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[Landlocked]

I just read Richard Simpson's article in Model Boat and realized the silver solder he recommended has twice the melting point as the stuff I bought from Micro-mark.  Is the 430 degree F stuff good enough for live steam or do I need the 55/56% stuff?

Landlocked

[derekwarner]

Landlocked...to answer you question requires a number of considerations 

1. Our typical model boilers when operating at say 3 Bar raise steam to approx 150 degrees C
2. 450 degrees F = 232 degrees C....so one may think that sounds acceptable, however we must consider factors of safety...the example here provides a factor of safety of approx 1.6:1 ...where as the requirement may be in the order of 4:1 or a silver soldering melting point of approx 600 degrees C
3. Certainly in UK & OZ, the hydrastatic first test of any model boiler is twice the rated working pressure
3. I see you are from USofA...I would be inclinded to ask a local model boiler inspector or certifier ...if he would certify a boiler constructed with 232 degrees C solder...my gut feeling is   

4. www.cupalloys.co.uk provide a worldwide service in the supply of silver solder wires & flux's & even have a Modeler Section in their WEB page...most of their silver solders are in the 600>700 degrees C melting range & hence offer an acceptable factor of safety

Keep us posted with your thoughts............Derek

[steamboatmodel]

The solder Micro-mart sells is Stay Brite which is a Silver bearing solder good for mechanical joints, but is not a Hard Solder which is needed for most boiler work. Try your local welding supply for proper Silver Solder.
Regards,
Gerald.

[frazer heslop]

I think the problem maybe the terminology in the UK silver solder has a different meaning than the USA. Look for silver brasing and as already mentioned check the melting temp
best wishes frazer

[Landlocked]

All,

You've confirmed what that sinking feeling in my stomach was telling me.  I need to use the higher temp stuff.  Fortunately I'm not making a boiler and I'm only three fittings into making my piping.  I'll definitely rework both ends of my steam line between my boiler and my combo RC steam valve/lubricator.

I'm not sure I'm going to rework the inlet manifold fitting. It's a TVR1A engine and there's not much distance from the manifold end to the first "T" inlet pipe.  I'm concerned I'll damage the soldered "T" fitting's integrity as I heat things up.  I might reconsider as my proficiency improves.

I agree on the terminology delta.  I noticed the 55% stuff showed up under "brazing" listings.  I also think the cutoff temp for "hard" solder various with application.  Plumbing, jewelry, electronics, and other uses seem to have different temps but good old Wikipedia sides with you'all.

Thanks,

Landlocked

 

[derekwarner]

Hullo Landlocked........all is not lost

1. It is literally near impossible to remove every trace of high temperature soft solder [HTSS] from a pre soldered joint & then try & rejoint with silversolder [SS]...so a previously HTSS joint should never be considered as suitable to SS 
2. If you have previously used HTSS, and you have some mechanical supporting constraints between joints ......just leave it & have a rethink 
3. Talk to that boiler inspector/certifier 
4. As crazy as it seems.........soldered tube work does not come under the examination of the British PER P.E.D.97/23/EC Standards when the actual boiler is being certified 

Derek

[kiwimodeller]

Also as you are talking about pipework connections and Graham reccommend not drying (or "superheating") the steam and say that they prefer wet steam at the engine it is probable that the steam temperature at the manifold will have dropped some from the boiler temerature so you should be safe with the solder you have used. It would be possible to check the temperature once you have steam up. I have used a laser thermometer and they have pinpoint accuracy and can differentiate between different temperatures of parts that are very close to each other. Try your pipework before scrapping it. Regards, Ian.

[ooyah/2]

Landlocked,
Don't worry about using the solder that you have started with and as Ian says try it before scrapping it .
Graham Ind recommend that the TVR1 engine uses up to 35 P.S.I. and saturated steam at that pressure is 281 F, even at 50 p.s.i. it's 298 F so you are well in with your solder temps and don't forget the temperature will be less as it hits the pipes going to your engine.
The one problem using soft solder is that you can melt a previous soldered joint if the heat is allowed to travel from the new joint to the older one.
To prevent this cut some strips of cloth,or flannel and soak them in water, wrap the cloth around the joint you wish to protect and you will be O.K.

I am aware of some friends who only use soft solder even up to 60 p.s.i. with no problems.

George.

[Landlocked]

Thanks guys,  I hate taking steps backwards.  The steam valve is not on the burner end of the boiler so that's another factor to my benefit.  I will use the hard solder on the gas regulator which is right next to the burner (about 1.5 cm away) which will means some rework.

I'm going to steady the control valve/lubricator with a stand so the weight won't be on the joints.  The steam line is short (but with a loop for expansion).  I'll try figuring out how to post some photos.

Ken

[Landlocked]

I'm seeing a silver solder paste with the flux pre-mixed in.  Temp is 1050F. 

Anybody have any experience with this stuff?  Web site videos make it look pretty simple to use.

Ken

[giovanni]

I use paste solder with hard solder wire. This insures a very good soldered joint. The paste solder is a better indicator than only using flux, alone, for alerting you when to melt the wire into the solder joint, as well. You tend to use less of the wire solder because the melting paste solder is slightly more viscous.

[Circlip]

A mate uses paste when making fittings and smaller units and swears by (not at) it in this application. Despite what some have said, Cupalloys use a tube for demonstration that is over two years old and it hasn't "dried out".

   Regards  Ian.

[Landlocked]

Here's where I'm at in the project.  Getting the steam plant setup before I go back to working on the hull.  Note:  In this picture, the steam pressure line to the gas control valve looks like it's going to the gas supply inlet.  It's an optical illusion.  It just happened to line up perfectly.  The steam pressure attaches to the bottom of the regulator.  I haven't decided how I'm mounting the gas tank.  Down low for stability or just below deck level for access without lifting deck sections.  The gas tank is under the foredeck and not within the cabin works.

Boiler is a semi-custom from Maccsteam.  Lengthened the tube "forward" of the chimney to make room for the steam valve.

Steam boat is the Sabino which is still afloat and in operation at Mystic Seaport.  The sponsons that were added to the narrow riverboat hull when it was upgraded for use in more open bays made the hull build "interesting."

Ordering silver solder rods tonight.

Ken