Just starting to retube my 735. It has drawn steel tubes, welded at the bottom end, and they have lasted about 12 years, condensing. Drilling them out; glad of my mag-drill!
Wondering whether to retube in copper, with steel ferrules. Would I then need to go over to non-condensing? Is there a significant improvement in steaming or thermal efficiency with copper tubes? Are they longer lasting? Are they more likely to weep on non-condensing running than welded steel tubes? I have read that they don't drop so much dust on the burner plate as steel tubes do!
Any comments would be welcome.
Posted by: les nelson (---.dynamic.dsl.as9105.com)
Date: February 10, 2013 05:50AM
there is no need to weld steel tubes to the tube plate if they are PROPERLY expanded, with the correct tool NOT a drift, I am not in favour of condensing, I soon took cond. out of our 735, and the MORRISS steamer, condensing is bad for boilers with either copper or steel tubes, and water is cheap enough so why try and save it at the expense of your boiler? good luck with your project, I look forward to reading your findings Les
Thanks for the advice, Les. What is the best tool? In the past I have tried a 3-roll taper expander, like a miniature version of the tube expanders I use on my traction engine; but it was not satisfactory. In the end, last time around (12 years ago), I recall I used a taper drift, but 'wobbling' it round, rather than hitting it. This seemed OK, but it expanded the tubes just behind the tubeplate a bit more than I would like. I guess that calculating the length and taper of the tool a bit more exactly might be worthwhile?
I also presume the tube and hole should both be clean and dry, without any lubricant, to promote the best metal-to-metal contact?
I take your point about non-condensing entirely. I have never been really convinced by any of the compact oil separator designs I have seen. But I would love to see a proven centrifugal separator,like a Dyson vac!
Posted by: Donald Cook (---.range86-177.btcentralplus.com)
Date: February 18, 2013 03:57PM
When I bought my 10hp Stanley the boiler was fit with 16 gauge copper tubes and no ferrules. I soon had trouble with the tubes leaking and was unable to stop them leaking regardless of what type of expander I used. So I bit the bullet and retubed it with steel tubes. I have had no trouble with leaking tubes since, it may take slightly longer to raise steam but once on the road the performance is the same as it was with copper tubes.
Just remember when youíre looking for small tube rollers your looking under heat exchanger tube rollers.
I use a battery powered 3/8 drill with an adjustable clutch, my drill clutch goes up to a 14, the most Iíve used is an 8 setting and hydro to 1000 PSI.
On re rolling scorched boilers the most Iíve goon is to is a 6 setting.
Last year I did a locomoble scorched boiler, I use 38 cal bronze wire brunches to clean the tubes first. Dirty tubes really can plug up the rollers. I use motor cycle chain oil to lubricate the rollers, it comes in a spray can. Works great when your laying on your back looking up.