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Post by Deleted on Jan 2, 2014 18:51:39 GMT
Thanks for that---one book duly ordered from Amazon !!
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jma1009
Elder Statesman
Posts: 5,913
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Post by jma1009 on Jan 3, 2014 0:14:56 GMT
i wouldnt expect anything less, but after a few steam ups expect the most almighty escape of steam and sudden drop of boiler water level then failure of the 1.625" dia main flue! and blobs of soft solder on the bottom of the end plates! miniature steam loco boilers can be strange things, and do strange things to the tyro! i remember very well a very old chap who recently joined the club who had built a ROB ROY. all the steam pipes on the backhead were soft soldered to the nipples etc. we gave it a 'sort of test' and allowed him to steam it up. it wasnt a public running day, and hadnt written out the certificate. we felt so sorry for him, as he had built this loco over many years and it was his pride and joy. anyway all the joints burst on the backhead steam pipe nipples and the smoke box door fell off as that was soft soldered on to the hinges too! never had to sign that certificate! needless to say it never made it off the steaming bay! rather than me saying 'you cant try steaming that up' we let him find out for himself, and at least have the dubious pleasure of steaming up the loco and finding out for himself the errors rather than us descending on mass with a heap of critism before lighting a match. cheers, julian
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Post by wdiannes on Jan 3, 2014 0:41:37 GMT
I was expecting to hear from you.
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jma1009
Elder Statesman
Posts: 5,913
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Post by jma1009 on Jan 3, 2014 0:47:13 GMT
happy new year, dianne! i do like the wooden gear wheel pattern by the way! lovely work! cheers, julian
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Post by wdiannes on Jan 3, 2014 1:16:44 GMT
Thank you Julian.
The tubes were all EXPANDED into the flue sheet and caulked with soft solder. I don't expect any problem with the steam test.
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Post by Jim Scott on Jan 3, 2014 13:05:27 GMT
Hi Dianne, and best wishes for 2014.
Good to see the progress thus far.
Did you expand all the tubes, including the main firetube? Its a pity you didn't hydraulically test your boiler before adding the high temperature soft solder as this would have settled many an argument and added much to the knowledge pool. My gut feeling is that, if properly expanded into a thick tubeplate, they would have sealed OK, with the soft solder an additional safeguard against leakage. As it is, we don't know whether the expansion or soft solder is providing the sealing.
I would be wary of soft soldering a non-expanded tube, even if the tubeplate is 1/4"thick and centrally stayed. Soft soldered joints have been known to fail on cyclically loaded joints even with very small loadings. However this should not occur if the tubes are held firmly in place by expansion.
Good luck with the steam test.
Jim S
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Post by wdiannes on Jan 3, 2014 15:20:15 GMT
I was able to expand both ends of all the smaller tubes and one end of the larger flue. The second end of the larger flue expanded somewhat but was not tight all the way around and I did not have the material to make a "hydraulic expander" so I decided to use soft solder caulking rather than chase leaks. That end IS expanded outside of the flue sheet so will not pull through but I just couldn't get it tight (to my satisfaction) in the flue sheet.
I know there are some engines in my local club built with expanded copper tubes in copper flue sheets but I don't know if we have any that have run any significant period of time. I also don't know if they have used any form of caulking as an additional seal - I will ask.
I am looking forward to doing a steam test, hopefully later this month, to push the boiler hard and measure the evaporative rate. I packed as much heating surface as I could into the available space but "by the numbers" it will be marginal. If the steam test shows the capacity of the boiler to be marginal, I may have to go right back to the beginning and redesign everything - no point having a loco that has to stop every 5 minutes to build steam pressure! I have my fingers crossed for that one.
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Post by andyhigham on Jan 3, 2014 15:30:09 GMT
If the staeming is marginal, one solution may be to make a new flue tube with water tubes crossing it.
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Post by wdiannes on Jan 3, 2014 21:38:03 GMT
I thought about incorporating Galloway tubes but the thing I don't like about Galloway tubes is that if the flue ever has to be replaced, you have to take the end off of the boiler or make one end a flanged fitting to get the flue out and the new one in. If it is close to meeting the required steam rate, I will try "tubrolators" in the tubes to slow down the gases and get more heat transfer. Had a productive afternoon in the shop! What I thought was going to take 4 or 5 days only took one afternoon. I was planning to make the front and rear smokeboxes flanged and bolted to the boiler like the original but I am really paranoid about tapping small holes in copper - steel is bad enough - and I had visions of breaking off a tap in the boiler so I decided to omit the flanged mounting and use studs through the smokeboxes. It didn't turn out too bad [It is sure a LOT easier silver soldering thin brass sheet than it was soldering 1/4" copper plate for the boiler! I did very little silver soldering before this project and even that was 30 years ago (but LOTS of soft soldering) and thought I had "lost my touch". It was reassuring to know "I have still got it" on the thinner stuff LOL!] Tomorrow's task: make the burner mount.
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Post by wdiannes on Jan 5, 2014 20:17:56 GMT
Too bloody cold to work in the shop (-33C with windchill to -47) so I brought the boiler into the house and gave it a coat of paint - I wanted to see if it is going to look like the Coalbrookdale locomotive! I think it will pass.
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Post by Roger on Jan 5, 2014 20:39:34 GMT
Too bloody cold to work in the shop (-33C with windchill to -47) so I brought the boiler into the house and gave it a coat of paint - I wanted to see if it is going to look like the Coalbrookdale locomotive! I think it will pass. Well, that certainly looks the part!
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Post by Deleted on Jan 5, 2014 23:18:13 GMT
-------- It'll soon look like this in no time !!......ps}--- Elegant wallpaper !! Attachments:
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Post by ettingtonliam on Jan 7, 2014 15:24:40 GMT
I must look for that myself. I've got 'The Oblivion of Trevithick' by Phillip Hosken, and I think its one of the worst written books I've ever read. Yes theres some useful bits about Trevithick, but mostly its a disjointed account of people he may have met and been influenced by, and a lot of speculation.
Richard
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Post by wdiannes on Jan 7, 2014 18:42:21 GMT
Don't know if I will be able to get it to seal (without an O-ring) but I made a beam type safety valve similar to the prototype - haven't made the weight yet. Hope this will be sufficient for the steam test - I am anxious to know how many pounds-per-hour the boiler is capable of evaporating! (In operation it will have a second spring-loaded safety.) Coming from a full-size background, working in 1:12 scale if forcing me to develop my (picayune) skills! LOL!
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Post by wdiannes on Jan 13, 2014 22:57:40 GMT
Got the boiler buttoned up enough to fire it up for the first time today. It seems my pipe thread compound doesn't like these fine threads (1/4-40 taper) 'cause most of the threaded connections leaked a bit. I will have to take it all apart and re-do it with a different thread sealer. My hand pump wasn't holding pressure either so I stopped the test to fix the problems ...... and while working on that I lost the small ball on the inlet check - just ### great! At least the boiler works LOL!
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jma1009
Elder Statesman
Posts: 5,913
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Post by jma1009 on Jan 13, 2014 23:06:00 GMT
hi dianne, not going to be coke or coal fired then? just gas? that's a bit of a shame as rather throws any attempt at accurately recreating the prototype 'out of the window' so to speak? cheers, julian
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Post by wdiannes on Jan 13, 2014 23:40:15 GMT
Quality coal has become impossible to find here.
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Post by Deleted on Jan 14, 2014 0:28:27 GMT
We could always send you some, I suppose ??...........
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jma1009
Elder Statesman
Posts: 5,913
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Post by jma1009 on Jan 14, 2014 0:31:17 GMT
i recently acquired over half a ton of welsh anthracite beans if dianne wants some, and doesnt mind paying the postage and packing and shipping!
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Post by wdiannes on Jan 14, 2014 1:02:11 GMT
That's a generous offer Julian but I hate to think what the postage would be!
I need to track some down closer to home, but like a few hundred pounds - I have a 1/2 scale traction engine that eats coal.
I do like propane in the smaller engines - quick heat, good heat control, easy shutdown, and almost no cleanup!
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