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Post by Steve Purves TBLR on Apr 15, 2019 9:45:48 GMT
I have acquired a large scale Bagnall Sipat. When I say large scale I mean 7.25 inch gauge, 4 inch to the foot scale, live steam and approximately a quarter of a ton. 20190330_155714 by 47845, on Flickr The loco was built in 1989 to a design by MJ Engineering and serialised in Engineering in miniature. I believe this was one of the first to be completed to this design and the loco sees very little deviation from the drawings. The engine was run around the north west of England for about 10 years until 2000 when its boiler was retubed (more of this later). it was used until (officially) 2003 when its most recent boiler ticket expired, whether it has been steamed in the meantime is pure speculation as the previous owner was not around to ask. For an engine with 15 years of storage under its belt I felt it was in incredibly good condition, nothing more than a light surface rust on some of the motion, nothing was seized and it made all the right noises when being hand shunted about meaning the steam circuit was still tight. I bought the engine with my eyes open. obviously storing a loco for so long in unknown conditions could take its toll, and there was the case of the last retube to consider. In 2000 the then owner felt it appropriate to install stainless steel tubes in place of the more standard steel or copper. The loco was inspected and passed consecutive years after this with apparently stainless steel tubes fitted even though it was always my understanding that stainless was a no-go in live steam. 'How could his club have certified it?' I wondered... 'It must be a mistake'. Speaking to my boiler inspector we concluded that everyone would be happiest if, prior to recertification, the boiler could be examined 'naked' and out of the frames. This would also give me chance to go over all the hard to reach places and investigate the stainless tubes better. work started immediately 20190409_194710 by 47845, on Flickr More to follow! Steve
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Post by Steve Purves TBLR on Apr 15, 2019 12:22:35 GMT
I managed to get the other images off the camera so here goes. I was working in a bit of a mess since I collected the loco as the garage had been accumulating all manner of wares to do a car boot sale (the fall out from re-decorating the house), The car boot came and went on Sunday giving me opportunity to clear some sort of work space. Just need to sell the bogie coach now as it too is in the way! The locos you can see in the picture below are obviously the Sipat taking centre stage. The small 5 inch gauge yellow diesel is in fact a Maxitrack battery electric 'Planet' sat on top of its driving truck and the loco on the bench is my 7.25 gauge Jessie which is awaiting its new owner coming to collect it. As you can see the boiler has now parted company with the frames. the steam raising blower can bee seen on top of the chimney also. 20190415_080017 by 47845, on Flickr The chassis has been cleaned a bit to get some of the 15 year old oil off. the brightwork will be cleaned up next and any paint touching up will happen soon so I can re-oil and protect everything on the bottom end. So far no shockers, everything adds up to show a very well made engine in the first place. 20190415_080029 by 47845, on Flickr The boiler took a little more persuasion to get off. The inside is a bit nasty but that was to be expected. I have cycled some descaler through the boiler a couple of times to break up some of the crap and flushed it clear. on Saturday I took it to the local garage to pressure wash it from every angle and in every opening. It now runs clear. I have my concerns about the inner firebox but I am having it ultrasonically tested for plate thickness on Sunday. This will determine its fate as to whether a new one is required or not. 20190415_080034 by 47845, on Flickr Back to the saga of the tubes, it turns out they re in fact stainless. I have heard conflicting reports about their suitability ranging from 'they are fine, leave them be' to 'take them out it is illegal' and most things in between. I will not be making any rash decisions until the thickness test is complete but currently the options are Thickness test fails - new boiler required Thickness test fails on firebox - possibly new firebox or boiler Thickness test passes - replace tubes for steel or copper Thickness test passes - test code rewritten and stainless tubes are accepted! 20190412_131432 by 47845, on Flickr Its a seemingly long wait until Sunday now! Steve
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smallbrother
Elder Statesman
Errors aplenty, progress slow, but progress nonetheless!
Posts: 2,269
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Post by smallbrother on Apr 15, 2019 12:48:46 GMT
Will be nice to see it running again Steve.
Mine has gone off to a professional workshop as I just couldn't cope in terms of space and weight. I am hoping mine will be running before the year is out but not counting any chickens.
These locos are certainly a very hefty piece of engineering and I know of one at a South Wales club which apparently pulls a decent load in spite of needing a bit of work.
Pete.
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Post by ettingtonliam on Apr 15, 2019 14:46:40 GMT
What exactly is the rule regarding stainless steel and boilers? I know that complete stainless boilers are not accepted in the UK, but we all use stainless steel in fittings attached to our boilers and wouldn't think of using anything else, so where is the line drawn between small bits of stainless being acceptable, and big bits not being? Is it down to the welding of the stainless for pressure vessels? I need to make a fairly large flanged gunmetal fitting which will be in the steam space of my boiler. I was going to attach the cover plate to the flange with a number of 4mm csk stainless allen screws, but an acquaintance I mentioned this to suggested that it might not be acceptable because of the ban on stainless steel in boilers.
Thoughts anyone?
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Post by andyhigham on Apr 15, 2019 15:30:46 GMT
Thinking about this in a logical way. We are happy to use stainless steel for superheaters. A superheater is subject to much greater heat than a boiler tube, probably glowing red hot with the regulator closed
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Post by Roger on Apr 19, 2019 21:39:03 GMT
I found this interesting article about Stainless Steel corrosion. The section called 'Bimetallic (galvanic) corrosion' explains the issues with Carbon Steels being in contact with Stainless Steel.
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Post by ettingtonliam on Apr 20, 2019 4:51:16 GMT
When I was involved in the installation of (very expensive) stainless steel vessels and pipework in the nuclear industry, we were totally prohibited from marking the vessels and pipes with felt tip markers, because they contained chlorides, and it had been found in America that at certain combinations of temperature and pressure, cracking could occur where the marker pens had been used. Aluminium bridge parapets were fixed with stainless steel security bolts, and quite a lot of trouble was taken with sleeving to ensure that the aluminium baseplates and the stainless steel bolts were not in contact with each other.
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Post by Roger on Apr 20, 2019 8:13:38 GMT
Personally, I think any Boiler Inspector would be taking a huge risk to pass a boiler with dissimilar metals unless that combination was explicitly stated as being acceptable. Galvanic corrosion will take place, it's just a matter of how much. There's a pretty big difference in the area of the tubes compared to the area of the boiler plates and wrapper, so it's possible that the rate of corrosion could be significant. It's probably best to re-tube the boiler with Steel Tubes in my opinion.
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Post by Steve Purves TBLR on Apr 25, 2019 8:21:16 GMT
Thanks for the comments guys, The overhaul is progressing slowly at the moment. 20190421_120840 by 47845, on Flickr I took the boiler to see my inspectors on Sunday and they said they would like to see it 'acid dipped' to remove all trace of rust and scale from the plates inside. This could potentially delay things and first I have to get the 32 old tubes out (not a simple task I must add) and find a reputable pace to 'dip' the boiler shell. This is so the inspectors can fully assess the levels of pitting in the crown of the firebox. The inspectors are currently unsure how thick the plates are due to the build up on them as such they couldn't advise if its either a scrap boiler or whether I can squeeze one last ticket out of it. mine currently looks like this.... 20190421_185445 by 47845, on Flickr As the boiler is being worked on separately my attention has turned to other parts of the loco so that it is ready to accept the boiler back when its done. this will speed up the re-assembly considerably as everything *should* fit straight back on where it came off and will be cleaned and steam tight. One of the clack valves can be seen below, This will now be stored 'clean' ready to go back on the loco when the time comes. 20190415_193012 by 47845, on Flickr More to follow if and when things progress! Steve
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smallbrother
Elder Statesman
Errors aplenty, progress slow, but progress nonetheless!
Posts: 2,269
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Post by smallbrother on Apr 25, 2019 8:54:37 GMT
Would it be easier to bite the bullet and order a new boiler? Seems a shame to me to have such a fine big loco back on track with something that may not last.
Pete.
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Post by gingerneer on Apr 25, 2019 9:33:57 GMT
A Pete Says might be a lot of work for the boiler only to last a couple of years. If you re boiler, you will know its full history and materials used in construction also any water treatment to help prolong its life.
Will
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nonort
Part of the e-furniture
If all the worlds a Stage someone's nicked the Horses
Posts: 277
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Post by nonort on Apr 25, 2019 9:38:25 GMT
dependant what paperwork you have for the boiler. It is a simple enough process to cut the old firebox out and weld in a new one. This is the main benefit of steel over copper. Almost any coded welder worth his salt would carry out the work in less than a day if you were supply the kit of parts. It may also be worth talking to Station Road Steam as their Stafford boilers are almost identical. When the job is done make sure that the boiler maintenance is properly carried out run with treatment from new and look after your investment. I suspect that most of the corrosion has been caused by dry storage? Fill the boiler at the end of each run and keep it full of treated and therefore oxygen scavenged water at least to a level above the top of the water gauge glass out of the top nut. Over winter fill the boiler with boiled water until it comes out of the safety valves, in Royal Navy terms 'water wedged'. Hope this helps.
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Post by Steve Purves TBLR on Apr 25, 2019 10:02:10 GMT
The only issue I have with re-boilering now is funds. I bought the loco at an agreeable price which meant should it need a new boiler I would still be the 'right side' but I am a little cash strapped at the moment. I am hoping to get at least one last ticket on the shell as is (with a retube)to enable me to put some pennies In the jar for a new boiler and get a season or two of running/snagging the rest of the loco. I have asked around regarding putting a new box in the existing shell and was told that it would be about half the cost of a new boiler for just a new box fitting, I think if that was what was required I would just start a fresh with a whole new unit rather than just putting a new firebox in for the sake of a few extra pennies. These locos are designed that they come to bits pretty easily, I managed to get the boiler off in a day. I'm not too fussed about having to do it again at some point in the future to swap boilers over as it will be easier the second time (plus all the fastenings will be properly greased and cleaned before they go back on)
Steve
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smallbrother
Elder Statesman
Errors aplenty, progress slow, but progress nonetheless!
Posts: 2,269
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Post by smallbrother on Apr 25, 2019 10:44:33 GMT
Steve - you clearly have a sound and viable plan.
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Post by Steve Purves TBLR on Apr 25, 2019 11:33:40 GMT
Steve - you clearly have a sound and viable plan. Haha! You would think so....
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Post by Steve Purves TBLR on May 10, 2019 14:12:02 GMT
Well after a modest battle over a week I have managed to get all of the tubes out. Image below shows the inside of the boiler barrel water space with just a couple of tubes left to come out. it can be seen how much 'loose scale' is in the bottom of the barrel. this has all come of the outside of the tubes and been scraped off the surface as the tubes were withdrawn from the boiler. 20190504_190014 by 47845, on Flickr The tubes are expanded in which means they are fatter at each end to make the seal with the tubeplate. when hammering out a tube its difficult to break the initial seal but when you get to the standard with dube you are only battling against the scale. what is difficult however is getting the tube out past the other 'fat bit' on the other end. the way around this is to draw the tube out by a certain distance, hacksaw off the 'fat bit' and push the tube back in to the boiler thus dropping between the tube plates at each end. the dropped tube can then be withdrawn through the larger diameter washout hole on the end. the various lengths of removed tubes are seen below as a result of this exercise 20190505_165624 by 47845, on Flickr With all the tubes out my boiler inspector is happy to pass the boiler to be retubed although due to its age he has granted me a ticket on a shorter inspection cycle of every year instead of every 2 years. with this in mind I have now ordered the tubes and will commence the retube as soon as they are delivered. 20190505_165807 by 47845, on Flickr Whilst I was cleaning up other areas of the loco I noticed what looked like a flake of paint behind the cylinder end cap. closer inspection revealed this to actually be the gasket from said cylinder that had blown clean out. Time for unexpected job number 2. I spent the evening stripping down the valve gear on both sides to gain access to the cylinders so I could replace the gaskets for both front and back caps both sides. better to do all at once than have to revisit it at a later date. I took this opportunity to withdraw the piston completely from the bore for inspection. Once I have some suitable gasket paper this will be put back together. 2019-05-10_02-54-55 by 47845, on Flickr The club open day and the locos potential first steaming are now 3 weeks away. nothing like a deadline to focus the mind! Steve
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Post by Steve Purves TBLR on May 14, 2019 12:30:29 GMT
The boiler tubes are now ordered and will be delivered on Thursday from TSS in South Wales. Luckily there are plenty of other jobs to be cracking on with. I spent Saturday PM refitting the regulator and main steam pipe as can be seen in the attached two photos, both open and closed. 20190511_191728 by 47845, on Flickr 20190511_191732 by 47845, on Flickr I also took this opportunity to refit the gauge glass fittings (no glass fitted yet so I don't damage it) and washout plugs (the latter at least until the tubes are fitted and it has a final wash out) 20190512_150722 by 47845, on Flickr
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Post by cplmickey on May 19, 2019 14:09:02 GMT
Are you going to make the open day Steve? 2 weeks to go!
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Post by Steve Purves TBLR on May 20, 2019 9:22:52 GMT
its getting close... Well the new tubes turned up on time on Thursday. A quick count and measure to make sure all was well meant that work could begin on the big job! 20190517_181349 by 47845, on Flickr The first task was to anneal the tube ends. This heating (to a dull red) and (slow) cooling cycle changes the structure of the steel and allows it to be 'expanded' in to the tube plates easier. 20190517_182814 by 47845, on Flickr With all the ends treated it was time to start fitting the tubes. Each tube was placed in its respective holes and expanded, starting from the outside working in a spiral fashion. The process was slow to start with but once I got in the rhythm its wasn't as bad as I had expected. All tubes were in by late afternoon Saturday. 20190518_145153 by 47845, on Flickr One to go! 20190518_153840 by 47845, on Flickr I had a bit of spare time at the end of the day so filled the boiler up with water, fitted the test blanks and had a go at putting some pressure on it. 50psi at first and few tubes were weeping at the firebox end. The problem areas were fettled and tried again, 100psi this time and both tube plates were dry. A bit more pressure, 150psi but the clack valves and water gauges started leaking a little - no problem, the tubes were holding at least - 180psi and the same, tubes were fine but due to other 'weeps' the pressure was not holding. 20190518_175901 by 47845, on Flickr Sunday evening I decided to put the boiler back in the frames. the small niggly weeps will be sorted as the rebuild progresses. The smokebox was refitted and sealed and the cylinders had new gaskets cut and refitted which allowed me to rebuild the valve gear 20190519_192419 by 47845, on Flickr Starting to look like an engine again. Tonight's job is to get the tank back on and the plumbing back together. The cab will only be loosely fitted at this time until I have put a fire in and tested the loco under steam. Fingers crossed nothing else raises its head!
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Post by a3lner on May 20, 2019 9:49:51 GMT
Looks like it will ready for your open day if all goes to plan as you are putting in some serious time in on this and doing a great job😃👍
All the best Tom
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