uuu
Elder Statesman
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Post by uuu on Nov 30, 2014 20:35:54 GMT
I don't think you can use Viton 'O' rings, the temperatures are too high... I've seen these used quite sucessfully. But they needed periodic replacement, the loco concerned is well used. When the old ones come out, they're not cracked or degraded, just worn flat, so they lose their seal. Wilf
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Post by joanlluch on Nov 30, 2014 20:59:01 GMT
I don't think you can use Viton 'O' rings, the temperatures are too high... I've seen these used quite sucessfully. But they needed periodic replacement, the loco concerned is well used. When the old ones come out, they're not cracked or degraded, just worn flat, so they lose their seal. Wilf There is a material named FFKM that stands up to 310 °C. Regular Viton (FKM) is just about 200 °C.
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Post by Deleted on Nov 30, 2014 21:30:51 GMT
I think Hagley is meaning the fix might be new pistons with the Viton oring. I have a couple of dozen of them on hand so I might try that route. I have also e-mailed Blackgates to see what the postage would be on a complete cast iron set. A question here ... If I go the cast iron route and make new cylinders, could I make the liners of cast iron as well for the valves? Cheers Tom ------------------- Yes, I should have made my response a tad clearer perhaps but if you re-read the post ( from the piston photo onwards ) you'll see that I was in fact agreeing with "young" Mr Parrot's posting ie}--- The simplest option would be new BRONZE pistons ( as the photo shows Bronze pistons originally fitted) turned to carry o-rings.....This is an already proven route by others.....Next then is the all-iron option...This would allow either classic metal rings OR the use of O-rings.....Yes, iron liners for the piston valves is ok....
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Nov 30, 2014 21:39:19 GMT
hi tom, i would say the pic of your pistons shows excellent square graphite packing very well fitted that hasnt worn at all and usual condition of pistons. unless the piston fit is sloppy (which from your description they sound tight rather than sloppy) i would re-fit them. soak the graphite in steam oil first before re-fitting. i dont like 'O' rings on pistons, but that's a personal view based on the sort of experience with other people's locos that wilf relates. cheers, julian
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Post by Roger on Nov 30, 2014 21:58:13 GMT
There's also the option to use exotic 'O' rings that are made of two materials such as Teflon encapsulated Silicone which are used in very aggressive chemical environments.
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Post by Deleted on Nov 30, 2014 22:06:36 GMT
"-------- to boldly go where no Man has gone before !!"...........and why not indeed ??...Isn't the SMEE the Society of Model and EXPERIMENTAL Engineers ??..............Plus, you'll get doors that open with the word "Swish".....( Not a "Trekky" ??---- never mind, someone will explain..)..... www.youtube.com/watch?v=hdjL8WXjlGI
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Post by Deleted on Nov 30, 2014 22:35:03 GMT
Thank You for all the replies.
I have sat and enjoyed a dram or two of the Irish amber liquid and thought about my options.
At this point, my goal is to get a runner. Nothing show stopping, but a good runner ... so ...
I will get some steam oil and follow Julian's advice and soak the pistons in it (Julian ... should I pull the packing out or leave it as is and dip the whole works in the oil?). Also, I am going to properly hone the cylinders and see if I can get a better fit with the piston.
The reason for going this way is I have no idea what else I might have to replace ... trying to get the thing running at least on air should show me a lot.
If postage is reasonable on the cylinder set I will get them from Blackgates ( unless someone has a set under their bench they would like to part with). That way, if I need them, I will have them. The ones I have are really ugly and I don't even know yet if they will work.
So, there you be (or there I be) far away from a York Brewery pub and not liking it. I feel the need for another cyber toast .... Cheers
Tom
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Post by joanlluch on Nov 30, 2014 22:35:33 GMT
"-------- to boldly go where no Man has gone before !!"...........and why not indeed ??...Isn't the SMEE the Society of Model and EXPERIMENTAL Engineers ??..............Plus, you'll get doors that open with the word "Swish".....( Not a "Trekky" ??---- never mind, someone will explain..)..... www.youtube.com/watch?v=hdjL8WXjlGICome on Alan, PTFE encapsulated o-rings are for real and used in Real applications. Why not in live steam miniature locos?
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Post by Deleted on Nov 30, 2014 22:46:46 GMT
Oh dear--------here we go again-----------( Damm language barrier) ------ JOAN, Yes I'm only to WELL aware of that fact.. What I'm advocating is that to experiment with, and make use of, them is exactly what the SMEE is all about ( and by inference--all of us as well....... )
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Nov 30, 2014 22:49:07 GMT
hi tom, dont disturb the packing. just soak in steam oil before re-fitting. whoever fitted the packing knew what they were doing. i dont think you can beat well fitted square asbestos graphite packing in gunmetal or bronze cylinders. the problems arise when the packing isnt properly fitted. i wouldnt touch the bores if after trying the oiled pistons in the bores they slide up and down ok - the loco has obviously had a bit of running and the bores should be pretty good with high spots worn off. cheers, julian
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Post by Roger on Nov 30, 2014 23:15:29 GMT
"-------- to boldly go where no Man has gone before !!"...........and why not indeed ??...Isn't the SMEE the Society of Model and EXPERIMENTAL Engineers ??..............Plus, you'll get doors that open with the word "Swish".....( Not a "Trekky" ??---- never mind, someone will explain..)..... www.youtube.com/watch?v=hdjL8WXjlGICome on Alan, PTFE encapsulated o-rings are for real and used in Real applications. Why not in live steam miniature locos? Joan, we all struggle with Alan's flowery punctuation and embellishments, so don't be surprised if you sometimes get the wrong end of the stick. I looked up Google Translate but there's no 'Alan' option in the dropdown box for languages to help.
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Post by joanlluch on Dec 1, 2014 8:08:15 GMT
Oh dear--------here we go again-----------( Damm language barrier) ------ JOAN, Yes I'm only to WELL aware of that fact.. What I'm advocating is that to experiment with, and make use of, them is exactly what the SMEE is all about ( and by inference--all of us as well....... ) I'm sorry Alan, I am doing my best. Acually, It's not usually a language issue, but one based on cultural backgrounds. Language is the easiest part, you can believe it. It's like if I mention the "super 3 club". I do not count on anyone here knowing what it is, but virtually every parent having children in Catalonia have joined it. I'm happy as long as some clarification follows any misunderstanding, which is what you just did and I am thankful for that. :-)
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Post by joanlluch on Dec 1, 2014 8:17:59 GMT
Hi Roger, Google translate is the funniest thing on earth. It's so bad I can't believe it. Not even an "Alan" to English translator would be usable.
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Post by Roger on Dec 1, 2014 8:53:14 GMT
Hi Roger, Google translate is the funniest thing on earth. It's so bad I can't believe it. Not even an "Alan" to English translator would be usable. I've used Google Translate to good effect on occasion, but you have to keep things really straightforward to get anything sensible out of it. Just for a bit of fun, here's Alan's original comment.... "-------- to boldly go where no Man has gone before !!"...........and why not indeed ??...Isn't the SMEE the Society of Model and EXPERIMENTAL Engineers ??..............Plus, you'll get doors that open with the word "Swish".....( Not a "Trekky" ??---- never mind, someone will explain..)..... and what Google translate makes of it when it's been changed to Catalan and then back again..... " -------- Boldly go where no man has gone before !! " ........... and do not really ?? ... There is Smee Society and Model Engineers EXPERIMENTAL ?? .............. Plus , you'll get that door open with the word " crack " ..... ( not a " Trekky " ?? --- - no matter , someone explain .. ) ..... It's surprisingly good, a lot better than I expected!
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Post by Deleted on Dec 1, 2014 10:11:52 GMT
KIF SIGH !!------
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Post by Deleted on Dec 1, 2014 10:27:26 GMT
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Post by ejparrott on Dec 1, 2014 10:35:40 GMT
I don't think it's going to today Al....not here at any rate
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Post by Deleted on Dec 1, 2014 10:59:53 GMT
Julian, Thank You for that advice, and that is exactly what I am going to do for now. A cast iron cylinder set will cost me nearly 150.00cdn (parts and postage) so I will not go that route unless I have to.
The one, very frustrating, aspect of taking on an already started build, is (in my case ) not having access to the previous builder. There seem to be three very distinct levels of craftsmanship in this model, and I get the very distinct impression that some of the parts have been used. The cylinders and pistons for example, do look like they have been used, and yet this engine was not at a running stage of any kind when I got it.
Alan, here, the sun is not even up yet, but I am having a "special" ( a wee drop of the Irish added) coffee anyway. (Purely medicinal)
I am hopefully going to be ready to start painting the frames later this week, which brings up another question .... I have decided on Britannia, and the very early, all black version ( to be repainted at a later date). I am still waiting for the reference books to arrive by post. Does "all black" mean both inside and outside of the frames were black, or is red still involved as well?
Cheers
Tom
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Post by joanlluch on Dec 1, 2014 13:52:19 GMT
... what Google translate makes of it when it's been changed to Catalan and then back... It's surprisingly good, a lot better than I expected! I've made many times such kind of experiments and curiously going back to the original language produces better results than the single first translation. I do now know how it works, but the thing eventually translates everything, even if it has no sense at all. It is like all the translation missteps and errors going forward are compensated by opposite missteps going back and thus recovering part of the original message. It's just incredible. I translated Alan's post to Catalan and I can tell that the result is almost impossible to decipher. It's totally surprising that the final back-to-English translation is almost identical to the original. I'd ask, how's that ever possible?
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Post by Deleted on Dec 7, 2014 23:30:16 GMT
Here in Canada we are not into painting weather and won't be for several months, so I have decided to try and get Britannia ready to run on air. There are several brackets not located at this point, and much to do. In that vain, my question ... does anyone know of any "breathing" problems with Britannia if built to LSBC plans? Would she benifit from slightly larger exhaust tubes coming from the cylinders? I am at the point of making those bits, so if it would help to make the pipes a tad larger, now would be the time to do it.
Cheers
Tom
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