I've got a popped stay!

[SteveM]

I'm evaluating a train for purchase, and I've been checking out the boiler. Managed to seal up enough of the leaks in the plumbing, put air in it and went around looking for leaks with soapy water. I made an earlier post about the turret.

The boiler was losing air faster than the turret would have done, so I put my ear to the smokebox and heard some hissing. OK, just what I need - probably a flue.

Get the soapy water and paint everything in the smoke box and no bubbles.

Turn it on it's side and put my ear to the firebox - louder hiss.

Paint the inside of the firebox with soapy water and I get bubbles just under the fire door. There are two stays there, and at least one has popped and the wall there is bulged. You can see that the stay on the left in the picture is pointing to the left.

OK, so what's the fix for this?

Drill out the stays, straighten the bulge and put in new stays? Or is this boiler now toast?

Steve

[Steamin]

If it was just a leaky staybolt, I'd say drill and replace it.

But a bulging firebox sheet raises my worry considerably. A sheet bulge is caused by corrosion/scale buildup, suggesting 1) the sheet is thinner in that spot than the rest (?how much thinner??), and 2) you are no longer circulating water in that area. Any fire is just heating the metal hotter and hotter until it reaches the yield point (don't want to be around for that!). It also makes me wonder how the circulation is in the other water legs - are they plugged too?

If you want to remove all doubts, you'll have to pull the firebox out of the boiler to see what condition issues you are really dealing with -- a boiler job.

Steamin
(assuming this is a steel boiler and not an all-copper boiler.)

[JJG Koopmans]

Hi,
I would suggest to inspect the inside of the boiler first, that is what these technical endoscopes are for.
Kind regards
Jos

[SteveM]

I would suggest to inspect the inside of the boiler first, that is what these technical endoscopes are for.

I actually have access to one (a medical one, but don't worry, it's retired from medical service).

Maybe a good test would be to drill a hole through both sheets between the two existing stays, check the thickness of the sheet metal, and then close it up by adding a new stay.

Steve

[cbrew]

The pictures sure looks like a copper boiler,
its it not?

[Fender]

My question is, what are the stays made from? You need to make sure they are copper or bronze, not brass. Brass will suffer from "de-zincification" and the other stays will fail as well.

[SteveM]

The boiler is all copper. Sorry that I missed that note on Steamin's post.

My question is, what are the stays made from?

The stays are identical in color to the boiler material and do not resemble brass at all.

BTW, the engine is a Raritan.

Steve

[Fred_V]

with copper the sheets are much thinner and might bulge with a broken stay. it would be easier to put it back in place than with steel and replace the stay.

[gwrdriver]

A couple of comments . . . .

Unless the boiler was disassembled and cleaned to bare metal you would never be able to get it clean enough to solder back together again. By the time you (or someone else) cut apart the boiler and did all the work involved with such an extensive surgery (if that would be possible at all), or dealt with the collateral damage of a full-heat soldering job, if the boiler survived you would have spent as much or more than the cost of a new boiler.

IMHO, from what little I can see and know, the best way to save this boiler, and squeeze a few more runs out of it, is to is to replace the soldered stays with mechanical stays. This might take the form of a carriage bolt-like stay with a broad head to the firebox side, bedded in some new-fangled heat resistant sealer, or simply caulked with soft solder, and likewise nutted and caulked on the outside. Nutting and caulking stays is frowned upon these days, we know differently now, but for decades it was standard procedure and I think it will squeeze some more life out of this one.

For this approach only the exterior surfaces need to be cleaned and when the old stays are removed and the head straightened you can measure the thickness of the plates and make a determination whether to go forward at all or not. Naturally you would want to take away as few thou' of metal thickness as possible and still leave a nice clean and flat nutting surface. If at the same time you found you needed to purge the mud ring area you could do so by putting a taper plug or two in the mud ring. If it was mine this is the direction I would go in.

[Bill Shields]

build another boiler...

[SteveM]

Took a closer look at it last night and it looks as though the stay is not actually broken, but just that the bulge in the sheet has caused a crack in the soldering around the stay.

The "carriage bolt" fix would cause another problem, as the frame sits on the outside right at the point where the nut would be, and that part of the frame is where the coupling connects. You can see the coupling in the picture.

Steve

[Bill Shields]

crack in the soldering....??????

not good steve....

how is is soldered?