Wile on a tour in July last year the boiler tubes on my 10 hp Stanley started to leak (bottom tube plate only) for no apparent reason. I always run my car with the gauge glass 7/8 full and I have never lost sight of the water and even when the water is in the bottom of the glass my boiler is still half full.

Since then I have tried to seal the tubes by using a tapered drift, a roller expander and additives as recommended by other steam car owners i.e. Potatoes, rad weld ect. All seemed to work for a short wile (a day or two in most cases) but the problem keeps coming back and is now a lot worse.

My boiler has ½” o/d copper tubes which are 16 gauge and don’t have ferrules fitted. Even with this problem the boiler never fails to siphon full of water every night. If I fire it up and set off before the burner cuts out it will run fine, but a minute after I stop and the burner goes off the tubes start to leak and now continue to do so until all the steam pressure has gone.

I have now removed the boiler from the car, again, and turned it upside down, filled it with compressed air and have tried to seal the tubes using the drift and expander once more, but they will not take up. I am wondering if any scale has got between the tubes and the tube plate. The previous owner used tanning in the boiler to combat corrosion and I am wondering if this may have got between the tubes and the tube plate making the tubes move more easily.

I don’t know what caused the tubes to leak in the first place but is my only option now to drill out all the tubes and replace them?

This seams a shame to me as the boiler has only been in service for 6 summers but it has got worse since it started 14 month ago.

Don.

Don

All I can suggest is to fit ferrules.

Knock them in lightly with the taper drift, if they still give problems then use the expander. The Ferrules will give that extra material thickness.

Is your expander a taper or parallel ?
I have found with both my steam car and roller that parallel are the best to use. Taper will eventually cut through the tube where it exits the tubeplate.

Cheers
Ian Vinton
PS: I have also suffered from this problem and found the parallel tube expander fixed it. However, my boiler has Ferrules.

Ian,

Thanks for the reply.

My tube expander is a parallel one.

Fitting ferrules was going to be my next job, but as I can’t get the tubes to seal with out them I thought the tubes may still leak after fitting ferrules, but it may be worth a try, what dose any one else think?


Don

Hi Donald,

As you know I too have had similar problems with the boiler on my EX. They also started leaking for no apparent reason and like you have always kept water in the sight glass and even fire it gently to allow for different expansion rates. As you also know both these boilers were built at the same time by the same comany and now suffer from exactly the same problem. The only difference is mine does have ferrules but for some reason they have been put in the top tube plate!!!! Maybe my boiler is upside down???? Iam even thinking of turning it the right way up!!!!

I have now swaged them twice and have run out of room on my roller swager. They seal a treat on hydraulic but obviously leak when the copper tubes get flame on them.

After consulting my steam guru (Jeff) I have come to the conclusion that I should cut my losses and buy a replacement from Don Bourden.

Terry



Edited 2 times. Last edit at 10/11/10 12:01PM by terryfry.

Leaky tubes? as many of you know I am a fan of STEEL tubes in boilers, simply to get round the differential of expansion of copper to steel, yes I am fully aware of many boilers operating with copper tubes succesfully, but as Don has pointed out trouble is never far away with copper tubes, I agree copper is far the best heat conductor but the question is DO WE NEED THIS FACILTY, I ran our MORRISS steamer in Norfolk and operate at 500 P.S.I. never once did the pressure fall below 400 P.S.I.
I contend that once heat flow is taking place i.e. everything is hot and burner on there is little to chose between copper and steel, RECOVERY is a different ball game copper will always beat steel if water is low and pressure is down and you need to pump lots of water in the boiler (usually on a hill?) but how often are you in this position?.
Ask a metalurgist to show you the Copper/heat strength deterioration at 600 P.S.I. it WILL frighten you, the temperature at 500 P.S.I is coincidentaly about 500 F (or nearly so) Copper does not have the same characteristics as steel, as copper gets hot it's strength deteriorates, and at 600 P.S.I. it is alarming.
I know of two steamers who are converting to steel tubes and before we get into corrosion you should expect 10 years from steel tubes with proper boiler care Don unfortunately has had 4 good years and 2 years of trouble. without ever scorching his boiler, and is now considering retube , it will cost 4 times as much over steel and who's to say he wont be "in the same boat" again. as a closing remark I retubed my boiler 5 years ago due to condensing and oil "eating" the tubes, I no longer condense. happy steaming Les Nelson

Les
I have to disagree with you to as to the loss of strength with the copper tube used in a fire tube boiler. It acts like an egg and is very strong. Copper by itself does loose its strength, as it gets hotter with heat but used in a Stanley boiler will never get hot enough to fail as long as water is in the boiler. See attachment. 600 psi =486 F or 855 K, Stanley ran 1300 psi in the Rocket in 1907

The real problem with the copper tube is its differential of expansion as you pointed out.
With a 14-inch high boiler the copper tube expanse 0.030 more then the steel shall. This means the top sheet dome’s, crown’s 0.015 as does the bottom sheet. The tubes in the center are in tension but at you move to toward the edge there more and more in compression.

They either compress or bend or move in the tube sheet. When you acquire a fire tube boiler you should know what the hole is. Straight drilled or taper reamed. You shouldn’t swedge a tube in a straight-drilled hole. Nor use a parallel roller in a hole that is tapered.
And always use a steel ferrule to lock the tube to the sheet. At the bottom tube sheet is where the copper can loose its strength do to heat, as there is very little cooling between the copper and the steel. And the bottom sheet is doing 90% of the work in the combustion chamber. The largest differential of temperature between the water at no more then 486 F and the fire at over 2300F this is the problem area of loosing compression with the copper tube from being rolled tight.
In my opinion the sheet should be no thinner then 3/8 inch per the ASME code. Anything less then 42 inches in diameter.

The steel tube has its problems as well. You have oxygen and hydrogen separation at the boundary between the water and steam layer. This is where the pitting takes place in the steel tube, pure oxygen at the waterline. Off course it’s the same at the shell but it’s a lot thicker. When my steel tubes failed in my 23 inch 1920 boiler it was at the water line. However as you pointed out it can be a long time, I’ve seen steel boilers last over thirty years. Mine was at least that.
Rolly

Hi Rolly thanks for your input but as a 72 year old timer engineer I am still in yards feet and inches so your figures (on the chart) mean little to me . what I would like to see is a chart showing the UTS against temperature this would be very graphic, unfortunately I have lost mine (chart/graph) and despite searching the WEB I have not found one to display the characteristics of copper exposed to heat . If memory serves me the stress line drops gradually then drops like a knee at a given temp. ( about the temps. we play with). anyway our boilers perform that is without question, but are we operating near stress/temperature limitations?

Les
I can understand your frustration; I’m the same age and have to work at all the conversions.
I have attached a chart and have added a table of conversions at the bottom from
MPa to PSI and Kelvin to Fahrenheit.

When its all said and done, copper works up to 1000 PSI in a well-built Stanley boiler.
I don’t know anyone running over 600PSI.

Last week I received my copy of the steam car. Enjoyed very much your model work.
You still have good eye’s
Rolly

Hi Rolly. many thanks for your kind words, the model is coming along nicely , looks nice with her new tyres on , these were molded in a liquid rubber by centrifuge (lathe) this part was a new venture for me and could not have turned out better.
I finished my "time" as tooling and special machine designer incorporating P.L.C. control, so every day was a new challenge and it was a PLEASURE going to work , I consider myself to have been very lucky in this respect and was very sad when I finished work , some of my collegues said " I cant wait to retire" how sad.
I am sure my modelling and light engineering work keep me young, I still help out with jobs for my friends who have vintage cars, and struggle to get special parts made, it is still great fun to work out how to make a part, and see the smile on the face of the recipient, and it pays for the power etc.
Keep on keeping on, may your boiler always provide the needed. Les

Hi Rolly I just had a look at the graph att. you kindly supplied relating to copper strength, I was supprised how closely it followed one I had recently drawn in AUTO cad, ( not the best for doing graphs), it was a bit of a stab at it as I used the figures supplied on the ASME site , ( the relationship is the same even if one does not understand the figures), By my reckoning there is aprox. 70 deg K margin at 600 P.S.I. before entering the "danger zone" or rapid weakening of the copper, interesting work but not of much concern to many I think.
I think I will kick Donalds leg next time I see him, hornets nest etc. O K can of worms if you like.
Thanks for your input perhaps we might be fortunate to meet if we are lucky, and chat over old proper engineering years. Les