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Post by Roger on Jun 4, 2020 21:05:14 GMT
When I first saw it I imagined that the plastic "cup holder" that you have made was for holding a wheel or wheel assembly for painting but I dont expect to be right. Hi Jon, I can see why you might think that, but no, it's not that either.
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uuu
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Post by uuu on Jun 5, 2020 6:12:31 GMT
Just a resting place for the spray gun?
Wilf
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Post by ettingtonliam on Jun 5, 2020 6:38:27 GMT
Either, as Wilf says, a resting place for the spray gun, or a holder for the paint tin.
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Post by Roger on Jun 5, 2020 6:44:16 GMT
Either, as Wilf says, a resting place for the spray gun, or a holder for the paint tin. Aha! Yes, for paint tins... but why?
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uuu
Elder Statesman
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Post by uuu on Jun 5, 2020 6:51:33 GMT
For a better timbre when drumming?
To stop leaving rings on the Chippendale?
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Post by springcrocus on Jun 5, 2020 7:02:03 GMT
Stand the tins in your ultrasonic cleaner (with a little liquid) to mix your paint. The ring will protect the base of the tank. Regards, Steve
Edit: been doing my little humbrol tinlets for some time.
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Post by Roger on Jun 5, 2020 8:02:30 GMT
Stand the tins in your ultrasonic cleaner (with a little liquid) to mix your paint. The ring will protect the base of the tank. Regards, Steve
Edit: been doing my little humbrol tinlets for some time.
Closest yet Steve, but it's not for the ultrasonic tank...
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don9f
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Les Warnett 9F, Martin Evans “Jinty”, a part built “Austin 7” and now a part built Springbok B1.
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Post by don9f on Jun 5, 2020 8:28:28 GMT
Does it fit the tee slots of your miller, then program it to do the paint mixing?
Don
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Post by runner42 on Jun 5, 2020 8:31:35 GMT
For holding the paint tin whilst it is underneath the pillar drill or milling machine which is operating a shaped stirrer. For thoroughly mixing the paint.
Brian
PS It looks like Don has beat me to the answer. The programming is to provide a figure of eight motion.
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Post by Roger on Jun 5, 2020 10:00:52 GMT
Well guessed chapsl. I'm not surprised you thought it might be for the Mill, since I use it for everything else! The feet clip firmly in the slots in the table, and the small paint tin fits in the through hole and sits on the table... 20200605_095744 by The train Man, on Flickr ... while the larger tin sits on the step. They just nip the cans so I won't have to struggle to get them in or out. Bob mentioned that I need to make a stirer out of rod and spin that for some time at speed to ensure thorough mixing. He noted that a lot of painting issues can be traced back to poor mixing, so I don't want to fall foul of that most basic requirement. I don't want to stand there and hold the cans for half an hour or more, and I could see it ending up painting the workshop and floor unless something was done to make it stay put. So, mystery solved. It's obvious when you know the answer! 20200605_095803 by The train Man, on Flickr
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Post by 92220 on Jun 5, 2020 10:21:40 GMT
Nice one Roger!!! What a brilliant idea!!! I shall have to make one. You won't need half an hour mixing. With the wire mixer, at around 1000 rpm, or the highest you can run without the paint spilling over, the paint will mix thoroughly in around 5 minutes.
Bob.
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Post by Roger on Jun 5, 2020 10:45:50 GMT
Nice one Roger!!! What a brilliant idea!!! I shall have to make one. You won't need half an hour mixing. With the wire mixer, at around 1000 rpm, or the highest you can run without the paint spilling over, the paint will mix thoroughly in around 5 minutes. Bob. Thanks Bob, that's how bad my memory is, I thought you'd said much longer! Still, it took all of ten minutes to design and start printing, so I think it was worth doing. I don't suppose there's any harm in leaving it for longer.
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Post by ettingtonliam on Jun 5, 2020 13:36:01 GMT
Oh Roger, you disappoint me! I'd have thought you would have whipped up one of those machines the DIY stores have that grip the tin and shake it up and down!
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Post by Roger on Jun 5, 2020 15:44:42 GMT
Oh Roger, you disappoint me! I'd have thought you would have whipped up one of those machines the DIY stores have that grip the tin and shake it up and down! Well, I won't rule that out if this doesn't work!
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Post by Roger on Jun 5, 2020 21:02:14 GMT
Ok, that's all of the screws filled in so now I need to be thinking about preparing this for painting. So I have a few key questions about that as follows... 1) Should I be filling in all of those holes with little pegs to stop paint getting in? Things like matchsticks and tooth picks spring to mind for the smaller ones if so. 2) Should I fit the stretchers, cylinders and gear frames and scribe lines around them so I can see the extent of the masking? I'm assuming that these won't even have etch primer on them, they'll just be bare metal? What stops those from rusting? 3) I presume that I'll need to mask the horn block bearing surfaces to make sure they don't get damaged by the grit blasting? 4) I presume I also need to mask any areas I've used filler on so protect them from the grit blasting too? 20200605_212838 by The train Man, on Flickr 20200605_212855 by The train Man, on Flickr
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Post by 92220 on Jun 5, 2020 21:14:26 GMT
Hi Roger.
Don't bother making one of those. They only work because there is no settled sediment in the tin. It's all liquid and the pigments already in suspension. The little wire mixer scrapes the settled pigment up off the bottom of the tin and mixes it in. Shaking just won't do that. As far as leaving the mixer in longer than the suggested 5 minutes. It won't do any harm at all.
As a little bit of an expansion on that, as far as you remembering the half hour mixing time, that is how long it takes to mix a tin of paint and get every bit of pigment fully into suspension....and that is using a spatula shaped hand mixer. Just as a point to add to that, if you use a screwdriver to mix paint, like some try to do, that will NEVER mix in all the pigment, because being a thin, round, 'blade', it just cuts it's way through the paint and doesn't cause it to move around the tin to get the pigments up into suspension, unless it is moving at the sort of speed the little wire mixer in the pillar drill does.
Edit: Sorry, this ended up not in the place I expected. I was referring to not bothering to make the gadget for shaking the paint tin, like they use in the decorators store.
As far as filling in the drilled holes before painting, that is really up to you. I assembled my frames, then grit blasted them, then gave them a coat of Corroless 'S' Rust Stabilising Primer, then applied the top coat. That was 18 years ago and not a trace of corrosion now. 2-pack etch primer would do the same as the rust stablilising primer, because it has a high proportion of phosphoric acid in the activator, that should kill any flash rusting that appears after blasting, though with the current weather, flash rusting is less likely.
Bob.
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Post by Roger on Jun 5, 2020 21:41:10 GMT
Hi Roger. Don't bother making one of those. They only work because there is no settled sediment in the tin. It's all liquid and the pigments already in suspension. The little wire mixer scrapes the settled pigment up off the bottom of the tin and mixes it in. Shaking just won't do that. As far as leaving the mixer in longer than the suggested 5 minutes. It won't do any harm at all. As a little bit of an expansion on that, as far as you remembering the half hour mixing time, that is how long it takes to mix a tin of paint and get every bit of pigment fully into suspension....and that is using a spatula shaped hand mixer. Just as a point to add to that, if you use a screwdriver to mix paint, like some try to do, that will NEVER mix in all the pigment, because being a thin, round, 'blade', it just cuts it's way through the paint and doesn't cause it to move around the tin to get the pigments up into suspension, unless it is moving at the sort of speed the little wire mixer in the pillar drill does. Edit: Sorry, this ended up not in the place I expected. I was referring to not bothering to make the gadget for shaking the paint tin, like they use in the decorators store. As far as filling in the drilled holes before painting, that is really up to you. I assembled my frames, then grit blasted them, then gave them a coat of Corroless 'S' Rust Stabilising Primer, then applied the top coat. That was 18 years ago and not a trace of corrosion now. 2-pack etch primer would do the same as the rust stablilising primer, because it has a high proportion of phosphoric acid in the activator, that should kill any flash rusting that appears after blasting, though with the current weather, flash rusting is less likely. Bob. Hi Bob, I'm trying to picture the stirrer spinning round, and I imagine that it's not touching the bottom or getting into the corners of the can. Does the stirrer being close to the bottom cause enough turbulence to free anything that's settled on the bottom of in the corners? Should I be scraping the bottom of the can with a screwdriver to loosen any pigment that may have settled before stirring? So have you painted all of the frame faces, even where the cylinders and stretchers mate? I thought from previous discussions that it was better to make these metal to metal so they were dimensionally accurate and also that the paint didn't creep under heat and load? When you say priming and then the top coat, is that how I'd expect to do it, ie just one top coat? I thought that rivets would show that dip around the edges if you didn't use several thin coats?
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dscott
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Post by dscott on Jun 5, 2020 22:37:59 GMT
Stirred NOT SHAKEN So we have been told the wrong way for years!!! Unless you own some lovely books on painting! Having some practice bits also helps especially with corners and deep holes where the surroundings get more paint and the inside gets very little. ibb.co/TYCKwjfA little practice in the garden on some inside bits goes a long way. Using several light coats on a NON GRIT BLASTED surface. Yes a long road to recovery but everything is construction and painting after we were down to BARE FRAMES!! David and Lily.
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Post by Roger on Jun 6, 2020 7:48:27 GMT
Stirred NOT SHAKEN So we have been told the wrong way for years!!! Unless you own some lovely books on painting! Having some practice bits also helps especially with corners and deep holes where the surroundings get more paint and the inside gets very little. ibb.co/TYCKwjfA little practice in the garden on some inside bits goes a long way. Using several light coats on a NON GRIT BLASTED surface. Yes a long road to recovery but everything is construction and painting after we were down to BARE FRAMES!! David and Lily. Hi David, Thanks for the advice. Actually, I do have books, and I need to dust them off and start seriously engaging with what they say.
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Post by 92220 on Jun 6, 2020 8:24:05 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.
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