Simon Wicks Posted May 3, 2014 Share Posted May 3, 2014 Today i learned my little forge can get up to welding heat and beyond. I was in the process of adjusting my tongs to hold some round stock to make a punch. I opened up my air valve (too much in retrospec) and turned to grab something from my work bench. I came back to find sparks poring out of my fire. I pulled my tongs out and i'd burnt the ends off! To make the best of a rubbish situation i tried to do a basic weld. I chopped off the burnt bit of steel (mild steel), folded over the metal back onto itself, applied some borax and crammed it back into the fire. After a few weld heats i was able to watch the centre of the fire turn from orange to yeallow then to white. Keeping the fire at this point i watched until i saw a few sparks from the top of the fire. I withdrew my work piece and hammered. Is this a correct way to determine forge heat or have i overheated the steel by this point? Most of the youtube videos i have watched on welding things like damascus billets have been with gas forges or in the case of coal forges you dont get to see the fire at all. I performed two heating/hammering cylcles, air cooled then ground the surface to check the weld. I didnt see any inclusions and it looked like a single peice of homogenous steel. From what i gather it has welded though i wont know how strong it is until i try some destructive testing of it. I wasnt trying to see if i could weld yet. It was on my list of things to try once i had made a punch and a better pair of tongs. But at least now i know i have the means to do it and i have done it successfully once (probably fluke but meh! :P ). I would like to know whether i'm doing things right or whether there are other signs to look out for? Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted May 3, 2014 Share Posted May 3, 2014 Welding heat depends on the alloy. For mild steel a few sparks are ok, for high carbon you are dangerously hot and for wrought iron you are ok to a tad cool. It also depends on your skill; I think Billy Merritt could weld locomotive axles with a kitchen match. If the day was particularly cold he might even light it!... Quote Link to comment Share on other sites More sharing options...
Simon Wicks Posted May 3, 2014 Author Share Posted May 3, 2014 Yeah this was mild steel..... i havent dared go near anything tool stee like. I guess if i'm getting it that hot with tool steel it'll end up like "cottage cheese"? I did that frequently as a kid at school. We had a gas forge that heated a pile of ceramic chips. I made more sparklers than useful tools with that thing - much to the dismay of my design and tech teacher. I'm stuggling to see the temperature of my work peice when its in the forge. There's too much stuff on top of it to watch it properly. I'm having to dive about at awkward angles to watch into the fire. Have i placed it correctly in the fire? Should i be placing it deep inside the hot spot or a bit further to the surface? Sounds like i might have to get my backside to someplace to learn how to do this properly. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted May 3, 2014 Share Posted May 3, 2014 Not to mention you DON'T want to be staring into the fire all the time without using proper safety glases with filters to avoid IR damage! Quote Link to comment Share on other sites More sharing options...
anvil Posted May 4, 2014 Share Posted May 4, 2014 try controlling your air flow and raising the temp slower. move some of the charcoal on the top with your poker so you can see the color of your steel or slide it out a bit to quickly do a color check. with practice, you will know the temp by how much time its in the fire and by the color of the heart of your fire. Quote Link to comment Share on other sites More sharing options...
EricJergensen Posted May 6, 2014 Share Posted May 6, 2014 With the light airflow that anvil is describing, your fire itself is just about at welding heat. So, when the brightness of the metal looks the same as the charcoal, you've reached welding temp. I find this fairly easy to judge at a glance. And, since it is relative, it's easy to do with welding shades on, in bright or dim light, etc. (Note: with thick metal section, you will need to hold at this heat for a bit to get full penetration.) Quote Link to comment Share on other sites More sharing options...
Simon Wicks Posted May 7, 2014 Author Share Posted May 7, 2014 Ah, good tips. Thanks guys! Quote Link to comment Share on other sites More sharing options...
Damastang Posted May 8, 2014 Share Posted May 8, 2014 Not sure about charcoal but in my coke forge you can see little tiny wispy sparks in the flames when the air is cut if the steel is at welding heat. It's pretty tricky to pick up on but once you can tell them apart from all the other sparks and embers from the fire it makes welding a lot easier. Quote Link to comment Share on other sites More sharing options...
Dan C Posted May 8, 2014 Share Posted May 8, 2014 With eye protection I watch the fluxed area to get a sticky appearance, waiting for sparks is too late. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.