Author Topic: CONWAY 0-4-0 3 1/2" GAUGE LOCO  (Read 59923 times)

Offline simplyloco

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #300 on: December 10, 2017, 01:50:10 PM »
I Hope so Bill.

I have noticed that the silver soldered joints seem to need more heat to re-melt than at first. So I have to take great care not to melt the adjacent joint/bush/stay

Cheers

Rich

Correct. The phenomenon is called 'Solvation', due to the alloying of the silver solder with the parent metal, hence the rise in melting point.
John

Online crueby

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #301 on: December 10, 2017, 01:57:54 PM »
When redoing a spot like that I would usually add more solder, to avoid having to overheat the surrounding joints. Not sure if that was the right thing to do, but I figured if there was a starved spot it needed more to fill it in.

Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #302 on: December 15, 2017, 09:12:09 PM »
Hi

I'm still struggling with leaks. Well not exactly leaks but minor weeps. Repair one and another rears its ugly head :facepalm:

Julian is having the same problems with his simplex boiler. We have put it down to the fact these are our first boilers so there is bound to be a learning curve.

Patience is a virtue I'm told ::)

Cheers

Rich

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #303 on: December 15, 2017, 09:33:44 PM »
Hi

I'm still struggling with leaks. Well not exactly leaks but minor weeps. Repair one and another rears its ugly head :facepalm:

Julian is having the same problems with his simplex boiler. We have put it down to the fact these are our first boilers so there is bound to be a learning curve.

Patience is a virtue I'm told ::)

Cheers

Rich
I had a bunch of redo's on my fourth one too.... It gets there eventually.

Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #304 on: December 16, 2017, 01:22:13 PM »
Hi

Well I got it upto 100 psi on the hydraulic test today. As far as I can see I have one weep in the smokebox but can't quite make out where it is  :noidea:

My best mate doctor Julian has an endescope so we are going to try that later

Cheers

Rich

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #305 on: December 16, 2017, 02:18:27 PM »
After silver soldering the copper is in an annealed state, and a few pressure ups and downs will work harden it again. I would suggest taking the static test pressure up to 100 and release a few times and see how it weeps. Sometimes it takes care bof itself as the metal is pressed into a low spot. May not change it, sometimes it does.

Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #306 on: December 16, 2017, 06:41:07 PM »
Thanks Crueby

I should have mentioned that I first pumped up to 20psi then released the pressure and worked upto the 100 psi releasing the pressure in between.

With Julians clever little gadget we think we have found the leak. Its at a point quite low down where the smoke box tube plate joins to the barrel so should be easy enough to get at.

Cheers

Rich

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #307 on: December 16, 2017, 07:39:34 PM »
Thanks Crueby

I should have mentioned that I first pumped up to 20psi then released the pressure and worked upto the 100 psi releasing the pressure in between.

With Julians clever little gadget we think we have found the leak. Its at a point quite low down where the smoke box tube plate joins to the barrel so should be easy enough to get at.

Cheers

Rich
Excellent - I am always really nervous about the joints that are really deep in and hard to get at.

 :popcorn:

Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #308 on: December 21, 2017, 08:47:49 PM »
Hi

The boiler has been soldered again and is back in the pickle, tomorrow if time permits another hydraulic test ::)

Meanwhile 5 eccentrics are needed. One for the axle pump and 4 for the valve gear. Straight forward turning job which I'm sure needs no detailed explanation. They do need to be quite accurate so I used a micrometer instead of my trusty digital calipres. Also it is apparently a bit awkward to set the eccentrics as the grub screw is in the centre which requires the eccentric strap to be removed to loosen/tighten/adjust the eccentric. The 2 inner eccentrics I have made double the width so that the grub screw is on the outside, the outer eccentrics are too close to the frames to have the extra width



All 5 eccentrics have the same offset, 1/4" so I have made a little jig. A piece of thick MDF bolted down to the table with both X and Y locked



Remove most of the waste with a Forstner bit



Finish off with a boring head



 
Until the eccentric is a snug fit



Clamp the eccentric in position



Move the table back exactly .25" and lock in position. Then drill and ream 5/8"



Repeat the process for all 5 eccentrics




Cheers

Rich

Online b.lindsey

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #309 on: December 21, 2017, 09:53:02 PM »
Rich, I hope the last resoldering will close up that last weepy place for you. The eccentrics look good as well.

Bill

Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #310 on: December 22, 2017, 09:31:54 PM »
Hi

Thanks Bill

The 5 eccentrics have been drilled and tapped 3/16" unf ( because thats the size of the grub screws I have in in stock )



After repairing the leak in the smoke box the boiler is set up for a hydraulic test at 50 psi



After 20 minutes 2 small weeps were detected





But there was no noticable drop in pressure ?? :thinking: :headscratch:

I increasd the pressure to 100psi and the weeps seem to have stopped  :thinking: :headscratch: :noidea: and after another 20 minutes no loss in pressure.

I have released the pressure now and will have another go tomorrow all being well

Cheers

Rich

Online crueby

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #311 on: December 22, 2017, 09:57:39 PM »
Looking good on the static test, I've seen similar things with very minor weeps sealing themselves up as the pressure presses the copper against the studs. The ones I had never came back. Its the ones that form drop after drop or little streams that are the problem ones.

Offline NickG

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #312 on: December 23, 2017, 03:08:42 PM »
Looking good Rich, I wonder whether they would soon seal up once the fire is lit and start to get baked with combustion deposits. Do all weeps have to be stopped or is it ok so long as the pressure doesn't drop a certain amount?


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Online b.lindsey

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #313 on: December 23, 2017, 06:56:28 PM »
Sounds like you are gaining on it Rich!  The eccentrics look even better finished and in place.

Bill

Offline Firebird

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Re: CONWAY 0-4-0 3 1/2" GAUGE LOCO
« Reply #314 on: December 24, 2017, 04:00:29 PM »
Hi

Thanks Crueby, Nick and Bill.

This is my first loco boiler build so I'm not sure as to the exact requirements of the hydraulic test. I believe it has to hold the test pressure of 160psi for 20 minutes.

Cheers

Rich