Silver Solder

All, I have a project going on that will require a little bit of silver soldering..... Looking through the books it seems that the "kits" are
available (containing the silver solder and flux) for about $45 or so, (varies with supplier). Anyone know where I can get a "little bit" of silver solder and flux. Of course I guess I could just buy the $45 worth, and there will be a lot left over for my kids to throw away when I die..... Anyhow... I remember someone years ago (I don't think Weller) used to sell a small plastic tube of solder and a little tiny toothpaste tube of flux as a little kit. Anyone know if a little kit like this is still available? (Or is *this* the $45 kit in the catalogs?). Thanks. Ken.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Ken, What kind of silver solder do you need? And what size (diameter)? I have some that is used for steel to steel work I could send, and I have some that is used for brass/copper to brass/copper also. There is annother type used for stainless to stainless work, don't have that. Both kinds I have use the borax type white flux, which I don't have, you would have to get that yourself. Thats the same type used in brazing, I think. Steve Steven
snipped-for-privacy@netzero.net (Ken Sterling) wrote in message

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
There are a lot of silver solders so you might say a bit more about your project so someone can recommend which one to use. I would look up welding suppliers in the yellow pages and shop there. You ought to be able to buy silver solder and flux there for less that $45. Sears used to sell silver solder in kits, but I have not looked there for years.
If you want low temp solder that contains a small amount of silver try Lowes or Home Depot. The real deal needs a propane torch to melt it.
Dan
snipped-for-privacy@netzero.net (Ken Sterling) wrote in message

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Gang..... I guess I should have been a little more specific in my intentions: I'm building (just started) a miniature hit n miss engine, finished length about 12-1/2" with about 6" flywheels. The prints call for machining some parts from brass, and silver soldering them to other brass parts (these are pretty small, like a sight glass oiler), but also going to be turning out a crankshaft from 4140 steel, 1-1/2" by 3/4" by 12". The plan calls for placing two centers in the ends of the bar, one for the connecting rod journal, the other for the main shaft journal, turning out the connecting rod journal first, then silver soldering a small chunk of metal in the "gap" formed by turning out the journal, then moving to the main shaft centers to machine out the main shaft. The little block of metal is to keep the bar from deflecting in the gap that's left by machining out the connecting rod journal. It is only a temporary "brace" and will be removed after the main shaft is turned. I have never silver soldered anything, but have done lots of copper water lines, etc. Also do O/A welding, cutting and Arc Welding with a little Lincoln Tombstone 225A. So knowing diameters, silver content, etc., is an unknown to me. A little help would be appreciated in this area also. Thanks for the post.... I'll have a look at Sears and as others have suggested, places like Lowes, Home Depot, etc., but I don't know how much silver content I need. I'm kinda in the dark here...... Ken.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

In that case I think you want what I would call silver-bearing solder - basically a low-temperature solder with some silver in it to up the strength. If you heat your part enough to use real silver solder (aka silver-braze) it may not be the same shape afterwards.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I use superglue to hold the metal block. The purpose of the block is to prevent you from compressing the gap when you are turning between centers. The metal block does all the work, the superglue is to make sure the block doesn't fall out. I have made two cranks this way and it works well.
It is also possible to make a crank out of two pieces of drill rod and two flat plates. Many people have good luck with this. One guy told me he made a dozen cranks and they all held up well. I had one made and it failed quickly becuase the silver solder did not flow very well. After my failure I leave a couple tips from the successful guys. First is that you need about 2 thou clearance for the silver solder to flow. Second is to cut some tiny grooves in the plates with a small triangle file to ensure the silver solder flows into the joint well.
chuck
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Thanks, Chuck. Good tips... and since they come from successful "crank turners" they are evidently valid. I never thought about CA glue - I guess it would work as you mentioned - compression strength rather than tension. Good idea. (I still want to learn silver soldering(brazing) just because it's something I haven't done - and I'm just *that way*. Thanks again. Ken.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I have made two cranks from 4140 bar strock. They take me about 30 hrs to machine from solid stock. Personally I would not use silver solder for this job because of the risk of warping the crank from the heat when you remove the block. Super glue works very well for this job and breaks loose at 300 degrees vs 1000 degrees. chuck
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Good point - ever had a block break loose on ya while machining? I kinda like the idea of not having to heat it up too much to remove the block (of course you could probably just tap it and knock it out of there also as it's not set into any kind of a recess or anything). Ken.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I have done it twice without any problems. The hard work is done before you install the block. The hard work is completely finishing the rod bearing. After the rod bearing is done, band saw off the excess stock leaving the main section square. I like to square the main up in the mill so I can get it square enough to hold in a 4 jaw.
Make a block that fits the rod web gap and super glue in place.
Holding one main in the 4 jaw and the other end with a live center turn the other main round and leave it oversize. Don't take too heavy of a cut because all the torque is going through the rod. Flip the crank and turn the other side round but oversized.
Now that the main is round you so can use a steady rest. Set the crank up between centers. I use a steady rest next to the rod. The configuration is like this. headstock ->left main (steady rest) |rod| right main <-tailstock | | ----- and turn the right main to size.
Flip it around and turn the other main to size. when I flip it around I make a bronze sleeve to fit the main and use it as a bearing between the steady rest and the main shaft. Otherwise the steady rest might mark the main shaft.
After turning I polish the shaft where the bearing will run. Start with 400 or 600 sandpaper and finish with 1200 or crocus cloth.
A follower rest might work as well or better, but I didn't have one to try.
Superglue turns liquid at 300 degrees and the block just slides right out. Scape off the remains. I have been told by a famous clock builder that Acetone removes the leftover glue.
chuck
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Chuck, A question in inbedded in the following.....

The plans I have indicate to turn between centers, rather than using the 4-jaw and tailstock. Maybe between centers would be easier? And another question below...

Why flip the crank? Couldn't you turn both ends of the main shaft while in one mounting?

I do have a steadyrest, but the crank is only about 8-1/2" long overall and it would probably just be in the way. I think I also have a follower rest - but it may get in the way of the throw of the connecting rod journal. Thanks. Ken.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Initially I put one square end in the chuck and support the outside with a center because the effect length is 1/2 this way. You could turn the whole crank between centers but it long and skinny and you cannot take very heavy cuts. It painfully slow to reduce the square crank to round turning the whole crank between centers but of course it can be done. My

I use the steady rest for two reasons. One is that it is tough to turn a 10 inch long shaft (1/2 inch diameter) without taper. The steady rest running next to the rod bearing effectly cuts the lenght in half. The second reason is that you need to face the outside parts of the web and the steady rest adds a lot of rigidity for this operation.
I made both of my cranks on an atlas 12x36 lathe which is not too rigid. Simpler techniques might be available on better machines.
chuck
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Thanks for the response, Chuck. I, too, have the Atlas 12 x 36 lathe and I may follow your suggestions as you seem to be satisfied with the results you received using this method. Ken.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Ken Sterling wrote:
<snipped> turning out the connecting rod journal first, then

I'd suggest soft soldering that "brace" and using "Tinners fluid" (acid flux) to make the solder wet the steel. There's a branded acid flux ("Duntons") which is often available in small bottles in hardware stores. That way you won't risk raising the temperature of the workpiece enough to start affecting its hardness. If you insist on silver soldering it you're probably going to have to use your O/A torch, a piece that large is too big a load for the usual Bernz-O-Matic size propane/air torch.
Jeff
--
Jeff Wisnia (W1BSV + Brass Rat '57 EE)

"My luck is so bad that if I bought a cemetery, people would stop dying."
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Jeff, I was planning on using the OA torch anyway... mainly because I'm pretty good with it and familiar with the heat/areas affected by it. I will check out the flux at the hardware store as you mentioned, (Dunton's). I've never heard of it, but I would imagine it's similar to the acid flux found in plumbers acid core 60/40 solder. I'm looking forward to learning/doing a little silver soldering (brazing) as I understand it's considerably stronger than regular ol' solder, and the strength can be an issue in certain situations. Besides the fact that it's just a good thing to learn new stuff. Thanks for the post. Ken.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Or maybe make a split bushing similar to the rod end to fill the gap?
michael
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Wed, 09 Jun 2004 02:29:18 GMT, snipped-for-privacy@netzero.net (Ken Sterling) vaguely proposed a theory ......and in reply I say!: remove ns from my header address to reply via email
I just wish that a guy with a name like Sterling would stop asking about experimental-type engines.... <G>.

*******************************************************
Sometimes in a workplace you find snot on the wall of the toilet cubicles. You feel "What sort of twisted child would do this?"....the internet seems full of them. It's very sad
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Chuckle.... ain't ya glad my name ain't Maytag? <G> Ken.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Fri, 11 Jun 2004 02:40:02 GMT, snipped-for-privacy@netzero.net (Ken Sterling) vaguely proposed a theory ......and in reply I say!: remove ns from my header address to reply via email

Fascinating! Mid-mounted engine! <G>
And only about $150K in today's money! *******************************************************
Sometimes in a workplace you find snot on the wall of the toilet cubicles. You feel "What sort of twisted child would do this?"....the internet seems full of them. It's very sad
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@netzero.net (Ken Sterling) wrote in message

Any saw shop will have it on hand to resolder carbide tips. How much would you like?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.