Two Silver Soldering Questions

This forum is dedicated to the Live Steam Hobbyist Community.

Moderators: Harold_V, WJH, cbrew

matthew-s
Posts: 8
Joined: Mon May 14, 2018 7:51 am

Two Silver Soldering Questions

Post by matthew-s » Mon May 14, 2018 10:39 am

Hi -

I am new here, and new to the hobby. I am building a Kozo A3. I have a decent portion of parts for the tender trucks complete (or nearly complete). Most everything except the arch bars, and silver soldering the columns.

1) I have EasyFlow 45 solder. I also have the dark (black?) flux from Superior. Do I need the white flux for parts of this size (relatively small)? Reading the board it seems like folks use both, but I don't want to burn up the column assemblies.

2) I made a milling mistake on one of my lower bolster. I offset the slot that locates the columns by ~0.010". Is it reasonable to use silver solder to build the brass back up on the short-side and re-mill the slot, or should the solder be used for affixing parts to one-another? It would be nice to save this part and the machining that has gone into it.

Thanks.

Matt.

User avatar
Builder01
Posts: 455
Joined: Mon May 18, 2015 5:26 am
Location: Erie, PA

Re: Two Silver Soldering Questions

Post by Builder01 » Mon May 14, 2018 11:21 am

Hi Matt,

Black flux works fine, even for very small parts. Since I have discovered it, I use nothing else.

As for building up your milling error, it might be difficult to build it up with silver solder. Silver solder flows are pretty flat, but, you could silver a small piece of brass to the spot in error then and re-machine. If you want to build up just solder, experiment on a scrap and see what happens.

David

jcbrock
Posts: 300
Joined: Tue May 22, 2012 7:50 pm
Location: Oregon

Re: Two Silver Soldering Questions

Post by jcbrock » Mon May 14, 2018 12:39 pm

Welcome to the forum. I second David's answers. I use black for everything and I would try soldering the brass shim into the slot as he has written. Good luck on your build.
John Brock

10 Wheeler Rob
Posts: 1428
Joined: Tue Mar 21, 2006 2:44 pm
Location: East Hartford, CT

Re: Two Silver Soldering Questions

Post by 10 Wheeler Rob » Mon May 14, 2018 2:58 pm

Get a few fire bricks to solder on making a three sided hearth. Holds the heat in nicely when working on small stuff. I have found that MAPP gas seems to work better than propane, for me anyway. I also use the black flux for everything.

Rob

User avatar
Bill Shields
Posts: 5101
Joined: Fri Dec 21, 2007 4:57 am
Location: Somewhere in the World
Contact:

Re: Two Silver Soldering Questions

Post by Bill Shields » Mon May 14, 2018 5:04 pm

you can get the bricks CHEAP from a place that supports fireplaces / stoves.

RUTLAND PRODUCTS firebricks => $30 for a set of 6

for many, +/- 0.01" is considered within tolerances..remember you are building a loco not a watch.

to add to David's suggestion -> if you are going to add a piece of brass, you may want to consider removing MORE material so that you can add a significantly sized chunk of brass....trying to add 0.01" may be more than your skills are up to at this point (been there done that...)

FKreider
Posts: 23
Joined: Fri Feb 02, 2018 8:44 pm
Location: Sturbridge, MA

Re: Two Silver Soldering Questions

Post by FKreider » Mon May 14, 2018 5:23 pm

I am also new to silver soldering, can anyone post a link to this "black flux" so I know what I am looking for? Also- does anyone have suggestions for the best place to buy silver solder online?
Last edited by FKreider on Mon May 14, 2018 5:23 pm, edited 1 time in total.
-Frank K.

jcbrock
Posts: 300
Joined: Tue May 22, 2012 7:50 pm
Location: Oregon

Re: Two Silver Soldering Questions

Post by jcbrock » Mon May 14, 2018 5:23 pm

Bill Shields wrote:
Mon May 14, 2018 5:04 pm
you can get the bricks CHEAP from a place that supports fireplaces / stoves.

RUTLAND PRODUCTS firebricks => $30 for a set of 6
There is a farm store here in Oregon called Coastal Farm. They sell the set of 6 for around 30 bucks, but they sell individual bricks for $3. :?: I bought the individual bricks.
John Brock

User avatar
Builder01
Posts: 455
Joined: Mon May 18, 2015 5:26 am
Location: Erie, PA

Re: Two Silver Soldering Questions

Post by Builder01 » Mon May 14, 2018 6:01 pm

Fire bricks will work okay, but, "insulating" fire bricks will reflect the heat back into the work, like these on Ebay:
https://www.ebay.com/itm/K-20-Insulatin ... 1438.l2649

I think the ones I used are K-23 There are light weight and actually a bit fragile. Stove firebricks can be used underneath a hearth made of these.

Black flux can also be obtained from Ebay:
https://www.ebay.com/itm/Harris-Stay-Si ... Swx2dYEhCL

This is not the exact brand I have used, but, this will probably work fine. (Mine is Wolverine brand)

As for silver solder, I got it also from Ebay as new old stock and it not available, it was quite cheap and I purchased way more than I needed for my job because the price was so "right". What you are looking for is 45% silver content and about 1/16" in diameter. Here is some new old stock on Ebay right now:
https://www.ebay.com/itm/062-diameter-x ... 0005.m1851

Real and "correct" silver solder ain't cheap! (Hey, it's got silver in it!!)

David

matthew-s
Posts: 8
Joined: Mon May 14, 2018 7:51 am

Re: Two Silver Soldering Questions

Post by matthew-s » Mon May 14, 2018 8:00 pm

Thanks for all of the great (and speedy) input!

I've been wondering about the bricks - I knew you wanted the "insulating" kind, but I had not pinned down a good source.

As far as my soldering supplies, I happened to use sra-solder.com. They were the only place I could find that had the exact solder described by Kozo.

Bill - thanks for the sanity-check on tolerances. I'll re-check my work - the slot width has a 0.002 tolerance, but the position of the slot is expressed in fractional inches. I suppose one approach would be to finish the part as-is if the slot width is in-spec, assemble the trucks, and see if it binds.

RET
Posts: 748
Joined: Wed Jun 07, 2006 8:36 am
Location: Toronto, Canada

Re: Two Silver Soldering Questions

Post by RET » Mon May 14, 2018 8:41 pm

Hi,

I started off using the white flux a long time ago, but I found that if I overheated it, it burned and then it didn't work any more. I found that the black flux wouldn't burn and was better for large jobs like silver soldering a flat car frame together.

For the truck frame you will probably need a larger torch than the Bernzomatic propane type. MAAP gas is a little hotter. Using insulating brick helps a lot in keeping the heat where you want it.

Don't be in a hurry, but let the parts come up at their own speed. The wash from the torch will protect the work from oxidizing as long as you keep the torch on the work. This can be important for large parts. Practice on scrap pieces before you commit yourself to the "real stuff." You will find that the solder will flow towards the heat and this allows you to control where and how the solder melts and flows. Capiliary action causes the solder to "wick" into the joint.

You don't need a lot of flux, just make sure its where it needs to be to protect the joint. You will also find that only a little solder is required.The closer the gap (as long as the solder can flow) the stronger the joint will be. Avoid Butt joints, although they can be surprisingly strong.

While they are both a soldering process, soft soldering and silver soldering require quite different techniques. Go "play" first to learn what works.

Hope this helps.

Richard Trounce.

User avatar
gwrdriver
Posts: 3007
Joined: Mon Jan 06, 2003 10:31 am
Location: Nashville Tennessee

Re: Two Silver Soldering Questions

Post by gwrdriver » Mon May 14, 2018 9:28 pm

"Refractory" is a key search word.
I lined my brazing hearth with the "firebrick" used for common brick masonry fireplaces which is a yellowish-whitish/tan in color. And $5 a brick for anything sounds ridiculously expensive.
GWRdriver
Nashville TN

User avatar
NP317
Posts: 1395
Joined: Tue Jun 24, 2014 2:57 pm
Location: Northern Oregon

Re: Two Silver Soldering Questions

Post by NP317 » Mon May 14, 2018 11:01 pm

Search Amazon.com for "45% silver solder" and you will find many choices that all should work.
I only use cadmium-free solders.
~RN

Post Reply