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Post by Roger on Jun 12, 2020 17:17:00 GMT
Agreed, there's no substitute for practical experience, but let's allow Bob the opportunity to explain how he achieves what most seem to think isn't feasible. I've indicated that I don't expect this to be a 'spraying by numbers' set of instructions. However, it should be possible to give an indication as to the general method and the rate of moving the Airbrush, number of coats etc.
I don't hold with the notion that you just have to pick up the tools and have a go. There are going to be some boundaries on what you should and should not be doing, and that's the sort of indication I'm looking for. Do you thrash the gun back and forth or take ages? See what I mean?
Clearly Bob is doing something different to the rest if he can do this and others can't. I think it's worth exploring how he achieves that.
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Post by Deleted on Jun 12, 2020 17:40:55 GMT
Paint consistency will change each time you use it, hence why to do a test each time...always spray before and after each pass and keep the nozzle at the same distance to the job being painted, ie don't move in an 'arc' motion. Paint mix to thinners will vary according to the paint used and the temperature on the day. Most paints give a baseline to mix too, I tend to use a little less thinners than normal and add some for the final pass to achieve a high gloss. But it still needs a test, the paint needs to be wet enough so that it dries after hitting the job, not on its way in the air. Pressure again depends on the gun, I tend to keep it below 30psi. Chris's book is an excellent introduction to painting and as it's a loco it's more relevant than looking at something like cars being sprayed. It really is one of those skills that develops with practice, it can still go wrong though, as my smokebox/running boards did due to trying to spray and a far too hot a day, close to 40c and with enamel too which likes much lower temps, lower than many might realise.
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Post by simplyloco on Jun 12, 2020 18:00:05 GMT
Agreed, there's no substitute for practical experience, but let's allow Bob the opportunity to explain how he achieves what most seem to think isn't feasible. I've indicated that I don't expect this to be a 'spraying by numbers' set of instructions. However, it should be possible to give an indication as to the general method and the rate of moving the Airbrush, number of coats etc. I don't hold with the notion that you just have to pick up the tools and have a go. There are going to be some boundaries on what you should and should not be doing, and that's the sort of indication I'm looking for. Do you thrash the gun back and forth or take ages? See what I mean? Clearly Bob is doing something different to the rest if he can do this and others can't. I think it's worth exploring how he achieves that. Roger. I never said it can't be done, it is just that it is easier with a mini spray gun. I won't offer any more advice and I'll wait for you to find out on your own... John
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Post by 92220 on Jun 12, 2020 18:17:58 GMT
Hi Folks.
Etching the inside of the airbrush is not a problem at all. It doesn't, while still liquid. The etching action starts once the primer begins to dry. If you leave any 2 pack paint, etch primer, epoxy or polyurethane, in an airbrush, or spray gun, you can chuck it away after 2 to 3 hours, depending on the paint manufacturer's specified drying times. It will dry by chemical action, even though there is no air around it, and it will go hard and never be removable. So using an airbrush to spray etch primer, is no worse than spraying any other type of paint, as long as you clean up after the painting session.
Hi Mike.
You don't need to spend a lot on an airbrush unless you want the fan pattern. A Badger 200 has a bottle reservoir that would allow painting the whole of a 5" boiler, in one go. I think the cost is around £70 from the cheapest supplier. You can buy cheap, bottle fed, double action airbrushes, for around the £20 mark, but how good they are, I don't know. Also, I wouldn't recommend a double action airbrush for a beginner. A single action is far easier to get to know how to use. You may well need to put another coat on later, but that is normal painting practice anyway....multi coats.
Bob.
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Post by Roger on Jun 12, 2020 21:23:10 GMT
As usual, the parts I want pictures of are missing from just about every picture I've got of 1501. However, if you look above the nut on the pipe elbow, you'll just be able to make out a washout plug which is partially covered by the cladding that bridges the gap between the Boiler and the Pannier Tank. IMG_1417 by The train Man, on Flickr There's another pair behind the Safety Valve Bonnet on the bottom edge of this photo. IMG_1415 by The train Man, on Flickr I'm machining these from Mild Steel using the High Speed Spindle. This is the first operaton to create the top surface of the washout surroud and start making the square plug. This is a 2.5mm cutter. 20200612_090825 by The train Man, on Flickr Then it was on to a 1mm cutter to create the square plug to 2mm deep and the inside diameter of the surround. 20200612_133702 by The train Man, on Flickr The whole thing is only 2.2mm deep, but for some reason it looks much deeper. I can't make it deeper than this because there isn't much thickness of insulation before it gets to the boiler surface. Hopefully these will be ok, but until I make the holes for them I can't be sure. 20200612_221052 by The train Man, on Flickr
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Post by 92220 on Jun 13, 2020 9:49:34 GMT
Hi Folks. If you use an airbrush like the Badger 200, with of 50mls bottle feed, it is quite capable of spraying large areas. The spray cone can be adjusted for 1/16" dia right up to at least 2" dia so that is more than enough for painting a 5" g loco. You do need to be able to get 50psi at the airbrush though, for large area painting, and experiment with the amount of thinning for the particular paint you are using. Don't buy an airbrush with a small paint reservoir integral with the main airbrush body. They are fine for small jobs but far too small for large area where you want a lot of paint. If you are able to spend the money on an Iwata airbrush, they have a large gravity fed paint can, and a nozzle for spraying a fan pattern on their top-of the range airbrush. I have a Devilbiss mini spray gun and also a Kite, but neither are likely to be used on the loco. Bob. Hi Bob, There's a lot of skepticism about the use of Airbrushes for painting larger areas, so I wonder if you could give an indication of the technique you would use to get a full gloss finish on say a flat piece measuring 100mm x 100mm which clearly can't be covered by the spray pattern of an Airbrush? The sort of questions that come to mind are these... 1) Just how thin does the paint have to be? 2) How would you set up the Airbrush for that kind of job? 3) How quickly would you expect to traverse across the job? 4) What kind of spray motion would you use? 5) How thick would the coat be in one pass? ie would you expect to get a continuous film or would that only happen when you go back and forth? 6) How many times would you expect to pass over each given spot to achieve the glossy finish. 7) What sort of time would be typical for straying something like this? 30 seconds, 5 miinutes? Obviously each job is different and it's unrealistic to attempt to tie you down on any of these since there are so many variables. However, it's hard to get any kind of handle on what we're talking about here without some expectation of what this job might entail. Hi Roger. Generally you can use 20% thinners but if you use a low pressure you may need more thinners, depending on the consistency of the unthinned paint. There is no 'setting up' of the airbrush if you use a Badger 200, or any other single action airbrush. You just adjust the size of the spray cone to whatever you want - small cone for small parts and up to 2" dia for large areas like tanks. Although, as others have said, it can be difficult to get a good gloss finish on large areas, with an airbrush, it can be done, but needs practice. However, you shouldn't have that problem because you are proposing to use an 'just off gloss' finish, anyway. As far as speed of traverse goes, I have to admit I've never thought about it. It is something you work out for yourself, with practice. However, as a rough starting point, 3 to 4 seconds to traverse 12" is about right, but it depends on how close you are to the job, which is why you need to work it out for yourself, with practice. When spraying, try to keep the airbrush at right angles to the surface being sprayed. That way you get a constant thickness coat. The thickness of paint applied in one coat depends on how thin the paint is and how fast, or slow, you traverse the airbrush, as well as spraying distance. When painting larger areas you will not cover in one coat. Your may need 4 or 5 coats to get a full coverage....again, depending on how thin the paint is and the spraying distance. The thinner the paint, the less glossy the final coat will be. As far as time taken to spray something, that is all dependent on how long it take you to apply a fully opaque coating. Another couple of points to remember..... Airbrush manufacturers recommend spraying from up to 6". Yes, that is fine if you are spraying ink, which is what airbrushes were invented for. To spray a decent coat of paint you should not be further than around 2" from the surface - 3" at the max. Many modelers spray with a pressure of around 20 psi. That is far too low for most jobs except spraying into a tight corner. An airbrush is quite capable of working at anything up to 50 psi (with practice). The higher the pressure, the less thinners you will need to use, and the glossier the final coat will be.You might think that is way too high, but if you use one of the propellant canisters, made for airbrushing, have liquid butane at 50psi inside! Hope that helps Bob.
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Post by Roger on Jun 13, 2020 10:40:37 GMT
Hi Bob, There's a lot of skepticism about the use of Airbrushes for painting larger areas, so I wonder if you could give an indication of the technique you would use to get a full gloss finish on say a flat piece measuring 100mm x 100mm which clearly can't be covered by the spray pattern of an Airbrush? The sort of questions that come to mind are these... 1) Just how thin does the paint have to be? 2) How would you set up the Airbrush for that kind of job? 3) How quickly would you expect to traverse across the job? 4) What kind of spray motion would you use? 5) How thick would the coat be in one pass? ie would you expect to get a continuous film or would that only happen when you go back and forth? 6) How many times would you expect to pass over each given spot to achieve the glossy finish. 7) What sort of time would be typical for straying something like this? 30 seconds, 5 miinutes? Obviously each job is different and it's unrealistic to attempt to tie you down on any of these since there are so many variables. However, it's hard to get any kind of handle on what we're talking about here without some expectation of what this job might entail. Hi Roger. Generally you can use 20% thinners but if you use a low pressure you may need more thinners, depending on the consistency of the unthinned paint. There is no 'setting up' of the airbrush if you use a Badger 200, or any other single action airbrush. You just adjust the size of the spray cone to whatever you want - small cone for small parts and up to 2" dia for large areas like tanks. Although, as others have said, it can be difficult to get a good gloss finish on large areas, with an airbrush, it can be done, but needs practice. However, you shouldn't have that problem because you are proposing to use an 'just off gloss' finish, anyway. As far as speed of traverse goes, I have to admit I've never thought about it. It is something you work out for yourself, with practice. However, as a rough starting point, 3 to 4 seconds to traverse 12" is about right, but it depends on how close you are to the job, which is why you need to work it out for yourself, with practice. When spraying, try to keep the airbrush at right angles to the surface being sprayed. That way you get a constant thickness coat. The thickness of paint applied in one coat depends on how thin the paint is and how fast, or slow, you traverse the airbrush, as well as spraying distance. When painting larger areas you will not cover in one coat. Your may need 4 or 5 coats to get a full coverage....again, depending on how thin the paint is and the spraying distance. The thinner the paint, the less glossy the final coat will be. As far as time taken to spray something, that is all dependent on how long it take you to apply a fully opaque coating. Another couple of points to remember..... Airbrush manufacturers recommend spraying from up to 6". Yes, that is fine if you are spraying ink, which is what airbrushes were invented for. To spray a decent coat of paint you should not be further than around 2" from the surface - 3" at the max. Many modelers spray with a pressure of around 20 psi. That is far too low for most jobs except spraying into a tight corner. An airbrush is quite capable of working at anything up to 50 psi (with practice). The higher the pressure, the less thinners you will need to use, and the glossier the final coat will be.You might think that is way too high, but if you use one of the propellant canisters, made for airbrushing, have liquid butane at 50psi inside! Hope that helps Bob. Hi Bob, That's great, exactly the sort of guidance I need to get started. With regard to the size of gun required to do a job, you wouldn't expect to cover a whole car bonnet with the plume from a spray gun. There are clearly common techniques that are used when you need to cover an area larger than the plume, and that's presumably no different whether you're spraying a large area with a large gun or a small area with a small gun.
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Post by delaplume on Jun 13, 2020 11:18:31 GMT
Hello Roger,
ooo--errr !.............. don't let cro see those washout plugs , LoL !!..............once again dear friend a lovely job...
Just a thought for later on}----- Apart from the 5" gauge loco tools that you actually use when driving, I assume you'll also be making the various scale dedicated tools for this loco ??...... eg... the GWR type coal shovel, pricker, coal hammer, ash paddle etc...One other item that could be added for display purposes would be a large wooden tray with 20 or so holes in......Each hole has a specific boiler location marked on it.........This is used when doing a boiler wash-out and ensures that each plug goes back into the particular location it came from....
Some Tech. spec. taken from E.J.Nutty's handbook on GWR 2-Cyl. Piston valve locomotives...}---- The plugs are made from cast Gunmetal ( or stamped Brass ), are tapered 1 in 8 and threaded 12tpi with a Whitworth form.....Diam. at small end = 1 + 5/16".....increasing by 1/16" increments to 1 + 9/16" for repaired boilers...The length of the threaded portion was 1 + 1/2" ...........The square head was 1" square by 1" long..
I hope that's of some use ??.............
PS}--- Plugs are re-fitted after cleaning, examination etc using some Graphite grease....
Alan
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Post by Roger on Jun 13, 2020 14:22:08 GMT
Hello Roger, ooo--errr !.............. don't let cro see those washout plugs , LoL !!..............once again dear friend a lovely job... Just a thought for later on}----- Apart from the 5" gauge loco tools that you actually use when driving, I assume you'll also be making the various scale dedicated tools for this loco ??...... eg... the GWR type coal shovel, pricker, coal hammer, ash paddle etc...One other item that could be added for display purposes would be a large wooden tray with 20 or so holes in......Each hole has a specific boiler location marked on it.........This is used when doing a boiler wash-out and ensures that each plug goes back into the particular location it came from.... Some Tech. spec. taken from E.J.Nutty's handbook on GWR 2-Cyl. Piston valve locomotives...}---- The plugs are made from cast Gunmetal ( or stamped Brass ), are tapered 1 in 8 and threaded 12tpi with a Whitworth form.....Diam. at small end = 1 + 5/16".....increasing by 1/16" increments to 1 + 9/16" for repaired boilers...The length of the threaded portion was 1 + 1/2" ...........The square head was 1" square by 1" long.. I hope that's of some use ??............. PS}--- Plugs are re-fitted after cleaning, examination etc using some Graphite grease.... Alan Hi Alan, Of course, now that Adam has his mini CNC, he'll be able to make those for himself if he feels to inclined. Oh yes, there will be at least the tools that you see slung across the back of the bunker on the hooks. As for the washout tray, probably not seeing as that would only be in the workshop!
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Post by Roger on Jun 13, 2020 18:13:10 GMT
Finally the half nuts and longer bolts have arrived, so here they are loosely fitted to the cabinet. They're in slots which leaves a bit of a gap, so I've added penny washers to the back which will also spread the load. 20200613_164803 by The train Man, on Flickr I've still had to counterbore the back of the moulded plastic frame, but nowhere near as much as if I'd used full nuts. It's also given room for a washer on top to cover the slot. So the top was loosely put in position and the half nuts tightened by lifting it enough to get an open ended spanner on them. Anyway, the gloves are now fitted too, so it's ready for a run. This is the place it's going to live. It's not ideal, but I can get past it without difficulty and it's easy to move if need be. The garden office is heated with its own radiator throughout the year, so this is much better than what I originally planned. 20200613_185140 by The train Man, on Flickr
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Post by Roger on Jun 14, 2020 13:26:53 GMT
A quick update on the Shot Blaster, using the Gear Frame as the first item that needs the temporary primer removing. 20200614_110700 by The train Man, on Flickr The Cyclone seems to be doing a good job... 20200614_121024 by The train Man, on Flickr ... having collected this in about ten minutes while the cabinet remained completely clear. The lighting is hopeless though, it needs an LED strip all the way round because there's no lighting from the front at the moment and it's too hard to see. 20200614_121049 by The train Man, on Flickr I've obviously missed a bit with the Silicone Sealant, but this appears to be the only place it's leaking. 20200614_121118 by The train Man, on Flickr You can see how the media has migrated onto the edges at the end with the vacuum. I'm not at all happy with the gun they supplied, it doesn't pick up the media very well. I changed the nozzle to a bigger one, but that didn't make any difference. Out of interest, I fitted the gun that I'd designed for the Soda Blaster, and that works way better, so I'll use that for the time being. I think it gives much more suction than the other gun, but it might just be that the much smaller media feed hole at the gun is what's making the difference. In any case, I'm not convinced that the large bore of media feed hose is the right thing for this. It might be worth getting some smaller stuff to see if that works better. Obviously you don't want too high a velocity in the media feed pipe else it might wear away the inside. 20200614_121137 by The train Man, on Flickr Anyway, so far so good, it works well enough to be useful. I've cranked up the RPM on the compressor to 40Hz from my usual 30Hz, but it might well work ok at 30Hz. I'll have to try it. That's how it was originally and it was hopeless... that is until I found there was a massive air leak inside the cabinet on the Tee piece! 20200614_121242 by The train Man, on Flickr I've done quite a bit more blasting now, probably about 50 minutes in total, and in that time the Cyclone picked up about half a cupful of media which I returned to the cabinet. Looking inside Henry's bag, I can't see any evidence of media in there, so that appear to be working really well. I've ordered this and this from eBay to rectify the lighting issue. That's 3 Meters of white LED strip, I bought the damp proof version, which I'll stick on the sheet metal outside of the glass. It would be easier to see if there was less Sunlight because there's a lot of reflection from the surface of the glass. I've also ordered some 10mm clear hose to try for the media feed. I'm wondering if a smaller size will create more turbulence and mixing. The corners have received another dose of Silicone to see if that's where it's leaking. It's actually leaking slightly on all of the corners. The compressor is more than up to the job, I haven't run it flat out because it can produce enough air as it is.
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Post by Roger on Jun 14, 2020 16:21:14 GMT
A few more experiments with the Shot Blaster. 20200614_155037 by The train Man, on Flickr This is the part that convinced me I needed an easier way to remove the old paint and get into all those awkward corners. 20200614_171155 by The train Man, on Flickr You can see the discolouration from welding the backs of the handles... 20200614_155050 by The train Man, on Flickr ... and now you can't. It's not perfect by any means, it will take a bit more work to get it completely even, but it's already probably good enough to paint... 20200614_171144 by The train Man, on Flickr ... except that I can now see that I haven't fitted all of the cosmetic rivets! I'd better get on and do those. I know that none of this is strictly necessary to get a good paint job, but what a game changer this is for cleaning things up that would otherwise be a nightmare. However long you took, I don't think you'd ever come close to preparing it like this by hand.
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Post by Roger on Jun 14, 2020 19:10:18 GMT
I've just created the large cyclone filter as a 'thing' here on thingiverse.com so anyone can print this out and modify it if they wish.
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milky
Seasoned Member
Posts: 120
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Post by milky on Jun 15, 2020 22:12:06 GMT
looking forward to the "tools" especially if the Manor Class carried the same.. they will need scaling up though ![:)](//storage.proboards.com/forum/images/smiley/smiley.png)
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Post by delaplume on Jun 16, 2020 10:16:36 GMT
Hi Roger, I might have missed this earlier on, in which case please accept my apologies but where is the central, upper lamp bracket ??............ I realise the lower three are actually mounted on the buffer beam but that upper one is clearly attached to the bunker platework..... Here is a short video that hopefully will spur you on to final running condition}--------- youtu.be/dlcj1H7HsiA ----- Alan
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Post by Roger on Jun 16, 2020 10:32:06 GMT
Hi Roger, I might have missed this earlier on, in which case please accept my apologies but where is the central, upper lamp bracket ??............ I realise the lower three are actually mounted on the buffer beam but that upper one is clearly attached to the bunker platework..... Here is a short video that hopefully will spur you on to final running condition}--------- youtu.be/dlcj1H7HsiA ----- Alan Hi Alan, This was part of a much earlier discussion. I don't think I'm going to fit the bracket, or at least it won't be there during running because it's going to be a real nuisance. So there are a number of options... 1) Leave it off - Probably the most sensible 2) Fit it - Prototypical but probably would be a nuisance 3) Make it removable - Not easy to make the attachment look right 4) Make it hinged so it can be flipped down while running. I don't think there's an ideal answer. I might make a bracket that just attaches with a magnet for display purposes, but even that will not look right This is how it looks from the inside on 1501, it appears to be welded to the inside of the 'T' shaped stiffener. Bunker inside3 by The train Man, on Flickr
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Post by steamer5 on Jun 16, 2020 10:43:56 GMT
Hi Roger, Make the whole thing from a magnet.....opens it own box of challenges!
Cheers Kerrin
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Post by Roger on Jun 16, 2020 11:28:11 GMT
Hi Roger, Make the whole thing from a magnet.....opens it own box of challenges! Cheers Kerrin Hi Kerrin, Strangely enough, I've tried something like that before, and it's an absolute non-starter. The only way to make a magnet in that shape would be to sinter it from powder. There are some tiny magnets I can use though.
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mbrown
Elder Statesman
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Post by mbrown on Jun 16, 2020 11:32:18 GMT
On both Lyn and the Burma Mines loco, the rear lamp iron would have been a hazard as one reached over to the controls. In both cases, I lowered the lamp iron from the prototypical position to one that still would accept a lamp. On the Burma loco, this created a problem with the lining out - the lamp iron broke up the whole lining scheme..... on balance, I think I should have adopted Roger's approach and left it off. In any case, when coupled to a train of any kind (including a driving truck!) there shouldn't be any lamps on the rear brackets anyway!
Malcolm
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barlowworks
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Now finished my other projects, Britannia here I come
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Post by barlowworks on Jun 16, 2020 13:54:55 GMT
Would it be possible to make a small pocket inside the bunker for it to drop into and then it would be removable.
Mike
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