Accucraft 3-cylinder Shay safety valve fail......................

JimmyB said:
Having come across engineering problems that have "stumped" me, suddenly it falls in to place and in your case you will wonder why you could not undo it.

A thought, though you may tried it is earlier, with whatever you are using to turn the dome apply turning pressure, then try tapping the dome with a small hammer (at thread height), this may take 2 people, or you may have a way of securing the loco whilst doing this.
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Worth a try.
 
Right now I'm thinking a small amount of explosives might do it..............but back on a serious note, a few taps might just serve to jar it a bit. I'll try it in the morning when I have more light to think by.
 
Tac, you know I am trying to help, so please put up with me on this question.

In order for anything to reach the threads, you must have the boiler upside down, and then put the penetrant into it, and fill until it comes out the dome... otherwise there is no way you are getting those threads wet.

Have you done this, the amount and the inversion?


Greg
 
Greg, I'm VERY loathe to put a potentially explosive petroleum-based fluid into the boiler, I'm certain that you understand why. However, given that I'd be able to flush it out afterwards as many times as was necessary, I'll give it a go.

I'll give you the address of the ward in the local hospital if it all goes t*ts-up, 'kay?

TBH, it sound like one of those 'here, hold my beer' moments.............................
 
Tac, stoopid question time:

Have you tried inverting the loco, with the dome in a container of 'E&P'?

My theory:
The 'joint' is on the outside, so (hopefully) less 'crud' and the oil can find a way in..
:think:

(please be gentle with me) :giggle:
 
tac foley said:
Greg, I'm VERY loathe to put a potentially explosive petroleum-based fluid into the boiler, I'm certain that you understand why. However, given that I'd be able to flush it out afterwards as many times as was necessary, I'll give it a go.

I'll give you the address of the ward in the local hospital if it all goes t*ts-up, 'kay?

TBH, it sound like one of those 'here, hold my beer' moments.............................
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I was going to say, leave me yer Porsche, but as it's got brown spots on it, I'm not so sure :think::think:
 
So, I take it that my suggestion to put it in the boiler and invert the boiler to ensure the threads get wet was never tried?

Also, filling the dome, would NEVER have engaged the threads..

I did point this out numerous times, and maybe it will finally be tried.... clearly a wash with solvent, the alcohol, and then water will rinse out the boiler afterwards, just like preparing an automotive gas tank for welding.

OK, I do hope that you actually try what I suggested many times, as it is CLEAR that putting penetrant in the dome can NEVER reach the threads.

Greg
 
Greg Elmassian said:
So, I take it that my suggestion to put it in the boiler and invert the boiler to ensure the threads get wet was never tried?

Also, filling the dome, would NEVER have engaged the threads..

I did point this out numerous times, and maybe it will finally be tried.... clearly a wash with solvent, the alcohol, and then water will rinse out the boiler afterwards, just like preparing an automotive gas tank for welding.

OK, I do hope that you actually try what I suggested many times, as it is CLEAR that putting penetrant in the dome can NEVER reach the threads.

Greg
Click to expand...

Greg, the loco has been upside down, with the boiler filled with penetrating oil, since the middle of last week. Tomorrow will see the serious bit of drilling an access hole clear through the dome, above the level of the safety valve, to put a silver steel rod though it to get some better purchase.
 
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Greg Elmassian said:
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Does it make sense to put in the boiler and leave the boiler upside down?

Then the penetrant could collect in the saddle, which should be surrounding the threads...

Just thinking that putting any liquids in the dome would just never touch the threads at all...
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Surely there is a safety valve in the boiler, so filling the boiler upside down won't get the fluid in to the threads. Filling the dome from the top with the loco right-side up will access the threads. What am I missing here?
 
tac foley said:
Tomorrow will see the serious bit of drilling an access hole clear through the dome, above the level of the safety valve, to put a silver steel rod though it to get some better purchase.
Click to expand...
Tac, that's the kind of approach I use. Cutting a slot across the top might also give you enough grip to turn it with a rod or flat piece of steel.
 
Fred2179G said:
Surely there is a safety valve in the boiler, so filling the boiler upside down won't get the fluid in to the threads. Filling the dome from the top with the loco right-side up will access the threads. What am I missing here?
Click to expand...

We are hoping that some of the penetrant will seep through the threads of the safety valve the small item that you can see sticking up in the centre of the boiler flange. It is totally inaccessible from the top of the dome and in any case, has also had its share of penetrant when it was right way up. The hole through the otherwise solid lump of brass that is the dome is just big enough for the safety valve to vent through and not more. The steam, condensing back into water over the last fourteen has obviously contained enough deposits, in spite if have been first distilled to use in the boiler, and then distilled again by making it into steam, to have seized up the threads.
 
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