ErictheRed1990 Posted January 2, 2012 Share Posted January 2, 2012 Now i know im doing something wrong but i cant seem to figure this out and its starting to ....XXXXXXX me off...lol at times it seems the metal will not get hot enough.. the coke burns well, and i have the metal buried in it and as sealed in there so little air escapes as possible...? but! it sometimes wont heat up enough..( im using a shop vac too :/) , BUT when it does heat up i pull it on out and when it hammer it it looks to be welded... but when i let it cools theres a VERY obvious seperation between the two pieces... any ideas on what im doing wrong here? Quote Link to comment Share on other sites More sharing options...
pkrankow Posted January 2, 2012 Share Posted January 2, 2012 If you have your fuel packed tight no air gets in so nothing burns and you don't have heat. You want the iron to be in the neutral part of the fire. What material are you using to practice welding on? did you clean the fire before attempting to weld? Are you using a flux? What type? Are you folding the end over to weld to itself or using two separate pieces? I have had success the first way, but not the second (still learning) I find taking a second (or even a third and fourth) welding heat helps make my weld stay stuck. Some bars of "mild steel" just won't stick for me. I use borax as a flux. Phil Quote Link to comment Share on other sites More sharing options...
Don A Posted January 3, 2012 Share Posted January 3, 2012 Also, if you are using a shop vac, you might be getting too much air. If you get the piece close to the grate, a strong blast can actually cool it. Otherwise, too much air = too much oxygen = mucho scale = no weld. You need a deep fire, gentle air blast, and patience to let the heat come up gradually. If it does stick, you might need to work through 2 or 3 (or more) welding heats to close all the gaps. You will need to wire brush and re-flux before each heat. Quote Link to comment Share on other sites More sharing options...
eric sprado Posted January 3, 2012 Share Posted January 3, 2012 Agreed: Air control is vital. You need a way to control the flow from that shop vac!!!! How hard are you hitting? A gentle tap is all you need to start the weld. Easy does it all the way around.You want the surface to look "greasy". Some folks don't like to see sparks,but I don't mind seeing a few to let me know I'm "there".Relax and keep practicing. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted January 3, 2012 Share Posted January 3, 2012 Note you can have a solid weld in the center of the piece but still have obvious lines on the outside edges. The break test is what proves a weld. Welding is something that an hour spent with a person who is good at it can save 50 hours of people typing about it... Quote Link to comment Share on other sites More sharing options...
kraythe Posted January 3, 2012 Share Posted January 3, 2012 I dont use coal but I would check into your flux and make sure it's a good brand. And I have an adaptation of the old maxim about discipline; spare the flux and you will spoil the weld. Also as Thomas says you can have lines still after welding. The only really good way to tell a good weld without 10k in equipment is to cut through it. Make practice pieces and then cut thin slices with an abrasive cut off wheel and inspect the result with a microscope or at least magnifying glass. And once you get that working you can try welding cable. That's a whole other pain. :) Quote Link to comment Share on other sites More sharing options...
ErictheRed1990 Posted January 3, 2012 Author Share Posted January 3, 2012 well i read somewhere that a silica sand works so i have silica sand which i ground down so its finer (by hand )lol. but ive seen stuff called "borax" in a grocery store its a detergent... thats not the same stuff is it??? but i never thought about the air flow coming UP will cool the metal i usually bury it pretty deep in the coal .... that could be a huge problem right there for me, but i have the shop vac on a ball valve so i can control it... i found that out the hard way when i started .....bloody burning chucks of (then charcoal) flying at me i looked like a retarded chicken dancing around hahaha. hmmmm for the first while i wasnt hitting too hard... buuuut as time went on i started to hit it quite a bit harder.. lol anger eh?. but ok thanks alot for the tips and advice guys. Quote Link to comment Share on other sites More sharing options...
divermike Posted January 3, 2012 Share Posted January 3, 2012 #1 dont be in a hurry #2 knock the scale and flux off prior to hitting it #3 if after 3 attempts you have not gotten it, start anew with fresh pieces #4 enjoy it without frustration, otherwise it's wasted effort. Quote Link to comment Share on other sites More sharing options...
pkrankow Posted January 3, 2012 Share Posted January 3, 2012 Yes, that is the Borax we are talking about. 20 Mule brand is the most common in the US. The ingredients are "sodium tetraborate" there are no soaps in it. The stuff is great, you can even make cloth fire retardant with it by soaking it in a solution of borax and water and letting it dry. The downside of this product is that it is the "decahydrate" form, it has 10 water molecules bound to the borax molecule. It will foam before it melts, so make a long handled spoon to apply it with. You can choose to melt it in the spoon, then it is easier to get where you want it to be. You can also dehydrate it by putting it in a pan in your oven at a high temperature for an hour or two. I have seen temperature recommendations from 350F to much hotter. I have not tried dehydrating my borax as it seems like a lot of effort for little gain. Borax is also available as "anhydrous" from pottery supply shops and other sources, but costs more. You can also "improve" on your flux by mixing boric acid into it. Boric acid melts, and evaporates, at lower temperatures than borax, so adding 10%-50% boric acid to the borax will increase (by lowering the cold range) the effective range of your flux. This is not necessary for simple steel though, but may help on alloys or brasses. Adding silica sand will extend the temperature range of the flux hotter, but is generally considered not necessary as borax is suitable to a high enough temperature for steel. Phil Quote Link to comment Share on other sites More sharing options...
ErictheRed1990 Posted January 3, 2012 Author Share Posted January 3, 2012 ahh ok well then ill have to go out and get some of this borax stuff and try again! thanks alot for the help! Quote Link to comment Share on other sites More sharing options...
freeman Posted January 3, 2012 Share Posted January 3, 2012 well i read somewhere that a silica sand works so i have silica sand which i ground down so its finer Go to the cleaning supplies section of your local grocery store and pick up a box of 20 mule team borax if you can find it. Toss some in a steel can and set it close enough to your fire that it cooks down to a solid. Bust that up and use the resulting powder as your flux. Works like a charm. Quote Link to comment Share on other sites More sharing options...
Jason @ MacTalis Ironworks Posted January 3, 2012 Share Posted January 3, 2012 And, again, as it can't be stressed enough... TAP it GENTLY together. Hitting it hard only serves to cause the molten metal and flux to spray out of your weld instead of bonding. I actually prefer the hydrous borax as the bubbling action tends to help "scrub" it deeper into your weld seams. Of course, that may be because the majority of welding I have done over the years has been pattern welding. I don't think it makes much difference when I am fluxing surfaces in drop tong welds and the like. Quote Link to comment Share on other sites More sharing options...
kraythe Posted January 3, 2012 Share Posted January 3, 2012 well i read somewhere that a silica sand works so i have silica sand which i ground down so its finer (by hand )lol. but ive seen stuff called "borax" in a grocery store its a detergent... thats not the same stuff is it??? but i never thought about the air flow coming UP will cool the metal i usually bury it pretty deep in the coal .... that could be a huge problem right there for me, but i have the shop vac on a ball valve so i can control it... i found that out the hard way when i started .....bloody burning chucks of (then charcoal) flying at me i looked like a retarded chicken dancing around hahaha. hmmmm for the first while i wasnt hitting too hard... buuuut as time went on i started to hit it quite a bit harder.. lol anger eh?. but ok thanks alot for the tips and advice guys. Oh wow. ... 1) Siica sand ground fine is VERY VERY bad for you. Not even metal casters use it anymore if they can avoid it. You need a real flux like borax. 2) You don't have to hit hard to weld, just QUICK. As soon as you yank it out you have to touch it instantly. If you have to reach for the hammer you are in trouble unless the rod is VERY hot. Once you pull it out, it starts dumping heat fast. Quote Link to comment Share on other sites More sharing options...
Tagg Posted January 3, 2012 Share Posted January 3, 2012 That shop vac is way to strong. Use a hairdryer on low or medium and it should give you plenty of air flow. Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted January 3, 2012 Share Posted January 3, 2012 Yes, that is the Borax we are talking about. 20 Mule brand is the most common in the US. The ingredients are "sodium tetraborate" there are no soaps in it. The stuff is great, you can even make cloth fire retardant with it by soaking it in a solution of borax and water and letting it dry. The downside of this product is that it is the "decahydrate" form, Technical complaint here.... Make up your mind please Phil, the 20 mule team is correctly labled as tetraborate, that is NOT 10 water molocules. the Decahydrate IS 10 molocules of water, and they are different, but your point made is correct. :D Quote Link to comment Share on other sites More sharing options...
Drewed Posted January 3, 2012 Share Posted January 3, 2012 Tetraborate is a salt or ester of tetraboric acid. Tetrahydrate is chemical compound with four molecules of water. But that is getting picky... Quote Link to comment Share on other sites More sharing options...
rockstar.esq Posted January 3, 2012 Share Posted January 3, 2012 Although I've only stuck a single weld so far, one thing I read over and over again in books is that the mating surfaces need to be rounded and aligned so that the centers touch first. The idea is that as the weld is pushed together, anything that shouldn't be there will get pressed out. I met a smith who added iron filings to his flux. He told me the filings will burn and sparkle just before the metal is at welding temperature. I don't know if he used cast, wrought, or pig iron for the filings. I'm not even sure if that would matter. I will say that his welds looked good despite all the sparkling. Good luck! Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted January 4, 2012 Share Posted January 4, 2012 Silica sand or ground glass was used as a flux for REAL WROUGHT IRON that loves temperatures that makes modern steels burn like a sparkler. *especially* when welding high carbon steels which weld (and destruct) at a lower temp than mild steel I would not suggest silica sand as a flux. Did we mention that silica sand was probably a bad idea? When shopping for Borax make sure you don't get "borax containing soap" but pure 20 muleteam borax. You might keep an eye out for Roach-pruf too as it's about 98% boric acid and so is often added in small amounts to borax to juice it's action up a bit. If you are welding in real charcoal most of the pile should be under your piece---with still a good pile on top. Charcoal uses so little air it would be hard to coke down most electric blowers for it. Quote Link to comment Share on other sites More sharing options...
Rob Browne Posted January 4, 2012 Share Posted January 4, 2012 Just scanned this thread for the size of the pieces to be welded and cannot find any mention. If this is a practice weld then make sure you are using metal of significant dimensions (old horse shoes are great) as thin metal cools VERY quickly and is hard to weld. Once you can weld the heavier pieces then you can progress to the finer work if that is your desire. Also, let it soak in your fire for a while to make sure its hot right through. This can take a bit of fiddling so the outside does not burn before the innards are hot enough but a gentle, steady air flow will help so your fire hot but not raging. Quote Link to comment Share on other sites More sharing options...
pkrankow Posted January 4, 2012 Share Posted January 4, 2012 When looking for roach powder for boric acid, review alternate names for boric acid (Google can help), there are a number of different chemical or trade names for boric acid. Know what you are buying. Phil Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted January 4, 2012 Share Posted January 4, 2012 As a comment on an important point Rob makes: I like to run the fire up *hot* and then insert the piece(s) to be welded and turn off the blast totally and go for a glass of water or a pit stop and let the piece soak in a reducing fire until it comes up to fluxing temp. The walking away keeps me from trying to rush the process. Of course I generally weld up 25 layer billets of band saw blade and pallet strapping and so heating them up without burning the outsides is a bit more tricky. Quote Link to comment Share on other sites More sharing options...
Maillemaker Posted January 4, 2012 Share Posted January 4, 2012 One word of advise that I received was to wait until the steel "Looked like butter melted in the sun" Practice is the absolute most important thing for learning how to weld. Keep a journal about your experiences, observing carefully. If you change how you do something, only change one thing at a time, and write down in your journal if it worked or if it didn't. Also, what weld are you attempting? A faggot weld or chain link will be easier than joining two separate pieces of iron! Quote Link to comment Share on other sites More sharing options...
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