Member postings for Ianmac

It is some time since I last posted on the forum. Health issue, now back to normal.

I am trying to complete the construction of a 7 1/4 Terrier (Don Young design).

The lubrication for the engine is Hydrostatic, The drawings dont appear to give one enough detail to build the lubricator and imply that the parts are (were) obtainable from Don Young.

I have looked at the possibility of fitting mechanical type lubricators. Its not easy but possible. Needs a drive from the front or rear wheel, which will look unsightly as will the positioning of the actual lubricator.

Anyone know where one can buy a good Hydrostatic lubricator or a set of proven drawings.

Many thanks

Ianmac

John thanks for the hint on using a conical seat.

I'll try one with a seat edge cut to as close as I can get to the angle of the ball circumference at point of contact with the clack seat.

I note that there are also different hardnesses of rubber avaiable from the pro suppliers. I can only find any comment on the rubber parameters on the Reeves site but still looking

Ian

Recently been bothered with unreliable injector operation which I eventually traced to the clack valve on the injector feed to the boiler (GWR 5" Pansy). Despite replacing this with a a self made and purchased unit, using both SS and Bronze balls I failed to get a perfect seal. My eventual cure was to use two clacks, one at the boiler and one fitted close to the injector.

The injector now operates to my satisfaction.

Looking further at this issue,I wondered if there was any mileage in using nitrile balls in these clacks.

No one in my club has any enthusiasm for nitrile but cant say definitively why.

Can anyone give me an opion on the use of nitrile ?

Boiler finished, Boiler inspector satisfied.

Thanks to all who posted info on my earlier thread -- Terrier Boiler

Yes,

I appreciate where you are coming from. The boiler had been away from heat for a few days before the test

From my point of view with a Boiler I prefer to opt on the side of safety. Club Boiler inspector is of the same opinion

I have been building my 7 1/4 Terrier Boiler as mentioned in an earlier post. I am following the drawings produced by Don young in 1990.

All has gone reasonably well until the first Hydraulic test. We took the pressure up to 100psi, water issues were minimal primarily a very minor leak on the foundation ring and some seeps on four firebox stays. I felt quite happy with this until a detailed inspection ( empty boiler) revealed a bellow on the front firebox tubeplate. This was positioned below the bottom row of boiler tubes and the top row of the throatplate stays.

There is a flat area of 1 3/4" * 2 3/4 " that is unsuported by stays. Every where else in the firebox stays are martixed at 3/4".

We reheated and gently pressed the plate back to where it should be. Fortunately the top bend on my outer throatplate where it meets the boiler outer was a sharp radius and I have managed to get 3 stays threaded into the centre of the unsuported area which continues the 3/4 " matrix stay layout over the flat area the front tubeplate. The new stays are in line with the stays on the sideplates.

Pressure test to 150 psi has been OK. I still have to go to 180 psi when Ive sorted the Foundation ring but do not envisage a problem.

It may be that on the drawing a row of stays has been missed.

Anyone building a 7 1/4 " Terrier Boiler may want to look at this issue closely.

Ianmac

Interesting buying copper, a wide variation in prices and responses to my enquiries

Found John Keatley Metals (recommended by Dave) to be excellent and will use them again without even trying elsewhere.

Likewise Cupalloys, they deliverd next day, I have started soldering and their combination of solder and flux works superbly.

One I will avoid is John Hood in Clydebank, they seem to be the only supplier in the Glasgow area but are part of a group based in Newcastle.

Ianmac

Thanks Michael

I did talk to others about alternatives to silver solder with better filing properties but was told that was largely a no no due to the material having already been exposed to silver solder.

For my rebuild I will follow the lines you suggest and go to a pro supplier of silver solder to get the graduated melting points. Im also considering using SS thin strip and flux inserted between mating surfaces prior to riveting.

I'm still trying to recover from the shock of the price of copper!. Its a minefield with some suppliers asking twice the price of other for individual sizes.

thanks again to all for their input,

I'll let you know when the new boiler is sucessfully completed

Ianmac

Thanks Keith, I'll be contacting you re the SS for my new build

A few questions to answer

Julian, the boiler is a 7 1/4 terrier to Don youngs design barrel OD is 5 1/2 * 10 swg. All external copper is 3mm. Inner firebox is 2mm.

Michael, I have delved as deeply as I can into the reason(s) for my problem. Cutting the boiler open has revealed the main issue. I think it was due to inadequate riveting between the firebox tubeplate and outer cover.

The build notes on the boiler suggests no rivets in a firebox roof. I followed these build suggestions. First water test showed no leaks in the firebox but one superheater tube didnt look good so a reheat was done to rectify this. It was after this reheat that the problem began to appear with hairline cracks in the SS joint initially between the firebox roof to tubeplate joint.

As Fizzy suggests we tried a reheat/resolder to no avail and the problem was getting worse. From the cut open boiler one can see that the firebox roof and top corners were moving away from the tubeplate leaving a gap too wide for SS to fill. Further reheates compounded the problem as the outer wrapper was not returning to its original position and could not,due to the infill of solder in the wide joint. Water tests could have been compounding the issue further by allowind debris to flow into the cracks and acid not penetrating the cracks to remove it so 2 and 3 in Fizzy's suggestion are active.

Its been a steep learning curve.

Ianmac

Thanks David

Have asked them to quote for my maikitagain project

Ian

Some months ago I posted a question regarding what appeared to be cracking on some silver solder joints in a Terrier boiler I was building. This boiler failed and is now scrap. I have been advised that part of the problem was possibly due to the wrong grade of copper being used on part of the boiler, primarily the firebox shell..ie not C106 grade copper.

Very painfull on my wallet.

I am now looking at starting again and buying material ( Reeves did a Kit at £650 before Xmas it is now £1040!). Having had bad experiences with one metal supplier can I ask if anyone can recommend www. m-machine metals .co .uk ? (or anyone else?) for the supply of C106 copper.

I have to admit to being very foolish in as much as I bought the boiler kit and castings from E-bay. What appeared to be a bargain has been an expensive excercise + 2 wheel castings and one cylinder casting u/s indeed club opinion is that the cylinder castings were the wrong ones for the terrier.

Should know better at my age.

Ianmac

Bob,

the drawings relate to Iron or Gunmetal and I assume the later if a gunmetal casting is used for the cylinder.

I have already been caught out with vague information on this build so am being cautious.

With one eye on when the drawings were produced, some 23 years ago, and what materials are available now, prompted my question. I hear of cases where a combination of cast iron for both piston and cylinder is very rust friendly and siezure can occur if the loco is left dormant for a period.

My motorbike with Cast iron liners in their cylinders use aluminium pistons?

Ianmac

Another request for some advice.

I'm just about to start to the cylinders of my 7 1/4 Terrier. They are cast iron.

What is the best material to use for the pistons?

Ianmac

Thanks for the feedback and the detailed info from Keith

Ianmac

We have built a few boilers in our club over the past three years all have been satisfactory until the last two using cadmium free silver solder.

Two boilers built in the last two months have both thrown up leaks on first water test which appears to be coming through hairline cracks in the Solder. Both were in areas where there were butt joints. ie no rivets.

Given the problem showing up on the first of these two boilers particular care was taken to ensure the second was fully heated before soldering and cooled as gradually as we could achieve to avoid any differential expansion and contraction. Propane was used as the heat source.

Is there an issue with cadmium free Silver Solder that could be causing this ? ie less tolerant than the older solder to expansion and contraction across a joint

Evaluating a possible project and dont want to fork out the cash for 7 1/4 Bridget drawings at this early stage. I have a set of Jessie drawings.

Is the boiler in Bridget the same as the unit fitted to Jessie?

Ianmac

Many thanks all for the feedback.

Looks like Ive scored an own goal by being slow and /or allowing the Acetylene flame to hit the SS.

I also used Cadmium SS ! Bought a batch at the right price just before it became illegal to sell it.

I'll revisit the affected areas after a clean / acid pickle

again many thanks

Ianmac

Currently building a 7 1/4 Terrier Boiler.

I had some issues getting the firebox door , foundation ring and firebox stays soldered due to the large mass of copper involved. I eventually used propane assisted by acetylene to get the heat where I though I needed it.

I am not happy with the visual look of some of the soldering where it appears as if tiny bubbles were on the surface and have left small craters and am concerned it may go or be porous.

What am I doing wrong ?

Ianmac

Posting this under steam locos as boilers are involved.

Two nights ago our clubroom and workshop was broken into.

Paisley Model Engineering Society on the outskirts of Paisley.

All our Copper, Bronze and Brass was taken together with 3 club members boilers

5" Bridget

5" Maid of Kent

3.5" Juliet

The Paisley Police have this in hand

We expect that they are destined for the scrap metal merchant but if the

******ds who did this realise they have a greater value they may appear on Ebay or other for sale sites.

In the slim chance anyone has any info please PM.

Think about your clubroom security and dont get caught like us.

Ianmac