# boiler making material?



## Amber (Jul 29, 2011)

Here's a question from a completely uninformed person when it comes to live steam. Is copper a common material for making small boilers, say 2-4 inch diameter? Can a person use hard copper pipe for a boiler shell? What about brass pipe? I understand the basics of how the big boilers are made, but translating that to smaller hobby size boilers is something I know very little about. I suppose there's a number of books on the subject, but which book to buy would also be another question.

Amber


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## SteveC (Jan 2, 2008)

Amber

Copper = Yes
Brass = No, although it has been used and there is a difference of opinion in various factions.

If getting into building live steam boilers, one thing you'll need to learn and that's "silver soldering" (it's actually brazing because of the temperature involved); so-called "soft soldering" that you may be familiar with won't work in live steam.

As for books, while they're not inexpensive I would say they're among the very best you can buy.

Kozo Hiraoka[/b]


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## Semper Vaporo (Jan 2, 2008)

Ditto to SteveC's comments!

Several years ago (early internet days), on the old usenet discussion boards there were old hands discussing building boilers, and brass was recommended by a few, but they got shot down by the majority with both anecdotal and scientific proof of problems with it. Different water chemistries can leach the various alloys out of the brass leaving just a sponge of copper for the shell. There were stories of old brass boilers "weeping" water all over their surface!

Then the discission turned to the type of copper to use. The general consensus at that time was to use Type "K" copper pipe. This is the thickest pipe that is most generally available. The actual thickness depends on the diameter of the pipe. I repeated that recommendation a few years later and got shot down by those that use cheaper (thinner) types "L" and "M" pipe. But, at least at that time, everybody seemed to recommend against using type "DWV" (Drain, Waste, Vent) pipe as being way too thin.

There are some "commercial" boilers that seem to be made of very thin tin. These are usually found on the toy "Power Plant" stationary boliers by Wilesco, Mamod and Jensen, amongst others. Usually these toy boilers are limited to pressures of less than 15psig and burn candles, sterno or a solid pellet fuel that do not get hot enough to melt solder.

Silver soldering: Again, use only true Silver Solder. Be careful about solders that are "silver bearing" as they are usually less than 10% silver. They are stronger than plain Tin/Lead solder (often called "Electrial Solder") but melt at much lower temperatures and are not suitable for model boiler work Even modern "non-lead" plumbing solders melt a too low of a temperature for boiler work. (Again, I have heard that the Toy stationary boilers sometimes use plain Tin/Lead solder but the fuels do not produce much heat and even if the solder were to "let go" there is not much water or pressure to cause anything catastrophic to occur (i.e.: no schrapnel flying around, but you could possibly get scalded by the steam if you have your hands or face near any rupture that might occur.) Silver bearing solder can be used for steam connections that are not on the boiler itself (i.e.: away from the fire, and not on anything that is directly in the fire (the boiler shell)).

I recommend Kozo Hiraoka's "Building the New Shay" book... even if you have no intention of building anything like a Shay locomotive, the book is so full of information about making parts and appliances (boiler, safety and other valves and locomotive parts, etc.) that it is well worth the price. His "step by step" instructions on how to build the various parts and appliances for a locomotive are easily translated to the same type parts for any steam engine (locomotive or stationary) of just about any size or scale.


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## Phippsburg Eric (Jan 10, 2008)

Use copper...copper pipe is readily available either new from a hardware store or used from a plumber. Used pipe is fine if it is in decent shape ... it should not be pitted or too dented.

I prefer to make my boiler match the diameter of the available pipe. that is not always possible. 



My current project (which I will post more about) is a coal fired converted Ruby. the boiler is 1 3/4" in diameter. the pipe available is 1 1/2" or 2 inches. I chose to flatten a 2" pipe and work from there. I sawed a slot along one side of the pipe using a power jig saw (Saber Saw). After heating the pipe with a torch until it breifly glowed red, and cooling it in a pickling solution. it was soft enough to flatten by hand and start the cleaning process.


here I laid out the design of the boiler shell including both the smoke box with rivets and the firebox.


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## Phippsburg Eric (Jan 10, 2008)

Here are some photos I took of building a boiler for a model boat. the shape and proportions are different than a locomotive boiler but the techniques are similar.








this is an end cap sawn out of a peice of flattened copper pipe, I am in the process of annealing it so that I can form the flanges around the edge so I can silver solder it into the boiler shell.









I made a former from hard wood. It has to be smaller than the inside of the pipe (because the cap will fit inside) and the thickness of the copper used in the cap has to be taken into account. I use light hammer blows around the edge of the disk to form the flange. I keep turning the work to keep the progress consistant all the way around.









This is the finished end cap. it should be a snug fit into the end of the pipe.








this shows the cap fit into the pipe. this happens to be 3" copper pipe which would be big for a G-gauge engine...say a modern super power engine or a big 7/8 scale engine. 

In the background, you can see the coil of silver solder under two more caps and firebrick on which to do hot work.








this boiler will be gas fired with a Roundhouse burner and fittings. as it turns out this boiler has a return flue which exhausts out the top of the boiler and up the smoke stack of the Tugboat.
I made threaded fittings to match the roundhouse parts. I machined the fittings from brass which I had on hand though Bronze is better.









I use an oxy-acetylene torch to heat the boiler while silver soldering. the flame of the torch is hot enough to do some damage to the boiler, so care must be taken when heating the boiler. I spend most of the time getting the entire boiler to nearly the temperature that wil melt the silver solder the concentrate on the spot where I am applying solder. I do not try to do all the soldering for the boiler in one step but work in stages or sub-assemblies. 










here is the finished boiler. you can see the purchased parts from Roundhouse engineering http://www.roundhouse-eng.com/ It can be a task finding the required fittings from their web site, I am not sure all of them are listed.


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## steamboatmodel (Jan 2, 2008)

That is a very good set of photos Eric, can you post some shots of your boat? 

Here is a short list of Books, that I borrowed from RC Groups Steam Boat section 
(Maybe not so short ;


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## HMeinhold (Jan 2, 2008)

Eric,
here my 2 cents: I prefer type L tube, as it seems to steam easier. Burst pressure of 

e.g. type L annealed 2" nominal diameter is 1910psi see:


http://www.copper.org/applications/...burst.html 

recommended working pressure which already contains a big safety margin is >180psi:

http://www.copper.org/applications/...table.html 

We also don't flange the end plates. Tests by the Aussies have shown, that a plain end plate is actually better than a flanged one.
BTW, so far we have built over 20 boilers, including the big ones for Bill's Quadruplex.

Regards


http://www.copper.org/applications/plumbing/techref/cth/cth_3design_burst.html


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## Amber (Jul 29, 2011)

Thanks for all the great info! I can see that there's a bit of a learning curve to live steam boiler making. I'll be doing a lot of reading on this. 
As for silver soldering, I have an oxy acetylene torch setup, I use propane for brazing thin metal like bicycle frames, so I should be able to do the silver soldering. I will have to find the proper solder, I can ask the people at the supply place where I get my oxygen tank swapped, they should have the right solder.


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## Phippsburg Eric (Jan 10, 2008)

I have done a little bit of brazing...I think that silver soldering is easier. Just take the time to ensure good fits and clean surfaces. Your welding shop should have the solder and flux. If not, it is available from McMaster Carr on-line.


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## xo18thfa (Jan 2, 2008)

Under the provisions of the Australian Miniature Boiler Safety Committee (AMBSC) Code, Part 3, Issue 1.0, dated 30 June 2006. Brass and soft solder are satisfactory materials for boiler construction as long as the following conditions are met:

- boiler barrel is under 52mm, 2 inch diameter for brass***

- operating pressure under 200kPa, 29 PSI

- for soft solder, the endplates are flanged from 1.6mm, 1/16" stock. For silver solder no flange is needed. You can around that by making flat endplates 3/16" thick.


- silver solder is the preferred method, but soft solder is fine. 


In paragraph 2.3, AMBSC calls these "low pressure". If you go above 29 PSI, largere then 2 inch or use coal as a fuel, that's a different category.


If you are running a small oscillator, like a BAGRS, brass and soft solder, you are in business.


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## xo18thfa (Jan 2, 2008)

When you start silver soldering, get a very wide rosebud tip for the oxy-acet rig. Silver solder flux is good only to 1400 degrees F. After that it breaks down chemically and will not work. If you try a regular welding tip you will vaporize the flux and nothing will happen. You want a large volume of low temp heat for silver solder, not pin point high temp. Use the 45% silver, cadmium bearing solder. It has a lower melting point (1160F) and very forgiving to use. Your welding supplier will have it. The trade name is either "Safe-T-Silv" or "Easy-flo". Be prepared for sticker shock, that stuff is $$$$$$$$$$$$$$$$$ Any jewelry supply house will have it too. Don't use what the plumbers and AC guys use. It's different.


Cadmium is highly highly poisonous. Read all the safety and follow.


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## Amber (Jul 29, 2011)

So, 15 % silver solder is not recommended for boiler work? I stopped at the welding supply place this afternoon to see what they have, and he told me that the HVAC people use the 15% stuff on their pressure pipes. I guess the question is how much heat will it take. Would a Mapp gas torch put out enough heat to solder with, using the silver solder, or will I be stuck using the oxy /propane setup? 
That 45% silver solder is crazy expensive!


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## Michael Glavin (Jan 2, 2009)

Amber, 

There is a difference between silver solder and silver brazing rod... The welding shop guy suggetsed 15% silver brazing rod, I use this stufff all the time. For small parts, a Mapp gas torch will do the job, anything with mass will more likely than not will be a problem with a Mapp gas torch (insuffiecent volume of heat or BTU's to heat the components). 

Michael


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## xo18thfa (Jan 2, 2008)

I wish to revise and extend my statement about what the HVAC guys use. In the olden days they used a copper phosphorous alloy because it was cheap, easy and required no flux. That alloy had no silver and got very brittle and cracked quickly. Don't use that. The 15% they use now will probably work fine. 


Part of the answer is that 45 is so widely used its become standard practice. Nobody questions it. It's always been that way. $214 for 5 ounces at McMaster Carr!!!!!!!!!!!!!!!!!!!!!!!!!


I bet the 15% will do a good job. Remember, when you build a boiler you are supposed to test it. The initial test is to twice working pressure and hold for 30 minutes. If it passes you won't have problems. Test annually after that to 1.5 pressure.


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## Semper Vaporo (Jan 2, 2008)

Silver provides better strength. It sticks to the copper well and is also hard to stretch. If you used plain lead or tin/lead it will also stick to the copper well, but it stretches easier and will, itself, split or pull apart under pressure. Silver is stronger and will not pull in-two so easily. So a little silver makes a stronger joint.

Another thing that Silver provides is a higher melting point. "Most" of your boiler parts will never exceed the boiling point of water at the pressure the boiler has in it; 212-degrees at 0-psig, 250-degrees at 15-psig, 274-degrees at 30-psig, 298-degrees at 50-psig, 307-degrees at 60-psig, to enumerate a few of the points in a 'steam table'. So "THEORETICALLY" if you limited the boiler pressure to, say 30-psig, then you could use solder that melts at anything over 274-degrees plus some safety margin.

So, you, being a good steam boiler engineer/designer, decide to use solder that melts at 350-degrees, and "YOU" KNOW to never let the boiler run dry such that the temperature of the boiler shell and the things soldered to it (like the end plates) will never get much hotter than 274-degrees and YOU are safe while operating it.

But you, to put it bluntly, are gonna CROAK someday and your heirs and assigns are going to look at your "TOYS" and decide they would rather have CA$H in their pocket than to store your junk, so they will decide to disperse them to the general public at a garage sale, and someone that is not so knowledgeable is going to buy it and decide that if they put a board on the safety valve and sit on it, it will stop making that noise that is so disturbing (like the Fireman did on the "Best Friend of Charleston" locomotive on June 17, 1831 and became the first person to die from a locomotive boiler explosion) or maybe they are just knowledgeable enough to know that if they increase the pressure the engine will run faster, or that if they use a propane torch instead of your alcohol burner they can make steam faster (and add heat faster than the water can disperse it) and thus hurt themselves or someone else when your "safe" tin/lead solder lets go.

Granted, if you have croaked already, then you won't be subject to fines or jail time for the injuries, and I guess if you really don't like your heirs and assigns maybe it is a way to harm them after you've gone. ("If you hadn't stuck me in that awful 'nursing home' I might have taken pity on you and warned you to not sell my stuff without proper warnings to the buyer! HA! That'll larn ya!") But do you want something that you made, to cause harm to some unsuspecting individual you probably don't even know?

One more thing... if you have already used plain tin/lead solder to bond two copper surfaces, and then decide you should have used silver solder... you MUST remove all the tin/lead solder, down to the bare copper before you add the silver solder. Otherwise you have a 5 layer sandwich of copper, tin/lead, silver, tin/lead, copper and those two layers of tin/lead eliminate the strength advantage of the silver.

Safety First!

Or as my son is so fond of saying, "Safety FORCED!".


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## Amber (Jul 29, 2011)

Another question, has anyone tried to make a boiler using stainless steel pipe? I found some today at the scrap yard while looking for a piece of copper pipe, which I didn't find. The biggest copper pipe they had was the typical 1 inch pipe, but this stainless pipe looks like it's about 4 inch diameter and thick enough wall to be schedule 40. I don't know how a person would go about welding or braising it, but it seemed like a good question to ask.


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## Semper Vaporo (Jan 2, 2008)

Yes, people have made boilers from stainless steel. Many will say they have no problems with it.

BUT! From what I have read, it is a bad idea. Stainless steel is subject to stress fracturing and again certain water chemistrys can attack it and cause it to weaken. I am sure if you do a search using Google you will find discussions about it.

One place in particular would be the Chaski Machinists board:

http://www.chaski.org/homemachinist/viewforum.php?f=8&sid=4a9adeb32d5c0a963abdff6f460ac955

The people that frequent that board are more into the ride on size live steam equipment and are quite knowledgable about the subject. I am sure a search of that forum will find enough info to discourage you from using stainless steel, although you will read from people that are doing it. There is a search box at the bottom of their page, enter "Stainless Steel boiler" and read to your heart's content.

People do use stainless and it sure makes a pretty locomotive, but everything I have read is to NOT use stainless steel for the boiler shell.


Lots of good info about machining and building locos on that forum. (But be warned, some of the fellows there are "old hats" and quite set in their ways and can be persnickety about stuff.)


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## Nutz-n-Bolts (Aug 12, 2010)

Amber, I know our Lowe's carries copper pipe up to 2.5" dia. They have short sections so you don't have to buy 10 feet of it. They also had .375" copper tube that's good for flues. If you need larger, try a plumbing specialty store.


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## Amber (Jul 29, 2011)

It's good to know about the stainless steel, I had heard in the past about the use of stainless in the outdoor wood fired water boilers for home heating and how they sometimes developed cracks in the firebox. I guess I won't bother trying that. 
I'll have to check out the Manards store that's close to see if they have the larger copper pipe, we don't have a Lowes within 100 miles of us, and the local Home Depot doesn't carry pipe that big. They have fittings up to 1-1/2 inch, but that's all. Which brings up the question, how would copper pipe fittings work for a small boiler, are they the same material as the pipes? The guy at the hardware store couldn't answer that question. 
I think I could make a decent little vertical boiler if I could get some of the 2.5 inch diameter pipe, maybe 3 flues through the middle. Even a monotube boiler would make some steam. Then to figure out what to burn to make steam. I'm sure there's lots of ways to do that, alcohol, butane, even sterno, I suppose, but it might be interesting to try wood pellets, just to see what would happen.


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## afinegan (Jan 2, 2008)

One note on sterno (from a guy who owns that little Regner Max), a very small amount of wind WILL blow the fire away from under your boiler.
The btu's that sterno produces is not enough IMO.

I bought the gas burner for my Max btw, runs like a champ


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## David Leech (Dec 9, 2008)

Amber, 
Not that I have built a boiler myself, and I know little about vertical boilers, however, may I suggest that you don't possibly waste your time just putting one together. 
The length and diameter of flue is VERY important to make steam. 
There have been many articles and seminars over the years on boiler design, and it would seem sensible for you to follow a plan of some sort. 
I would decide first of all what type of fuel you will be happy working with, and then find a design for burner and boiler to suit. 
My brother purchased a beautiful locomotive many years ago that was well built except for the boiler, which hadn't a chance of even keeping water warm unless perhaps enriched plutonium was used! 
I just don't want to see you go through the effort of making something that will not work the way that you think it should. 
All the best, 
David Leech, Delta, Canada


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## Amber (Jul 29, 2011)

Well, I figured that my first boiler would be experimental, to see if I can actually build one that will hold pressure. It doesn't have to be efficient or fancy, it will be a lesson in silver braizing more than anything else. 
I might try making one from copper pipe fittings if I can't find any copper pipe that's big enough. I found the pressure relief valves on e-bay, so that's one thing I need to get. A sight glass would be nice also, and the steam valve, of course. I still have to figure out how to get the water into the boiler, I might make the first one a single fill type boiler just for ease of use. The hand pumps aren't too pricy, but I don't know that I would need that right away.


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## xo18thfa (Jan 2, 2008)

Posted By Amber on 11 Feb 2012 09:28 AM 
Well, I figured that my first boiler would be experimental, to see if I can actually build one that will hold pressure. It doesn't have to be efficient or fancy, it will be a lesson in silver braizing more than anything else. 
I might try making one from copper pipe fittings if I can't find any copper pipe that's big enough. I found the pressure relief valves on e-bay, so that's one thing I need to get. A sight glass would be nice also, and the steam valve, of course. I still have to figure out how to get the water into the boiler, I might make the first one a single fill type boiler just for ease of use. The hand pumps aren't too pricy, but I don't know that I would need that right away. 
Check with some commercial plumbers in your area. They would use bigger copper pipe and might have a short stick of 2" in the truck. Another web resource for boiler making is the Home Model Engine Machinist (HMEM) webiste. They recently opened a boiler forum. http://www.homemodelenginemachinist.com/index.php For the fittings you want, you'll need boiler bushings to solder into the boiler weldment. Get them from PM Research. It would be cheaper then buying taps to make your own. http://www.pmresearchinc.com/store/home.php. Copper pipe fittings will work fine. Maybe later make a more complex boiler. McMaster Carr has copper pipe to 3" diameter. Low pressure "M" wall is all you need. Do a search for "copper pipe" http://www.mcmaster.com/#

For the first boiler build something simple with all the silver solder joints on the outside. If there is a leak, it is on the outside where you can fix it easily. When you are proficient in silver soldering and know what a good joint looks like, then do more complex work with inside joints. 


Your boiler will either hold pressure fine or not at all. First time you test your boiler, that will become very apparent.


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## Michael Glavin (Jan 2, 2009)

Amber, 

If you don't have any luck locally, I can send you a scrap of 2" type M copper (2-1/8" OD), I have 2-1/2" and 3" as well. PM me if you want to discuss same. 

Michael


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## Amber (Jul 29, 2011)

Michael, if I can't find any copper locally, I'll take you up on that.  
I ran into an interesting boiler on e-bay this morning. It's a steel boiler shell with copper flues, I thought that was interesting. I wonder how they keep the flues in the end plates, silver braizing perhaps? It's a pretty big vertical boiler, 14 inch diameter, if I remember correctly.


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## xo18thfa (Jan 2, 2008)

Posted By Amber on 12 Feb 2012 12:32 PM 
Michael, if I can't find any copper locally, I'll take you up on that.  
I ran into an interesting boiler on e-bay this morning. It's a steel boiler shell with copper flues, I thought that was interesting. I wonder how they keep the flues in the end plates, silver braizing perhaps? It's a pretty big vertical boiler, 14 inch diameter, if I remember correctly. 
Occasionally they are silver soldered, but mostly rolled in with a tube expander. I want to try a steel boiler someday. Bill Harris had (has) a homemade tube expander idea that uses rubber washers. Compress the rubber washers with a nut/washer/bolt arrangement to expand the tubes into the endplate. I've read that it works very well. Easy to do.


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## Amber (Jul 29, 2011)

I just found a really good deal (I think) on a length of 2 inch type L copper pipe. The Lowes in Marquette, MI was blowing out their 2 inch copper pipe for 64 dollars for a 10 foot piece, normally it's 108 dollars, so I bought it. I ended up selling half of it to a friend for my cost, so I got half the money back, and I have 5 feet of 2 inch type L pipe to work with now.  
The next question is, has anybody used soft copper tubing for flues in a small boiler? I can't seem to find any hard copper pipe smaller than 1/2 inch.


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## xo18thfa (Jan 2, 2008)

Soft copper tubing works fine for flues. Straighten it out as best you can by hand. Cut to length, clean up the ends. Put the flue on a hard flat clean surface and roll it with a board or piece of plywood. That will take out the last of the kinks. You in business.

You can cut the endplates for the boiler shell from that 2" pipe. Cut 2 pieces, heat to cherry red and let air cool. That 's called annealing. It will be soft enough to flatten mostly by hand. Re-anneal and smack it good between two pieces of plywood and that will flatten it right out. 


Are you going to flange the endplates or leave them flat? You can leave them flat, but flanging is not hard to do.

Are you going to use the 15% silver solder? What kind of flux did they recommend?

You will need a "pickle bath" to clean off leftover flux from soldering and clean off the black oxide crust from the torch. One type of pickle is 1 part battery acid in 10 parts water. Or use citric acid dissolved to full saturation in water. Citric acid is much safer then battery acid. Health food stores sometime carry it. Citric acid makes a rather tart lemonade drink.


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## Amber (Jul 29, 2011)

I was planning on using the 15% silver solder, they recommended Stay-Silv flux made by Radnor, the company that they carry that also makes the silver braizing rod. I found another welding supply in town that will sell me the 15% rod for 5.00 each, so I don't have to buy a tube of it all at once, which is good for my budget. I don't know if I'm going to make flanges on the endplates yet, but I might try it. 
I also have to decide if I want to burn solid fuel or alcohol, or a gas like butane or propane. Solid fuel might be the easiest way to do it at first, but an alcohol burner should be fairly easy to make. 
As for the pickle solution, I will probably check with the welding supply to see what they might have, I suppose I could get battery acid from the car parts store.


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## HMeinhold (Jan 2, 2008)

Sulfuric acid even when diluted has a very nasty effect: A couple of days after you pickled something little holes appear all over your clothes. This is the reason most of us stay away from sulfuric. As I mentioned earlier, flanged end plates are not better than plain ones. Main reason is that with plain plates the silver solder makes a nice fillet around both sides and also between plate and tube. With flanged plates it is not that easy to achieve such a good penetration. Boilers with plain plates have been tested to more than 1000psi turning to a "baseball" but without the end plates failing.

Regards


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## Amber (Jul 29, 2011)

I was just looking at the link posted on another thread about Sparex no 2 pickling compound, it's inexpensive enough that I think I'll go with that. 
The only advantage that I can see with flanged plates is that they're more forgiving of a size error. If you cut a non flanged endplate too small, you have to cut another one. At least with the flange, you can adjust it to fit. On the other hand, making the flange is a fair amount of work, so maybe careful cutting would be less time consuming.


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## Phippsburg Eric (Jan 10, 2008)

Posted By HMeinhold on 16 Feb 2012 10:22 PM 
As I mentioned earlier, flanged end plates are not better than plain ones. 

Regards


Hey Henner, now you tell me!!! I think what i am doing in the other post is fun but it is not easier or neater than non flanged plates, I'll have to experiment with that!


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## HMeinhold (Jan 2, 2008)

Plain end plates are cut over-sized, bolted to a piece of wood using a hole destined for a tube and carefully turned down to a good fit. Use a lathe bit with plenty of rake and cutting fluid, as copper does not machine very well.
Regards


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## xo18thfa (Jan 2, 2008)

Posted By Amber on 16 Feb 2012 10:36 PM 
....If you cut a non flanged endplate too small, you have to cut another one..... 
Hehehehe. You are entering the "black art" of boiler making. Don't look in our scrap bins, we won't look in yours.

Flat plates will do the job. If you have a lathe, turn them. Otherwise fit as close as possible buy hand filing. You'll get it. 


Try to find citric acid if at all possible for the pickle. Battery acid works, but it's dangerous and the fumes will rust everything in the shop. If you ever forget a steel part in battery acid pickle, it will dissolve (how do I know that??)


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## HMeinhold (Jan 2, 2008)

One more tip: Break any sharp edges where you want silver solder to flow. If there is a little ridge, the solder stubbornly refuses to penetrate.
Regards


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## Grimm (Oct 5, 2009)

If I'm remembering correctly in the Australian tests, that the rough, poorly made boilers were stronger then the nicely made, more exact ones. I think it was because the rough ones had better solder flow then the other ones?


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## xo18thfa (Jan 2, 2008)

Actually, if you are worried about fitting the endplates inside the barrel, you don't have to. They can go on the ends too. Just make sure the plate it flat and the ends of the barrel are square. Cut the plate slightly over sized then trim after soldering. This is a G1MRA "Project 0-6-0" boiler I did a few years back for an LBSC "Chingford Express" The back head plate is on the end of the barrel. The forward tube sheet is inside. 




















This boiler runs like a bat out of ****. Chingford can do about Mach 3 at 75 PSI lifting the safety the whole way.


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## Amber (Jul 29, 2011)

Bob, are you using a gas burner in that boiler? That looks like 1 fairly large flue inside the firebox.


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## David Leech (Dec 9, 2008)

Amber, 
This is the G1MRA Poject boiler, and is designed for alcohol firing. 
In the flue the should be five cross tubes, alternatively angles at 45 degrees, to allow for heat transfer and water movement. 
In the firebox there are normally three cross tubes, again angled alternatively, but Bob's look almost flat and very low down in the wrapper, but maybe it's just the camera angle. 
It is an extremely efficient boiler design and has been used, and still is, in probably thousands of Gauge 1 locos. 
There is 'the' book available from the G1MRA that describes how to build the locomotive, with detailed instructions on the boiler. 
The basic boiler design is attributed to a Freddy Wrighton who built exquisitly designed Gauge 1 locomotives back in the 50's. 
In more modern times, the John Van Riemsdijk type 'C' boiler was designed, again for alcohol. 
Here is a very good PDF from a very very talented Swiss G1MRA member from a series he wrote for the Association newsletter. 
http://tinyurl.com/75nv4bb 
Enjoy your boiler building and make sure you take photos to show us how you're doing. 
All the best, 
David Leech, Delta, Canada


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## Amber (Jul 29, 2011)

That's a really handy article! Thanks for the link!


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## xo18thfa (Jan 2, 2008)

Chingford runs alcohol. On the backhead, the upper bushing is throttle, the lower one on the right side is blower. The firebox has three cross tubes from 1/4" copper refrigerator line. David is correct. The G1MRA "Project" has then angled slightly, mine are in flat and slightly lower. There are only two cross tubes in the flue as opposed to 5. This boiler is much shorter to fit the Chingford Express chassis. . The flue is from 3/4" "coupler tube". Plumbers use it for coupling and repairs. Lowe's has it. This is .95" outside dia, just tiny bit larger then the G1MRA "Project"


Here's the flue, firebox, backhead and stand pipes before final assembly










The link David gave shows a Type "C" boiler designed by the late John van Riemsdijk from G1MRA. That is a superior design too and much simpler to do. It has all joints on the outside where you can get to them. Mr van Riemsdijk's Type "B" is also a very simple and great design. Aster uses it on the Mikado.


BTW what are you thinking of building?


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## SteveC (Jan 2, 2008)

Amber

You might find the following web site to be of interest, it has a great deal of good information regarding "silver soldering/brazing." Take note of the following three menu items in the "Why Braze?" box located on the left; i.e. Best Brazing Practice, Silver Soldering Tips, & Strength of Silver Solder Joints. In addition to all the other information available.

CuP Alloys of Chesterfield[/b]
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## Amber (Jul 29, 2011)

Bob, I don't really know what I'm going to build yet, I'm still trying to decide that. I'm leaning toward a vertical boiler for the first project, to get some practice with silver soldering. I'd like to build a vertical boilered engine with a gear or chain driven flycrank drive to start with. I think that would be an easier starter project, especially since I can't afford the cylinder setup for a standard rod engine. Those castings are pricey, and I don't have a way to machine them. 
Eventually, I'd like to build a 1/6th scale version of a 2 foot gauge 0-4-0 for the mine tram, probably about the size of an 18 ton Baldwin. It would run on 4 inch gauge track. That idea is still in the "dreaming" stage.


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## xo18thfa (Jan 2, 2008)

Earlier, Gerald posted a link to KN Harris' boiler book. In the back are several plans. Plan #5 on page 157 is straight forward. Have to fabricate a firebox and smoke box separately. I want to do a half sized version of #8 on page 162. That one is completely self contained. The first silver soldered boiler I did was an adaptation of #9. Barrel was 3" dia and 9" long. Firebox was 2.5" dia about 3" long. 19 flues, 3/8" dia as I recall.


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## Amber (Jul 29, 2011)

I downloaded that PDF last week after he posted the links, very good information! Plan # 5 is pretty much what I wanted to try as a first project. I don't want to try a firebox surrounded by water at this time, I think I'll have enough to do without trying to figure out the stay bolts for the firebox. # 8 is interesting with it's cross feed water tubes in the fire box. I think # 9 would be the next logical step from # 5, similar construction, but with a firebox surrounded by water. There's a few really interesting, but complex designs in there too, such as # 6. That would be a "project" to put together! 
If I do # 5, I probably won't put the outer ring of flues in the boiler to allow a bit more room for water inside the boiler. This would probably be a "fill it and run it" kind of boiler, no feed water pump for now. 
After looking at all the pictures on some of the links on here, I have an idea for a horizontal boiler using a single large fire tube with water tubes going through it. I just would need to figure out how to make a gas burner for it, or an alcohol burner.


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## HMeinhold (Jan 2, 2008)

There is a nice set of drawings from Bob Bath for the Guinness. You can "steal" some ideas for boiler/gas burner.

http://www.16mm.org.uk/newsite/files/default.html 

Regards


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## Amber (Jul 29, 2011)

Interesting link, Henner! The link itself didn't work for me, but I went to the main website and found the drawings from there.


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## xo18thfa (Jan 2, 2008)

There are no stay bolts needed for a round fire box such as plan #9. The mud ring on the bottom, firebox door tube, firebox tube sheet and flues. That's it. In a silver soldered boiler, the flues act as stays between the tube sheets. Stay bolts are in boilers that have flat surfaces.


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## Amber (Jul 29, 2011)

Ah, for some reason, I was thinking that the sides of the fire box would need stays. I wasn't thinking about the fact that the firebox on that boiler is round.


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