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Post by delaplume on Apr 9, 2019 2:20:58 GMT
When I got mine I was disappointed to find that it was virtually just a solid blob of metal paste, as if it dried out in storage. I spoke to the makers, and they told me to add Bakers fluid and stir it up, which is what I did. So - Bakers fluid. Many thanks for the info--------have just done the same as you and with the same good results, so one tub saved from the rubbish bin !! Following on from that I tried these two with good results also....Both were applied sparingly to a pieces of uncleaned 18g Brass sheet with a medium flame applied underneath...and in both cases the metal was cleaned and the solder ( plain, non-cored ) took evenly....
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Post by Roger on Apr 9, 2019 21:31:24 GMT
I've finally got round to making the balance pipe. On the full size locomotive it's made from a large diameter Copper pipe that's flattened and shaped at the ends where it's attached to a flange that bolts to the bottom of the tanks... ... like this. DSCN5643 by Roger Froud, on Flickr It's not really feasible to do it that way, so I've opted to make the rounded oblong cross section in two halves that will be tack welded then Silver Soldered together. Here's the blank having an undercut made with the nibbler I bought a few years ago and have never had the need to use. Here it makes light work of removing that unwanted material. 20190409_173507 by Anne Froud, on Flickr 20190409_172803 by Anne Froud, on Flickr I'm using quite a bit bigger blank than I really need because it's not easy to keep it registered on these first few bends and I didn't want it so end up without enough material on one side. 20190409_121241 by Anne Froud, on Flickr I'm not going very far with this first bend since the material hasn't been annealed yet. 20190409_121414 by Anne Froud, on Flickr 20190409_121611 by Anne Froud, on Flickr In total I annealed this around 8-10 times. You can see how easily it forms at the middle, but getting it into that tight inside corner is a bit of a challenge. Here you can see the edge of the former is digging in, ideally it would have been a bit longer. 20190409_122006 by Anne Froud, on Flickr 20190409_122014 by Anne Froud, on Flickr I used a piece of Steel strip to knock those inside edges up where it's digging in so that the material can move towards the inside of the bend. 20190409_122839 by Anne Froud, on Flickr You can see just how much the material is going to have to stretch to get into the corner. There's also a ton of material at the outside that's going to have to go somewhere. 20190409_122857 by Anne Froud, on Flickr This piece of Delrin helped to move the material into the corner. 20190409_123704 by Anne Froud, on Flickr 20190409_151547 by Anne Froud, on Flickr I didn't go very far each time, it's not worth fighting metal that's work hardened. It's far better to just anneal it again. 20190409_152429 by Anne Froud, on Flickr 20190409_155420 by Anne Froud, on Flickr Although this looks almost done, there were another three cycles before it was all tight against the former. 20190409_162808 by Anne Froud, on Flickr 20190409_162816 by Anne Froud, on Flickr 20190409_165626 by Anne Froud, on Flickr 20190409_165645 by Anne Froud, on Flickr The height gauge has a Carbide blade which is ideal for marking this out... 20190409_203100 by Anne Froud, on Flickr ... and the smaller side of the 'vice on a stick' is ideal for holding it to cut it to size. 20190409_212156 by Anne Froud, on Flickr I'm gradually getting there. I need to be careful because these need to fit nicely together to make welding and Silver Soldering easier, and it needs to be pretty close to the drawing so I can attach it to the flange sealing pieces. 20190409_220737 by Anne Froud, on Flickr
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JonL
Elder Statesman
WWSME (Wiltshire)
Posts: 2,912
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Post by JonL on Apr 10, 2019 13:43:05 GMT
I would never have believed it was possible to form it that accurately. Can you just keep annealing ad infinitum or is there a limit?
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Post by Roger on Apr 10, 2019 14:02:25 GMT
I would never have believed it was possible to form it that accurately. Can you just keep annealing ad infinitum or is there a limit? You can just keep on going, the material recrystalises and you are back where you started. It's important not to keep bashing away because you're damaging the internal structure if you do. Lots of small steps is the way to go. In terms of accuracy, you have to bear in mind that the material has to stretch and shrink in different places, to it will be thinner where it's stretched and thick where it's compressed. If the changes are severe, the change in thickness can be quite marked. When you're working on an outer corner, you knock one part down only to see another part spring up. It's like that game at the fair with the hedgehogs popping out of holes and you knock them down with a mallet! Just keep going and they eventually give up and stay down.
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Apr 10, 2019 17:08:25 GMT
It's like that game at the fair with the hedgehogs popping out of holes and you knock them down with a mallet! Just keep going and they eventually give up and stay down. That seems a very cruel sport at the fairs you attend, Roger
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Post by Roger on Apr 10, 2019 18:02:59 GMT
It's like that game at the fair with the hedgehogs popping out of holes and you knock them down with a mallet! Just keep going and they eventually give up and stay down. That seems a very cruel sport at the fairs you attend, Roger Come to think of it, I think they're supposed to be Moles...
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Post by jon38r80 on Apr 10, 2019 19:25:16 GMT
I thought it was called "bat the rat" or at any rate it was when my daughter was at school
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Post by chris vine on Apr 10, 2019 19:35:36 GMT
It is GWhack a Mole. Arghh!!
Chris.
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Post by Roger on Apr 10, 2019 20:48:06 GMT
I thought it was called "bat the rat" or at any rate it was when my daughter was at school I thought that was the one where you had to hit the rat when it was slit down a drain pipe and you had to react quickly enough to hit it as it came out?
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Post by Roger on Apr 10, 2019 21:01:00 GMT
This is finishing off the outside of the tank coupler. This part is soldered onto the bottom of the tank. 20190410_143327 by Anne Froud, on Flickr I managed to scrap the first two because I messed up on the program and machined all of the flange off! Doh! The 'O' ring seals on the inside of this piece... 20190410_151119 by Anne Froud, on Flickr ... and on the outside of this one which retains it. 20190410_195025 by Anne Froud, on Flickr 20190410_211257 by Anne Froud, on Flickr I've got the balance tube as good as I can get it, so it's time to tack it together. With TIG welding, you either need material pressed on the backside of the joint, or flood it with Argon. Here I've folded a scrap of Mild Steel sheet to clip over the end in an attempt to stop the Argon from the Yellow tube falling straight out again. 20190410_205928 by Anne Froud, on Flickr The other end has a similar restrictor to try to get the tube full of gas. I've got a 3.5 second initial purge on the torch and this auxiliary feed and I've cranked up the flow a fair bit. 20190410_205959 by Anne Froud, on Flickr This way up is a bit easier because the gas is heavier than air so it will sit in the bottom. 20190410_211656 by Anne Froud, on Flickr I've had to wind up the current to 175 Amps for the high and 30 Amps for the low on a 60% mark space ratio to get it hot enough. Copper really sucks away the heat. They must have a mighty powerful welder to do a boiler, or use Nitrogen to get the required heat. 20190410_212153 by Anne Froud, on Flickr Anyway, it's pretty much tacked together, and I'm considering going back and welding it up rather than Silver Soldering it. It's not easy to control the heat, but if I do it in really short runs I think I might be able to do it. 20190410_214145 by Anne Froud, on Flickr
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Post by andyhigham on Apr 10, 2019 21:10:05 GMT
I think Helium gives most heat
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Post by Roger on Apr 10, 2019 21:24:51 GMT
I think Helium gives most heat You're absolutely right, I'm remembering the wrong gas. I asked the Copper Boiler builders at one of the shows if they used Helium, and they said they didn't. I should have asked if they pre-heat the boilers in any way. ..... stop press..... I've just noticed on Steam Technology's facebook post that they do use pre-heat. The boiler they show is very oxidised, it would be interesting to see how clean it looks while they're welding it. I somehow doubt if they pre-heat it in an inert gas, but I might be wrong.
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Post by jon38r80 on Apr 11, 2019 10:36:33 GMT
"I thought that was the one where you had to hit the rat when it was slit down a drain pipe and you had to react quickly enough to hit it as it came out?"
Now you mention it, I am sure you are right!
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Post by Roger on Apr 11, 2019 10:38:55 GMT
So today I had visions of TIG welding all of this up, but immediately cocked it up. Doh! That's left a huge molten blob of copper hanging on the inside. I was being careful, but clearly not careful enough. 20190411_085056 by Anne Froud, on Flickr This is what I should have had there in the first place, a piece of Steel bar wedged with a shim to make it touch the surface. So here I've wound the current right back and had several attempts at getting it hot enough, each time increasing the current until it Just started to melt. Then, as it's melted I've shoved a load of Copper wire into the void and let it cool down to see what I've got. I've filed the top of the lump away. Clearly there's a void on the left and it hasn't fused on the right, but it's a good start. Copper seems to want to create a big pool given half a chance and just melt right through. 20190411_091202 by Anne Froud, on Flickr Here I haven't added any more filler wire, I've just tried to fuse what's already there and close the void. 20190411_091611 by Anne Froud, on Flickr Then it's on to adding a bit more filler wire... 20190411_091809 by Anne Froud, on Flickr ... which clearly hasn't melted right through, there are huge pits in the underside. 20190411_092459 by Anne Froud, on Flickr So I've flipped it over and put some Steel shim against the surface and gingerly stuck the electrode as deep as I can and added more filler wire. That could have ended in tears, but surprisingly went rather well. 20190411_093303 by Anne Froud, on Flickr After about half an hour with an assortment of files, this is the end result. 20190411_102851 by Anne Froud, on Flickr Considering it was a bit of a disaster first thing, I'm pretty pleased with the recovery. A bit of a waste of a morning, but I'm a bit wiser for the experience! 20190411_102927 by Anne Froud, on Flickr Anyway, I've decided it's a bit risky to fully TIG weld it with my level of expertise and the fact that I can't get inside to repair a big hole if I do the same elsewhere. So it can sit in a bath of acid in the corner overnight to reflect on the trouble it's caused me. Tomorrow I'll Silver Solder it!
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Post by jon38r80 on Apr 11, 2019 10:49:21 GMT
Does it realy need to be silver soldered? As it is just a balance piope surely its not under ant significant pressure, just the head of water in the tank, and soldering iit like domestic plumbing would be more than adequate?
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Post by Roger on Apr 11, 2019 11:00:12 GMT
Does it realy need to be silver soldered? As it is just a balance piope surely its not under ant significant pressure, just the head of water in the tank, and soldering iit like domestic plumbing would be more than adequate? That's a good point, but I dislike Soft Solder because it's so weak. I still have the end plates to attach and they need to be robust. I think it's a much more satisfactory solution to Silver Solder it, and I think it's probably easier too. I have to attach two further pipes to the balance pipe to connect the Axle driven pump into the circuit. Again, I'd prefer to Silver Solder those fittings. I think Soft Solder is best avoided anywhere unless it's absolutely necessary. If the Pannier Tanks weren't going to distort, I'd have Silver Soldered those too.
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Post by jon38r80 on Apr 11, 2019 11:25:54 GMT
Its funny how experience colours opinion, I dislike silver soldering but dont mind soft soldering and I havent found it weak (it stands up to watermain and gas main pressure) if there is sufficient contact surface. I tend to resort to silver solder when I cant get a reasonable area of contact between pieces. Soft solder is easier to clean up after. I know from past posting that the opinions on soft soldering widely differ in particular about fluxes you should use. Each to their own.
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Post by Roger on Apr 11, 2019 11:39:37 GMT
Its funny how experience colours opinion, I dislike silver soldering but dont mind soft soldering and I havent found it weak (it stands up to watermain and gas main pressure) if there is sufficient contact surface. I tend to resort to silver solder when I cant get a reasonable area of contact between pieces. Soft solder is easier to clean up after. I know from past posting that the opinions on soft soldering widely differ in particular about fluxes you should use. Each to their own. It's true that a large solder area can give a stronger joint, but just the fact that you can pare it with a craft knife tells how strong it is. I wouldn't want to put a spanner on a fitting that was soft soldered for fear it it shearing. Silver Soldering does take a bit of experience to figure out what works and what doesn't, but that's no different to Soft Soldering really. Agreed it takes more cleaning up if you apply too much Silver Solder, but the trick is not to do that. As you say, each to their own, but now I've figured out how to do it, I rather enjoy Silver Soldering.
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Post by Roger on Apr 11, 2019 20:24:47 GMT
Here's a quick reminder of the sealing arrangement of the balance pipe... Balance pipe seal arrangement by Anne Froud, on Flickr ... this being the inner 'O' ring seal and retainer that's Silver Soldered to the balance pipe. Again it's being machined from the 1/4" Phosphor Bronze bar I bought from eBay 20190410_211257 by Anne Froud, on Flickr It's going to be pretty strong when it's all Silver Soldered together, but the flange is only 0.8mm thick, so I'm machining that... 20190411_200813 by Anne Froud, on Flickr ... on a fixture. 20190411_203436 by Anne Froud, on Flickr So these are the two elements that form the seal. The 19mm 'O' ring is the right calculated size, but it needs to be a bit smaller to make it hug the flat side a bit more else it's going to be hard to assemble. I've ordered an 18mm one to try. You can get them in 0.5mm increments if I need to move either way a little more. 20190411_211406 by Anne Froud, on Flickr
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Post by Roger on Apr 12, 2019 10:28:41 GMT
The balance pipe cleaned up nicely overnight in the Citric Acid bath. I've noticed that resting items on any sort of fire brick tends to damage the surface where they touch, so I wanted to avoid that on the bottom of this. The wire supports are made from Titanium Welding rod which is ideal with its high melting point and not wetting with Silver Solder. 20190412_095509 by Anne Froud, on Flickr I want to be pretty generous with the Silver Solder to guarantee it reaches everywhere through the joint since I can't get to the other side. It will also cover up any minor discrepancies between the two halves. Tippex is being used to keep the pool of Silver Solder in right region. 20190412_100055 by Anne Froud, on Flickr I've laid quite long lengths of Silver Solder wire on the joints, which will inevitably ball up since the Copper blobs from tacking stop it laying flat. I did consider filing those flat first, but thought it would stay put better if I left it until later. 20190412_100727 by Anne Froud, on Flickr 20190412_101155 by Anne Froud, on Flickr I used a pointed piece of Titanium Welding rod to push the molten Silver Solder around to make sure it reached everywhere. 20190412_101405 by Anne Froud, on Flickr It's leaked out a bit in the middle, but it does appear to have flowed where it needs to. You can see some nasty marks on the inside of the tight bend where it took a bit of convincing to form. I'll probably fill those before painting. 20190412_111212 by Anne Froud, on Flickr 20190412_111221 by Anne Froud, on Flickr
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