding any steel that could be worked, soaking it in vinegar and grinding it off to be safe. I did come across a piece of metal I was actually going to ask on the forums about. It was an old spanner, no rust at all despite sitting in the shed for probably a decade and was dark grey in colour or at least coated in something grey. I soaked it in vinegar, sandpapered it, then soaked it again and then decided to just use an angle grinder to grind everything back. It was magnetic and had a decent amount of sparks when I grinded it, I just thought it was cast iron or something and it was a nice thick piece that looked good to practice on. Upon putting it in the forge today, it took a very long time just to get to a dull red and a green crust formed over the metal (I had a respirator on and was in a open area just in case). This green crust ended up spreading to the charcoal somehow and I had bits of green charcoal in the forge. When the metal cooled, it was black and the crust looked like fried egg stuck to a pan (no joke! I'll put the photos underneath this). (After the two vinegar soaks and sandpaper but before the grinding, It had what looked to be air bubbles or something all over it so I thought it was just cast iron). I'd love if anyone could figure out what this metal could be! I checked the website (EziPier) but they had no information on what the spanner was made of

I may of got too excited and done a silly, I stuck the four bottom pieces of brick together with mortar (probably reversible right?). I'll see if I can get the tuyere higher or at least coming in at a downward angle, if not, I'll just have to fire it up an see how it goes. In hindsight I am starting to see how the box design might be a bit inconvenient with charcoal. When I wake up tomorrow I might have to do some redesigning

Hey everyone, I decided to go with the side blast as it seemed much easier than the bottom blast. Is how I have it positioned in the photos okay or should it sit flush with the base or is the height it’s at now okay?

Ah I see, I decided to take the easy route and purchased a hand cranked forge blower instead. Hopefully that’ll be more efficient and quieter than the hair dryer and less physically intensive than a hand pump. I am still torn on the tuyere design, the idea was bottom blast using a pipe with a long gap running through the middle ( like in the photo below). Charles however mentioned a side blast and that seems so much easier than having to carve out the firebrick and cutting a line down the pipe. Would it work something like how I have it configured in the photo below? ( the pipe will sit much lower, just using regular brick to test it )

XXXX, that double bellows looks a bit too complicated for me haha. That manual air pump ( or even a bike pump) might actually be a good fit for my forge!