Gerald Boggs Posted February 15, 2009 Share Posted February 15, 2009 NO clue where you got borax lowering the melt temp of iron. That's why I wrote "I heard" :-)Boric acid is added to the plain borax to make the flux more aggressive Could you go into greater detail on this? Quote Link to comment Share on other sites More sharing options...
Mark Aspery Posted February 15, 2009 Share Posted February 15, 2009 What I understand about fluxing. Borax: Two: It dissolves the scale already present, making it easy for the scale to squirt out during the first blows of a well formed scarf. Three: I've heard that borax also lowers the melting temperature of iron, therefore making it easier to reach a welding heat. Gerald, My understanding is that the Borax chemically attacks the scale and puts it into a liquid form. Without this chemical process, we would have to wait until the scale melted and became liquid. Thus flux helps us weld at a lower temperature. So I think your point 'Three' is part of your second point. Quote Link to comment Share on other sites More sharing options...
Mark Aspery Posted February 15, 2009 Share Posted February 15, 2009 NO clue where you got borax lowering the melt temp of iron. Boric acid is added to the plain borax to make the flux more aggressive, I use it for higher alloys. I know many that prefer to use Sand, as using clean silica sand is common in many places. I don't know of any real proven reason to mix them. Steve, I don't know why Boric acid is added to Borax. My limited chemistry tells me that : Borax is a mix of two salts, acid and alkaline... and a bit of chemical water. There is more alkaline than acid so when it goes to work, it works as an alkaline corrosive. Adding acid would cancel more of the alkaline out. If you added just the right amount, you could neutralize the borax flux and make it as good as sand. Any ideas or thoughts?. Quote Link to comment Share on other sites More sharing options...
Woody Posted February 15, 2009 Share Posted February 15, 2009 Boric Acid H3BO3, Borax Na2B4O7. Sodium, Na, is an alkaline metal, it would tend to neutralize the "acid" in boric acid. The basic function of a flux is to protect the metal from oxidization and float off the impurites. Many smiths weld without flux, some weld with the dirt off the floor, some have secret recipes that are closely guarded. The basics of forge welding are start with clean metal. Flux lightly if you use flux. Bring to welding heat and use light hammer blows to set the weld. Most welds fail to take because of insufficient heat or hitting the metal too hard or starting with dirty metal. Flux will not lower the melting temperature of metal as far as I know. It has been stated on another blacksmith forum that if the metal were perfectly clean it could be welded at room temperature so perhaps the cleaner the metal the lower temperature at which welding will take place. Quote Link to comment Share on other sites More sharing options...
Mark Aspery Posted February 15, 2009 Share Posted February 15, 2009 Boric Acid H3BO3, Borax Na2B4O7. Flux will not lower the melting temperature of metal as far as I know. It has been stated on another blacksmith forum that if the metal were perfectly clean it could be welded at room temperature so perhaps the cleaner the metal the lower temperature at which welding will take place. This has been my experience. Not necessarily how clean but how smooth and clean on a microscopic level. In a machine shop, if you have a highly polished (smooth) leveling plate made of steel and place a calibrating block (again polished) for a micrometer on it, removing all the surface oil first (clean), they will stick - maybe not well - but they will tack if given sufficient time. Pressure and time.... isn't that geology? Re boric acid. Will the boric acid alone melt into a glass or does it need to be suspended in something -such as borax- to be held in place?:confused: Quote Link to comment Share on other sites More sharing options...
Gerald Boggs Posted February 15, 2009 Share Posted February 15, 2009 Borax and Boric acid: I'm still a bit confused, what has happened to the Borax after it's been turned into Boric Acid that mixing the two as a flux, is an improvement over using each alone. So far Mark has come up with the "makes sense" explanation on why to mix the two. The alkaline gets neutralized by the acid. Which would explain why some mix Borax and Ammonium chloride together as a flux. If one looks around, you can find Boric Acid listed as the main ingredient of the Anti-Borax fluxes. Which would lead one to conclude that Boric Acid alone works pretty good as a flux. I already know that Borax does the same. What I'm, as I already have wrote, still fuzzy on, is the mixing of the two. Many smiths weld without flux, Woody, I fall into that catagorey. 80% of the time, I don't use any flux and get forge welds that are just fine. It's when I'm doing something tricky (or someoone is watching) that I like the extra help. Quote Link to comment Share on other sites More sharing options...
Woody Posted February 15, 2009 Share Posted February 15, 2009 (edited) To condense this down to technical terms, it's whatever works for the particular smith. If the weld sticks, it's magic, if it don't, it's bad karma. I use boarx for everything, however I have never tired to weld some of the medium chrome alloys etc. For that you might need something more agressive and much more toxic. This may be of some help to your http://www.iforgeiron.com/Stories-000-100/s0002.html Edited February 15, 2009 by Woody add additional info Quote Link to comment Share on other sites More sharing options...
Mark Aspery Posted February 15, 2009 Share Posted February 15, 2009 (edited) Borax and Boric acid: I'm still a bit confused, what has happened to the Borax after it's been turned into Boric Acid that mixing the two as a flux, is an improvement over using each alone. Gerald, Firstly let me say that I am answering well above my pay grade. Borax is a mix of two salts. An Acid and an Alkaline. The acid (already contained in borax) is Boric acid, the alkaline is Sodium Hydroxide (lye) -again, still contained within Borax as you buy it in the box. When the two get to ducking it out the Sodium Hydroxide wins making borax slightly basic or alkaline. This alkaline is corrosive and will attack the oxides present on the surface of the steel-dissolving them. Adding more acid will take away the alkalinity until there is no more corrosive ability within the mix-it is neutral. Adding then more acid at that point will make the mix acidic-back to being corrosive. I am presuming that there is no saturation point at that one becomes suspended in the other rather like anti freeze and water. I don't know the action of Boric acid and what it likes to eat -oxides, parent metal or not fussy. So why just not add the boric acid to the weld without using the borax - that is where I am at a loss? Answers anyone? Sorry to labor the point. I had two fluxes -both worked very well. The container on one degraded and broke. I combined the two thinking I might be creating a 'super-flux' - a big flop. The combined flux didn't do half the job as either of the fluxes would individually. Edited February 15, 2009 by Mark Aspery Quote Link to comment Share on other sites More sharing options...
Alwin Posted February 16, 2009 Share Posted February 16, 2009 I use boric acid with some iron oxide mixed in for welding higher carbon steels- nothing on mild steel. One benefit to boric acid is that the weld made with it doesn't leech that white stuff over time. I am guessing that white stuff is a salt, though I really don't know. Plain boric acid does work well by itself as a flux and is available as a roach poison for those who don't know. Quote Link to comment Share on other sites More sharing options...
Dutchmancreek Posted February 16, 2009 Share Posted February 16, 2009 This has been my experience. Not necessarily how clean but how smooth and clean on a microscopic level. In a machine shop, if you have a highly polished (smooth) leveling plate made of steel and place a calibrating block (again polished) for a micrometer on it, removing all the surface oil first (clean), they will stick - maybe not well - but they will tack if given sufficient time. Pressure and time.... isn't that geology? Re boric acid. Will the boric acid alone melt into a glass or does it need to be suspended in something -such as borax- to be held in place?:confused: Highly polished gage blocks "wring together" easily. Some people think they are magnetic, but it's the surface finish that does it. Proably the same with welding. I know of one artist blacksmith who uses straight boric acid (roach powder) as flux with amazing results. Of course many rears of experience probably also contribute. Quote Link to comment Share on other sites More sharing options...
Woody Posted February 16, 2009 Share Posted February 16, 2009 If you use Boric Acid for flux, buy it in the drug store, they sell it very cheap as opposed to Roach Powder which is more expensive. I have never had a problem with white stuff leaching out of my welds, if it does I am thinking that the weld was not completely joined. Quote Link to comment Share on other sites More sharing options...
Alwin Posted February 16, 2009 Share Posted February 16, 2009 Next time I will look in the drug store. I know a lot of smiths who have used borax and had a little white residue show up on weld sites later. Visually the welds looked joined but who knows. Maybe some of the others who use borax can tell whether they have had that experience. The flux recipe I was given was, I'm pretty sure, half boric acid and half iron oxide. It is only when I am working with higher carbon steel that i use it, but it works great then. Quote Link to comment Share on other sites More sharing options...
dimenickel Posted February 16, 2009 Share Posted February 16, 2009 the mp (melting point ) of iron oxide is quite high... borax lowers the mp ... as far as i understand.. ... once the oxides mp is low enough it will become liquid.. Quote Link to comment Share on other sites More sharing options...
Gerald Boggs Posted February 16, 2009 Share Posted February 16, 2009 Come on guys, this should be a subject of interest to every smith on this forum. I started it to try and get us thinking and talking about flux and why we use it. If one is welding mild steel to mild steel, one doesn't even need to use flux to weld. So why use flux at all? Well for one thing, it can be a big help. It helps overcome any problems in the fire that would interfere with the weld. Like I posted, if I'm going to have problems with a weld, it'll be when I've a audience. Using flux helps me overcome the stage fright :-) But back to the question first asked, why mix borax and boric acid together? Why use sand and borax? For the first I have no answer, if you visit the web site of Superior flux, Superior Flux & MFG. Co. you'll find lots of different mixes of flux, all claiming the same results. Maybe it's true and one works as well as the other. So back to the start of the thread, why mix them? I not suggesting that its wrong to mix them, just I don't understand why For the second, I have a idea and it goes back to the "Olde days" Back in the day, most smiths were using wrought iron, which with the silica already in it, didn't need flux, it was built in. So the only time one need to use flux was when welding iron to high carbon steel i.e. an axe. Sand was readily available and this is important, inexpensive. We often forget how much was done by barter back then. Hard money was hard to come by and borax would have cost money. As borax became more readily available, it started to find it's way into the shops, but still it's hard to break old habits and rather then simply use borax, it was mixed with the sand to make it go further. Remember, this is a guess. But a guess based on understanding how much was done, not because it was the best way, but because it was the best way they could afford. So here it is Monday morning, anybody with ideas? Quote Link to comment Share on other sites More sharing options...
jimbob Posted February 16, 2009 Share Posted February 16, 2009 Hey Gerald you were taking about iron filings in the flux ...about how much do you add. I like the idea of it sparking before you burn the steel...kind of a signal Quote Link to comment Share on other sites More sharing options...
Reid Neilsen Posted February 16, 2009 Share Posted February 16, 2009 I guess because store bought borax is probably just more commercially available. You can buy it at your local grocery store in the laundary detergent section. That would be my guess. it is just easier to come by. I only weld with good old borax as a flux. It sticks on contact, melts and coats nicely. I very rarely get inclusions and oxidation in the weld. Just my humble opinion. Quote Link to comment Share on other sites More sharing options...
Gerald Boggs Posted February 16, 2009 Share Posted February 16, 2009 Jimbob, I haven't actually mixed my own stuff, but I've heard of people that do. Some started because they felt the old cherry heat worked a lot better then the new. If you visit here, you can see the mix for new Cherry Heat and EZ Weld are both about 35-45 percent steel chips. Superior Flux & MFG. Co. Mr. Neilson, it's not so much which to use, but why mix the two. What's the benefit? Anti-Borax No. 2 is a mix of both. Why? While we all cross our fingers when we forge weld, or at least I do :-) It's not luck or magic that makes it happen. So if I'm doing something, I like to understand the WHY along with the HOW. Quote Link to comment Share on other sites More sharing options...
Frosty Posted February 16, 2009 Share Posted February 16, 2009 I've never run a head to head comparison but it SEEMS my mix of 1pt boric acid to 4pts borax works better than plain borax. I'd buy a commercial flux if shipping weren't ridiculously high. A 5lb tin cost $32.00 but shipping UPS was $37.00 per tin and I got no reply when I asked if they'd ship via USPS flat rate, they could send four tins for around $15.00. I don't do a lot of forge welding and am a looooong way from a chemist. You've got me curious though and next time I have some free time I'll try dong a comparison and will let you know how it goes. Frosty Quote Link to comment Share on other sites More sharing options...
Gerald Boggs Posted February 16, 2009 Share Posted February 16, 2009 Frosty, that's what I'm thinking of doing. In particular, if used alone, does boric acid welds white up after a period of time. Because that's the only issue I have with Twenty Mules borax. Maybe some of the guilds would get in on this and do a series of blind testing. I'm going to Dan Boone's Pasture party and the BGOP's Spring Fling this year. I could get mixes ready and see if folks would participate in a blind test. Quote Link to comment Share on other sites More sharing options...
Woody Posted February 17, 2009 Share Posted February 17, 2009 To my way of thinking, any weld that leaches white stuff is not completely fused. If the weld is completely fused, the flux along with any disloved goop in it are forced out by the initial hammering allowing the clean hot unoxidized surfaces of the metal to meet and be fused together under the hammer. Quote Link to comment Share on other sites More sharing options...
Frosty Posted February 17, 2009 Share Posted February 17, 2009 Gerald: A blind test would be a lot more objective. I was just going to do some welds with the different components and the mix to see what I think. I don't care which theory is better, I only want the easiest most sure welds so THINK I'd be objective in my testing. . . Still. That's to my way of thinking too Woody. Then again What I think often just ain't so. Frosty Quote Link to comment Share on other sites More sharing options...
Alwin Posted February 17, 2009 Share Posted February 17, 2009 Boric acid alone when used as a flux does not create the white residue that borax does. That is my understanding and one of the main reasons people use it instead of borax. I would love to see a strength test of welds made with different techniques. Are welds with flux as strong as ones without? Is a weld with a flux that has iron oxide as strong as one without? etc. Quote Link to comment Share on other sites More sharing options...
Woody Posted February 17, 2009 Share Posted February 17, 2009 I have welded up many damascus billets using only borax, I have yet to have one develop white residue. 20 mule team borax melts into a black glass like substance at a red heat, in fact borax is a major ingredient in glass. I have never experienced a problem with borax, perhaps some poeple are confussing Boraxo, a hand soap containing some borax, with 20 mule team borax. Quote Link to comment Share on other sites More sharing options...
Alwin Posted February 17, 2009 Share Posted February 17, 2009 In making damascus the acid etching of the final product might halt the residue which I suspect is a salt from being formed. The white residue isn't something that forms right away in my understanding, it shows up over time. Quote Link to comment Share on other sites More sharing options...
blksmth Posted February 17, 2009 Share Posted February 17, 2009 (edited) A long time ago, if I remember corectly, I read in an ABANA affilliate newsletter that when the old E - Z Weld Anti Borax Compound Company with a 1902 pattent and located in Fort Wayne, Indianna sold out to The Superior Flux & Mfg. Co. located in Cleveland, Ohio that the new company acquired, in the purchase, several train cars full of wrought iron filings which were apparently used in the old E - Z Weld mixture and probably in the new mixture. Lots of blacksmiths say the old E - Z Weld was better than the new E - Z Weld so maybe they ran out of wrought iron filings? The current Anti-Borax E - Z Weld has iron filings in it which are hard to remove from the forge weld area. The same company the Superior flux & Mfg. Co. also makes Crescent Forge Welding Compound, which does not have the iron filings in it. The current E - Z weld can says it "Contains silica powder - avoid breathing dust". That same statement is not on Crescent Forge Welding Compound. Borax (20 Mule Team or Anhydrous) which is not highly acidic at room temperature becomes highly acidic at a high temperature such as 2000 degress F. In addition to coating the metal to keep the air out, the acid cleans the metal, while floating the crud out. I watched a video where an old German forge welds logging tools with an acetylene torch. He uses hydrated lime as a flux available at agriculture and garden supply stores - it is cheap. When welding without flux, it is helpful to have a powerful blower that will very quickly heat the metal to the welding heat, which must be at a higher temperature than when using flux. The problem, for even those that forge weld often without flux, is that there is not much difference between the forge welding temperature and the temperature where the metal is too hot, burns, and is crumbly (A36). Also all A36 doesn't seem to be the same and some works better than others. Nevertheless, some good blacksmiths such as Tom Ryan of New York City makes all his welds, and there are a lot of them, without flux. He makes very high end gates, railings, etc. I make a flux out of anhydrous borax and add 10% boric acid and 10% iron oxide (either black or red). I'm not picky about the exact formula. I like it, but I also think 20 Mule Team Borax is about as good if you get use to using it. Peter Ross uses borax and E -Z Weld. He says that at the time of the American Revolution (his specialty), in 1776, borax was available and in use. Thanks for listening and now you know everything I know or at least think I know, Edited February 17, 2009 by blksmth Quote Link to comment Share on other sites More sharing options...
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