Coppersmithing a Boiler - Southern Railways Bulleid Pacific

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Coppersmithing a Boiler - Southern Railways Bulleid Pacific

Postby tsph6500 » Thu Mar 03, 2011 5:13 pm

My steam loco mate at MLS, Keith Wood, posted a how-to series on our club's forum and I thought some folks here would find it interesting. So posted here with his permission... is the step-by-step construction of Keith's third copper boiler. He has successfully built a Rob Roy (0-6-0) and a Castle Class (4-6-0), both 3/4" scale, previous to this project.

Feel free to ask questions of Keith here as he does monitor this forum.

Jim Leggett
Montreal Live Steamers


Boiler Building #1
by Keith Wood » Wed Sep 29, 2010 4:17 pm

I have started the construction of my latest project, the boiler for my Southern Railways Bulleid Pacific.

I will endeavour to record each step in construction to provide a guide to anyone else who would like to build a boiler.

I have taken advantage of some new technologies to help with the design and fabrication of the copper plates, everything else will be traditional boiler making as described in Martin Evans book "Model Locomotive Boilers".

The Design.

In order to build a boiler that meets the requirements of the safety fraternity, I selected the LBSC Britannia boiler as my starting point, the prototype locomotive boiler was based upon Oliver Bulleid's design.

The plans provided me with material thicknesses, stay location and spacing, flue sizes etc.

The main difference between the Britannia boiler and the Bulleid boiler being the fact that Bulleid has the tapered portion of the boiler inverted, it is horizontal at the top and tapered underneath, also the full length of the Britannia boiler is tapered where the forward barrel of the Bulleid is parallel.

I used a 3D CAD system to define the geometry, as my day job is a designer, this was relatively quick.

boiler-1.jpg
ISO VIEW


Once the 3D models were created I used the flat pattern development software to create the flat patterns for all the copper plates and the templates for the flanging blocks.

Flanging Block Construction.

I pasted the trimmed flanging block patterns to some thin steel sheet and cut the steel templates to shape.

boiler-2.jpg
FLAT PATTERN DEVELOPMENT


I work with a gentlemen who does a lot of wood working in his spare time, he was good enough to make the flanging blocks for me (using the steel templates) out of many pieces of maple wood glued together butcher block style, he did a really nice job, he even routered the bend radius on the edges of the blocks. Its such a shame that you only use them once.

boiler-3.jpg
TEMPLATES AND BLOCKS


Copper Plate Construction.

The flat patterns were printed out on regular copier paper, after verifying that the flat patterns were 1:1 I trimmed the shape and pasted them on to pieces of copper sheet using a glue stick (holds well and is easily removed)

Each copper plate was trimmed using my band saw and hand shear, final shaping was completed by hand filing, each plate was deburred to remove sharp edges.

boiler-4.jpg
COPPER PLATES


The boiler plates are:

Backhead, throatplate and outer wrapper are 1/8" copper sheet.

Firebox plates and wrapper, and the tapered barrel are 3/32" copper sheet.

The front barrel is 4 1/8 O/D x 1/8" thick copper tubing that I purchased from a member of my club.

Next episode - Forming the copper.
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Re: Coppersmithing a Boiler - Southern Railways Bulleid Paci

Postby tsph6500 » Thu Mar 03, 2011 6:00 pm

Boiler Building #2
by Keith Wood » Wed Sep 29, 2010 4:43 pm

Episode 2 - Forming the copper

Copper sheet is quite hard when purchased (as rolled).

In order to allow the copper to be easily formed it needs to be annealed, this is where the copper is heated until it is a dull red and then cooled either by quenching in water or allowing to air cool.

boiler-5.jpg
Annealing


boiler-6.jpg
Annealing continued...


The annealed plate is then aligned with its flanging block in a bench vise, make sure to add a block between the vise jaws and the plate, this stops the soft copper from being marked by the jaws and stops most of the ballooning of the flat portion during forming.

boiler-7.jpg
Block set-up (front tubesheet is already formed)


Using a hard rubber mallet, the copper is beaten around the block until the copper work hardens, see stage 1 below:

boiler-8.jpg
Stage 1


The part is then annealed again and then beaten again until the copper work hardens, see stage 2 below:

boiler-9.jpg
Stage 2


After the third beating the block is rough finished, avoid using a metal hammer as it may bruise the copper.

boiler-10.jpg
Rough Plate


A quick pickle in Sulphuric acid and a polish with steel wool and voila:

boiler-11.jpg
Cleaned Plate


One effect of forming the copper around a round block is that the material increases in thickness in way of the flange, to remove the additional material and allow the plate to be slid into the barrel, the plate can be gently held in the lathe and skimmed down to the required diameter making sure not to machine thinner than the basic sheet material.

boiler-12.jpg
Machining


The above process is repeated for all the flanged plates: Backhead, throatplate, firebox plates.

Next Episode - Tapered Barrel

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Re: Coppersmithing a Boiler - Southern Railways Bulleid Paci

Postby tsph6500 » Thu Mar 03, 2011 6:11 pm

Boiler Building #3
by Keith Wood » Wed Sep 29, 2010 5:03 pm


Episode 3 - Tapered Barrel

The next step was to make the tapered barrel.

The cut plate was annealed using a large weed burner in the back garden during the evening(I think the neighbors freaked out at the three foot flame).

The bending rolls (clamping rollers) were roughly adjusted using a scrap of the same thickness copper to ensure the plate would be gripped by the rolls, the bending roller was adjusted to generate a large curve.

The annealed sheet was then rolled to a large radius.

The sheet was re-annealed and rolled again to a slightly smaller radius.

The bending roller was then adjusted to have a tapered gap between it and the upper grip roller, the annealed sheet was then rolled again, this closed the radius up so that both edges were touching.

boiler-13.jpg
Tapered Barrel 1


The tapered tube was then pickled in sulphuric acid and scrubbed with steel wool.

A strap of the same thickness copper as the barrel was then made and rivetted to the outside of the tapered barrel, this holds the two edges together ready for silver soldering.

As a note, any strap used in a boiler barrel must be installed on the exterior and visible if the loco is to be used in the UK.

The assembly was coated with flux and heated using a propane torch on the brazing hearth, a nice bead of silver solder was run on each side of the strap.

Another pickle and scrub and the joint can be checked.

See finished result below:

boiler-14.jpg
Tapered Barrel and strap


So far so good.

Next Episode - Forming the wrappers
Best regards,
Jim Leggett

Montreal Live Steamers
www.montreallivesteamers.org

A Founding Member of the Tinkerbell Scale Society - Northern Division
I'm an A.R.S.E. (Association of Railroad Steam Engineers)
Toad Swamp & Punk Hollow Railroad - Head Tycoon
The Juvenile Traction Company - CEO & Apprentice Machinist 3rd Class
White Mountain Central RR - Engineer

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Re: Coppersmithing a Boiler - Southern Railways Bulleid Paci

Postby tsph6500 » Thu Mar 03, 2011 9:42 pm

Boiler Building #4
by Keith Wood » Tue Oct 05, 2010 9:39 pm


Episode 4 Wrappers & firebox

Forming the wrappers is probably one of the most difficult tasks, getting the right shape to mate with the flanged plates is the key.

I took the pre-trimmed wrappers and rolled three different radii, the two sides of the wrapper being a big lazy radius and the top of the wrapper being a tighter one.

Once the correct profile was achieved I clamped the plate between a piece of steel bar and a tube of a slightly small radius than required in the shoulders of the wrappers.

I then pulled the wrappers over the tube, manipulating the plate until the correct profile was achieved.

I then did the same for the other shoulder, getting the correct distance between the two tight radii of the shoulders is critical, too large a distance and the plates gap, too tight a distance and the plates will not mate at the top.

boiler-15.jpg
Outer Wrapper


Firehole Ring

The firehole ring is made from thick walled copper pipe 1.5" dia x 1/8" thick, a step is machined on one end, 1/16" deep by 0.140 wide, this locates into the backhead, the other end is faced to length then another step is machined 1/16" deep by 0.120 wide, this locates into the firebox rear plate.

Once machined the ring can then be squeezed in a bench vise until the correct oval shape is achieved, a quick adjustment with a rubber mallet and the part is ready.

boiler-16.jpg
Firehole Ring


The firebox rear plate can then be marked off using the ring as a template and the hole cut for the ring.

Firebox Tubeplate

The firebox tubeplate is marked out for the flues, once marked the hole locations are centre punched and drilled out 0.005" smaller than the outside diameter of the tubes, this will be explained in the next episode.

When drilling copper use a low RPM with steam oil as a cutting fluid.

Firebox Assembly

Once the plates are gently adjusted to fit the wrappers (maximum gap around 0.005") they can be assembled into the wrapper, holes drilled and temporarily attached using a number of 3/32 screws.

boiler-17.jpg
Assembled Firebox with temporary screws


boiler-18.jpg
Firehole installed


Once the assembly looked good, the parts were pickled and re-assembled using 3/32" domed rivets (head inside the firebox)

The assembly can then be fluxed and silver soldered using a high meting point solder 24% silver, 740-780 degree C melting point, this prevents the firebox solder from melting during the assembly of the boiler.

A quick pickle and clean, job done.

Next episode - Tube installation

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Re: Coppersmithing a Boiler - Southern Railways Bulleid Paci

Postby tsph6500 » Thu Mar 03, 2011 9:46 pm

Boiler Building #5
by Keith Wood » Wed Oct 06, 2010 9:19 pm


This episode will show the process of silver soldering the tubes to the firebox.

Front Tubeplate

Mark off and centre punch the front tubeplate in preparation for drilling the flue holes, stay holes and steam outlet port.

Drill the tube holes approx 0.005" in diameter less than the tubes, this will prevent the tubeplate slipping down the tubes during the soldering process, pre-drill the stay holes and open up the steam port to the required size.

boiler-19.jpg
Front Tubeplate after drilling


Firebox Preparation

In order for the silver solder to run through the firebox tubeplate and onto the ends of the tubes a small triangular nick is filed into each hole with a needle file, depth approx 0.005".

The flues are faced off at one end in a lathe, turning copper can be problematic so use a cutting fluid, I used buttercut, after facing, machine a small step around 0.003" deep, this will stop the tubes falling through the firebox tubeplate during silver soldering.

Once all the tubes have been machined at one end, cut them to length and face off in the lathe as before, also machining a step.

Degrease all the tubes to remove any cutting fluid residue using a solvent and steel wool and pickle one end (approx 2") to clean ready for silver soldering.

Pickle the complete firebox assembly rinse and dry ready for soldering.

Place the firebox in the hearth packing the rear plate so that the tubes will point vertically up.

Mix the flux and apply around each flue hole on the outside and inside of the firebox.

Apply flux to the end of each tube and insert into the firebox, the small step in the tube ends prevents the tube from falling through.

boiler-20.jpg
Tubes Inserted


boiler-21.jpg
Fluxed tube ends


Ensure that all the area is well fluxed.

Make a silver solder ring for each tube and slip down the tube so they sit on the firebox tubeplate.

boiler-22.jpg
Solder rings


Place the front tubeplate at the upper end and engage the tubes into the repective holes, measure and sight the tubes to ensure that they are vertical and not twisted.

Apply heat inside the firebox until the silver solder melts and forms a fillet around each tube.

boiler-23.jpg
Applying Heat


boiler-24.jpg
Starting to melt


After soldering allow to cool, pickle and rinse and soak in hot water to remove any flux, inspect for full penetration of the solder in the inside of the firebox.

Next episode, Outer shell assembly
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Re: Coppersmithing a Boiler - Southern Railways Bulleid Paci

Postby tsph6500 » Thu Mar 03, 2011 9:47 pm

Boiler Building #6
by Keith Wood » Sat Oct 23, 2010 8:20 pm


Outer Shell Assembly.

This episode describes how to assemble the outer shell of the boiler.

The first sub assembly to create is the tapered tube to the throatplate.

Offer the soldered tapered barrel onto the throatplate, scribe the outside profile of the barrel on to the throatplate, chain drill with a line of 1/8 dia holes then, using a piercing saw, cut out the disc.

File the hole in the throatplate until the tapered barrel slips inside and the end of the barrel is around 0.050" protruding from the inside of the throatplate, , pickle the parts set up in the brazing hearth, flux the assembly and silver solder from the inside of the throatplate ensuring a good fillet of solder around the joint, check the external joint between the barrel and the throatplate to ensure full penetration.

boiler-25.jpg
Throatplate & Barrel


boiler-26.jpg
Throatplate & tapered barrel (front barrel temporarily inserted)


The next task is to position the outer wrapper onto the throatplate, once the two are mated drill 4 1/8 dia holes and temporarily fasten with brass screws and nuts.

Gently beat the copper to close any gaps down to a maximum of 0.005", remove the brass screws, pickle the throatplate and wrapper, flux the contact faces and rivet together with 4 1/8 dia copper rivets.

Set the assembly on its end in the brazing hearth and re-flux the joint, heat and silver solder ensuring good penetration of the solder in the inside, do not forget to silver solder the rivet heads also.

Pickle the assembly when cool, pickle the front barrel, flux the barrel and slide it into the tapered barrel until it is in the correct location, stand on its end in the hearth and silver solder the joint.

Once cooled, pickle the assembly.

boiler-27.jpg
Outer Shell Assembled


The firebox and tube assembly can now be located into the outer shell assembly for a fit check.

boiler-28.jpg
Fit check with smokebox tubeplate


Next Episode:- Mudring & Backhead
Attachments
boiler-29.jpg
Rear View
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Re: Coppersmithing a Boiler - Southern Railways Bulleid Paci

Postby tsph6500 » Thu Mar 03, 2011 9:49 pm

Boiler Building #7
by Keith Wood » Sat Oct 23, 2010 8:49 pm


This Episode - Mudring & Backhead.

Mudring


The mud ring parts are made from 1/4" x 5/16" rectangular copper bar.

The first part to make is the piece that fits between the firebox tube plate and the throatplace.

Radius the two end corners so that the piece nests nicely into the throatplate with minimum gapping (note the mudring pieces should sit slightly below the edges of the firebox and outer wrappers so a nice fillet of solder can be created), once made set the firebox centrally between the sides of the outer wrapper and set the firebox height distance from the inside of the outer wrapper to the top face of the firebox, temporarily clamp the throatplate, mud ring piece and firebox assembly together.

The next job to do is to cut the holes for any bushings and the hole for the firehole ring into the backhead.

Mark off and drill the holes for any bushings.

Offer up the backhead into location within the outer wrapper, using a combination of scribing and measurement, mark off the location of the firehole cut out.

Chain drill, saw and file the hole to shape ensuring the minimum gap possible.

boiler-30.jpg
Backhead in position


Once the backhead is inserted the rear piece of mudring can then be made as per the front one, ensure minimum gaps and a nice tight fit.

Clamp the backhead, piece of mudring and firebox together with temporary clamps.

The two side pieces of the mudring can now be made once again ensuring minimum gapping.

Any large gaps can be rectified by brazing on pieces of copper bar and filing them to shape, ensure you flux well and use a high melting point silver solder.

boiler-31.jpg
Mudring Pieces


Once you are happy with the fit, the rivet holes can be drilled through (2 per piece, see picture), drill 1/8"dia and temporarily attached together using nuts and bolts.

boiler-32.jpg
Mudring in situ (notice mudring is not flush with plates/wrappers)


Now you start to have something that resembles a boiler.

Next Episode - Girder Stays
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Re: Coppersmithing a Boiler - Southern Railways Bulleid Paci

Postby tsph6500 » Thu Mar 03, 2011 9:52 pm

Boiler Building #8
by Keith Wood » Sat Nov 20, 2010 8:05 pm


This episode - Girder Stays.

Once the firebox, outer shell and backhead are drilled off with the mud ring then the girder stays can be made.

The backhead is removed whilst the shell and firebox are still attached.

The girder stays support the top of the firebox and the upper portion of the upper wrapper.

Some builders use regular stays in this area but the Britannia boiler I am using as a basis has the girder stays.

The three stays consist of a pair of I section stays made from two channel sections attached together and a centre stay consisting of two angles attached together.

The centre stay is made by gluing paper templates of the stays onto 0.062" copper sheet, cutting out, drilling the holes and bending in the brake.

The two pairs of channels that make up the outer stays are more difficult, I made four card stays, trimming and bending the card to get the best fit between the top of the firebox and outer wrapper.

Once made the card templates can be used to trace around on the 0.062" copper sheet, the stays can then be cut out, drilled and bent in the brake.

boiler-33.jpg
Girder Stays


boiler-34.jpg
Trial Fit


Stay Assembly

Once made, the stays are drilled as a pair for the installation of 3 copper rivets.

Pickle the stays and rivets and coat the mating faces with brazing flux, install the rivets.

The top of the firebox is marked out for the location of the stays, gently scribe a line using the correct measurements.

The firebox is then pickled and rinsed, the top is fluxed and the three girder stays put into position.

The stays can be rivetted to the top of the firebox if desired, I used a weight on the top of each stay to hold it in position.

The assembly is then heated and the stays silver soldered to the top of the firebox ensuring no gaps.

boiler-35.jpg
Stays soldered in place


The firebox and stay assembly is the pickled and rinsed.

Firebox to Shell Assembly.

The next step is to solder the outer shell and firebox assembly together.

Both parts and the front tube plate are picked and rinsed.

The firebox stay upper faces are fluxed and the assembly is located within the shell and the mudring temporary screws installed.

The front tubeplate is fluxed and installed at the forward end of the barrel, the outlet bushing is also pickled, fluxed and inserted into its hole.

The assembly is then inverted , strips of solder are located next to the edge of each stay and the assembly is heated on the brazing hearth.

Maximum heat is applied on the exterior of the outer wrapper until the solder starts to melt and flow into the gaps.

Ensure no gapping exists and that there is a good fillet of solder everywhere.

Whist still hot the whole shell is rotated so that the front tubeplate is at the top and the barrel vertical, the front barrel is heated and a nice fillet of solder run around the end of each tube, the bushing and the edge of the plate.

boiler-36.jpg
Soldered Stays


boiler-37.jpg
Front Tubeplate


Pickle and rinse.

Next episode - Backhead and Mudring soldering.
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Re: Coppersmithing a Boiler - Southern Railways Bulleid Paci

Postby tsph6500 » Thu Mar 03, 2011 9:52 pm

Boiler Building #9
by Keith Wood » Sat Nov 20, 2010 8:42 pm


This Episode - Backhead and mudring

The next step is to pre-install the bushings on the backhead, pickle and rinse the backhead and any bushings, flux the parts and silver solder together.

boiler-38.jpg
Backhead and bushings


Pickle and rinse the backhead assembly.

The mudring pieces should then be removed from the shell assembly.

The shell assembly should be picked and rinsed.

The pieces of the mudring should be pickled and rinsed.

Flux the shell in way of the mudring, flux the pieces of mud ring and assemble the three pieces with suitably sized fluxed copper rivet, I placed the preformed head on the inside of the firebox.

Take the backhead and flux the flanges, the area in way of the firehole and the area in way of the mudring, offer up the backhead and install the mudring piece, rivet togeter using suitably sized fluxed copper rivets.

Silver Soldering the assembly.

The assembly is placed in the brazing hearth inverted (mudring up), pieces of firebrick being stacked around the assembly to prevent excessive heat loss.

The amount of copper is now getting large and as a consequence the heating time and amount of heat required is multiplied.

Add strips of silver solder around the edges of the mudring in way of each seam.

Heat the backhead and outer wrapper until the silver starts to flow, ensure a good fillet everywhere especially in way of the joints between the pieces of mudring.

Once the mudring is complete, run a fillet of solder all around the seal between the outer wrapper an backhead, once this is done run a fillet of solder around the firehole.

Cease heating and let the assembly cool, once you can handle it pickle the assembly and rinse.

Sorry, I did not take picture of this stage.

Preliminary Leak Test

At this point the boiler is starting to become a vessel, a preliminary leak test can be carried out by filling the boiler with water up to the level of the backhead bushings, lifting it off the work bench with spacers and leaving for some time.

I placed a piece of shop towel on the bench below the firebox to show any leaking.

I left the assembly overnight, at first there was no leakage, in the morning the bench was wet and I discovered a small leak in the corner of the mudring.

I re-pickled the exterior of the boiler and re-soldered the offending area.

Bushings.

The next step is to drill any holes in the outer shell for any bushings.

I had the main steam dome bush, two inlet bushes, one for the injector and one for a axlepump and three safety valve bushings and a blow down valve bushing.

The bushings are made from 660 bronze, not brass!

I use a sheet metal cutting coned cutting tool, using twist drills in copper can be problematic.

boiler-39.jpg
Bushing Holes


Pickle the assembly and the bushings, flux the mating faces and silver solder on the brazing heart, ensure a nice fillet around each bushing.

boiler-40.jpg
Bushings 1


boiler-41.jpg
Bushings 2


Pickle the exterior and allow the inside of the boiler to fill with pickle, allow to sit for 10 minutes, drain and rinse thoroughly.

You should now have something that looks like a boiler, hang in there, not far to go now.

Next episode - Longitudinal stays & first pressure test.
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Re: Coppersmithing a Boiler - Southern Railways Bulleid Paci

Postby tsph6500 » Thu Mar 03, 2011 9:54 pm

Boiler Building #10
by Keith Wood » Sun Dec 05, 2010 11:03 am


Longitudinal stays & preliminary pressure test.

After the first unpressurized leak test, the next stage is the longitudinal stays.

These are made from 3/16" dia copper rod, they are inserted from the front tubeplate and engage into 4 holes on the backhead.

I drilled the 4 holes on the backhead around 0.005" smaller than 3/16 and machined a small rebate on the end of each stay to prevent them falling through when heated.

Pickle the boiler and stay ends and assemble with flux, heat and run a nice fillet of silver solder around the end of each stay.

I had left my stays long at the front tubeplate end so I trimmed them to almost the correct length.

A good pickle, clean, rinse and inspection and its on to the next stage.

boiler-42.jpg
Stay holes in front tubeplate


boiler-43.jpg
After silver soldering & trimming.


Preliminary Pressure Test

Martin Evans recommends that a preliminary pressure test be carried out at this stage, full pressure can not be applied due to the lack of firebox and lateral stays.

I made some temporary blanking plugs for all the bushings, installed the dome with a gasket and made an adapter for my test gauge.

After filling the boiler with water and connecting a small handpump sat in a reservior, the pressure can be applied, slowly bring the pressure up to 10psi max and inspect for leakage.

I had one small weep from a superheater tube end, this will be re-soldered during installation of the firebox stays.

So far so good, only one minor weep and no distortion of any plates.

Next episode - Rest of the stays.
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Re: Coppersmithing a Boiler - Southern Railways Bulleid Paci

Postby tsph6500 » Thu Mar 03, 2011 9:54 pm

Boiler Building #11
by Keith Wood » Sun Dec 05, 2010 11:32 am


This episode - Stay Completion

Once the preliminary pressure test was completed it was time to install the remaining stays.

The outer wrapper of the firebox was marked out using a sharpie pen, the locations were double checked.

The 5 holes for the lateral stays that run from one side of the wrapper, across the top of the firebox and through the other wrapper were marked out.

The locations were triple checked and each location centre punched.

The boiler was set up on the drill press, the angle of the boiler being re-set for drilling each longitudinal line of stays 5/32" dia, the holes need to be drilled as perpendicular to the wrappers as possible.

The 5 lateral stay holes were drilled 3/16" dia.

The holes were de-burred and all the 5/32" holes and 3/16" holes through the outer wrapper were opened up with a taper reamer to allow a space for the silver solder, maximum depth being half the thickness of the wrapper.

The whole assembly was well pickled and rinsed.

Next step is to pickle the stays, for stays I used 5/32" domed headed copper rivets inserted from the firebox side, this provides a clean firebox interior.

The rivets were pickled and inserted with a good coating of flux.

A ring of flux was brushed around each rivet head inside the firebox and around the tail of each rivet on the outer wrapper.

The lateral stays are 3/16" dia copper rod, they were pickled fluxed and inserted with around 1" excess material at each end, once again a ring of flux was brushed where each stay protruded from the wrapper.

Soldering

The next stage requires a large amount of heat so the boiler was set up on the brazing hearth (inverted) and surrounded by firebricks to prevent excess heat loss.

Heat the assembly until the soldering temperature is achieved then apply silver solder to the head of each stay inside the firebox, I used the lowest melting point silver solder available (around 595 deg C) so as to not disturb any previous soldering steps.

I re-soldered the superheater tube where it was weeping.

Carefully remove the firebricks and rotate the boiler so access to the other ends of the stay can be achieved.

Re-heat and apply a nice fillet of silver solder around the tail of each stay.

Allow the assembly to cool, see below...

boiler-44.jpg
Porcupine


boiler-45.jpg


boiler-46.jpg
Superheater Tube Weep Repair


boiler-47.jpg
Inside Firebox


Next Episode - Boiler Testing.
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Re: Coppersmithing a Boiler - Southern Railways Bulleid Paci

Postby tsph6500 » Thu Mar 03, 2011 9:56 pm

Boiler Building - Final Installment
by Keith Wood » Sun Dec 05, 2010 11:56 am


This episode - Boiler Testing.

After pickling rinsing and cleaning, the boiler is inspected all over for dry joints etc.

Once happy with the job the next stage is the hydro test.

Install all the blanking plugs previously used for the preliminary leak test, install the dome, handpump and pressure gauge, fill with water.

Slowly apply pressure to the boiler looking for leaks or distortion of any parts of the boiler, a few weeps from the blanking plugs were cured with some teflon tape.

30 PSI
boiler-48.jpg
30 PSI


80 PSI
boiler-49.jpg
80 PSI


120 PSI
boiler-50.jpg
120 PSI


160 PSI
boiler-51.jpg
160 PSI


Notice the weep from the dome gasket.

The pressure was held for 30 seconds then slowly released, no leaking noticed apart from the dome gasket, zero distortion.

Next Stage - Steam Test.

The boiler was emptied of water down the the normal water level, the two blanking plugs in way of two of the safeties were removed and the safeties installed.

The boiler was levelled and heat applied in the firebox using a propane torch.

Pressure rose quickly.

boiler-52.jpg
She lives! Propane was used for the steam trial. She is a coal burner.


Soon the pressure reached 90 psi and the safeties blew, no leaks noted. :D

boiler-53.jpg
Blowing Safeties


Trimming the stays

After allowing the boiler to cool, it was pickled inside and out for one last time.

Each stay was then shortened so that only 3/32" protruded through the wrappers.

The end of each stay was chmfered off slightly with the Dremel then domed slightly by applying a rivet snap to each tails and tapping the snap with a hammer, this removes any sharp corners from the stays.

A quick hydro test to verify watertightness and voila, your boiler is finished.

I hope you have enjoyed this series of articles, hopefully I have removed some of the mystery from the process, its not that difficult, take your time, ensure cleanliness and use good quality solders and fluxes.

If you need any advice or help, you know where I am.

Best regards.

Keith Wood
MLS
Last edited by tsph6500 on Sat Mar 12, 2011 8:41 pm, edited 1 time in total.
Best regards,
Jim Leggett

Montreal Live Steamers
www.montreallivesteamers.org

A Founding Member of the Tinkerbell Scale Society - Northern Division
I'm an A.R.S.E. (Association of Railroad Steam Engineers)
Toad Swamp & Punk Hollow Railroad - Head Tycoon
The Juvenile Traction Company - CEO & Apprentice Machinist 3rd Class
White Mountain Central RR - Engineer


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