# Copper boilers



## GWRdriver (Oct 3, 2009)

I'm pretty good, no I'm actually very good, at designing and building copper boilers. I've designed and built over 100 boilers from 1.5" to 6" diameter for locomotives, stationary, and marine engines (all of which models I build for myself) and I'll be glad to advise anyone who needs information and guidance on design, materials, tools, and processes including silver soldering. I can design a steel boiler, but since I'm a terrible welder I don't build steel boilers. It also occurs to me that the Board might benefit from having a seperate "Boiler" topic heading?


----------



## ozzie46 (Oct 3, 2009)

Welcome GWR, This is a great place.

 I want to build a boilers in the future so I will probably pester you to death when the time comes. :big: :big: I'm slowly learning silver soldering at this time on a small marine steam engine. So far things have gone well.

 Ron


----------



## GWRdriver (Oct 3, 2009)

Diymania  said:
			
		

> Did you come here to gloat ? Kinda seem like it.



No, I came here to offer my experience (45 years of it) to others who might benefit from it, but if that's going to be viewed as gloating then I can find other things to do. I always appreciated having folks who knew more than me to guide me through the maze and the model engineering tradition is to pass it on, but there will always be a few who resent it.

To see one picture simply click on the small photo under my first post. This is a coal fired boiler with an OD of 2", one of a matched pair made for model Climax Type-A locomotives in 1/2" scale for someone in the USA.


----------



## vlmarshall (Oct 3, 2009)

GWRdriver  said:
			
		

> ... boilers from 1.5" to 6" diameter for locomotives, stationary, and marine engines .



Nice! As I'm just getting started in the locomotive-building side of this hobby, I'm interested in seeing horizontal boiler designs. Please post some photos!


----------



## GWRdriver (Oct 3, 2009)

Vernon,
The gauge/scale of the model will determine what design, or range of designs, should be applied and what material should be used. The smaller scales (Ga1, 2.5"ga, etc) tend to need one set of design parameters and the larger scales (3.5"-7.5"ga, etc) need another. Smaller sizes typically require copper, for good reasons, and the larger sizes may use either copper or steel depending upon several determining factors. These factors could include your skill, capabilities, equipment, and material resources. For instance my silver soldering skills (and equipment) are far superior to my welding skills, as I mention above, so my tendency would be to build in copper rather than steel although steel material would be considerably less expensive than copper. Yer pays yer money and yer takes yer seat.

Since miniature boilers have been made for 150 years, with improvements to technology (and safety) continually being made, there are a lot of well-tried standards which we (those of use who have built a few) use in construction. But as with any technology there are differences of opinion, sometimes great differences, even among the experienced as to what is "best" or even acceptable practice. For instance, perhaps the most active current discussion is over whether stainless steel, which has KNOWN safety issues but is being use anyway, is appropriate for minature boilers.


----------



## vlmarshall (Oct 3, 2009)

GWRdriver  said:
			
		

> The gauge/scale of the model will determine what design, or range of designs, should be applied and what material should be used...


True. For now I'm just building from plans, and all in 16mm scale, so there's no real "design", other than either "single fire tube", or "teakettle"...but I still like looking at the big stuff; coal-fired multitube with superheat, anything with a real backhead. It's fun to dream, anyway. ;D


----------



## GWRdriver (Oct 3, 2009)

Vernon  said:
			
		

> It's fun to dream, anyway.


Without getting too smarmy I would say that every next project starts with a dream. All mine have, and I took it one step at a time. I would disagree that there isn't much design in 16mm or other small scale boilers. Most of them start out as a problem looking for a solution and coming up with those solutions, even if it's as simple as where to run a blower line, is Design. One of the cleverest design solutions I ever saw was a very small saddle tank engine (in 16mm IIRC) which made the saddle tank (heavily built and adequately stayed) the Boiler! What would normally have been the boiler barrel was the firebox. BTW I am an architect in real life and that's how a building design starts . . . needs or problems looking for solutions.


----------



## tel (Oct 3, 2009)

Hello Harry - when did you sneak in? Welcome anyway.


----------



## shred (Oct 3, 2009)

Every so often I see statements like "some of the things <XYZ> used to do aren't acceptable anymore" (where XYZ is some famous ME personage; LBSC, ME, EV, GS, etc..), but no details on what is and isn't best practice anymore. Is there a list somewhere?

Thanks.


----------



## zeeprogrammer (Oct 3, 2009)

Welcome to the forum Harry.

I've never made one but I know a boiler is in my future. Always glad to have another teacher around. Thanks now for the future help.


----------



## GailInNM (Oct 3, 2009)

Welcome to HMEM Harry. There is a lot of interest in boiler making on HMEM and your input to keep us on the straight and narrow will be welcome. I have missed chatting with you at steamups, but I don't get out much anymore. Just stay home and build toys.
Gail in NM
Gail Graham


----------



## GWRdriver (Oct 3, 2009)

tel  said:
			
		

> Hello Harry - when did you sneak in? Welcome anyway.


Hello TEL, and Howdy GAIL, you old sod. Where have you been!? I'm glad to know you're still kicking around and likewise I don't get to any meets much any more myself. There's too much too much to do around here these days.

Shred,
I don't know of a "list" per se, over time and much reading we acquire mental and paper files of these things and apply them when the time comes. I've built enough boilers so that I have my own set of basic practices which I use on every boiler but naturally there are variations in how I do it and how others do it. Vive la difference, as long as certain minum standards and practices are observed. The variations I use typically exceed the minumum standards and allow me to do a better job with my skills and equipment.

I'll give you an example of one technological change, or change in accepted practice, from say the heyday of LBSC. Curly very often called for screws and fittings to be screwed directly into the copper sheet and consequently, as the models aged (and probably when they were new) the copper would wear or stretch and leak and after a point could never again be made to seal. Most such boilers I see have been goobed up with thread compound or soft solder in futile attempts to seal the leaks. Nowadays it is almost universally accepted as good practice that all boiler penetrations be bushed. This true of both copper and steel construction. In copper the preferred material both in the UK and the US is phosphor bronze (US/CD510) with "gunmetal" (a red bronze) being near equal in preference in the UK. Copper and other bronzes such as SAE660 bearing bronze can be used for bushings, but not brass. I use a lot of 660 bronze because it's available locally at a walk-in counter. The reason phosphor bronze is a first choice for bushings is it will silver solder like copper but it will hold a thread like steel. It's drawback is it is not as commonly available as say a bearing bronze and it's tough as nails to machine, but I love the stuff.

There are number of changes like this and most of them were made to make boilers safer, more maintenance-free, longer lived, and more efficient. As I said though, opinions vary among experienced boiler builders.


----------



## CrewCab (Oct 3, 2009)

Welcome aboard Harry, boilers are a popular subject here so you could be quite busy 

CC


----------



## ChooChooMike (Oct 4, 2009)

Welcome GWRdriver Thm: !

I follow some of your posting over on the Chaski Live Steam forum. Glad you found your way over here. Always great to see talented folks offering their experience to help us machining neophytes !!

My goal is to work up to to build a live steam locomotive. Starting out small and working my way up to larger engines. Got an Allen mogul in mind since I know Gene Allen !

Mike


----------



## black85vette (Oct 4, 2009)

Been putting off boiler building since I don't know beans about it. So welcome, good to have you join us.


----------



## GWRdriver (Oct 4, 2009)

Thanks for all the welcomes. This appears to be a very busy place.


----------



## Maryak (Oct 5, 2009)

Harry,

Welcome to our forum. 
	

	
	
		
		

		
		
	


	




Best Regards
Bob


----------



## 4wheels (Oct 5, 2009)

I definitly do not wish to upset our friend GWRdriver but if standards are required then the Aussies have come up with 3 sets of standards.

They are the products of the "Australian Miniature Boiler Safety Committee" AMBSC. There are 3 parts.

1. Copper Boilers. Covering up to total enclosed volume of 50 litres. These cover most boilers required for passenger carrying miniature railway use. Typical of Model Engineering Club usage.

2. Steel boilers. Same as for copper except made from steel. Covers locomotive type boilers and vertical fire tube boilers for steam boat or stationary use.

3. Sub-Miniature Boilers. something of an afterthought to cover the "toy" sized boiler and particularly the live steam garden railway people (of which I am one!). The scope is up to 77mm (3") external diameter, volume up to 1 litre and operate at a pressure not greater than 75psi (520kPa). Covers 9 boiler types used in G0 & G1 outdoor railways and 2 water tube boilers for model boats. 

The good point of all these standards is that they cover all required details so that they allow plenty of flexability in general design as long as the details are covered.

I have heard some say these standards are a bit tough and over the top but for my money I like that as the boilers built to the standards ensure a level of quality which translates into safety - a state we all should hold up as the most important condition of playing with live steam.

Brian


----------



## GWRdriver (Oct 5, 2009)

> . . . I like that as the boilers built to the standards ensure a level of quality which translates into safety - a state we all should hold up as the most important condition of playing with live steam. - Brian


And in this we completely agree although as always there are more ways than one to bake a cake. One of the things I find problematic is the tendency of some folks to read just one book . . . that is, to take one source or authority, such as LBSC or Kozo, or the AMBSC, as gospel to the virtual exclusion of all others and in doing so throw out valid practices which have served well for many years. Likewise it's occasionally good to throw out outdated practice when better alternatives are developed. It should be noted that the world model boiler safety record after the advent of the AMBSC is no better or worse than it was before the appearance of the AMBSC so those of us who don't strictly adhere to the AMBSC must be doing something right.

A few years ago a few vocal Australians (dizzy from hanging upside down too long?), attempted to push the AMBSC off on the rest of the world and ended up getting told (in other forums long ago and far away) to back off. To their credit this advice was taken and what was accomplished IMHO was to allow everyone a bit of breathing room where the AMBSC code could be considered on its merits (or lack of) without feeling it was being forced down anyone's throat, which some of us were feeling, or being told we were looney if we didn't embrace this code. Many of us are still in consideration mode. It might be of interest to know that a few years ago I was asked by colleagues in Oz to review, comment, and possibly contribute to the embryo sub-miniature boiler portion of the AMBSC hoever I found it to be generally comprehensive and well done and not in need of comment from me.



> I definitly do not wish to upset our friend GWRdriver but if standards are required . . . .


IF is the key word here. The UK is obliged (some might say burdened) to follow certain standards of construction and certification for insurance purposes.  The AMBSC was likewise originally developed in concert with regulators and insurors to provide a set of mutually agreed upon standards. Please correct me if I am far off the mark on this.
	Things are different in the USA and one significant difference is the US live steamer's native independance (or obstinance), the tendency to resist being told what to do, especially with regard to hobby activities. So far as I know all attempts to develop a model boiler code in the US have been shouted down or in some way torpedoed. One reason we are free to indulge ourselves in this way is that the insurors don't much care about boilers, we fly under their radar. Their primary concen is with passenger safety and liability, because that's where the majority of injuries have occurred and where the claims originate. That doesn't make sense to us but that's the way it is. If the insurors were to come down on us and say "OK boys, codify, certify, and test your boilers, or else we won't insure you" then we would very quickly have a code also.

PS - Lest I seem to be short-fused with Brian, and/or the AMBSC (hopefully not), I ought to clarify that my boiler building techniques come mostly from guidance gleaned from The Model Engineer (mag), and its writers, and from local mentors, and then tempered by personal experimentation with those techniques. I also learned that knowing what NOT to do is as important as learning what To do. That's how I learned what I know and so far it has served me well.


----------



## CrewCab (Oct 5, 2009)

GWRdriver  said:
			
		

> This appears to be a very busy place.



It is, and it's very friendly too ............ that's what makes it so popular 8)

I've been reading quite a few of your posts and threads Harry and they are very enjoyable, informative and helpful, thank you, please keep up the good work.

CC


----------



## Orrin (Oct 6, 2009)

> Did you come here to gloat ? Kinda seem like it.



It pained me to read this impolite welcome and I will not let it go unchallenged. 

I've been reading GWRdriver's posts for many years and have come to have great admiration and respect for him. His posts are level-headed, restrained, intelligent, polite and knowledgeable. Take my word for it, he packs enough gear to be able to say what he did in his introduction. I did not take it as a gloat because I know the man would never stoop so low. 

Welcome aboard, Harry. 

Best regards, 

Orrin


----------



## ghart3 (Oct 7, 2009)

Harry,  sure could use some advise.   The project is for a 5 diameter copper vertical fire tube boiler for a Coles model American LaFrance fire engine.  The plans are dated 1964. I quit on this projects a few years ago because of the boiler. Engine, pump, wheels, frame and a few other things are done.  Drawings may be OK.  Instruction think are a little lacking for the novice that I am. I quote the instructions for the boiler.  

Page 8 of instructions
Section 8  Boiler
  It is believed about everyone has their own pet ideas about boilers. The one shown may not be to your fancy. O.K. Make changes as you wish. 

OK, gets some books and read.  I got stuck on first basic question Not being very smart and barely passing high school and having taken only the minimum in math a little over 50 years ago Never could figure out the calculations for a safe boiler.  

Am A little shy from drawing thickness for some of the copper.  Outer shell is listed at 1/8 wall and have .106 wall thickness.  The 3/8 fire tubes shown in drawing say .035 wall and have about .031 wall.

Am at a loss to figure out what the safe working pressure is for this boiler.  Attaching sketch of the boiler.

Question.  On the stays between outer boiler shell and fire box.  Are these all done after the fire box and boiler tube are riveted together?  Is the procedure tap drill both, clearance drill boiler outer, tap inside?  Screw stay in and put nut on stay?  Silver braze both joints?

Question.  There is a big bunch of things needing silver brazed besides the seams there are 14 bushings for gauges and plumbing plus some brackets and studs. Having done some silver brazing, I'm a little intimidated at doing all this at one go.  Would rolling the 46 fire tubes in using the squeezing rubber trick be OK? 

Appreciate any advice or ideas.

Gary


----------



## GWRdriver (Oct 7, 2009)

> sure could use some advise.


Hi Gary,
Let me say right at the start that you are to be congratulated for the substantial work you've done so far, this engine is not a simple project. And thanks for the boiler sketch, that has made answering your questions far easier.


> Never could figure out the calculations for a safe boiler.


You shouldn't have to be bothered with this. Them's wot we pays our drawin' money for, to have that information worked out for us in advance by the designer. We could reverse-calculate the max safe WP (working pressure) for this boiler but I wouldn't bother. I can just look at the design details and say with a fair amount of confidence that it will be good for 100psi.

It has traditionally been accepted that the maximum practical working pressure for a properly designed copper boiler is about 125psi. Above this pressure steam temperatures are such that copper begins to lose some tensile strength, enough to begin to affect the design safety factor (ideally 8X), so most copper boilers are generally assumed to be operated at 100psi or less. Although it can be mathematically substantiated I ask you to accept my statement that this practice is "widely accepted" without supporting evidence. As above, I don't see anything about this boiler design that would prevent it being steamed at 100psi WP, if you wanted to, but knowing what I do about small engine behavior my thinking is it would be happiest running at somehere between 60 and 80 psi, but that's just a guess. Somewhere in your documentation it should state what the inteded operating pressure is.


> Page 8 of instructions . . . Section 8  Boiler - It is believed about everyone has their own pet ideas about boilers. The one shown may not be to your fancy. O.K. Make changes as you wish.


Hmm . . well OK, but if I'm paying good money for drawings I don't want to have to guess what to do next. Also, it's easy for the inexperienced (or short-cut takers) to say "That oughta hold . ." There is another aspect of this is, liability, but I won't go there today.


> I am a little shy from drawing thickness for some of the copper.  Outer shell is listed at 1/8 wall and have .106 wall thickness. The 3/8 fire tubes shown in drawing say .035 wall and have about .031 wall.


I think all your tube thicknesses are adequate for the intended service. I always prefer as much wall thickness in flues as can be had and it appears what you have is Type L (.030" nominal wall thickness) but tube thickness varies a bit from mill to mill. If you were to use coal firing, a Type K (.035" nom) flue would be better from a cleaning wear standpoint but there would be no appreciable gain in safety AND 3/8" Type K is very difficult to find in small quanities.


> Question. On the stays between outer boiler shell and fire box. Are these all done after the fire box and boiler tube are riveted together?  Is the procedure tap drill both, clearance drill boiler outer, tap inside? Screw stay in and put nut on stay?  Silver braze both joints?


This needs a lot of explaining and I'm running out of time this morning but in a nutshell, I would eliminate all but maybe one ring of of waterleg stays. Although there are crush limits, generally speaking tubular sections such as you have here are self-staying and need no stays however I would put in one row (or ring) about 2/3 way up in the water leg to maintain internal alignment of the inner and outer tubes. Also, ALL the joint strength in a silver-soldered boiler is derived from the silver solder so riveting the thing to death really doesn't gain you anything. You can use only enough fasteners to hold the thing together for soldering and not lose any strength. More on this later.


> Question.  There is a big bunch of things needing silver brazed besides the seams . . . there are 14 bushings for gauges and plumbing plus some brackets and studs. Having done some silver brazing, I'm a little intimidated at doing all this at one go.  Would rolling the 46 fire tubes in using the squeezing rubber trick be OK?


I would do this boiler in two stages, possibly three. I would first assemble the inner firebox tube, the firehole ring, firebox head, and flues and solder that all up. Rolling the tubes wouldn't be needed. I would deform them a bit so that they push/pressed into their holes and stayed there on their own and then temporarily slip on the top head to hold them in alignment while the firebox assembly is soldered up. I would then slip this assembly into the assembled outer shell and finish up with a second heat. It will be VERY important that you have a large heat source for this job. More on soldering in assemblies when I have time.

Sorry I had to cut this short for today.


----------



## zeeprogrammer (Oct 7, 2009)

Thanks for the detailed reply to my question on 'chilled cast iron'.
Also thanks for the detailed information for Gary.
Someday I'll do a boiler...so I'm interested in anything about it I come across.


----------



## ghart3 (Oct 7, 2009)

Harry,  thanks for quick response.  It is quite a load of my little mind to not have to prove mathematically what is needed for boiler pressure requirements.  Feel much better about not having to do the sliver soldering (brazing) all in one heat.  Is there not much problem in bringing a silver soldered joint back up to or close to flow temperature a second time?

Went back and read the 13 pages of instructions that came with the drawings.  No mention is made of intended working pressure of the boiler.  
There is mention of adding (1) Superheater tube.  (2) valve and jet to produce blower.  (3) A blow down opening, near the mud ring.  

 Don't know about a superheater tube but would like to have a valve & jet for draft blower and also a blow down opening near bottom for draining boiler.

In the addendum page 12.  A builder states he feels that stays are not necessary between the boiler and fire box.  Like your idea of one row of stays.

I'm near completion of couple other projects and hope to be back on this boiler in a month or two.  With your help I'm looking forwarded to getting started back on the boiler.   Tanks.......gary


----------



## GWRdriver (Oct 8, 2009)

ghart3  said:
			
		

> Is there not much problem in bringing a silver soldered joint back up to or close to flow temperature a second time?


Gary,
Most people will say you need solders of two temperature ranges in order to solder in phases, and I wouldn't argue against that if one is a little short on experience. However one of the convenient peculiarities of 45% silver solder is that it takes a bit more heat to re-melt it than to melt it the first time. With some careful planning and weilding of the torch I have found that in the great majority of situations I can get by with one solder. We can revisit this later when the time comes.


> There is mention of adding (1) Superheater tube. (2) valve and jet to produce blower. (3) A blow down opening, near the mud ring.


You can get by without any of these but I think all of them are worth having, and if you fire with coal or other solid fuel a blower is a must. The so-called "superheater" tube would be more accurately described as steam "dryer" because that's about all it actually does for us, but I think it's very beneficial as it will make the model less "slobbery" while its running and you know how we hate slobbery engines.


> In the addendum page 12.  A builder states he feels that stays are not necessary between the boiler and fire box. Like your idea of one row of stays.


  A tripod (three) would do the job but I would put in maybe six just for good measure. Remember these don't have to be threaded although certainly you'll need some way to hold them fast in place while the soldering is carried out. You don't want to be interrupted while you stoop to pick up a stay that's landed on the floor! One common practice is to use copper rivets with the heads inside. The long (outer) end of the rivet, or the outer hole, is then deformed in some way (a center punch will do this) to hold the rivet in place. Once the soldering and pickling is done the long end of the rivet is snipped and filed off.

I might a well go ahead and add this now. It is not good practice to cut stays off flush with the surface of the copper because this can cause weeps and leaks. It is my practice to countersink stay holes slightly, the amount varies with the diameter of the stay, but no more than 1/2 the thickness of the sheet. This gives the solder a place to "puddle" and completely surround the stay shank. The surface of the puddle (or resulting meniscus) usually come up to flush with the surface of the copper, or a little more, after which (if needed) the stay can then be snipped off nearly flush with the barrel surface.


----------



## ozzie46 (Oct 8, 2009)

This is great info.

 How about 56% solder? Is it like 46% with respect to the reheating?

 There are boilers in my future too. ;D ;D


----------



## GWRdriver (Oct 8, 2009)

ozzie46  said:
			
		

> How about 56% solder? Is it like 46% with respect to the reheating?


Ozzie,
I don't know. Everything I've ever bought for myself has been 45% (mostly Harris Safety-Silv 45) but I've also been supplied with small amounts of silver solder by folks I was doing work for. If some 56% sneaked in on me it was in a stituation where I wasn't concerned about reheating but my guess is that the 56 will behave the same way as the 45.


----------



## ozzie46 (Oct 8, 2009)

Thanks GW.

 Forgot to sign my name on last post.


 Ron


----------



## Orrin (Oct 9, 2009)

I'm sorry to have to do this, but for the first time, ever, I've gotta add my 2¢ worth to a thread for the second time. To explain: 

Ghart3 said 





> I got stuck on first basic question Not being very smart and barely passing high school and having taken only the minimum in math a little over 50 years ago Never could figure out the calculations for a safe boiler.



Mr. GHart doesn't give himself the credit he is due. He says he's not very smart, but don't believe him. I've drooled all over the inside of the shop, repeating to myself all the while, "This guy is a clever genius." 

Never, ever, have I seen such a well organized, neat and clean machine shop. Frequently used hand tools are located at the machine, within short grasp of where they are needed; not at arm's length, mind you, but right at ones fingertips. If I lived to be a hundred I could never have come up with such a clever layout. 

I'll go you one further. His CNC mill sports a scraping job that is a work of art. The ways and dovetails are gorgeous! Furthermore, it is a _working_ mill and the things that GHart turns out on it make me turn green with envy. 

How many of you have ever seen a left-hand and a right-hand nut on the same bolt, the same set of threads? Neither have I until GH gave one, each, to a whole bunch of us, along with a generous supply of other goodies. 

Then there's the matter of craftsmanship. Superb. Need I say more?

The man is one-in-a-million and I'm very proud to have made his acquaintance, button-bustin' proud. 

He's one of the smartest men I know. 

I'm sorry if I embarrassed you, GH, but I had to do this.

Best regards, 

Orrin


----------



## firebird (Oct 10, 2009)

Hi Harry

Welcome to HMEM. 

I will also have plenty of questions in the future. I love steam and have completed 2 small boilers, both of which I have posted on this forum. My intention is make a few more yet so I will need some help.

Cheers

Rich


----------



## ozzie46 (Oct 10, 2009)

GWR. Are there any good alternatives to copper for boilers? I priced a 1 foot by 4in dia length on the web and it was appox. $127.00. Thats a lot more than I want to pay. maybe boilers are out of my league. At least in that size.

 Ron


----------



## GWRdriver (Oct 10, 2009)

Hi Ron,
The only practical alternative is carbon steel, but even then anything smaller than about 6" diameter makes it difficult to build a boiler with proper internal clearances and an allowance for corrosion (which is advisable.) Some will ask why not stainless steel, and there are quite a few stainless model boilers, but I'm not a proponent of stainless because there are known electro-chemical problems with it which make it unsuitable for miniature boilers.

It's unfortunate that copper has gotten to be so expensive. I try to keep my eyes open for scraps and cutoffs (new, never used material) from local plumbing and mechanical contractors. That used to be an good source, and it still can be, but because the price of salvaged copper is so high shorts and cutoffs aren't allowed to lay around very long. An alternative is to roll the barrel from sheet stock but that's not always more economical than buying tube.


----------



## Orrin (Jan 3, 2010)

> Are there any good alternatives to copper for boilers? I priced a 1 foot by 4in dia length on the web and it was appox. $127.00. Thats a lot more than I want to pay. maybe boilers are out of my league. At least in that size.



Depending upon where you live, you might want to check with salvage/recycling yards. One in our area frequently has brand-new short ends of usable lengths. My best score is a piece of new 6" copper about two-feet long and several other shorter pieces. Hopefully, it will some day be the basis for a vertical boiler. 

I'm always finding smaller stock on the order of three-inches. They are useful for reservoirs on water-cooled projects, gasoline tanks, etc. 

Regards, 

Orrin


----------



## GWRdriver (Jan 3, 2010)

A 48" length of 4" Type L copper tube has been on eBay for a while at $100/Buy it Now and didn't move. Finally last week someone bought it for $100 . . . $25/foot or $4.65/Lb. Cheap . . . if you need 4" copper.


----------

