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[raflaunches]

I must admit I like the era that your model represents- it was an era of new technology and innovation which created some fantastic vessels like the TBDs. Before I was put into forced isolation I fetched out my tiny 1/96 scale HMS Velox hull which I had fitted the four 2mm diameter prop shafts and the equally minute props from Prop Shop. As previously mentioned by Geoff and others, the excellent book British Destroyers is a stunning history of the destroyer (my copy took a few years to find at a price I could afford) but Norman Friedman’s book is equally just as good.
I’ll look forward to your progress 

[KNO3]

Hi David, to save you much possible frustration later on, I think you should do a steam test of the steam plant as soon as you can, to see if the boiler provides ample steam for both engines. This kind of engine is known to be steam hungry and two of them will be even more so. If you can, do the test with the propellers in water, so the engines have a load. Then you can measure the rpm that the boiler can keep up.

[DBS88]

Thank you for the advice re the burner, thats most helpful. With the boiler full of water, no air gaps, I thought I could find out two things, a position for the burner so I could make up an adjustable holder for it and also by applying some gentle heat, expand the water and raise some small pressure to test for leaks. So with the boiler in the garden, I nervously introduced the flame into the fire tube. I moved it forward and back, listening to the roar of the flame and watching its colour and also the overspill of flame as a back pressure forced some of the flame back out of the boiler fire tube. I was not convinced the burner was right before I started, now I was even more convinced it was wrong, far too much flame and the fumes stunk, they were awful, made my eyes sting, so definitely incomplete combustion. Anyway the heat did raise the pressure, just a few psi, less than 10 but enough to show me leaks from fittings that would need addressing before I could get the boiler pressure and steam tested for its safety ticket. So the outcome - research for a new burner and strip the boiler fittings required.

[KNO3]

Jerry at Clevedon Steam can make custom gas burners. He builds a type with metal gauze-like surface which gives a shorter flame. Why don't you ask him if he could make you one?

[Vintage]

Another  for Jerry at Clevedon Steam, he's an incredibly knowledgeable and helpful chap on all things model steam.
That's an impressive looking boat and power unit. If it's the one I think it is (offered for sale by Paul D) I was very tempted myself were it not for the size ...
I'll watch this thread with interest.
Mark

[DBS88]

Thank you for the tip about Clevedon Steam, I knew they did replacement burners and adaptor rings were available to order so that the burners would fit different size fire tubes, i didn't realise custom size burners were also possible, so lesson learned. I find Jerry to be both helpful and quick in supplying parts.
Anyway having to strip the boiler down is proving to be a blessing because it has revealed some things that may have caused a problem either at the pressure test or once it was up and running under steam. One job that needed to be done before the pressure test was to replace the broken union cock valve used to isolate the sight glass, it was siezed solid and in the process of trying to unsieze it, I snapped the handle off. I disconnected the sight glass assembly and then removed the fittings connecting it to the boiler and here is what I found. There was chalk deposits, despite having used descaler, the fittings had been sealed with dubious sealant and also been soft soldered in place to prevent them turning or leaking - I believe an older and previously fairly widely used practice

[DBS88]

While I was removing the sight glass a shard sheared off rendering it useless, so I had to replace it, well it was a 3/16 dia glass and the drama surrounding its replacement is the subject of another thread under Steam R&D called cracked sight glass, so I  will not repeat here what happened, save to say thank you to all involved especially Steamboat Phil who went above and beyond the call of duty to help me. Any way it was that thread that prompted the start of this one, so in terms of a time line we are now almost upto date with where I have got to. Probably one more post to follow re the boiler then we will be in real time.


Now I have never silver soldered anything before. I understand its very strong so thought I would try to use silver solder to repair the broken handle from the union cock so heres the results

[DBS88]

During this project I have been helped by a number of people, both from my club and from this forum, I would not of made such good progress without you, thank you.
Having removed the fittings from the boiler i set about cleaning them up. First soaking them in descaler to remove any deposits and by mechanical means, wire brush etc to remove other muck. Then I resorted to the blow lamp to de-solder the fittings since the excess solder was unsightly and i was uncertain what the boiler inspector would make of it? Now whatever had been used melted at a fairly low temp and did not run like normal plumbing solder, it was a sticky mess - any wire brushed the worst off while it was still liquid. I then used a 5/16 26 die to clean the male threads for the fittings and a 5/16 26 tap to clean the female threads to the boiler. I then reassembled using copper washers to space the fittings so that when tightened they ended up in the correct orientation. I reassembled the fittings and got the boiler ready for its pressure test.

[KNO3]

You have cleaned them up very well. Take care with those valves as they are prone to leaking. You might need to lap the conical part to get them tight.

[Mark T]

This is an amazing boat and I take my hat off to you for trying to preserve it using the fittings and burner supplied.  I am terrible for ripping out the old stuff and upgrading it for modern.  This just removes the heritage and what the boat is about.  Really good luck with your build - what a treasure you have there 

[DBS88]

Now I was lucky in regards to timing, I booked the boiler test with my clubs boiler testers, which happened to be the last day before we went into the second and current lockdown. Now club boiler testers really are unsung heroes so I am truly grateful to anyone who undertakes this roll so that we might be able to keep our steam boats safe on the water.  So it was somewhat nervously that I attended the test venue, we socially distanced. The boiler was visually inspected and the test equipment set up. Now anyone thats waited for one of these tests will probably tell you its a scarey time, you  arrive with a very expensive boiler and could leave with a worthless pile of scrap if it fails. Because of the boilers size 1.4 litres, its working pressure of 80psi (just over 5 Bar) and its unknown manufacture it had to be tested to twice the working pressure so 160 psi. The pressure was ramped up in 10 psi increments, we listened and watched 50, 60 psi a small leak from the union valve showed up, this was duly tightened, 90, 100 psi the pressure was holding, the pressure continued to be released and then reapplied, 120, 130, now I was sweating, hoping all would be ok. The consequences of the boiler failing filled me with dread. 150 then 160 now we waited, the boiler had to hold this for 10 minutes. After an eternity all was declared well and the pressure released. Then followed a further visual check. Next came the steam test so the boiler was emptied to about half full of water and then fired up. The boiler began to hiss and bubble, a minor weep of water came from the freshly fitted safety valves, the pressure began to rise and the leak stopped. The pressure rose slowly to start with 20 psi then 30, there was a whiff of steam from the union valves, so they were again tightened down, the pressure rose faster 70, then 80 psi then the safety valves lifted, first one, then the second, their opening stopped the pressure rising and then they closed again. So after being nervous I was now elated, the doom and gloom, the fears of the boiler failing had vanished and the project to restore this glorious torpedo boat destroyer was now a real possibility. 
The burner was made specially for the boiler by Pendle Steam, it was machined from a solid 2 inch brass bar, its flame is much more stable and less spectacular, than the previous torch burner, I will try and get some better photos of it. Gone was the bad smell from the previous burner, now just a steady burn, we will have to wait and see how both the boiler and burner perform together later, to see if they can produce the steam that is required to drive those twin Sun Engines that have sat idle for far too long. I am however confident that the new burner will give the boiler the best chance it has of producing as much steam as it is capable of.

[Mark T]

Wow what great news     I too would have been very nervous!  So you went for a Pendle burner - Nigel is a top engineer and really knows his stuff.  The back up he supplies with his products is amazing.  Mind you I'm biased as he's a mate of mine     Good luck with your build and keep the pictures coming!

[KNO3]

Nice burner. Is it ceramic or some other type?

[KBIO]

Hello!
It will be interesting to know how long it takes with each burner to reach 3 b, for example.
Also ,  to see which one keeps up the pressure when the engines are running at the same RPM.
Cheers!

[KBIO]

You!
And the jet size also is important to know.
Thanks DBS88!

[DBS88]

Have tried to take some better photos of the burner, however, not easy since it needs to be dark to see the flame. Anyway heres the photos, the burner, its constructed from solid brass bar and is not ceramic, it is a push fit into the 2 inch dia fire tube. Re the gas jet size its fitted with the jet supplied, a No 5 jet which is small at 0.2mm dia to deliver 59 grams gas per hour at 15 psi. I did discuss the jet size with Nigel from Pendle Boilers and he said that increasing the jet size does not always result in better performance, it can just use more gas without the expected increase in heat output due to the nature of the combustion in the fire tube. So will have to experiment. I don't mind it taking a while to get this boiler hot so long as when its up to temp it maintains the best possible amount of steam, so will have to give it a few runs on the bench with the No5 and a No8 to compare. No8 uses 93 g/h, No 12 - 135 g/hr and No 16 184 g/hr. Obviously using the gas faster than needed is wasteful but leads to pressure problems with the gas cooling effect. Re comparing it with the torch burner, that I feel is unlikely, the fumes from it made my eyes sting and it stunk, it was not burning nicely.
A closer look at the photos also shows that I wasted my time using polish to clean the brass and copper work, the heat from running the boiler upto 80 psi for the steam test has coloured both the brass and the copper.

[Colin Bishop]

Your photography is superb!

Colin

[ballastanksian]

Ooh, another exciting project for the winter! These early destroyers are superb machines to read about and see. I have one of the books on these early vessels and they were mostly powerplant and fuel with a few nooks for ammo and crannies for crew. Thy even got 'Hard Lying' rates (Like submariners) as they were so unpleasant to serve in 


When I read about your issues with soft solder I was concerned for a moment that the boiler had been home made and soft soldered together which is a real no-no these days, and you cannot reliably silver solder soft soldered joints, thus making a soft soldered boiler an expensive ornament.


Re the hull, there is no evident layering of timber though there are hints if straight lines which might show bread and butter. If sanding the hull down well for a repaint, Might I suggest a sand down to the wood where it needs repairing as then we can all see some model archaeology!


A far as carving a solid block into a hull, while not easy, it may be no less difficult than cutting lots of layers out and finishing the shapes off, you are just replacing one set of efforts for another. Mind you, a solid piece of timber can move and split etc, and if the baulk was an edge piece, it may have had sapwood in places. Bread and butter comes from the way casting patterns are made from layers of timber built up and shaped. There are interesting You tube videos showing this occurring from way back.


She's a gorgeous model and I look forward to reading your updates.

[derekwarner]

That is an impressive 2" Pendle gas burner Dave    neat compact installation and todays technology over the 'unwieldry' Plumbers Gas torch 


Many will talk about Stainless mesh elements over Ceramic inserts for superior heating performance, however many also comment on the 'Howling" from the top of the boiler funnel under burning load


Does this burner with the Ceramic insert create Howling?


Secondly, increasing the gas jet size and corresponding gas flow when combined with the same gas supply tube bore sizing can introduce the freezing issues in the supply tube as evidenced by the icing on the externals etc [adiabatic? heat transfer]


Derek

[DBS88]

When I first realised that some of the joints on the fittings (including the seats to the union cocks) that had been screwed into the boiler had been sealed with a type of soft solder my heart did sink, I feared the worst. But rest assured, it was not anywhere on the boiler itself. It appears to have been done to lock the fitting in the correct orientation and to stop leaks at 80psi. Some limited research also indicates that this was an older and commonly used practice. To overcome this I cleaned all the threads and reassembled using a variety of thicknesses of copper washer so that when the fitting was in the correct orientation it was also tight. Thankfully some patience and persistence in doing so paid off because the joints did not leak at 160psi. The only problem on the pressure test was with the sealing the union cocks, not the joints I had made, but with the rotation of the lever through 90 degrees. These had to be rotated back and forth a few times and then tightened down before a decent seal was achieved.
Re some model archaeology - it looks to me like some thick pieces of wood have been glued together and then the inside taken to shape using an adz type tool. From the paint damaged areas, there are multiple layers of paint, it goes wood, white, grey, light blue, grey. The quality of the finish to the wood is astonishing, not a sign of any grain and a perfectly smooth finish, not a run or brush mark to be seen, whoever did it was a true craftsman. It has left me with a really good base to work on, once I find out what colour Turtle Back Grey is?
Re howling from burners, I have only fired the boiler for the steam test and it did not howl, the burner is made from solid brass, here is a link to an interesting video, from Pendle Steam/products/video demonstrations  on how the burner was made and how it performs even in a sealed tube  [size=78%]https://youtu.be/OLDE_MJfjBI [/size]
In terms of freezing i will be doing all I can to avoid it and keep the gas temperature up and to ensure the gas pressure remains constant.

[Colin Bishop]

If the hull is very old it could be made of yellow pine which was quite difficult to get back in the late 1950s but famed for its lack of knots and smooth grain.

Colin

[ooyah/2]

Colin, At the start of the 1900's all the big flour mills that had 5-6 floors of milling machines used Yellow pine to make the spouts that carried the ground wheat by gravity from floor to floor had spouts made of yellow pine.
In 1955 when I started my engineering apprenticeship it was in the Largest Flour mill in Scotland, it had 6- flats of milling machines 6- across and 12 in the length all powered by a triple expansion engine which stood about 20 ft high.
In the joiners shop there was a stack of yellow pine boards from 12 ' wide to 24 " wide planks all wedged down to stop any warping.


The mill went on fire the year after I left and the capacity was moved to Leith out side Edinburgh,
During a visit there the spouts were all made of round Aluminium tubes as Yellow pine had become very difficult to get and expensive, I think that this was the same at The Baltic Mill in Newcastle.


Today I know of no place that sells Yellow pine but if any model maker wants some keep your eyes open for any old church that is being demolished as most had the pews made from Yellow pine, the seats were 18" wide x 1'' thk and if you talked to the demolition team telling what you wanted some seats for they are only too willing to help,
The seats are usually carved with the initials of the Sunday school pupils taught but being so thick can be plained down, it's a useful source of timber and then you can talk nicely to some joiners shop to rip it up into strips for you.


It's a beautiful wood to work with and some excellent finishes can be had as you can see in Dave's M.T.B. which is built on the bread and butter method.


I must say it was an excellent find for Dave and I don't blame him for buying the boat and this new burner with a brass perforated plate from Pendle steam is also an excellent buy, mind you Think he should rename it H.M.S. Hernia, it will be a big lift, it's a good job that  has an estate car.


Keep up the good work Dave it's interesting to see how an old boat was made and as to how advanced you have become since starting out on steam vessels..


George.

[Colin Bishop]

Thanks for that info George, really interesting. When I started modelling and used bread and butter for the ic Smeed Empress of Britain liner I had to settle for Parana pine which had knots and tended to split. I did make the hull but it was too heavy really and unstable so the model never got finished.

Colin

[pendlesteam]

Just to add a note regarding the burner, if it howls it is simply not correctly matched to the flue correctly. Of the many hundreds I have made two howled and were easily sorted by altering the air flow into the sides of the burner. This air is purely to combat unwanted harmonics and plays no part in the combustion process (theres a lot more to making a good burner than meets the eye!). This burner has a brass gas/flame interface but I also make ceramic burners for our twin flue boilers as the all brass design is simply too brutal at start up. The ceramic ones are a much softer burn, that said, there is ceramic and there is ceramic. The stuff you can buy from UK model outlets will melt rather quickly in our burners unless you turn the heat right down. Our ceramic will not melt under any bench test conditions (and subsequently costs an arm and a leg!).
Nigel @ PSB

[ooyah/2]

Nigel


Thanks for that, even the ceramic that you can buy as Silver Smiths anvils will melt if the burner is 2" dia, in some cases it will not melt but will sag unless a bracer is made across the dia
It always amazes me when people talk about howling burners, some how they never experiment to see if it will stop by adjusting the position of the gas jet.


George.