GNR 5in Sterling Single boiler test.

[Thomas ClarkeParticipant @thomasclarke78224]

Has anyone ever bought something and had second thoughts afterwards. Well last year my implosive nature got the better of me and I purchased a wonderful 5in gauge Sterling Single at auction. The price I paid for the engine did not reflect the time taken to make the engine or material cost, they never do unless the engine has won gold at the prestigious Model Engineering Exhibition. People at my model engineering club thought it was not a wise decision to buy a locomotive without a valid certificate especially if one does not have any experience on working on 5in gauge locomotives which in my case was true. My next plan of action was to have my club carry out a pressure test on the boiler by one of their boiler inspectors but was politely told that no one in the club could do this as there was no provenance with the boiler. At this point my second thoughts were kicking in and I was beginning to think that I had made a huge mistake and was the owner of an expensive piece of scrap copper. my next port of call was The Steam Workshop who kindly offered to do a pressure test on the loco for me which they don’t normally doe on other peoples locomotives. Like eagerly waiting for test results to come back to your GP I phoned them a couple of weeks later to receive the bad news that it had failed the pressure test and that I might need a new boiler made. At this stage I felt like I was dealing with a sick patient and I was not going to abandon my patient no matter how much it was going to cost in time and money. I now found myself looking for reputable boiler makers who could make me a new boiler and decided to go to the Harley street of boiler makers, Western Steam for advice. I asked Helen of Western Steam if she could take a look at the boiler for me and give it another pressure test and see if she could fix the leaks that were showing. She kindly obliged but the boiler would have to be removed from the locomotive with all its fittings removed. I felt I had set myself a challenge here having only worked in 4mm scale before but was up for the challenge. Taking something apart is often easier than putting it back together I thought so I was meticulous in taking photos as I proceeded with the exercise. This is where forums like this one really come to the aid for someone like myself where I was able to post questions if I got stuck and needed advice. Also being a member of an engineering club also helps and there are plenty of people there willing to give you advice if you need it.
I finally was able to separate the boiler from the locomotive ready to be taken down to Western Steam. Luckily Burnham-on-Sea is not to far way for me to get to and in the process I got to see seaside town and Helen’s wonderful workshop that reminded me of some of the wonderful back street workshops you see in the city of Rome. The day after I got a miss call from Helen. I phoned her back fearing the worst and thinking I might have to put down a deposit for a new boiler. To my surprise she had passed the boiler which only needed the tightening of one of the fixings I had left on the boiler.

The next stage is to fit the boiler back onto the locomotive but before I do that I thought I would take advantage of giving the boiler a good clean and descaling which I have done. The boiler will need another pressure test at one and a half times the working pressure and so it is important that all the fittings that go back on the boiler are water tight. This is where I could do with some advice with regards to what I put on the threads. There seems to be several schools of thought regarding this and I am inclined to use gasket sealant although there are other products such as ptf tape and special loctite gasket sealant. My concern is some of these sealants set after awhile and if you need to tighten the nuts up you could brake the seal so should I go for a flexible one. The gauge glass might need to be replaced but for some reason it is a strange size, 5.5mm in diameter. I could fit a 6mm one in but it would be a tight fit and have been advised this is not a good idea. The chimney will need painting  and the running boards will need a colour change to black. Any thoughts on these issues would be most appreciated and welcomed.

[Les RileyParticipant @lesriley75593]

I would suggest that whilst you have the boiler out of the engine that you take it back to your club and let them inspect it so that going forward you can get it tested without tears?

[Paul KempParticipant @paulkemp46892]

That is quite a tale, well done for persevering, a lesser mortal may well have given up!  Accepted there is often different sides to every story but from your account, for me anyway, it raises a few questions.

The request for the club to test it; fair enough I can understand reluctance to test it with cladding on and mounted to the frames without any previous history.  However, any reasonably competent club tester could have said “if you dismount it and pull its trousers down we can give it an inspection and test it as a new boiler” (2wp).  This is the sensible approach and it sounds as if that is what Western Steam did.  For a copper boiler there is nothing in the club code that prevents this approach either that I am aware of.  If a club tester feels he could not make a judgement on this (as his right under the code) then I would perhaps be nervous about asking him to do a retest on an older copper boiler.  Just because it doesn’t leak at 1.5wp cold doesn’t mean it doesn’t have a defect like an internal failure of a silver soldered crown stay that has caused deformation of the crown – the visual is just as important as the pressure test!

TSW I am assuming were given the brief just to pressure test it without performing other work?  If it leaked then fair enough it failed the pressure test.  However the leap to the conclusion the boiler is toast without investigating or recommending to you they do further investigation to confirm where the leak actually was is possibly a bit of a stretch, maybe they did say they needed to dismantle further to investigate?

WS took absolutely the right approach I would say.  They asked for the bare boiler, pumped it up, gave it a good looking at and discovered the leak was nothing more than a fitting.  In truth they did no more than your club could have done and if they were not comfortable in doing that then Les’s comment bears some serious thinking about and maybe you should ask before putting it back together if they will be now be happy to do the 1.5 on the frames and the steam test?  I can only suppose that if they are, their comfort will be from someone else underpinning their work?

To me this just illustrates how subjective a boiler test can be dependent on the inspectors experience and perception of risk and the brief they are given.  You could well have ended up scrapping a perfectly serviceable boiler!

For screwed fittings and gaskets if you must apply sealant to gaskets Rocol Steamseal is your friend.

Paul.

[noel shelleyParticipant @noelshelley55608]

I’ll second the use of Rocol Steamseal and at about £15 a tin worth it. So pleased for you that all was not lost and an end is in sight. Boiler testing can be a bit of a nightmare.  Good luck.  Noel.

[duncan webster 1Participant @duncanwebster1]

Have a good look to see if there are any numbers stamped on the boiler, usually near the foundation ring

[Brian Baker 2Participant @brianbaker2]

Greetings Thomas, I very much like the look of your single.

On most of the many locos and boilers I have owned, I have always used Loctite 572, a white sealant which does not set, but goes very sticky.  The fitting come out easily after time and joints break easily, but you usually have to make a new gasket.

It is a white paste, almost like liquid PTFE, but the only trouble is it’s Loctite number has recently been changed to a four figure number I cannot remember.

Sold in tubes, a little goes along way.

Regards

Brian B

[Grindstone CowboyParticipant @grindstonecowboy]

I’ve always had great success with Rector-Seal Tru-Blue pipe sealant, available from Toolstation (probably other places too).

Link to the data sheet here

Or the ridiculously long URL in full is

https://cdn1-originals.webdamdb.com/13771_83091321?Policy=eyJTdGF0ZW1lbnQiOlt7IlJlc291cmNlIjoiaHR0cCo6Ly9jZG4xLW9yaWdpbmFscy53ZWJkYW1kYi5jb20vMTM3NzFfODMwOTEzMjEiLCJDb25kaXRpb24iOnsiRGF0ZUxlc3NUaGFuIjp7IkFXUzpFcG9jaFRpbWUiOjIxNDc0MTQ0MDB9fX1dfQ__&Signature=oR4GOjWV3OvtFNsceSG0dglfGVMfqckB~Zegyo~v2YZ8X7RkPOnOE38yyG-5e~MB364P~XNKwibj7C~P7ny-cv-SbF9PxJBO73t~lZclKrLBUmv2KBCONIVUGPc0IOSL-OLKIUPxYHYRKD5Mg-C4pT4MoHMVGNRX~8BYZnJbjYWLFLsCwpwmlRF7IBCB6~sJcCGnTNmMztsDjxAZQ1ARc40lFrEBPkZxgDkYei1mkE887v32owpx9x15R6MQvgf567FM24ii8jd3iHBarLKW6ZE0epaitnbh~sdO2cBV2~NGPYTw3Pq~OtdFV~xdetrWk9ZaYb4sfBD7PumbtdQdrg__&Key-Pair-Id=APKAI2ASI2IOLRFF2RHA

Rob

[Nigel Graham 2Participant @nigelgraham2]

The one not to use, so we learnt at a boiler-testing seminar, is PTFE tape. It can shred and send particles into places like gauge-glass water-ways and injectors.

I talked about this to a friend who is a registered gas-fitter along with installing plumbing generally. He said he barely uses any PTFE tape in his line of work.

[Thomas ClarkeParticipant @thomasclarke78224]

Thanks for all the replies. I have ordered some Rocal Steamseal which is enough for about a 100 locos but one is enough for now. I will get the club to test the loco once it is back on the frames as it has been given a clean bill of health. If it does pass all the test the next learning curve will be learning how to operate it which I’m looking forward to. The one thing that did cross my mind was would it go round the tightest curve of the clubs track due to the design of the front bogie splashers sitting inside the frames. Luckily it does but I’m not expecting it to pull many passengers with that wheel arrangement.

 

[bernard towersParticipant @bernardtowers37738]

Its Rocol Thomas just so you dont chase your tail.

[duncan webster 1Participant @duncanwebster1]

I think you’re better off taking it to your club for test as it is. Easier for inspector to turn if over for inspection inside firebox. Speak to him first before re-mounting boiler.

[Thomas ClarkeParticipant @thomasclarke78224]

Before I put my boiler back on the locomotive I want to reattach some of the fittings. There is one fitting, the water gauge glass which I am finding hard to replace. It is 5.5mm in diameter which I can’t find anywhere. The union nuts have a 6mm diameter hole which will take 6mm gauge glass but I have been told this would be too tight a fit for the glass and could risk having the glass brake if I was to install this size gauge glass. My plan is to drill or ream out the hole in the nut to take the 6mm gauge glass. Could someone advise me what size hole this should be. I look forward to any replies.

[Thomas ClarkeParticipant @thomasclarke78224]

Thanks

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