OzzyO
Western Thunderer
Any chance of a photo?
Being lazy I bought a replacement tube from Eileen's emporium for a fiver I think, and cut it to shape in about 10 minutes much easier than trying to solder up the pre rolled piece in the kit, some of the detail you can hack off and add boiler bands and rivets if you're that fussy.
richard carr
Western Thunderer
So that is meant to be the "secondary boiler" bit or whatever it was ?
Richard
Richard
Nick Dunhill
Western Thunderer
Tony
I think 'interesting' is the word to describe both of the last tasks. The boiler to firebox join looks like it will be a 'ball-and-bat' to get right, but I'm sure you'll manage it ok. Can't imagine how it's possible to roll a small long tube like that, although pre-rolled bits from manufacturers often don't help the task in hand. Are there any formers for it?
Nick
I think 'interesting' is the word to describe both of the last tasks. The boiler to firebox join looks like it will be a 'ball-and-bat' to get right, but I'm sure you'll manage it ok. Can't imagine how it's possible to roll a small long tube like that, although pre-rolled bits from manufacturers often don't help the task in hand. Are there any formers for it?
Nick
OzzyO
Western Thunderer
If I'm reading this drawing correctly, looking at Nos, 8,19, 20,21 &22 it looks like some of the exhaust steam was also used to warm up the water at the coolest part of the preheater, talk about over egging the pudding.
The 9Fs. had a good boiler and did not need this to help them produce steam.
OzzyO.
The 9Fs. had a good boiler and did not need this to help them produce steam.
OzzyO.
Stupid question perhaps, but how did the water in the pre-heater get into the main boiler? Do the feedwater outlet pipes go to injectors? I recall that most injectors didn't like hot water and could be made to pick up by throwing cold water on them. Time for a Google perhaps.
OK think I have found the answer: the preheater was at boiler pressure and connected via clack valves. So presumably the conventional injectors forced cold water into the preheater which then would have had higher pressure than the boiler, opening the clacks and pushing water into the main boiler. Is this correct?
OK think I have found the answer: the preheater was at boiler pressure and connected via clack valves. So presumably the conventional injectors forced cold water into the preheater which then would have had higher pressure than the boiler, opening the clacks and pushing water into the main boiler. Is this correct?
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Steph Dale
Western Thunderer
Yep, that's my understanding of the principal.
Steph
Paul,
The purpose of the Franco-Crosti boiler isn't to improve steaming, it's to improve efficiency by making use of heat that would otherwise disappear up a chimney to provide feed-water heating.
There were two issues with the BR implementation, one was the exhaust gasses becoming too cold which not only reduced efficiency, but also lead to the precipitation of sulphuric acid, so increasing maintenance.
The second, much simpler one is that exhaust injectors are relatively uncommon in European practise and the combination of the already good 9F boiler with exhaust injector had pretty high efficiency to start with.
Steph
Steph
Paul,
The purpose of the Franco-Crosti boiler isn't to improve steaming, it's to improve efficiency by making use of heat that would otherwise disappear up a chimney to provide feed-water heating.
There were two issues with the BR implementation, one was the exhaust gasses becoming too cold which not only reduced efficiency, but also lead to the precipitation of sulphuric acid, so increasing maintenance.
The second, much simpler one is that exhaust injectors are relatively uncommon in European practise and the combination of the already good 9F boiler with exhaust injector had pretty high efficiency to start with.
Steph
dibateg
Western Thunderer
Yes - I have all the 9F books Paul! I might buy some tube for the pre heater if there is a suitable size at Telford. I think the original intention was to save coal, by trying to make a more efficient boiler as coal prices were going up.
The main boiler has 3 clacks... was there a direct feed?
I'm enjoying the build, it is an interesting challenge. Yes, the kit has some deficiencies, but without it, the model would have to be adapted from another kit or scratch built.
The main boiler has 3 clacks... was there a direct feed?
I'm enjoying the build, it is an interesting challenge. Yes, the kit has some deficiencies, but without it, the model would have to be adapted from another kit or scratch built.
Nick Dunhill
Western Thunderer
I once tried to modify a DJH 9F to a Crosti in 4mm using a Crownline conversion kit (designed for a Hornby 9F). I soon found that not a lot is similar. Boiler and firebox completely different and therefore cab front. Footplate quite different too. Turned into a nightmare. Managed it though.
OzzyO
Western Thunderer
I should have added, more efficiently.
As you say the exhaust gasses did start to get cool so could that be why the pre-heat boiler has a steam jacket at the coolest part of the pre-heater.
I'm not sure how the exhaust injector helps with the boilers efficient in producing steam. The exhaust steam injector helped make more efficient use of the steam that would have just gone to atmosphere.
Looking at this photo,
the front clack has lagged pipework so that looks to be the feed from the pre-heater and the same on the other side. When you look at the pipework to the second clack valve it's un-lagged so that looks to be a cold water feed. Looking at the pipe work under the elbow to the chimney you can see a grease trap (the ball shaped thing), so did these locos have two injectors under the cab on the out side like the normal 9Fs? Then one between the frames. Or one live steam injector on the out side (the direct feed to the main boiler) and live and exhaust steam injectors between the frames? Or the two injectors on the out side of the frames with diverter valves on the feed water side.
The more I think about it to get the best use of the exhaust steam having two exhaust steam injectors feeding the preheat boiler could be the best bet. But where did they place them?
OzzyO.
dibateg
Western Thunderer
So after a day - the smokebox, boiler and firebox are all one now. I had to shorten the boiler by about 2mm and adjust the angle of the smokebox. I couldn't get on with the half etched boiler bands, they looked awful, just too thick. So these are slightly thinned Slater phosphor bronze. They are slightly too wide but look far better with half the profile of the etched ones. Its all just chucked together here on the shelf, so nothing is lined up properly yet, but it's going in the right direction.
Attachments
mickoo
Western Thunderer
looking good 
Just curious, what are you using to clean the work after soldering to remove the flux, or are you one of these folks that doesn't need to clean after your work
I've been using Viakal but suddenly the Nickle Silver is developing an orange tinge where ever the flux was used, same for the brass on the A3, very annoying.
Just curious, what are you using to clean the work after soldering to remove the flux, or are you one of these folks that doesn't need to clean after your work
I've been using Viakal but suddenly the Nickle Silver is developing an orange tinge where ever the flux was used, same for the brass on the A3, very annoying.
Dan Randall
Western Thunderer
So I'm guessing you're not on a water meter then Tony?
Regards
Dan
dibateg
Western Thunderer
It's been a post Guildex week, repairing casualties, fortunately not too many of those apart from a grumbing 08 which made it into the station once to drop of some p-way men before succumbing to shorts and erratic running and both 20s out of action with no motor drive from the decoders. I was chancing my arm with MX645s with twin motors, so decoders with more va va voom are going in.
I thought I'd work through my box of client repairs at the same time, so this Clan is having some pull rods and stretchers added as the brake were just dangling in the wind and very vulnerable.
I thought I'd work through my box of client repairs at the same time, so this Clan is having some pull rods and stretchers added as the brake were just dangling in the wind and very vulnerable.
