Bronze

[21st century pict]

Hi, I found a nice big bit of rose wood washed up on the beach the other night, perfect for the scales of a knife or sword handle, so now I'm back in the mood to try casting a bronze knife.
So here's is my question, I can pick-up the copper all over the place no problem, I just have to walk out off town to the wood and gut the wiring out off the TV's and stuff people dump, " coincidently it's crazy, the people who fly tip on this road have to drive passed the local dump gate to get to the wood crazy " anyhoo I digress, I can also source some bronze from some car parts, so here goes, the big Q without forking out any cash, as I want to make it out of entirely scavenged stuff, what's made from pure tin? or where or in what can I find some Tin. cheers for any replies in advance.

 

[bobnewboy]

You will be extremely lucky to find any tin around as a material. Especially for zero cost. If you are very, very lucky, your best chance would be to recycle existing bronze from another source - e.g old sintered bearing blocks etc. Even then you will need to make your own firehearth and crucible that will withstand up to 1100-1200 centigrade, hardly a simple thing. The hearth is possible - I have done it on a Will Lord bronze casting course (see my second Flickr page), but the crucible is almost impossible to make yourself. Even Will Lord would tell you that.

 

[tsitenha]

Copper could come from CU water pipes, some tin mix can be had from linotype from old printing presses.

 

[21st century pict]

Cheers Guys, I was planning / hoping to make the crucible from local clay and just pour the bronze into an open cast mold of wood or clay then shape the knife from the billet, I don't know the fail rate of the bronze age crucible's, I have seen plenty broken fragments. Just looking into the bronze age crucibles and linotype now. Cheers again guys

 

[mr dazzler]

if you want b20 bronze (80%copper 20% tin) get on ebay and buy up a few cracked zildjian or sabian cymbals, melt them down and recast

 

[Tengu]

`Bronze` to an Archaeologist is pretty much any copper alloy.

Have a word with Blue Hills tin streams, in Cornwall, they stream for Sn.

 

[21st century pict]

if you want b20 bronze (80%copper 20% tin) get on ebay and buy up a few cracked zildjian or sabian cymbals, melt them down and recast

Hi Mr Dazzler,
I was hoping to keep it to around the average bronze age 10-12% tin mix, I have a mixed bag of old scrap bronze fittings lying around , I don't know what metals they are alloyed with, there is quite a variation in colour, but you never know, I might just use one big bit and go for it. I like the cymbal idea all the same, I have a couple of pals who were drummers back in the day, come to think of it, they were cracked to. Cheers Bro.

`Bronze` to an Archaeologist is pretty much any copper alloy. Have a word with Blue Hills tin streams, in Cornwall, they stream for Sn.

Hi Tengu
Your probably right, and I should just go for it, but I've been stuck on sourcing some Sn for to long now. Is streaming and panning the same thing?
Now you mention Cornwall that reminds me I need a lump o Serpentinite to to make a polished axe head some time. Cool now I have to go to Cornwall some time, oh nuts "Old Jamaica Inn" another tangent. Cheers.

 

[Tengu]

http://www.bluehillstin.com/

http://www.bronze-age-swords.com/index.htm

(Hes in Penwith, doing Swordfest 4th september...I think? Dave Budd knows for certain.)

Im not in Cornwall untill early september or I would ask around. (Im going a-viking.)

 

[21st century pict]

(Im going a-viking.)

Cool, have a blast :viking: https://youtu.be/hN_WEmNsrQI enjoy Bro,

 

[Dave Budd]

If you are going to find any tin free, unless you plan to strip the tin plating off a lot electrical components (contacts are often plated with a thin 10micron thick wash of tin before soldering), then you are pretty much going to have to smelt your own from the ore. Smelting tin isn't too tricky, not compared to smelting iron, but is laborious and will cost more in fuel than buying pure tin as an ingot on Ebay.

As for the copper element, you could use pipe and old water tanks, but electrical wire is a better bet as it is cleaner and won't have any surprises in the alloy (such as brass fittings, solder, paint, etc). Again you could smelt it as fo tin, but is more tricky and costly

Using reclaimed bronze. Unless you know what it is, don't bother. It may be a form of brass (containing very toxic zinc) or a form of bronze that is just as nasty (such as Ali bronze). Some alloys will melt more readily than others too. So PB1 or PB2, mostly seen in bearing and industry, have quite high melting points and need to be ept oxygen free when casting. Other alloys like Silicon bronze (used for sculptural things) cast freely and are easy to use.

Mixing alloys. Not a good plan, you have no idea what the final alloy will be and if you put something dodgy in then it can release toxic vapours, explode or just not melt together properly.

Crucibles. Buy a graphite crucible for £10, don't mess about with something that can explode or break when full of liquid metal! Sure you could make your own refractory products such as crucible and furnace, but you will need to work out the recipe of clay, temper and binder as well as shape and thickness.

Casting bronze is good fun, but don't make it more difficult than you meed to

 

[mr dazzler]

Hi Mr Dazzler,
I was hoping to keep it to around the average bronze age 10-12% tin mix, I have a mixed bag of old scrap bronze fittings lying around , I don't know what metals they are alloyed with, there is quite a variation in colour, but you never know, I might just use one big bit and go for it. I like the cymbal idea all the same, I have a couple of pals who were drummers back in the day, come to think of it, they were cracked to. Cheers Bro.

The other standard alloy that zildjian and sabian use is B8 cymbal metal which is 92% copper 8% tin, a bit closer to your 10-12% figure. Paiste use that too, and meinl. But beware some entry level cymbals are cheap pressed brass. If you check out their websites it tells you which ranges are B20, B8 or other cheapie metal.
The major cymbal makers are very fastidious about production quality, if they say it is 80/20, I would trust them

 

[21st century pict]

,, Mixing alloys. Not a good plan, Casting bronze is good fun, but don't make it more difficult than you meed to

Hi Dave Budd

I know some solders are very high in Sn, 70% one of them, a little lead helps the bronze flow better, more for fine detail in sculptures really, but 30% Pb is still way to high, I have a fair bit of bright copper lying around, no problem there. The bronze scrap I have is all different alloys, I can tell by the colour. DB Quote "Mixing alloys, not a good plan," No Worries,, I was going to try making a big Celtic Bronze Boar in wax and try the lost wax process. I did have a look at some nice crucibles for another job, I seen a guy melt gold instantaneously once in a crucible, electric arc, one flash and he had a bead of gold rolling around the bottom of the crucible, I was impressed. If I go for a crucible then graphite it is Dave. I know what you mean about not making it any harder than it need be, but I want to try making a tool primitive style, old school stuff you know, even if its just a Otzi type copper axe, its as much the challenge as anything else, but sourcing a bit of scrap Tin has always been the one metal that has got away from me. cheers Dave

 

[Tengu]

I have lots of 70%tin30%lead from old wargames figs.

Any way to get the lead out? Some chemical that likes lead but not tin?

 

[21st century pict]

The other standard alloy that zildjian and sabian use is B8 cymbal metal which is 92% copper 8% tin, a bit closer to your 10-12% figure. Paiste use that too, and meinl. But beware some entry level cymbals are cheap pressed brass. If you check out their websites it tells you which ranges are B20, B8 or other cheapie metal.
The major cymbal makers are very fastidious about production quality, if they say it is 80/20, I would trust them

B8 8% tin sounds nearly perfect, I have a pal who works in the local music shop, I'll ask him to keep an eye out for me, what are the very small cymbals called again? a high hat, a ride or a crash or something? cheers Bro.

 

[21st century pict]

I have lots of 70%tin30%lead from old wargames figs.

Any way to get the lead out? Some chemical that likes lead but not tin?

just checked it out on Wikipedia , sounds complicated, it would seem most of the processes are more about recovering the lead with the tin being a tin and lead chloride scum mix, now if it was the other way round that would be fine but not from what I have read so far. I'll keep and reading see if anything else turns up.

 

[21st century pict]

crucible that will withstand up to 1100-1200 centigrade, hardly a simple thing. The hearth is possible - I have done it on a Will Lord bronze casting course (see my second Flickr page), but the crucible is almost impossible to make yourself. Even Will Lord would tell you that.

Just researching some home made clay crucibles recipes at the moment , Silica sand and fire clay looks like it might make a viable crucible, adding carbon to the clay seems common, also powdered china pottery or graphite, even horse poo gets a mention, but as Dave Budd advised, if all else fails I'll get a graphite crucible.

 

[mr dazzler]

Hi hats are the small cymbals that are played together in a pair on a stand and they clap together with a foot pedal. Ride cymbals are big, heavy sometimes up to 6 or 7 pound weight, up to 22 inch diameter or even bigger Crash cymbals are thinner anywhere from 14 to 18 inch diameter usually. Very small ones are splash cymbals (8 to 13 inch diameter generally) or efx (effects cymbals)
B8 is used for entry level or intermediate cymbals, slightly cheaper than B20
This link might help you a bit.
http://www.moderndrummer.com/site/2011/10/what-you-need-to-know-about-cymbal-alloys/
It tells you which lines (there are hundreds these days!) are B20/B8 or others. Apparently Meinl and Zildjian have both produced some cymbals with B10 or B12....could be exactly what you are looking for.

LOL in 30 + years of playing I have never cracked a cymbal, but some heavier hitters do it regulalry. Once they DO crack they are rendered virtually useless as a decent instrument even though people try things like drilling holes at the ends of cracks to try to stop it splitting, or cut out an entire damaged section, or even just change eg an 18 inch down to a 14 inch. But the sound quality is invariably ruined. Thats why cracked ones are usually to be had for cheap on ebay.

Hope you get sorted and the project turns out well

 

[boatman]

Why not open cast copper to start with. Nice copper axe would be good but but but as indicated a crucible of molten metal is something to be cautious about.

 

[21st century pict]

Why not open cast copper to start with. Nice copper axe would be good but but but as indicated a crucible of molten metal is something to be cautious about.

I'm definitely planning on making a Otzi the ice man style axe some time, stunning looking axe, copper is a lovely metal when its polished, If I get hold of a big-enough lump of copper Ill just make it from that otherwise and as you said, its a open mold job. I read horrible story once about an accident with vat of molten lead OUCH very nasty.