Silver soldering

[Roger Pellett]

Phil (Dr Pr)’s post above exactly sums up the techniques that I have stumbled onto for soldering brass; Liquid flux, taking advantage of the latent heat of water for a heat sink, and avdab of solder on the the soldering iron tip.  I would add one other thing-  Find a solder that flows.  It seems that there are dozens of proprietary solders all advertised to have magic properties.  I have tried many.  For reasons that I don’t begin to understand some simply do not work for me.  For example, I have never had much luck with the solder-flux pastes.  While they work well for others, they don’t for me.  I don’t know why.  I have recently been using a lead free 1/32 in dia Weller formulation that flows beautifully (at least for me).

 

Druxey-  Regarding your jeweler’s trick, I suspect that the water is the heat sink.  The yellow ochre powder forms a paste to keep the water in place.  I use a tiny piece of wet twisted paper towel to do the same thing.  I have read that yellow ochre is used as a masque to prevent solder from flowing where it is not wanted.

 

Roger

[druxey]

Roger: there is very little water in the paste and it evaporates rapidly. The ochre must be the inhibitor, I think. Not much is needed, either.

[No Idea]

I also think if you haven't done any silver soldering at all before you may not know what you're looking for in a finished joint.  The flux tends to go dry and then blow up from the joint a little - it then looks like it's getting very hot and its so easy to take the heat away too early.  When the solder runs it looks like liquid chrome running around the joint.  I've silver soldered stainless steel to brass without any problems but it does take a lot of focused heat.

[allanyed]

21 hours ago, druxey said:

slurry of yellow ochre powder in water

Druxey

Great tip, thank you.  Do you know if yellow ochre tubed artist paint would work as well?

Allan

[druxey]

I don't know, Allan. Tube water color would be an expensive way to go and contains gum arabic which might inhibit the action. Powdered yellow ochre is inexpensive. For example:

 

https://www.amazon.ca/Icles-Ochre-Natural-Mineral-Pigment/dp/B073NPH91W/ref=sr_1_39?gclid=CjwKCAiAjPyfBhBMEiwAB2CCIj06luu1IY5HeJkdJAAG2XqKJa-BSQcHs5OXBn6kBINFpJnfXpebTBoCRyAQAvD_BwE&hvadid=595964043576&hvdev=c&hvlocphy=9000745&hvnetw=g&hvqmt=b&hvrand=241234424768893934&hvtargid=kwd-792993069&hydadcr=20572_13350556&keywords=ochre+pigment&qid=1677676446&sr=8-39

 

This will last you a lifetime of soldering! (Or you can re-market it to other modelers in 10cc packages.)

[hdrinker]

I’ve struggled and am still struggling with silver solder. Can’t seem to get even “easy” to melt with my mini butane torch. I thought using silver solder at different hardness’ would allow the successive joining of very small parts adjacent to one another without melting what I had previously soldered. But I’ve completely failed at this effort. Any suggestions?

Henry

 

This is a great discussion! I’m away from my shop for a few weeks, but will take all this advice to heart when I get back and post my results. Thanks to everyone.

Henry

[allanyed]

2 hours ago, druxey said:

This will last you a lifetime of soldering! (Or you can re-market it to other modelers in 10cc packages.)

LOL.  Thanks Druxey.   

[druxey]

Henry: Without seeing exactly what you are doing, it is hard to diagnose what your issue is. (It could be one - or more - of a number of problems.) Might I suggest you find a jeweler to teach you the techniques that you need?

[Snug Harbor Johnny]

On 3/1/2023 at 10:12 AM, hdrinker said:

I’ve struggled and am still struggling with silver solder. Can’t seem to get even “easy” to melt with my mini butane torch. I thought using silver solder at different hardness’ would allow the successive joining of very small parts adjacent to one another without melting what I had previously soldered. But I’ve completely failed at this effort. Any suggestions?

Henry

 

This is a great discussion! I’m away from my shop for a few weeks, but will take all this advice to heart when I get back and post my results. Thanks to everyone.

Henry

  Silver soldering is tricky business.  I did a few samples in shop class years ago, and the workpieces have to be very clean at the start and well fluxed.  We got the heat needed by using oxy/acetylene torches.

[64Pacific]

Reading Harold Underhill's Plank-on-Frame Models and Scale Lasting & Rigging Vol. 2, PG 40:

 

He says in reference to making scale chain, touch the area to be soldered (with flux) using a fine brush. Lay the chain on a charcoal block, and from a length of silver wire add fine filings alongside the area to be soldered then move along the chain with the blowpipe. He noted that you will see the silver filings jumping to the joint and when cool it will be soldered. 

 

Have been wanting to try this to build anchor chain for my current tug model but I've had no spare time of late.

 

 

[Roger Pellett]

Underhill appears to be doing it the hard way!  Of course he was writing many years ago and new tools and materials have become available since.

 

Unless oyou are planning to put your chain under considerable tension, high temperature silver solder is not necessary.  Lead free solders are now available in a wide range of diameters. I have recently been using .010” diameter solder with good results.  Like Underhill, I like the liquid fluxes applied with a small brush.  They do a good job of drawing solder into the joint.  Finally, I prefer a fine tipped electric soldering iron to a torch.  With the very small sizes involved here an electric soldering iron will fuse the joint instaneously.

 

Roger

[BANYAN]

I'm with Roger; I prefer the use of fine pointed irons, but in my case I use resistance soldering.  WRT silver solder (the item not the technique) I use products that are for different melting points with no issue.  However, as some have pointed out/suggested, these may not be true silver solders but rather solder with silver rather than tin content.  Either way and pedantics aside, I find them much stronger than normal soders, and the differing melting points in conjunctioon with the ability to dial up or down the level of resistance (heat), I find I can deal with very small parts effectively.

 

cheers

 

Pat

 

 

[64Pacific]

Very interesting, I've never had good luck with soldering, silver or otherwise when it comes to model parts. It always seems to take forever to heat the part that I intend to join, and rarely the parts are fixed together.