SReynolds

Sand Flux? Found a bag.

16 posts in this topic

Found a bag of 100% silica. It says so on the bag........So I heated a section of 1/8 by 1" wide with the Oxy Acetylene torch. Not the forge. I simply wanted to see what it looks like when sprinkled on hot (bright orange) But it didn't do anything. Unlike Borax, which melts even at red heat.I was looking for it to melt and run a bit.

So.....the smithing book says clean sand. Doesn't say what for sand or how clean. Free from rat droppings I assume? Looks clean to me as it is intended for sand blasting. Very fine sand,,,,cream colored with a few black specks (maybe dark brown?) Books says to mix one part Borax to two parts clean sand. This is for high carbon steel but I wanted to try with low carbon steel 1018. Books say iron and low carbon steel won't require any flux. Which I often times weld w/o a flux.

So will it melt and form a glass inside the forge fire? How about a mix of 50-50? Forget about it and just use the Borax I suppose?

I have the Homesteaders Blacksmithing book and it simply mentions sand. No borax. Just the sand. Not what for sand. Just says "sand"

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Sand is a hold over from the days of wrought iron. It welds at a much higher temp, and sand melts at a higher temp

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Number one. If you are a mod...............on this site....can you please let folks know where the topic/thread went to? Reading about forge welding tricks and tips under Blacksmithing but this topic is moved.............

No rhyme here.

Number two. Sand; it say in book that sand is used for higher carbon steels. soooo.........what gives? Sand wasn't used to weld wrought. nothing is used from books I have, as it simply doesn't require a flux. sooo..........back to sand. If you use sand top flux high(er) carbon steel ......and it melts at a higher temp.......how is it used to weld high(er) carbon steel? (cuz it welds at a lower temp/must be welded at a lower temp) 

that don't add up.

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Bad info exists in books, just isn't as common in print as on the net.  Low carbon aloys melt at lower temps than high carbon aloys. This is how one can use cast as hard facing. Sand melts at a high temp (glass) and one risks burning steel. Clean sand was used with wrought, infact as wrought contained a percentage of silica slag one has to get it nearly white hot to fore it to keep it from delaminating.  

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Moxon mentions using sand for forge welding: "take a little white sand between your Finger and your Thumb and throw upon the heating iron"  _Mechanick Exercises_ pub 1703 most written before 1700.

_Practical Blacksmithing_  Richardson, 1889, 1890, 1891; Vol 3,   pgs 101-104  Lists 11 fluxes ranging from "nothing" to quite complex ones including cyanide.  6 of them include sand; 1 is pretty much anhydrous borax and another uses powdered glass which might be considered an "alloy of sand"....

Sand is mentioned with regard to welding wrought iron and IIRC there is a discussion elsewhere in the book on switching to borax for welding the "new" bessemer steel 

As I recall the Foxfire book on iron working mentions sand and  suggests dirt dauber's nests as a different flux.

Japanese katana are welded up using rice straw ashes and clay.

I think this indicates that real wrought iron will weld pretty much whatever you do to it  and mild steel finds more active flux compounds useful though not necessarily necessary .

 

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When necessary for a particular weld sequence, either mild steel or wrought iron...Alan Knight (the smith I trained with) would use "silver sand" as a flux...I understood it was to protect the area behind the weld upset from being eaten away with successive heats.

Silver sand was sold as such in horticultural supplies places...Gardencentres...

I have a biscuit tin with some in which has been sitting in the forge unused and unopened for the last 38 years. I rarely fire weld and there is not much call for it with tig and mig welding...

Alan

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Sand is not a chemically well defined substance. It is the product of decomposited rock that later may have been sorted by moving in water or wind. This also applies to clay altough clay is formed from other types of rock. Silica sand, which is common in the eastern part of the US and is fairly pure silicondioxide, has a relatively high melting point - higher than iron in fact. However if mixed with soda, borax or certain other minerals, the melting point is lowered - this is what is done when glass making. Sands may have ower melting point because they are not pure silica.

I would assume that some of the silica sand flux recipies can be considered to be glass-recipies based on the originally available local sand and may or may not work depending upon the sand available to the smith.

Borax or (boron generally) has a tendency to form compounds with low melting point together with metal (and metalloid) oxides. This is why borax is a good flux. It will combine with the iron oxide to some kind of iron-boron-oxygen compound that has a relatively low melting point and will be squeezed out of the joint when forge welding.

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That is interesting gote.

I just did a search on the "silver sand" that I have, and found the description..."It consists largely of quartz particles that are not coated with iron oxides. Iron oxides colour sand from yellows to rich browns."

That would tie in with Thomas' quoted description of "white sand". 

Do you think that the absence of iron oxides and the presumable propensity of the quartz particles to attract them could be the reason 'smiths use it for a flux?

Alan

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I have no idea. It is an interesting thought. Considering the high melting point, pure silica sand would be fairly useless but glass - like Iron/steel - becomes soft before it becomes liquid. Silica is the same but the window of temperature, in which it can be formed, is smaller and higher.  Technicus Joe made  a point that Iron oxide has a lower melting point than Iron. Maybe something happens between the oxide and the sand. I have some very pure silica sand available. I will try it one of these days to see if it melts in the forge and how it adheres. I am not a good forge welder so I have always stuck to borax (Or C2H2  ;))

   

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Rehashing this old thread a bit because I was just reading the same references in "practical blacksmithing" mentioned above.  Adding to the mix of opinions from that book there is one reference which says he stopped using sand (uses nothing) and never went back.  Another specified "quartz sand".

Anyway...the issue got me thinking about sand in today's spectrum of things rather than 100 years ago.  You can now get pretty much pure dry glaze powers for ceramic use--so basically really fine powdered clear glass "sand" with no extra herbs and spices in the mix.  Looking it up, a small 6.4 oz container is about $ 1.49 USD and it drops from there as volume goes up.  There are "cone 5" versions which flow at 2200F (1200 c) and is right in there at the general steel forge-welding temperatures you are shooting for (according to a quick search of this site)

People mentioned in other threads about having some problems with moisture in borax fluxes as well as some lining-eating properties of the borax.  These glaze powders should not absorb water the way borax does.  I'm curious if anyone ever tried the old-school sand, comparing relative to borax.  Is borax really giving something that the newer pure sand powders aren't?  Borax just the current preference because it's cheap and easy as well as inertial habit?  

Nothing but following up on curiosity here to see if tech improvements have made "sand" a viable or even positive option again.  As a butcher of metals, I don't do enough welding to know the realities of it in more critical welding.

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I THINK sand as flux stopped being the standard when mild steel became the norm. Silica sand would blend pretty seamlessly with wrought iron and it's silica slag content.

Borax has a much lower melting temperature than sand, is caustic and will cover the entire joint surface. The more recent addition of boric acid is less contradiction than it sounds borax is a base boric acid is an . . . acid the results would be a salt. What boric acid does is melt at a much lower temp than borax and speeds up the oxygen barrier function or modern forge welding fluxes. 

Why is an oxy barrier important now and not for wrought iron? The silica slag in wrought has a lower melting temperature and forms a natural oxygen barrier, wrought iron is known for not rusting like steel. Steel on the other hand has no inherent oxygen barrier and so needs a more aggressive flux.

Of course that's just my opinion I could be wrong. -_-

Frosty The Lucky.

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Frosty,

You are right.

SLAG.

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6 minutes ago, jlpservicesinc said:

Thumbs up Frosty.. 

That brings a . . . visual I don't think I'll share here. Monday I had my "Welcome to Medicare, bend over and spread them" physical. THUMBS up Frosty! :o Eh . . . Er . . . cough cough.

Once again I'm my own straight line. I had to share the laugh once I stopped laughing myself.

Frosty The Lucky.

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11 minutes ago, Frosty said:

That brings a . . . visual I don't think I'll share here.

Commas can save you a lot of ... discomfort. 

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52 minutes ago, JHCC said:

Commas can save you a lot of ... discomfort. 

:lol: :lol: :lol: :lol:

Frosty The Lucky.

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