Soldering brass - trying to find low melt, lead-free solder wire

[Pennyalbert]

Hi. I am trying to find very low melting temperature (150c, 300f), pre-fluxed solder wire for use with costume jewellery. I can get this in the US but it has lead:

US Listing: This is silver coloured, prefluxed soft solder wire, with an acid core and a 300 degree melting point. Use in well ventilated area. Contains lead and cadmium.

Im having a lot of trouble finding a lead-free soft solder wire in Europe with such a low melting temp.

Can anyone help?

[Dennis]

You might consider this, which comes more cheaply as a paste, bu if you use wire, there is flux in a syringe (bottom of page) to go with it.

http://www.somersetsolders.com/tin-b...older-wire/p58

However I'm not sure whether bismuth is less toxic than lead. Dennis.

[ps_bond]

Is there a specific reason you have to go quite so low? Standard Multicore lead-free is only 227C MP, but is readily available (and pretty inexpensive).

[Pennyalbert]

Hi Dennis

Many thanks for your response. I looked at this but was told that bismuth is quite brittle and wouldn't hold up to wear and tear.

Penny

[Pennyalbert]

Hi Peter

I am trying to go so low so that I can use plated brass too without burning off the plate. I have seen them do this really successfully in the US, with just a soldering iron or even a hot air gun, but only with very low melting pointing solder (which sadly, contains lead and cadmium). I have spent all day today trying to solder using my little smith and my kitchen torch.

I am pretty useless at getting the higher temp solder to flow nicely and it does, of course, burn off the plating.

I am resigned to the fact that I will have to use raw brass and get it plated afterwards, but I am still having trouble at these higher temperatures.

To think I used to find hard soldering a challenge!

[ps_bond]

I am trying to go so low so that I can use plated brass too without burning off the plate. I have seen them do this really successfully in the US, with just a soldering iron or even a hot air gun, but only with very low melting pointing solder (which sadly, contains lead and cadmium). I have spent all day today trying to solder using my little smith and my kitchen torch.

OK, but... Does the plating really burn off at 227C and not at 150C? I've got a moderate amount of experience using rework heat guns and soldering irons, although not in the realms of soldering larger objects together. Usually very small ones.
Hard solder isn't solder, of course - it's actually braze.

[Pennyalbert]

Any advice would be gratefully received Peter! I really want to work out how to solder these delicate brass bits together at 220c!

[ps_bond]

If the solder will wet the metal satisfactorily, is it worth trying to do the job in a small oven? It'll ensure that the metal isn't conducting heat away from the joint.

Might be worth getting a cheap one rather than using the domestic one... Aldi had one in the other week for not much.

[Pennyalbert]

If the solder will wet the metal satisfactorily, is it worth trying to do the job in a small oven? It'll ensure that the metal isn't conducting heat away from the joint.

Might be worth getting a cheap one rather than using the domestic one... Aldi had one in the other week for not much.

That sounds like a really good idea. You can tell I'm a complete 'soft solder' novice though because, I have heard the term 'wet the metal' but don't really know what it means!


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[TeeDee]

You might consider this, which comes more cheaply as a paste, bu if you use wire, there is flux in a syringe (bottom of page) to go with it.

http://www.somersetsolders.com/tin-b...older-wire/p58

However I'm not sure whether bismuth is less toxic than lead. Dennis.

Hi Penny,
Long time no see. Hope all is well with you. If you're in Tavi at all do drop in to say hello.
That said, if you don't get anywhere with the 220ishC solders you may want to revisit Dennis's suggestion.
Yes - Bismuth itself is a brittle element but many elements when alloyed with other materials have completely different properties.
Bismuth is less toxic than lead and indeed is now used in alloy form (with tin I suspect) by wildfowlers in areas where lead shot is prohibited.
Looking at the data sheet it looks to have good tensile strength but that is not the whole story so it may be an idea to contact Somerset solders and see if the bismuth/tin solder alloy would be suitable for your application.