Admanfrd Posted January 8, 2014 Share Posted January 8, 2014 Compiled by Adam Ford COMPARISON BORAX followed by BORIC ACID FORMULA Na2B4O7·10H2O H3BO3 MOLAR MASS 381.37 g/mol 61.83 g/mol MELTING POINT 1,369°F (743°C) 339.6°F (170.9°C) BOILING POINT 2,867°F (1,575°C) 572°F (300°C) DENSITY 1.73 g/cm³ 1.44 g/cm³ SOLUBILITY Water Water IUPAC ID Sodium tetraborate decahydrate (so-dee-um tet-ra-bo-rate dec-a-hi-drate) Trihydroxidoboron, Boric acid (tri-hy-drox-ide-o-bo-ron) DIFFERENCES BORAX followed by BORIC ACID Differences FORMULA Na2B4O7·10H2O H3BO3 BORAX much more complex MOLAR MASS 381.37 g/mol 61.83 g/mol Difference 319.54 g/mol MELTING POINT 1,369°F (743°C) 339.6°F (170.9°C) Difference 1029.4°F (554.111°C) BOILING POINT 2,867°F (1,575°C) 572°F (300°C) Difference 2295°F (1257.222°C) DENSITY 1.73 g/cm³ 1.44 g/cm³ Difference 0.29 g/cm³ In the end, You will have to heat the metal a lot less to be able to get the metal fluxed with Boric acid. This is JUST A REFERANCE SHEET I am NOT ADVOCATING FOR ONE OR THE OTHER, THAT IS YOUR CHOICE This sheet may be used as you want. Redistribution is fine by me Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted January 8, 2014 Share Posted January 8, 2014 Wax will melt even lower; but doesn't flux as well. More to it than melting point. Now one recipe for flux: Hrisoulas' "Metal Glue" has a number of different items in it to deal with the various different temp actions Quote Link to comment Share on other sites More sharing options...
Admanfrd Posted January 8, 2014 Author Share Posted January 8, 2014 I'm sure that there is another point, but i just thought someone would find this interesting. That last bit was just a conclusive statement thanks for reading Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted January 8, 2014 Share Posted January 8, 2014 What we need is a guide to how active various fluxing compounds are at various temperatures---sounds like a thesis topic! (And the arguments about how to measure "activity"...) Quote Link to comment Share on other sites More sharing options...
Admanfrd Posted January 8, 2014 Author Share Posted January 8, 2014 Metallurgists need to contribute something here because I dont know how to measure activity other than it's chemical potential to store heat. (which i dont know how to measure) Quote Link to comment Share on other sites More sharing options...
ianinsa Posted January 8, 2014 Share Posted January 8, 2014 Admanfrd, based on what I've seen smiths in Egypt, Syria, Kuwait & UAE use sand, the UK no flux and USA borax and borax mixtures and a couple That are also now fluxless. :) I think it's try something by all means but if you have something that works use it. I have tried all the above and I have managed all except the sand and believe me I've tried! ian Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted January 8, 2014 Share Posted January 8, 2014 Sand and glass were traditional wrought iron fluxes (along with rice straw ash...) Real wrought iron is prettymuch self fluxing anyway. If you get the metal hot enough to melt the scale then flux is not so important. The problem is that high carbon modern steels have trouble getting that how without burning and so fluxes really help prevent cottage cheesing or burning of such steels by over heating. IIRC: Practical Blacksmithing, Richardson, a collection of articles from a smithing journal from 1889, 1890, 1891; has a discussion of how the "modern" steels (Bessemer, Open Hearth, etc) required different fluxing and welding than the familiar wrought iron and wrought iron derrived steels. I was thinking on "activity" and if you could take standard samples oxidized to a standard level and then weigh them and immerse them in the flux at various standard temps for a set time and then clean them and re-weigh them to see how much oxidation was removed might be a possible method; but rather a pain to do. This is a rather armchair gedanken experiment though. Quote Link to comment Share on other sites More sharing options...
ianinsa Posted January 8, 2014 Share Posted January 8, 2014 I recon you might be shy on gedanke on this site should you be in the mood to try Thomas :D Ian Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted January 8, 2014 Share Posted January 8, 2014 One thing you left out of your consideration for the flux temps. I do add Boric acid to my fluix mix beause of its low melting temp, but you did not show what it is doing at the actual welding temps. If it used alone one needs to know that as well. Example of a test some one did is a borax test I saw where a person was "proving" borax is useless as flux. His testing showed it does not effect scale and added that it is not good to have the moisture on the steels. He forget that borax behaves differently at welding temps. His testing was done at room tempratures. At near welding temps its liquid, the water hgas evaporated, and its Ph is 2.2 which of course is very active on steel. So his room temp testing was of no value to a smith, except for hand washing. Context matters. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted January 8, 2014 Share Posted January 8, 2014 Exactly! So a mix that would provide an O2 barrier at temps from below scaling temp to approaching welding temp and an active aggressive flux at welding temps might be a good thing. (I think the "steel glue" flux was designed that way) and then there are the recalcitrant oxides like chrome where toxic fluorine is used.... So from an old post on this forum: "Steel Glue: Flux mix is as follows: 5 parts anhydrous borax 2 parts powdered boric acid 1 part powdered iron oxide (the real STUFF NOT the concrete dyes) 1/2 part Flourspar 1/4 part sal ammoniac This stuff sticks most anything together" Warning Use proper respirator with this mix Quote Link to comment Share on other sites More sharing options...
Rich Hale Posted January 9, 2014 Share Posted January 9, 2014 I have less shop time than I used to....When I do forge I am less intersted in trying new things or methods..I grab wot I keep on hand, for flux it is either twenty mule team or the same with a bit of boric acid in it.. .And I have used JPH's flux,,wonderful stuff. New folks may find the data a starting point to delve into how things work and why...I just like that they do workl. Quote Link to comment Share on other sites More sharing options...
Admanfrd Posted January 9, 2014 Author Share Posted January 9, 2014 I would LOVE to talk to my chemistry teacher about this... heck, maybe i'll record it. Quote Link to comment Share on other sites More sharing options...
oof Posted January 9, 2014 Share Posted January 9, 2014 Boiling at 572, wouldn't boric acid used alone be gone by the time you reached welding temps? mark Quote Link to comment Share on other sites More sharing options...
Admanfrd Posted January 9, 2014 Author Share Posted January 9, 2014 if you put it on just before welding heat it would probably be perfect. Quote Link to comment Share on other sites More sharing options...
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