99 3462 Build diary

[mbrown]

Firehole Door and Inner Dome


There are still a number of things I can do toward progressing the boiler before I start assembling the inner firebox and tubes to the outer wrapper. I kept back a ring of bronze which I parted off when I made the matching flange on the dome seating to go on the boiler. Combined with a length of bronze bushing turned to size, and a lump of similar bronze for the top, the inner dome is made from the three pieces.


IMG_20211128_125416 by malcolm brown, on Flickr


The three sections were silver soldered together and cleaned up very well. The holes for the safety valves still need tapping to full depth (3/8" x 32)


IMG_20211128_171944 by malcolm brown, on Flickr




I also pressed on with the firebox door assembly but ran out of time before being able to finish it. When I had got the domed shape of the door about right, I trapped it in the machine vice on the mill and cut two 5/32" slots into which I jammed lengths of BMS and brazed them in. A lot of filing ensued before they looked suitably like the hinges, including the lug on the top hinge to prevent the door swinging too far back.

The hinge blocks on the backing plate were made up as one, with a cut-out between the two parts on the under side so that when it was soldered in place it was easy to cut through and reveal the two blocks all lined up nicely. The door on the full size loco appears to be held to the hinge pin solely by the set screw visible in the earlier photo. This feels inadequate, even in full size, as the door is quite weighty and the connection between the hinge and the pin feels very slack on the real loco. So I made my pin with a square to mate with a squared hole cut in the top hinge. That holds it nicely, although I might add a 10 BA set screw just as belt and braces.

I made some progress with the catch and operating handle, including the little ferrule for the wooden handle. Wooden grips on hot handles seem to be a typical German feature - and a good idea too. I will probably make the handle from Tufnol, as I find it easier to machine than wood in this small size. I also need to add the latch to the backplate.


IMG_20211128_172022 by malcolm brown, on Flickr


Finishing it off, and using the backplate to mark the backhead for the blind bushes to secure it all, will have to wait a couple of weeks now.

Best wishes

Malcolm

[mbrown]

No workshop time at all this weekend - but the Boiler Inspector has OK's the outer shell and inner firebox/tubes assemblies, so I can now press on and finish the boiler over the next few weeks.

Malcolm

[mbrown]

Firebox door concluded.


Although I was all ready to press on with the boiler itself, it has taken all this afternoon to finish the firebox door. It was actually just the right sort of fiddly job to be a change and a rest from boiler bashing itself.

The four bolts through the door on the prototype secure a thin plate inside the door which I imagine is a sacrificial face to the inside of the door which can be easily replaced as and when it burns away. The door itself is a casting with a fairly thick section which fits quite neatly inside the firebox ring. I made that bit from 1/4" BMS plate and I reckon that will last the lifetime of the loco. As the door "casting" is in two parts in my case, the four bolts hold the two halves together. They are filed off flush on the inside so that they don't interfere with the shovel.



IMG_20211211_175554 by malcolm brown, on Flickr


The catch is simple enough but needed a lot of fiddling to get it to work properly. The fit in the fork of the pivot pin has to be "just so" in order to stop the latch dropping down too low when the door is open and, as on the prototype, the lift of the handle is limited so that it doesn't flip over and back. I managed to get it all adjusted so that the door latches shut when pushed to. That should make it easy to close with the shovel after firing.

The catch plate had to be silver soldered to the backplate and I was nervous that the hinge blocks, which are soldered but have no mechanical attachment, might come adrift. I clamped a chunk of 3/8" square BMS to the hinge blocks, both to keep them in place and to act as a heat sink, and it all went smoothly.

Anyway, here it is, with the photo of the real thing as a comparison. You can just make out the blind bushes in the backhead to which the door plate will be  attached with 8 BA screws. The dimensions of the door are taken from the measurements made on site, so I suspect the apparently different shape of the elliptical door is to do with perspective. I also added a little 10 BA screw, as on the real thing, to keep the door firm on the pivot pin.


IMG_20211211_175339 by malcolm brown, on Flickr


DSC00462 by malcolm brown, on Flickr


The handle is Tufnol. I have probably made it a little too long, but that sort of thing is best adjusted in service when I know how easy it is to use.

Tomorrow I hope to make a bit more progress on the boiler itself.

Bets wishes

Malcolm

[mbrown]

Incidentally, I made another small step forward this week. I had been wondering for ages how I could do the painted lettering on the loco which is in a rather distinctive Germanic script. The photo here shows some of it....


Foto Randolf_Jaentsch 002 by malcolm brown, on Flickr


Unless one of our German-speaking members corrects me, the wording on the left hand panel says that the loco is fitted with a steam brake, then notes the latest overhaul date (in 1966) which took place at the railway workshops at Gorlitz where the DR maintained its narrow gauge stock. "DSF" puzzled me for a long time, but I understand it is a Communist-era slogan standing for "German-Soviet Friendship" (or perhaps co-operation). On the right hand panel are notes of the region and the main depot overseeing the loco maintenance. The tender also has a panel giving the overall weight, the weight of coal and the volume of water.

I was wondering if I would have to spend a small fortune to get transfers made. But then, messing about on my laptop, I discovered a font in Word called "Bahnschrift". I guessed that this might be German for "Railway Script" and, sure enough, it was a very near match indeed. By playing around with Condensed, semi-Condensed, and semi-Bold fonts in various sizes, I think I now have a very good facsimile of the prototype lettering, ready to be turned into waterslide transfers as soon as I can get some decal paper and am near a decent photocopier.

It is not an absolutely perfect match - the letter "t" has a curved tail which the ones on the loco do not - but it's nothing that couldn't be adjusted with a tiny paintbrush. It will be a long time before I am in a position to add lettering, but nothing like being prepared!

Malcolm

[lennart]

Hello,

your translation and explanation of the wording is spot on excep one minor detail.

In the DDR / GDR, being a soicialist country and part of the Warsaw Pact, they had close connections to other eastern Europe countries, especially the USSR.

Large industrial facilities, factories, and powerplants often were named after polititians and communist activists, like Karl Marx  (e.g. VEB Lokomotivbau Karl Marx Babelsberg = publicly owned enterprise locomotive works "Karl Marx" at the city of Babelsberg). Also political slogans like the above mentioned DSF (= german-soviet-friendship) or Völkerfreundschaft (= friendship-of-the-peoples) were often used.

These solgans always had peace, the success of socialism or the wealth of the working people in mind.

The acronym "Letzte Br.-Unters." = Letzte Brems-Untersuchung translates to last examination of the braking system. As you have said, this was carried out at RAW Görlitz in November 1966.

Dates of major overhauls (hauptuntersuchungen) were and still are placed onto the front bufferbeam.

eg: Unt. Mei. 05.10.19. = Untersuchung Meiningen, 05.10.2019. -> The locomotive was outshopped from Meiningen works on the 5th of October 2019 (which is still active and currently builds the boiler for the new P2).

The so called Bahnschrift typeface was derived from the original DIN 1451. That's the one that was and still is used by the german railway companies for lettering their rolling stock. The Deutsche Reichsbahn used east german equivalent which was TGL 1451.

As with all industrial norms, the typefaces also changed a little over time. When I designed the lettering for my DB class E69 electric locomotive, I used the correct old DIN 1451 typeface with the correctly shaped t. I could send you the typeface file if it is of any help. Then your lettering could be made prototypical in any aspect.

It might still be possible that a perfect match is not possible. Even though there was a standard typeface, the lettering was eiter hand painted or cast in aluminium, brass or bronze. This all led to some inevitable deviations from the norm. So a little tweaking here and there might still be necessary.

[mbrown]

I suspected you would respond Lennart! You are a mine of helpful information and I am very grateful.

Thanks for the offer of the font file, but I think I am as close as possible already. The only variance I can see is the tail on the "t" and I can paint that out. The lettering certainly varied in position over the years although my earlier photos are not clear enough to see if the font was identical. And some of the colour photos I have show that the lower lines of lettering were yellow while the rest was white!

Thank you again. I love the research aspect of modelling an actual prototype!

Best wishes

Malcolm

[mbrown]

Progressing the boiler - slowly!


Not much to show for four hours in the workshop today... The bushes on the backhead and tubeplate have been soldered in with high-melting point silver solder and the elbow for the top of the water gauge had been fitted. It will be soldered up when the backhead is fitted to the shell.

Tenacity flux certainly lives up to its name... after 30 mins in the sulphuric acid pickle and another 40 mins soaking, there are still some stubborn deposits around the bushes.

Other bits and bobs included the 20 rod stays for the firebox crown and four hollow stays which will accommodate stainless pegs to support the "brick" arch. These are turned from thick-wall copper tube. I have started lining up the firebox and tubes with the outer shell and the front section of foundation ring is fitted to the throatplate- just needs bolting to the inner firebox tubeplate. Then I can start marking out for stays etc...


IMG_20211212_172357 by malcolm brown, on Flickr



More next week, I hope.

Malcolm

[mbrown]

Bad light stops play


On with the boiler today. On previous boilers, I have used the tubeplate itself to support the tubes when silver soldering the firebox into the shell and doing the staying, but it can be a pig to remove for the next stages. I saw Don's (don9f) idea of a false tube plate from thin sheet on his Austin 7 thread and decided to make one for myself. With the tube holes a tad bigger than for soldering, and a cut out and a couple of screws to grip on, it is easy to put in and to remove but will keep the tubes aligned. Thanks Don!


IMG_20211218_172009 by malcolm brown, on Flickr


I also made up the remaining three sections of the foundation ring.

With the firebox and tubes assembled inside the boiler shell, held by two screws in the front foundation ring, the false tubeplate and the foundation ring sides clamped in place, I was able to mark out and drill for the side and crown stays. This took longer than I anticipated, not least deburring the insides, but it is done now.


IMG_20211218_172109 by malcolm brown, on Flickr

IMG_20211218_172150 by malcolm brown, on Flickr


Unfortunately by this time the light had gone and I wasn't keen on starting the next brazing job by the light of nothing but the gas torch itself... So the next heat will be tomorrow.

Best wishes

Malcolm

[mbrown]

Stays


Today, the inner firebox and tubes were fitted into the outer shell with a couple of rivets through the throatplate and the front foundation ring. The dummy tubeplate held the tubes in place. I decided to do the throatplate stays at the same heat as soldering in the foundation ring and this was straightforward. I turned the boiler on end after soldering the stays and dropped the blowdown bush in place and soldered it at the same heat. It would have dropped out if I had tried to do it with the boiler horizontal for the foundation ring and stays. The stays are all askew because I bent them over to stop them dropping out if, by any chance, the solder was still molten when I upended the boiler.

Here it is in the hearth just starting to cool down....


IMG_20211219_114406 by malcolm brown, on Flickr


After that, I moved on to the rest of the stays. I didn't take pictures until they were done as I wanted to finish them before I lost the light again. As it was, I retrieved the boiler from its final pickle by torchlight and moving very carefully....

The stays went in the following order:

Roof stays, soldered on outside - plus manifold bush.
Roof stays soldered on the firebox side, plus the inside of one set of side stays.
Outside of those side stays and inside of the other set.
Outside of the second set.

I used solder rings on all the stays and touched in a few spots with a stick if I thought they weren't getting enough.


IMG_20211219_170012 by malcolm brown, on Flickr


That roof stay on the right will probably get a touch more solder when doing the firebox door plate - it does have a witness of solder on both sides of the join but I would prefer a bigger fillet before it is too late to do anything about it.

I am at work tomorrow, but a couple more days in the workshop should see it finished.

Best wishes

Malcolm

[mbrown]

Closing the fourth wall of the firebox

First job today was to inspect all the stays for good fillets of solder each side of the join. This was the last opportunity to do any more soldering inside the firebox. I had a few doubts about three or four stays - probably groundless, but better safe than sorry, even if it did mean I ended up with rather too much solder slopping around the inside of the box. It runs wherever there is flux and wherever gravity takes it.....

So, after two heats, I was satisfied with the stays and moved on to the firebox doorplate. The firehole and stay holes were marked out from the backhead, drilled and cut out, and the ring and stays soldered in with 438 silver solder. Yes, the stay on the right is larger in diameter than the others. I accidentally picked up a 9/64" drill instead of a 1/8" one and only realised after drilling that hole in the backhead. It meant turning up a special stay from 1/4" copper rod - not too much trouble.


IMG_20211221_152751 by malcolm brown, on Flickr


The door plate was then fitted into the firebox wrapper and held in place with two clamps at the bottom. Once I was satisfied the fit was good and the plate was level, it was back to the hearth. Here, the flux is just bubbling up...


IMG_20211221_154456 by malcolm brown, on Flickr


I started at the top corners and when the solder flowed, ran the torch gradually toward the middle of the top and then down the sides. Before reaching the bottom, I let the solder set, then knocked the clamps off with a pair of old pliers and carried on at the bottom edges until the joint was sealed all the way around.


IMG_20211221_161240 by malcolm brown, on Flickr


Because of the radius on the flanged plate, the fillet looks bigger than it is. The slight bow in the roof is unfortunate but only applies to the very edge where I was tapping the plate down to fit the flange. The actual roof is quite flat.


IMG_20211221_171152 by malcolm brown, on Flickr



The fit of the flanged plate to the firebox wrapper must have been less tight than I thought as some blobs of solder have run through. The one on the edge of the flange is Ok really, but one blob ran down and settled on the stay heads which is a bit unsightly, although it won't affect performance. The bits of black are just flakes of oxide from the steel plate which I used to protect the tube ends when soldering inside the firebox - they wiped out with a rag but I hadn't noticed them when I took the picture.

Tubeplate, foundation ring and backhead to go....

Malcolm

[mbrown]

Out of gas: out of light...

Some delay to progress today as the Propane cylinder was nearly empty and I didn't want to start on a big heat and run out part way through. So off to the Garden Centre where I usually get gas - no stock. That meant a trip to the filling station a few miles in the other direction - and success! Last time I needed gas, I tried the filling station first and they didn't have any, but the Garden Centre did. Ain't life like that...

Anyway, I got sorted and put in the tubeplate and longitudinal stays. The stays are nutted to stop them falling through. They will be soldered into plain holes in the backhead.


IMG_20211222_153014 by malcolm brown, on Flickr


I then fitted the sides of the foundation rings, which was straightforward as the front and rear pieces are shaped to fit around the plates so no complicated joints were needed. And that left the backhead, which has gone nicely into place. Here it is with solder rings ready on the stays.

IMG_20211222_164345 by malcolm brown, on Flickr


At this point, however, I had a good look at the tubeplate (which I should have done before) and found that, although the solder had pooled nicely around the tubes, it hadn't "wetted" two or three tubes near the centre of the tube stack. I suspect this is because I kept the flame on the outside of the barrel, to keep it away from the tube ends, and let conduction melt the solder. It seems the tubeplate itself reached melting point but some of the tubes were still taking heat away from the join. So that will need another heat.

By this time it was yet again too dark to continue, so the final heats - tubeplate again, backhead and stays, rear foundation ring - are now tomorrow's job.

Malcolm

[jma1009]

What a master class!

For the backhead, Malcolm, I wouldn't add rings of silver solder. They risk getting melted in the flame before the copper is up to the correct temperature. I would instead add the silver solder only when the job is up to heat, waving about a stick of the stuff with as much accuracy and skill as possible. Fill the inner firebox with cut to size thermolite blocks, and after fluxing up generously and up ended whack the heat onto the fire hole which is the joint that is most problematic.

Leaving the firehole ring proud by quite a bit assists for us amateurs using propane. It can be reduced as to its overly long length later same as the stays.

Excellent progress! And very interesting and informative!

[mbrown]

Many thanks Julian.

I'm not sure about "masterclass" - this is only my fourth boiler and, as I only do a boiler about once a decade, each one feels like learning the skills from scratch. I really set out this time to keep the soldering really neat and "professional" but, as you can see, an amateur's "better safe than sorry" approach means there are runs and dribbles all over the place. It's not as if it's a complicated boiler either.

Thanks for the tip about the backhead. It's too late to leave the firehole ring significantly proud, unfortuately. But I have peened it firmly into the backhead opening and hope the heat will conduct through OK. I have a big 2.5" burner on one torch and, for jobs like this, a second torch with a 1.5" burner - and a pair of welder's gauntlets to protect from some of the heat! I will probably combine your method with mine, leave the solder rings in place but top up the joints with a stick if necessary. Yes, I know that implies having three hands, but I can put one torch down when the work is up to heat!

Anyway, I will soon know how it has gone and will report accordingly...

Best wishes

Malcolm

[mbrown]

Almost there... but...

Another day's work and I was confident of getting the boiler finished. Never a clever thing to be....

Reheating the tubeplate was straightforward - all the tube ends are now nicely surrounded with solder. Here it is toward the end of the day with the dome perched in place.


IMG_20211223_165147 by malcolm brown, on Flickr


Then the backhead, and although it took a while to get to temperature, using two torches, it went well. I put a piece of vermiculite block (a broken piece from the hearth) inside the firebox and played the small torch on the inside of the fire hole ring and the big torch on the outside. The solder rings on the stays flashed just as a tell-tale piece of solder on the outside of the fire hole ring also flashed - so it was all up to the same temperature, and the edge of the backhead, the stays and the rear of the foundation ring were all soldered at one go. Here it is just cooling off, having been lifted part way out of the hearth....


IMG_20211223_132405 by malcolm brown, on Flickr


A lengthy session then ensued, trimming the stays and filing the stubs back and tapping out the bushes. Then I did a check that I like to do when the copper is still soft - screwing lengths of rod into the top and bottom water gauge bushes and checking for parallelism in each dimension. They were spot on, even though the perspective of the photo makes it look as if they aren't. If they hadn't been, it would have been easy to correct while the copper was still annealed.


IMG_20211223_163314 by malcolm brown, on Flickr


However, at this point near-disaster struck. I managed to knock the boiler off the bench when my sleeve caught one of the rods and, although I sort-of caught it, it landed on the elbow for the top water gage fitting ad cracked it. The elbow is made from a gunmetal casting. I bent it back OK and tomorrow will try to run a bit of silver solder into the crack which isn't too extensive. If that fails, I will have to make another elbow, drill out the old one and re-solder... I will see if I can do that before Christmas duties intervene.

Malcolm

[don9f]

Commiserations on that mishap....must have been very disappointing!
Anyway well done for the rest of it. You are racing ahead of me, as I’m stalled now on my 7F boiler, waiting until the New Year to be able to “borrow” the Oxy-propane pepperpot set again to do the foundation ring and smokebox tubeplate.

Merry Christmas Don

[mbrown]

Thanks Don. Having slept on the problem, I think I have a plan for dealing with it.

I take my hat off to anyone making a large boiler. The amount of heat needed for this one (the barrel is 4" dia by 2.5mm thick) was pretty formidable and made it difficult at times to get the solder stick in the right place - hence some of the blobs. No idea how you did all the stays on your big boiler and I guess oxy propane or oxy acetylene would be essential for the really heavy bits.

Good luck!

Malcolm

[mbrown]

Christmas present to self...

After sleeping on the problem, I figured that another heat at this late stage might be courting trouble - but then a work-around suggested itself. I cut off the elbow, carefully filed the top flat, and then tapped it out to form a bush. I can now make up a new elbow to screw into place. As it is always going to be a bit vulnerable, at least until the boiler is permanently mounted in the frames, it can be replaced easily if another disaster should strike.

Incidentally, when tapping out the bushes, I made sure that I had ground the sharp point off the end of the tap. On a previous boiler, I put a perfect dimple in the side of one of the flue tubes when tapping out a clack bush. Soft copper offers almost no resistance to the point of a tap going in with all the leverage of 40 tpi... and the flues (and, indeed, the firebox door plate) are pretty near the end of the bushes when you have gone past the lead-in on a second cut tap.... On that occasion, I stopped just in time, but it's not a risk I want to repeat.

So then it was off to the scullery for a good scrubbing down with a Billo pad, and I think the result looks pretty good. Of course, I won't know how good it is until it is tested, and before then I need to make up some blanking plugs for the regulator bush and wet header. But that will be a post-Christmas job.

Anyway, here it is, with the drawing of the full size boiler behind. By the way, the long "skirts" on the firebox sides are a deliberate (but non-prototypical) feature - all to do with the way I intend to mount the grate and ashpan. All will be revealed in due course....


IMG_20211224_120055 by malcolm brown, on Flickr


IMG_20211224_120158 by malcolm brown, on Flickr


IMG_20211224_120041 by malcolm brown, on Flickr


Happy Christmas all!

Malcolm

[steamer5]

Hi Malcolm,
Nice fix! The boiler is looking very good! Fingers crossed for the pressure test.
Great tip on tapping into a boiler, filing that away for future use, hope I remember as it’s awhile away at the moment.

Merry Christmas!

Cheers Kerrin

[timb]

If mine ends up being half as good I will be well pleased. Fantastic work Malcolm!

Merry Christmas!

Tim

[mbrown]

Oh dear....

Well, I plugged up all the bushes, the regulator flange and the wet header, and fitted the dome. Then I rigged up the test gear...

Result - I have a nasty leak at the top corner of the inner firebox tubeplate - about the most inaccessible spot you could imagine. This was a perfectly good joint when inspected, but what seems to have happened is that, during the staying, the solder has run out and left a small gap. There is a stay head very close to the joint.

So what to do? This is the first time a boiler of mine hasn't been tight from the word go - the worst I have had to deal with in the past was a tiny pin head leak on an outside stay. Clearly I can't re-solder it with propane now that the firebox is complete. I must see if I can find someone with oxy-acetylene who could tackle it. I must start asking around....

Hey ho. I hope it is remediable - the thought of starting the boiler all over again is too demoralising to contemplate. I think I would take to drink if that happened....

Malcolm