jma1009
Elder Statesman
Posts: 5,913
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Post by jma1009 on Jun 6, 2020 23:22:37 GMT
Hi Roger,
It's just gloss black enamel!
You have a black BR (ex GWR design) shunting loco with signal red in between the frames and on the buffer beams that was all applied in 'A' shop as the loco was being assembled with fitters still adding bits.
We can argue over whether signal red was used between the frames; it was probably red oxide varnished over, but it might have been new paint from a tin at the time of signal red.
(I hesitate to contradict Bob. He has been of immense help to myself and Jim Scott; though his swatches of LBSC Stroudley IEG have caused quite a lot of comment privately.)
But stirring a paint of gloss black enamel isn't that difficult!
Cheers,
Julian
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Post by Roger on Jun 7, 2020 5:59:33 GMT
Hi Roger, It's just gloss black enamel! You have a black BR (ex GWR design) shunting loco with signal red in between the frames and on the buffer beams that was all applied in 'A' shop as the loco was being assembled with fitters still adding bits. We can argue over whether signal red was used between the frames; it was probably red oxide varnished over, but it might have been new paint from a tin at the time of signal red. (I hesitate to contradict Bob. He has been of immense help to myself and Jim Scott; though his swatches of LBSC Stroudley IEG have caused quite a lot of comment privately.) But stirring a paint of gloss black enamel isn't that difficult! Cheers, Julian Hi Julian, I really don't know anything about the Science of paint, how pigments are made or added, or what happens to them when you leave them to stand for long periods. Oil isn't black, so presumably there's pigment of some kind in Gloss Black to make it black? It seems to me that paint always needs stirring, it says so on every can I've ever come across, and to that end it seems sensible to stir it thoroughly. Whether it's Gloss Black or any other colour, I'll give it the same stirring treatment and then there can't be a problem. I'm not sure why this is seen to be controversial.
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Post by 92220 on Jun 7, 2020 9:29:22 GMT
Hi Roger. When the mixer is in the tin and it is held in the jig you printed, just gently bring down the drill quill, while revolving, to just rub on the bottom for a few seconds. The mixer will get close enough into the corner to drag out the pigment. Unless the paint has been standing for 2 or 3 years, the pigment won't have gone so hard that a few seconds won't get it loosened. If it is old paint, either break it loose with a screwdriver, as you suggested, or just run the mixer scraping the bottom for around half a minute, at around 1000 rpm. Once loosened, raise the mixing speed to the highest you can without the paint vortex coming over the edge of the tin and painting the workshop. If the mixer just fits through the top of the tin, the max speed is around 1500 rpm. If the mixer is small enough to fit a 50mls tin but you are mixing a 250mls tin, raise the mixing speed to around 2000. Make sure the mixer is always fully immersed while revolving. When i painted my frames, I made a metal plate to match the mounting flange of the cylinders and bolted that in place of the cylinders, to mask the area. Any masking would do for this, and you are right. Cylinders should be metal to metal, as should the rest of the frames assembly. Then I masked the sliding surfaces of the horns. Everything else got painted. This is where bead blasting is better than grit blasting. With grit blasting, any dampness in the air can cause flash rusting within seconds. Bead blasting doesn't have anywhere near such an aggressive action and flash rusting is much less likely. You are right in thinking that a number of thinner coats are better than one thick one. Just remember though that using several coats of a colour to get the paint thickness, will give you less than a full gloss finish. That might actually be what you want. Using several thin coats, built up, can give almost any finish from eggshell up to around a 90% gloss. If applying several coats, it is worth experimenting to see what sort of finish you will get as it depends on how thin the paint is, what air pressure you are using, and how far away from the surface the spray nozzle is. Spraying distance can vary the final paint finish from full matt to full gloss too, so it is important when using several coats of thinned paint, to try and keep the spraying distance as near constant as possible. This is not recommended for anyone wanting a matt finish though as the paint will have partially dried between gun and surface, and will lose adhesion. For our work, the ideal spraying distance is around the 2" (50mls) mark, and definitely not more than 3". The amount of thinning and the air pressure should be adjusted to enable spraying at this distance and achieving the wet surface without runs. You can tell if you are too far away as the sprayed surface should appear wet, to flow out, for a short while after the spray cone has moved on, but not wet enough for the paint to make runs. I'm afraid it's practice practice practice, to get the perfect finish. Starting with the frames is good because the finish can be anything from mediocre to excellent and generally they look the same after everything is fully assembled. It's the boiler, tanks and cab that everyone focuses on! Bob. Hi Bob, That's great, I'll make two mixers for the two sizes of tins. I've got both gloss and matt black which I intended to use to have a less glossy finish on the frames. Actually, I don't like the full gloss look on the rest of the locomotive. There was a locomotive like that at the Midlands ME Exhibition, and it really put me off the idea. It looks to Toy like in my opinion, and it must be a nightmare to keep looking good. I'd prefer to take that excessive gloss away. I presume you like the Air Brush for jobs like this because you can work your way around the shapes and angles from a relatively short distance away. It's hard to see how you'd use a larger gun on the inside of the frames and still get into the corners. Would you still use the Air Brush for the Pannier Tanks, even though the sides are quite large areas? The ends and tops have brackets and steps, so I can see why you would want to use the Air Brush for those. It's certainly going to be interesting. Hi Roger. Yes I would use a bottle fed airbrush for all the spraying. It is much more controllable than a fullsize spray gun. Even the half size ones are still unweildy compared to the airbrush. A bottle full of paint, in the aibrush, should be more than enough to paint one side tank, though I wouldn't fill it more than half full as there is a tiny airhole in the lid, and when full, paint can leak out when the airbrush is pointing downwards. The airbrush can also give a much finer finish than a fullsize spray gun. Bob.
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Post by 92220 on Jun 7, 2020 9:41:33 GMT
Hi Roger.
What Chris suggests is the best way to go. Don't varnish over the whole surface, just lip the vanish over the transfers and JUST ENOUGH over the edge of the transfer to seal the edges, but not enough to be obvious. The reason for varnishing transfers is that the adhesive is a very mild one that dampness in the air can cause loss of adhesion. Also, as Dave (kipford) says, applying transfers to gloss (or just off gloss) is best. Trying to apply them to a matt finish will cause problems due to the microscopic 'dustyness' of the matt surface. The transfer adhesive isn't strong enough to hold the transfers down effectively on the matt finish. The way all paints are made matt is that micronised talc is mixed into the gloss paint, and when it is painted out and dried, the microscopic crystals (between 5 and 0.5 micron) project from the surface of the gloss paint, and reflect light in all directions, so the eye sees it as a matt finish. These crystals break up very easily and become dust on the surface, spoiling the adhesion of the transfers.
Bob.
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Post by 92220 on Jun 7, 2020 10:20:30 GMT
Hi Roger.
In simple terms, all paints are made by adding powdered pigment to a varnish carrier. The pigment powder gets thoroughly mixed in and micronised during manufacture, but after being tinned, it can stand for a long time before being used. How many times have we bought a tin of paint to paint something in the house and then put the lid back on and stuck it away in a cupboard because only a few brushfulls have been used. 3 years later we get the tin out again, and because the tin is, for all practical purposes, still full, the paint is still liquid and able to be used. When you take the lid off the first thing you notice is that the paint doesn't look anything like the colour it should. In fact it will look like a murky tin of varnish. The pigment, over the time it has been stored, will have settled towards the bottom of the tin. It may well not have packed down hard, but the concentration of pigments will be far greater towards the bottom of the tin, than it is at the top. In fact after about 12 months storage, the pigment concentration at the top of the tin will be around 25% to 50% of what it is when it comes off the production line. Leave it for 3 years and the pigment concentration will be near 0% at the top of the tin. As far as making Black paint goes, it's no different to making Vermilion paint, basically. It is a coloured powder mixed into a clear varnish, along with other chemicals. When I was making paint, I bought 50Kg bags of carbon black pigment, mixed it into the resin, added driers and solvents to thin the mixture, added surfactants to help the resins adhere to the pigment, and in turn adhere to to painted surface. The whole mix was them passed through the bead mill 2 or 3 times, until the pigment size was sub micron. All paints will settle out over time so you are quite right, to make your tin holder and mixer, for the painting. Anyone who doesn't mix thoroughly will NOT get the ultimate finish.
Others might disagree with me but I do have over 30 years actually making paints from basic raw materials, and sorting out model engineers and modellers painting problems. Keep up the good work and keep posting. You are approaching the painting in exactly the right way!!
Bob.
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Post by 92220 on Jun 7, 2020 10:29:20 GMT
Hi Julian.
As far as the Red paint used between the frames on BR locos goes, the official BR livery drawing specifies the Red between the frames as (quote) B.S.colour No.537 Signal Red. The colour is also specified for the buffer beams and buffer casings. Right at the end of steam, though, I would guess you are right that they would have used whatever was available rather than order in a new tin of paint.
Bob.
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Post by Roger on Jun 7, 2020 10:30:25 GMT
I left the axlebox reservoir filled with oil overnight with the hornblock holes exposed, and there was no evidence of oil finding its way through the 0.4mm diameter holes. I presume that the surface tension is enough to keep the oil from passing through, so I decided to open them out to a much larger size ie 1mm Don't forget that the oil holes for these are still well above the bottom of the reservoir, so there's no way this oiling will starve the axles which will continue to get fed oil until the bottom part of the reservoir is empty. The idea is just to guarantee that the normal filling of the reservoirs also adds a little to the horn blocks without having to ever oil them explicitly. I really didn't want to split the axleboxes to do this, so I just added a couple of holes in a big piece of Steel to support the axleboxes while opening them out. 20200607_092323 by The train Man, on Flickr 20200607_092333 by The train Man, on Flickr 20200607_093345 by The train Man, on Flickr This last one couldn't be reached with the pin chuck, so I quickly knocked up a 1mm extension to do these last two. 20200607_110041 by The train Man, on Flickr 20200607_110445 by The train Man, on Flickr And this is how it looks, both on the inside and outside. 20200607_111416 by The train Man, on Flickr Yes, I know this is wholly unnecessary, and how hard is it to oil the horns once in a while? Absolutely true, but it's fun to experiment and do something just for the joy of doing it!
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Post by silverfox on Jun 7, 2020 10:35:19 GMT
Bob
Great reading
Is there aan brush you would recommend? I know there are two types? one with a little bowl on the top and the other with a glass jar that crews in from the bottom.Are they any pros and cons on either? I would rather do some checking forst than buy one only to find it is a wrong'un!!
Ron
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Post by Roger on Jun 7, 2020 14:50:56 GMT
So here are the axles with the close fitting fine gauze filters trapped under the reservoir covers. I've cleaned the oil from the faces where the Red Threadlocker drops are. I shouldn't ever need to remove these again, but it should be possible with a little lever inserted into the feed hole to break the Threadlocker. I held these down with thin parallels resting on top of the covers after the photo was taken because they wanted to spring up. 20200607_154416 by The train Man, on Flickr
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Post by coniston on Jun 7, 2020 20:00:24 GMT
Hi Roger, when I painted my Manor after a complete rebuild, I fitted all stretchers in place before painting, you really shouldn't get any rust problems unless you had assembled them in a very damp atmosphere. I assembled the cylinders after painting, they had gaskets anyway so I considered a thin coat of paint wasn't going to make any difference. Yes you will need to mask the bearing surfaces before grit blasting, you can keep the masking in place for painting if it is still ok. I didn't grit blast so used petroleum jelly on the bearing surfaces to keep the paint off, just wiped it all off after painting. Definitely practise on something to get the hang of the process and to get the spray gun adjusted to suit your technique. Have fun it is really quite rewarding when you see the results.
Chris D
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Post by Roger on Jun 7, 2020 21:19:10 GMT
Hi Roger, when I painted my Manor after a complete rebuild, I fitted all stretchers in place before painting, you really shouldn't get any rust problems unless you had assembled them in a very damp atmosphere. I assembled the cylinders after painting, they had gaskets anyway so I considered a thin coat of paint wasn't going to make any difference. Yes you will need to mask the bearing surfaces before grit blasting, you can keep the masking in place for painting if it is still ok. I didn't grit blast so used petroleum jelly on the bearing surfaces to keep the paint off, just wiped it all off after painting. Definitely practise on something to get the hang of the process and to get the spray gun adjusted to suit your technique. Have fun it is really quite rewarding when you see the results. Chris D Hi Chris, How did you spray paint evenly over the stretchers? I can picture spraying flat surfaces, but ones with faces at 90 degrees to each other and with nooks and crannies could be really challenging. So your cylinders bolt to the frames with gaskets in between? I was warned of that idea, but it's something I quite liked the idea of. I think the argument was that the gasket would relax and the cylinders might become loose. I wanted to do it more from a heat transfer point of view, to stop heat being transferred into the frames. I wonder what they did in full size? Anyway, I'm sure a lot of the painting issues will resolve themselves when I come to do it. I'm actually rather looking forward to it. I've just ordered a half mask with respirator filters, but that's going to take a couple of weeks to arrive. I didn't want a full mask because being a glasses wearer, I know that it's really hard to keep them from steaming up even with a simple face mask. All good fun!
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Post by springcrocus on Jun 7, 2020 22:02:54 GMT
I bought one of THESE for wish I can buy different filters to suit the application. I also wear glasses and have no problem using this mask.
Regards, Steve
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Post by steamer5 on Jun 7, 2020 22:54:37 GMT
Hi Roger, Quick question, I guess you opened the holes up in your lids for the axel boxes that feed the horns? I just looked back & the picture you posted of them looked like they were the same size as the 4 small holes at 0.4.
Cheers Kerrin
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dscott
Elder Statesman
Posts: 2,440
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Post by dscott on Jun 7, 2020 23:58:49 GMT
ibb.co/zZ1Ct1BAnd we find the picture yesterday of Kens wonderful oiling system. Sorry Model Engineer if it is still under Copyright from 1970. Fair and personal use. It is just superb and for anyone turning up at the track just a quick splosh into the box and we are off. None of this "I can't reach the eccentrics so I will blast half a pint in the general direction and hope for the best. All you will succeed in doing is to upset the 3 1/2" Boys and girls. This seems to give a nicely balanced amount. I expect the heat will help move the oil in the pipes. OH and just before Roger and I get to paint our frames. Well at least we are not racing out and onto a track anytime soon. David and Lily.
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Post by Roger on Jun 8, 2020 8:01:42 GMT
Hi Roger, Quick question, I guess you opened the holes up in your lids for the axel boxes that feed the horns? I just looked back & the picture you posted of them looked like they were the same size as the 4 small holes at 0.4. Cheers Kerrin Hi Kerrin, If you put the two photos next to each other like this, you can see the difference. In the first one, the hole is almost invisible. 20200606_215118 by The train Man, on Flickr 20200607_111416 by The train Man, on Flickr
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Post by Roger on Jun 8, 2020 8:04:05 GMT
I bought one of THESE for wish I can buy different filters to suit the application. I also wear glasses and have no problem using this mask.
Regards, Steve
Hi Steve, I didn't see that one. This is the one I ended up buying on eBay.
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uuu
Elder Statesman
your message here...
Posts: 2,846
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Post by uuu on Jun 8, 2020 9:20:42 GMT
Darth Froud!
Speedy... (suck blow) I am your father.
Wilf
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barlowworks
Statesman
Now finished my other projects, Britannia here I come
Posts: 877
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Post by barlowworks on Jun 8, 2020 9:40:24 GMT
Hi Roger
A handy tip I picked up about spraying anything black is after priming to go over all the edges with a black permanent marker so the primer doesn't show through on the edges.
Mike
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Post by Roger on Jun 8, 2020 14:36:04 GMT
Another small step forward. Today I've found all of the pieces necessary to hook up the Hydrovane compressor to the Airbrush even though the compressor is in the Workshop and the spraying is going to be done in the Garden Office. The only parts I've had to make is the M5 x 0.5 (fine) male thread and tap a mating thread in a 6mm push fit adaptor so I can use 6mm clear tube between the regulator and the small tube of the Airbrush, and an 1/8" BSP bung. I've got a whole reel of 8mm clear hose, so I've drilled a hole in the walls and fed that to where it's needed. I've just fired this up and it works a treat. 8mm pipe is plenty big enough since the compressor is pushing out 100psi and I need less than half that for that Airbrush. I've also tried the freeze drier that's mounted on top of the compressor and is never used. That seems to still be functioning after being idle for over ten years, so that's a big bonus. 20200608_151742 by The train Man, on Flickr
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Post by Roger on Jun 8, 2020 20:31:49 GMT
More preparatory work for shot blasting and painting. This time it's pieces of the M3 threaded rod I bought for the job being cut to length ready for attaching to various pieces that can be supported that way. Thanks to Chris Vine for this idea. The first of the three larger rods has an M3 thread, but the idea is to tap the others with the other sizes required to hold smaller parts. The large bush on the left has an M8 to M3 thread conversion so that can be attached to the handle and motorised turning arrangement. 20200608_212408 by The train Man, on Flickr I've done the same for the Balance pipe, with an M8 x 0.75 (fine) thread on one end to mate with the fitting and M8 to attach to the turning arrangement. I'm sure there will be many more of these as I progress, but hopefully most of them will only need to be made once and re-used for different parts. I've got other threaded rod and long bolts so I can do the same for other sizes as they arise. 20200608_212433 by The train Man, on Flickr
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