Author Topic: Calbourne - 5" gauge boiler  (Read 6034 times)

Offline flying fox

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Re: Calbourne - 5" gauge boiler
« Reply #15 on: January 30, 2023, 12:21:00 PM »
Looks good Steve, you are getting on well with the loco.
Regards
Brian B

Offline springcrocus

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Re: Calbourne - 5" gauge boiler
« Reply #16 on: January 30, 2023, 12:51:09 PM »
Thanks to everyone for your comments and encouragement, I will endeavour not to bore your collective socks off by making this thread too long.

Great looking parts so far  :ThumbsUp: but I bet that the moment you noticed the Boring Head starting to unscrew was a heart stopping one  :o

Will follow with interest  :cheers:   :popcorn:

Per

Per, I have been using lathes, mills, drills etc for fifty years or so and I still make stupid mistakes.  :facepalm: The one thing I have improved on is how fast I can hit the STOP button.  :Lol:

Brian, nice to have you along but I think you've seen this before. When the weather improves, I will get back into the workshop and start getting things assembled.
Regards, Steve
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Offline vtsteam

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Re: Calbourne - 5" gauge boiler
« Reply #17 on: January 30, 2023, 05:14:00 PM »
This isn't boring! I like reading and seeing the details. Make this as long as you want. You're doing great work!  :ThumbsUp: :ThumbsUp: :popcorn: :popcorn:

 And I noticed the same problem of a threaded R-8 adapter and no left handed bars in the kit with my boring head, although I didn't put the mill in reverse. I just did the part in my lathe. But a search online turned up no left hand bars for this boring head. People seem to either Loctite it to the arbor, or add a set screw as you have when the want to use the end holes.

Enjoying your build.  :cheers:
Steve

Offline Admiral_dk

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Re: Calbourne - 5" gauge boiler
« Reply #18 on: January 30, 2023, 06:31:44 PM »
Quote
Per, I have been using lathes, mills, drills etc for fifty years or so and I still make stupid mistakes.  :facepalm:

Yeah well - some claims this is part of being Human  :embarassed:

Quote
The one thing I have improved on is how fast I can hit the STOP button.  :Lol:

 :lolb:   :lolb:  -  thanks for the laugh  ;D  -  but you're right - this IS very handy to be able STOP NOW!

Per

Online Kim

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Re: Calbourne - 5" gauge boiler
« Reply #19 on: January 30, 2023, 06:50:24 PM »
Nice work on fitting the throat plate and boiler sheet.  I'm almost to that stage! (not quite, but almost.)  I did already have some problems milling the pointy ears on the throat plate. You made fine work of that with the wood backing.

Certainly enjoying following along with what you did here.  Very instructive.
Kim

Offline springcrocus

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Re: Calbourne - 5" gauge boiler
« Reply #20 on: February 01, 2023, 07:46:14 AM »
Before going any further, I wanted to make sure that the firebox fitted as it should in the outer wrapper. With it resting on a piece of 1/4" square material, it seemed to fit as it should. The backhead was held loosely by the spring of the wrapper.



Satisfied with that, I then set about cutting the wrapper and backhead to length. The throatplate is already to the size on the drawing and is square to the barrel so this was used to mark across to the other components.



With the wrapper now to length, I was able to mark out and fit the two blowdown bushes each side at the bottom as well as the safety valve and manifold bushes on top. The wrapper was given a good, long soak in the pickle to clean it up for soldering and the three top bushes prepared. The top faces and the thread were painted with correction fluid , the outsides coated with flux and the holes in the wrapper fluxed as well. This last may seem unneccessary but I have had failures in the past for ommiting this step. I think it's about wetting the surface to break surface-tension.



On the underside, the bushes protruded about 1/16" and solder rings were placed over these. I used 40% silver solder for all the bushes because of it's higher melting temperature, which were fitted first, and 55% silver solder for everything else. More flux was added on top of the solder rings.



A hearth was build from lightweight building blocks (Celcon/Thermalite-style in the UK) and the wrapper placed as shown. The bushes are kept in place by resting on the thin piece of block and the side blocks keep the wrapper upright but also enclosed to preserve heat. If the workpiece was out in the open it would spend much of the time radiating the heat away again, wasting it. Lifting the wrapper in this manner allowed me to apply heat from below to draw the solder through.



After a single heat-up, followed by gentle cooling and a spell in the pickle, I had a perfect set of joints with nice fillets on both sides. They may not be the prettiest and I've used more solder than needed on the manifold bush, a full ring of 1.0mm solder rather than a partial ring that I used on the other two.



The two blowdown bushes were done one at a time and this is how it all looks with the backhead clamped in it's approximate position.



That's as far as I went on my own, the bushes in the barrel needed a lot more heat in a short space of time so I asked my mate Wilf to come and help. Meanwhile, a note about the kit we will be using. I have two 13Kg propane bottles and the standard Sievert body with a range of nozzles and my mate brings his Sievert with the pilot-flame handle and his own nozzles. I will be using the 2941 standard nozzle which produces 7.7kW and Wilf will be using a 3525 cyclone nozzle which produces about 10.3kW flat out. The regulators on the gas bottles will both be set at 3 bar.

Regards, Steve
« Last Edit: February 01, 2023, 10:49:00 AM by springcrocus »
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Offline vtsteam

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Re: Calbourne - 5" gauge boiler
« Reply #21 on: February 01, 2023, 03:49:03 PM »
Looking good! :ThumbsUp: :ThumbsUp:
That's some serious heat you boys are carrying!  :popcorn: :popcorn:
Steve

Offline vtsteam

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Re: Calbourne - 5" gauge boiler
« Reply #22 on: February 01, 2023, 04:10:05 PM »
I have a friend, Kevin Moreau, who is a wonderful whitesmith. He specializes in making locks and keys. They are truly amazing examples of craftsmanship. http://antique-padlocks.com/pc_moreau.htm Anyway, I asked him one day if he would show me forge brazing, which he did over a blacksmith forge.

The amount of wide area heat available there is very intense, yet very controllable via the draft. Brazing a fairly substantial pair of iron blocs together took less than a minute. The seam was perfect. I know It would have been very difficult to do the same with even a big torch (at least on my part).

I've often wondered since about the applicability of coal forge (or furnace) brazing at least some parts of a boiler's construction. I do know that in past ME issues and older print reference works sometimes coal (or coke) was used as a bed for brazing when using paraffin (kerosene) torches. The bed apparently added heat, and reduced oxidation, even though a torch was being used for local heating. Might this facilitate single operator brazing for parts presently needing two torches? I don't know, but something I've thought about.
Steve

Offline TimB

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Re: Calbourne - 5" gauge boiler
« Reply #23 on: February 01, 2023, 04:46:16 PM »
I have a friend, Kevin Moreau, who is a wonderful whitesmith. He specializes in making locks and keys. They are truly amazing examples of craftsmanship. http://antique-padlocks.com/pc_moreau.htm Anyway, I asked him one day if he would show me forge brazing, which he did over a blacksmith forge.

The amount of wide area heat available there is very intense, yet very controllable via the draft. Brazing a fairly substantial pair of iron blocs together took less than a minute. The seam was perfect. I know It would have been very difficult to do the same with even a big torch (at least on my part).

I've often wondered since about the applicability of coal forge (or furnace) brazing at least some parts of a boiler's construction. I do know that in past ME issues and older print reference works sometimes coal (or coke) was used as a bed for brazing when using paraffin (kerosene) torches. The bed apparently added heat, and reduced oxidation, even though a torch was being used for local heating. Might this facilitate single operator brazing for parts presently needing two torches? I don't know, but something I've thought about.

LBSC (Curly Lawrence - a British Loco maker of some fame to ME's in the UK) always advocated using coke as a bed and to fill any voids when soldering boilers.  He apparently used a paraffin (kerosene) pump up blow lamp for his boilers.  He later raved about using Sifbronze but I guess he would have to use Oxy-acetylene to get the required temperatures to melt that. 

I am envious of the clean lines you get on your boilers Steve!

Tim

Offline FKreider

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Re: Calbourne - 5" gauge boiler
« Reply #24 on: February 03, 2023, 02:22:09 AM »
Thank you for your post in my silver soldering help thread, I'll definitely be following along with this thread, great stuff !   :popcorn:
-Frank K.

Offline springcrocus

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Re: Calbourne - 5" gauge boiler
« Reply #25 on: February 03, 2023, 08:53:39 AM »
Glad to have been of help, Frank, and a pleasure to have you following along.

The first job was to join the firetubes and superheater tubes to the firebox frontplate and to fix the firebox outer wrapper, all in a single heat-up. All the parts were pickled for a couple of hours beforehand and then we fluxed up all the parts and assembled them together. Solder rings were made for the tubes and placed on the outside of the frontplate. Solder was also placed in the join around the perimeter of the firebox. After the tubes were in place, the tube support was clamped to the frontplate and the assembly carried through to where we'd built our hearth. I meant to take a picture of the preparations but got carried away and forgot all about it.

Moving on, Wilf used the cyclone burner to heat the inside of the firebox and I used the standard burner to heat the sides and top of the wrapper, starting gently. As the colours started to change we increased our flame sizes and watched to see the solder just start to glisten. At this point, I backed away a little and let Wilf use his heat to draw the solder down. This first picture was taken a few minutes after we removed the heat completely.



In that picture, a white area is visible below the tubes. This is where I painted correction fluid on the frontplate to stop the flux and solder running away. If the flux dribbles away, the solder always seems to follow it.

The next picture is from the back of the setup and shows the tube support plate. I'd forgotten to spigot the two 22mm tubes so a pair of small clamps stopped them falling into the firebox. The block on top of the tubes was to help keep the heat in, otherwise all Wilf's efforts would be going straight up the chimney, as it were.



Once that had cooled sufficiently to be held in bare hands, it was placed in the pickle and left for an hour or so. Meanwhile, we fitted the two clack bushes to the sides of the barrel with 40% solder. This time, the solder ring was placed on the spigot of the bush and the bush rested in the hole. As usual, correction fluid was painted onto the face of the bush and also the thread. A nudge with a prodder as the solder melted ensured a good seat.



Back to the firebox and a good, all-round inspection. We couldn't see any daylight through any of the seams and we appeared to have good penetration through all the joints.





After the boiler inspector had checked over all the soldering to date, the next job was to solder the dome bush into the barrel with 40% silver solder so Wilf prepared the parts with correction fluid in the threads and around the barrel opening whilst I made some more 6BA countersunk copper screws ready for the next job.



This was set up in the hearth with the dome bush resting on a packer and with the solder laid around the bush on the inside of the barrel. Heat was applied from the outside only.

While this cooled, we then prepared to close the firebox by soldering the backplate into position. This was set up on the hearth so that the tubes hung over the edge of the blocks with a weight keeping the assembly balanced. The firehole ring had been made and soldered into the backplate earlier but I didn't record this. 55% solder was placed around the perimeter and heat applied mainly inside the box by Wilf with the cyclone burner and me adding extra heat to the outsides of the firebox. As the solder melted, I moved away and left it to Wilf to draw the solder down. The block in the opening is to protect the ends of the tubes from accidental overheating.



With the barrel cooled and pickled, we then set about assembling the throatplate and the outer wrapper to the barrel. Preparation for this took quite a while as, once lightly screwed together, I had to do a bit of light tapping to gently ease the edges of the wrapper and throatplate together. It's easier to do this with the flux already between the joints (so that it spits in your eye) and then add more afterwards. A pair of small clamps were added to the bottom corners to stop these edges springing apart. Same procedure as before and this is after the melt has occurred.



The firebox assembly had to go back for a reheat because the two lowermost screws hadn't soldered in. That's the advantage of copper or bronze screws; if you can unscrew them afterwards, just take them out, clean up the area, re-flux and solder them back in with a ring of fine solder wire around the head.

These are the two assemblies after the final spell in the pickle and, I have to say, these are the neatest bits of work we've done to date. There is an unbroken seam of solder around the whole of the backplate.



This one I'm particularly pleased with. The wrapper and throatplate to barrel joints are nigh-on perfect with full penetration but no wasted solder. Most of the credit for these goes to Wilf because he did the majority of the preparation while I was fiddling with screws and other odd jobs and, without good preparation, we would not have this level of success.



A hint for first-timers: regardless of how clean they look, I always pickle the copper parts for about half-an-hour, followed by a rinse in clean water, just before fluxing up. I know the job of the flux is to clean the work but I think the extra effort is worth the time spent.

Regards, Steve
Member of a local model engineers society
www.stevesbritannia.co.uk

Offline Firebird

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Re: Calbourne - 5" gauge boiler
« Reply #26 on: February 03, 2023, 09:30:46 AM »
Hi Steve

You are doing an excellent job :ThumbsUp:

I'm following along with great interest. I have made a couple of boilers, one for Conway which is shown in an earlier thread on this forum and one for my current loco build a Chub. No where near as neat as yours I must admit.

My good mate and fellow live steam enthusiast Julian (alias barneydog) and I will shortly be tackling a pair of Sweetpea marine type boilers.

Coincidentally I have just bought a Sievert cyclone torch but haven't tried it yet.

I am going to try your trick of the correction fluid on a few scrap pieces as well

Cheers

Rich


Offline wagnmkr

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Re: Calbourne - 5" gauge boiler
« Reply #27 on: February 03, 2023, 12:23:49 PM »
It must be very satisfying to see that result! :cartwheel:
I was cut out to be rich ... but ... I was sewn up all wrong!

Offline vtsteam

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Re: Calbourne - 5" gauge boiler
« Reply #28 on: February 03, 2023, 03:16:58 PM »
Really great work! :ThumbsUp: :ThumbsUp: :popcorn: :cheers:
Steve

Offline Admiral_dk

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Re: Calbourne - 5" gauge boiler
« Reply #29 on: February 03, 2023, 04:09:35 PM »
Amazingly great soldering - looks absolutely fantastic  :praise2: and I can see why you are very pleased with the result  :cheers:

Per

 

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