Silver soldering fire box stays

[Kevin]

Hi Paul

many thanks for the very informative link

Kev

[runner42]

Hi Paul,

the torch is using oxy-acetylene, but it appears to me that the mixture is something different from what you would normally use for say welding ie not adjusted so the small blue flame is present. I assume that this is a cooler flame but giving a broader heat coverage more suitable for silver soldering. Am I right?

The penetration through the stays to between the wrappers is achieved by having the requisite gap between the stay and the inner wrapper but doesn't the science require that the silver solder flows to the hottest point meaning that the heat should be applied between the wrappers, which is difficult to achieve?

The preheating which we didn't see was I assume applying the propane torch between the wrappers which would have to some degree improved the silver solder penetration.

The fluxing seems to be light on I can't see any on the stays, has it melted during the preheating?

Brian

[david123]

Looks like he is using flux coated rods

Mar 26, 2016 6:30:44 GMT runner42 said:

Hi Paul,

the torch is using oxy-acetylene, but it appears to me that the mixture is something different from what you would normally use for say welding ie not adjusted so the small blue flame is present. I assume that this is a cooler flame but giving a broader heat coverage more suitable for silver soldering. Am I right?

The penetration through the stays to between the wrappers is achieved by having the requisite gap between the stay and the inner wrapper but doesn't the science require that the silver solder flows to the hottest point meaning that the heat should be applied between the wrappers, which is difficult to achieve?

The preheating which we didn't see was I assume applying the propane torch between the wrappers which would have to some degree improved the silver solder penetration.

The fluxing seems to be light on I can't see any on the stays, has it melted during the preheating?

Brian

[chiptim]

Thanks for making the video Paul. Much appreciated.
Having read Alec Farmer's book its certainly good to see how its all done using oxy-acetylene with propane pre-heating.

Tim

[chiptim]

Yes the cameras in hand held mobile devices are really getting very good, and what you filmed was a challenge due to the light contrasts inside the firebox with and without the bright flame.
I should think that boiler construction techniques vary quite a bit depending on the heating apparatus to hand. I tried Oxy-propane and failed, even with the largest burner, but then I didn't try a pepperpot burner. I didn't have access to oxy-acetylene.
I mentioned Alec Farmers book because lots of people say it is one of the most useful however it's only really useful if you have access to oxy-acetylene.
So you actually removed the propane once started with the oxy-acetylene rather than just turned it down so it still provided some background heat? If you took quite a long time with the oxy-acetylene, say like a beginner might, would you eventually need to apply some more background heat or is the oxy-acetylene able to keep up? Of course if you take too long the flux runs out and turns black. Does the use of oxy-acetylene burn the flux out quicker due to the higher temperature thereby shortening the available soldering time compared to propane?
Tim

[Jim]

Thanks for making that very informative video Paul, as the others have said watching the process makes it all so much clearer.

I've switched over to oxy-propane since it's now possible to purchase your own D sized Oxy cylinders with refills are on a swap and go basis the same as propane.
The oxy-propane heats much the same as the oxy-acetylene but without the intense pinpoint central cone and so gives a 'softer' flame. Flux coated rods would be handy but as far as I know they aren't available here in Australia.

I hope you don't mind but I thought a photo of the oxy-propane torch in action on a 5" Britannia fire box may be of interest in comparing the two styles of flames.



Jim