I have had my boiler welded and inspected and now begin the ardous process of fitting the almost 300 copper tubes.

The information I have is to anneal the copper tubes (pre cut to length) and flare one end.
Then fit the tube and drive a punch into the flared end to hold it and flare the other end.

Then fit the steel ferrell with a series of punches and the ball from a ball peen hammer.

But I have tried a few and am not overly happy with the result.

The ferrell does not always seem to "seat" properly and in one case fell out when "tapping" (bashing) the adjacent tube.

Apart from the fact that it is incredibly slow I am convinced ther MUST be a better way.

Can anyone advise?

Locosurrey

I do hope after you had the heads welded on you had the boiler stress relived.
Unless the tube holes are reamed to the same taper as the swedgeing tool you should be using a tube roller.
They work great with a battery-powered drill that has an adjustable clutch on it.


[www.tcwilson.com]

Rolly
My tools

Dear Locosurry, So that your ferrules will expand and stay put when you swage them, everyone of them has to be annealed before installing. If you do not, your tube sheet will become warped from the continued pounding on the ferrules to keep the the boiler tube ferrules in. Also if you do not anneal the ferrules, when you turn your boiler over to do the other side, the ferrules will fall out of the other side when that side is turned down and the tubes are swaged from the opposite end. To anneal the ferrules, while the ferrules are on the bench, take your propane hand torch and get the ferrules just red hot and let them air cool slowly. They will become soft enough so that they can now be easily expanded when swaged. And they will stay put too.



Edited 1 times. Last edit at 06/29/10 03:20AM by SSsssteamer.

Thanks Rolly & Steamer,
yes the shell & end plates have been relieved, I have a good contact who is a long time boiler inspector and even though the current Australian pressure vessel standards only refer to fully welded vessels, he is able to certify my boiler. He has been very strict on testing the welds, with all of his black magic dyes and x-rays but has given the required tick of approval.
(cost a fairly decent bottle of malt!)

anyway, I did not discuss with him tube fitting as I had fairly extensive notes, which I have since decided are only slightly better than toilet paper.

Thank you both, I am heading out this morning to purchase the rolling tool.

and the ferrells -about 1/3 have been annealed already, but the remainder will be correctly heated, I have another contact who has offered to pop them into his annealing furnace with his next lot of machine tools (that he makes for the mining industry) and pass them back butter soft.

Once again I am indebted to Jeff and the SCCofGB members for making this antipodean restorer fell a little less isolated.

regards

locosurrey

Interesting day.

I met and had a long discussion about the black art of tube expansion.

using all sorts of old books, extensive experience and interest he has shed new light on the process.

Essentially the ferrells are nice to prevent flame impingement etc, but the seal must be by the copper tube expansion, the hole must be reamed, the tube annealed and then the expander expands the tube to a point where the wall thickness of the tube is reduced by between 8 and 10% to obtain the seal. The roller must also stop the expansion 1/16th of an inch before the inside of the plate to prevent the creation of a weak point where the tube exits the end plate- the expansion beyond the plate end cuts into the tube setting up a fracture point.

So once the copper tube is fitted - which he suggests doing in a even pattern (rather like doing up head bolts) to prevent undue strain on the steel sections between the tube holes. it is purely a matter of fitting the ferralls, he is insoucient about whether they are even expanded in, suggesting just knocking them in as the protective shield for flame etc.
as I said an interesting day.... so much more fun than work.

locosurrey