boiler stays

[daveclm]

hi
 im nearly at the stage off silver soldering my boiler, i would be grateful if any could advise me if these stays are ok. i have built 4 other boilers but never done stays before. the stays are made off pb 102 3/16 bronze, the end fixings are 660 bronze. i have looked all over the net but nothing in detail. this is how i was going to do them. i have turned the 3/16 bar down on the ends and threaded them, the bushes are tapped to fit the ends, then i was going to silver solder one end with the bush on with silver flo 24, only on the threads, then install in the boiler silver solder the end that i have solderd with silverflo 55,
then silver solder the other bush at the back end with silverflo 55. hope this as made sense. have enclosed some pict.

[steamer]

I'm sure Sandy will pipe in here shortly.

To be of any assistance, we need to know what the materials are.

Has the design been reviewed?

Dave

[Jasonb]

I would have thought it better not to have reduced the diameter of the ends as now the effective cross section is the core dia of the thread rather than the 3/16" dia of the stay.

You could have just soldered solid stays straight in or if you wanted ones with nipples then tap the endplate and thread the OD of teh nipple (bush)

Dave, all the materials are given

[steamer]

Ah....Yes.    Not sure about 660 bronze, but Phosphor bronze is acceptable.

What did the plans call for on the stays?

Dave

[daveclm]

Ah....Yes.    Not sure about 660 bronze, but Phosphor bronze is acceptable.

What did the plans call for on the stays?

Dave
hi steamer
the drawings show that the stays are 3/16", all the bushes are bought from a well known steam fittings place.Bronze - SAE660 Free machining Leaded bar
Not subject to dezincification. Ideal for boiler bushes, bearings etc.
thanks dave.

[Jo]

Bronze - SAE660 Free machining Leaded bar

Leaded bronze  I am not sure you want to use that for stays.

Jo

[daveclm]

Bronze - SAE660 Free machining Leaded bar

Leaded bronze  I am not sure you want to use that for stays.

Jo
you have not read the first post that i did correctly,  the stays are 102 ph bronze rod, no lead in. its the bushes that are 660 bronze.

[Jo]

I am pleased to hear that 

I have a few bits of both leaded bronze and Ali bronze that are both kept well away from any bronze that I may want to silver solder.

Jo

[steamer]

Hi Dave,

If the plans call for the materials, and the dimensions specified, what is the question then?

Dave

[daveclm]

Hi Dave,

If the plans call for the materials, and the dimensions specified, what is the question then?

Dave
the drawing tells you what materials to use and sizes but not how to do the stays. like i said in my first post.

[steamer]

Hi Dave,

Don't worry about quoting, it's all there.    Do you mean how to silver solder them into place?

Your pictures show one of them installed, but nothing silver soldered yet

Dave

[steamer]

I do see that your flue tube has been silver soldered.

Dave

[Jasonb]

As I said earlier if using bushed stays then all the ones I have seen thread the full dia of the stay. The bush is then threaded internally to fit the stay and externally to fit tapped holes in the tubeplate. I suppose you could just solder in te bushes but I would prefer to see then full dia all the way.

I'll scan a picture later of a drawing that shows then done this way.

I have never had a problem silver soldering 660 and it is resistant to dezincification so no problem in a boiler though I mostly use it for fabricated cylinders.

J

[steamer]

As I said earlier if using bushed stays then all the ones I have seen thread the full dia of the stay. The bush is then threaded internally to fit the stay and externally to fit tapped holes in the tubeplate. I suppose you could just solder in te bushes but I would prefer to see then full dia all the way.

I'll scan a picture later of a drawing that shows then done this way.

I have never had a problem silver soldering 660 and it is resistant to dezincification so no problem in a boiler though I mostly use it for fabricated cylinders.

J

Jason, understood, but my point is what is drawn on the drawing?, was the drawing signed off for construction?, and does the part conform to the drawing?

I'm being pretty anal about this, because it's a boiler, and I know the laws on that side of the pond are pretty strict.   Now would be a good time for Sandy or a Boiler inspector to inspect the components and make a judgment before it's all silver soldered together.   It's far easier to recover from an error now before that happens.   Now if you're that guy...GREAT!   ....but I am approaching with a great deal of caution.    I have yet to see any stamped drawing that says this is right or wrong.   

Dave

[Jasonb]

Dave, as the OP has said the drawings do not show how to do the stays only that they are 3/16" dia.

"the drawing tells you what materials to use and sizes but not how to do the stays"

My comment was that I did not think reducing their diameter was the best way to do them as all the threaded ones I have seen thread the full dia to give max cross section and therefore strength.

Daveclm, can you let us know what boiler design you are following please.