Two Silver Soldering Questions

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Trainman4602
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Re: Two Silver Soldering Questions

Post by Trainman4602 »

Hi Matt

Nothing beets a oxygen and acetylene setup. They can get expensive. One of first pieces of equipment I collected was a set of regulators and a torch. I still have them and this was over 50 years ago. The good ole Harbor Freight (the dollar store for tools) has a small set that will work for you torch and tanks for $320.00 advertised.
This will get you started. To go a step further get the mini torch as well for small stuff.
ALLWAYS OPERATING MY TRAIN IN A SAFE MANNER USING AUTOMATIC AIR BRAKES
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Builder01
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Re: Two Silver Soldering Questions

Post by Builder01 »

Kozo is quite explicit about not using oxy-acetylene or oxy-propane. Check out page 238 of his book and Kozo explains why this is not recommended for a beginner. Propane, with the proper burner, will work just fine. Smaller, cartridge type torches work well for the smaller parts and for the boiler, a larger Sievert type burner is a must for the boiler. I did my entire 1" scale copper boiler that has a 5" diameter barrel, 19" long, using just propane. It passed it's hydro test in May of last year.

David
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Bill Shields
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Re: Two Silver Soldering Questions

Post by Bill Shields »

When I first bought bricks, $1.5 was the going rate...but that was in a different century (actually a different MILLENIUM).

if you go to McMaster-Carr and look up firebrick, they are around $10 each + shipping....granted they don't weigh much but at $30 for 6 delivered by Amazon...it's a reasonable (and competitive price).

If you have a local place that sells common masonry firebrick...jump on it..

out here in the middle of cow country where the new houses either don't have fireplaces or have simulated sheets of firebrick, the individual bricks have to be chased round robin hood's barn
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Bill Shields
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Re: Two Silver Soldering Questions

Post by Bill Shields »

heating methods are in the eye of the beholder.

I am with Dave and use my O2 / C2H2 for most everything including heating water...but..

if you don't know what you are doing with what Dave describes you end up with overheated solder and / or a puddle of metal sitting there looking at you....propane / air gives the newby a lot more wiggle room.

We all have to remember that we were ALL BEGINNERS at one time and someone off on his own may not know what to do with an O2/C2H2 torch...to say nothing about the safety hazards
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Greg_Lewis
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Re: Two Silver Soldering Questions

Post by Greg_Lewis »

Bill is right about o/a for silver soldering. I, too, use it but it has to be done right. My reasons for using it are that the tanks hold lots of fuel and are handy next to my workbench. The propane torches I've tried have been troublesome and I always seemed to run out of propane at the wrong time.

Silver soldering is a skill that has to be learned through practice. You can't just read about it and then go out and have great success every time. It is not like electrical soldering. You will make mistakes and ruin parts. Not only do you need the right flux, but you have to analyze the parts and figure out how to hold them in position, where to apply the solder and where to apply the heat. Since every situation is different, there is no easy way to explain this except that it takes skill and experience to be able to analyze the specific situation. Holding the parts is critical as they will tend to move with the heat and/or blow from the flame. I just tried a quick-and-dirty job last week and in spite of knowing better I got an unsatisfactory result because the parts moved with the heat.

I prefer the cadmium alloy solder, which I get from McMaster. I find it flows better than the non-cad stuff, and when used with common sense and good ventilation, I don't see a hazard from the cadmium.

The problem with o/a is folks setting the torch flame as one would for welding, and then applying it directly to the part, thus overheating the works, burning off the flux, and making a mess of things. This gets everything way too hot. I set the flame for a long feather, perhaps 12 inches or so. Then I heat the back or underside of the parts away from the solder joint, waving the torch slowly back and forth and applying the end of the feather to the parts, letting the parts heat up slowly. This is important. You want the heat to soak through the parts and melt the solder. You do not want the flame to melt the solder. For small stuff, about the size of the end of your thumb, I set the parts on top of a piece of angle iron held in the vise. Then I heat the underside of the angle and let that soak through to the part. Solder is applied by setting small snippets of it on the joint areas. I do not feed solder into a joint like you might do with electrical work. I have a piece of 1/16 welding rod about 10 inches long that's bent over at the end about 3/8 of an inch, which I use for a scratch rod to encourage the solder to flow, or push it around if it moves as the flux melts.

Finally, as others have said, cleanliness of joints is paramount. I beadblast with clean bead media (not the stuff you used to clean the intake manifold off your truck) and then clean off any blast residue with an air gun.

I might add that Bill mentions safety hazards. O/A can be dangerous and I don't recommend just buying a set and turning it on. I took a welding class at the local community college evening program, and it was well worth the time. Learning to work safely was a big part of the course. I seriously recommend that anyone considering o/a for either welding or soldering take such a class. (And let's not get into [whisper] boilers. One thing I learned in that class is that I will never try to weld my own boiler.)
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Harold_V
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Re: Two Silver Soldering Questions

Post by Harold_V »

Greg_Lewis wrote: Tue May 15, 2018 10:18 pm One thing I learned in that class is that I will never try to weld my own boiler.)
I'm of the opinion that one can learn to weld well enough to weld a boiler, but it takes a serious effort and a lot of experience in order to produce visually pleasing, as well as mechanically sound (no inclusions, no undercuts) welds.
Welding is one thing that one can't fake. You can weld, or you can't. It does not come easily for most folks, as it requires good hand/eye coordination as well as a very steady hand. I took an evening welding class for two semesters and managed to pass an x-ray test, vertical up, with 7018. It was not easy for me. I still do NOT consider myself a weldor. What I've learned is that many think they are weldors, simply because they can burn rod. If only! :roll:

H
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BClemens
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Re: Two Silver Soldering Questions

Post by BClemens »

matthew-s wrote: 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.
You can use 50/50 bronze brazing rod and just use borax flux to do a quick and strong build-up of a snipe like you mention. It flows nicely and will also build quite well too. Save your silver.
BC
matthew-s
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Re: Two Silver Soldering Questions

Post by matthew-s »

BClemens wrote: Wed May 16, 2018 11:19 am You can use 50/50 bronze brazing rod and just use borax flux to do a quick and strong build-up of a snipe like you mention. It flows nicely and will also build quite well too. Save your silver.
BC
Ok - please school me: what is 50/50 brazing rod? A quick search showed up 50/50 lead/tin sticks that appear more like solder. Is that what you are referring to?
BClemens
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Re: Two Silver Soldering Questions

Post by BClemens »

Matt,
Old school.... Ordinary Bronze brazing filler rod (we always used bare rod and a can of borax brazing flux) that has 50% Cu alloyed with tin to some percentage but low a strength (50,000 psi) alloy. We used it as a cheap, general filler rod for steel and cast iron and is usually what you get when you ask for basic bronze or brass brazing rod. Some brands of brazing rod have a very low percentage of silver and some have cadmium. Cadmium is not safe without an air supplied respirator (actually any brazing should use such safety breathing equipment) because tin is bad stuff to breathe too. If you happen to purchase coated brazing rod at a 'big box' home improvement store or similar - it will be ~50% Cu and 50K psi tinsel strength depending on the brand and etc. It would be fine for your repair - fills well and machines nicely. We have always referred to it as 50/50 Brazing Rod.

50/50 solder is lead/tin - we were discussing brazing rod or brass filler rod for oxyacetylene or propane brazing. Sorry for being vague about it.
BC
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Builder01
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Re: Two Silver Soldering Questions

Post by Builder01 »

Matt,

Since you are building Kozo's A3, stick to his methods described in his book. The process is simple, the equipment is simple and it works well. I built a slightly larger boiler, 1st time build, using his techniques, because it works!

Here's a link to my copper boiler build using Kozo's methods: https://supersimplex.yolasite.com/Plate ... es---2.php

The link is for the second page of the build which has much of the silver soldering. There are a total of 5 pages with many photos for the boiler build. One of the pages is for flanging copper plates, one is for the super heater and smoke box piping, and another just for making all of your own boiler fittings.

David
matthew-s
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Re: Two Silver Soldering Questions

Post by matthew-s »

Builder01 wrote: Thu May 17, 2018 5:18 pm
David
David, that is one clean build! That must be way bigger then 3/4” scale, no?

I don’t know that I will bother trying, but for the brazing rod can that be done with a MAPP or propane torch?

I may just end up making a new part. We’ll see.
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gwrdriver
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Re: Two Silver Soldering Questions

Post by gwrdriver »

Just in case there might be any misunderstanding, do NOT use brazing rod for a copper boiler!
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