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Author Topic: Oxcott [Thames valley 1989/Network SouthEast]  (Read 13960 times)

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Online njee20

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Re: Oxcott [Thames valley 1989/Network SouthEast]
« Reply #225 on: April 17, 2020, 11:47:08 AM »
Airbrushes lay down a very thin layer of paint. You have immeasurably more control over them than an aerosol, which just aren’t designed for detail. You do still need to mask etc to stop errant paint, but you won’t have that same issue of a ‘step’ at the edge of the paint.

Clean up can be a pain I admit, but the compressor occupies a space about 8” cubed. You have a vast shed with two behemoth layouts, surely you can fit in an airbrush compressor?!

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Re: Oxcott [Thames valley 1989/Network SouthEast]
« Reply #226 on: April 17, 2020, 12:08:16 PM »
Airbrushes lay down a very thin layer of paint. You have immeasurably more control over them than an aerosol, which just aren’t designed for detail. You do still need to mask etc to stop errant paint, but you won’t have that same issue of a ‘step’ at the edge of the paint.

I am having some trouble understanding this in the context. A certain thickness of paint is necessary in order to cover the black of the underlying plastic. This thickness is achieved by multiple coats. This is necessary both with brushing and with aerosol spraying.

Thus, if an airbrush were to give a thinner coat than an aerosol, it would simply require more coats to cover the black and the overall thickness would be the same, and thus the step issue would also be the same.

Thus, I do not understand how an airbrush can assist with this specific issue. Is there something specific that I am missing in this understanding?
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Re: Oxcott [Thames valley 1989/Network SouthEast]
« Reply #227 on: April 17, 2020, 12:44:10 PM »
You’re talking about microns of thickness. An aerosol is a blunt instrument and isn’t just pure pigment, there’s other “stuff” you’re spraying onto the model. You could say the same with brush painting. If you needed x microns of coverage regardless of application then you’d get the same result brush painting as spraying.

There’s a reason no professional resprayer worth their salt uses aerosols for detail work.

If I may turn it around you’ve been told it numerous times on RMWeb and here, why do you still think an aerosol is just as good?

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Re: Oxcott [Thames valley 1989/Network SouthEast]
« Reply #228 on: April 17, 2020, 01:22:28 PM »
You’re talking about microns of thickness. An aerosol is a blunt instrument and isn’t just pure pigment, there’s other “stuff” you’re spraying onto the model. You could say the same with brush painting. If you needed x microns of coverage regardless of application then you’d get the same result brush painting as spraying.

There’s a reason no professional resprayer worth their salt uses aerosols for detail work.

If I may turn it around you’ve been told it numerous times on RMWeb and here, why do you still think an aerosol is just as good?

To answer your question, because I have not had a clear and satisfactory explanation of the basis on which an airbrush is superior for the specific applications that I have in mind.

I am afraid that I still do not follow the explanation. To my understanding, the paint in an aerosol can and the paint in a tin (for either hand brushing or airbrushing) consists of broadly three components: (1) pigment; (2) thinner/solvent; and (3) additives, such as matting/flatting agent. When applied to the surface, the thinner/solvent evaporates, leaving the pigment (and possibly some of the additives - I am not sure whether the matting agent works by remaining in the pigment layer or evaporating).

To cover a black area with yellow paint, a certain thickness of pigment is required, as the yellow pigment (in particular) is slightly translucent. That thickness of pigment is so great that it will leave a visible ridge if there is a hard line between the painted and unpainted area. It is difficult to see how it is possible for the method of application to alter these basic physics.

The only way of mitigating this effect is to have a gradual transition between the over-painted and the factory painted area. This can be achieved with hand brushing. On a much larger model, it could possibly be achieved by very skilful use of an airbrush, but I doubt that this is realistically possible in N gauge (and if it is, the skill level required would be beyond what is realistically achievable for me).

For my understanding, the reasons that people especially serious about painting often use an airbrush are:

(1) more control is possible, giving more ability to influence subtly the finished effect and also to spray in specific areas, which is useful for weathering and freehand painting;
(2) a greater range of paints are available for use with airbrushes than with aerosol cans; and
(3) less paint is wasted because the airbrush tends to spray a narrower area.

Of those things, only (1) is potentially relevant to this issue, and, as described above, it is not clear from the information that I have that this would make any difference to the particular issue that I am having.

The issue is not that the aerosol can makes a very thick layer: it does not. Each individual coat of the aerosol paint (at least, the Railmatch paint that I am using) is extremely thin. However, because it is so thin, a very large number of coats are needed to cover the black of the underlying plastic exposed by modifications to the model. There is still no explanation of why this number of coats would need to be any fewer with an airbrush. It is very doubtful that there would need to be any fewer coats.

Thus, whilst airbrushes no doubt do have significant advantages in some very specific ways, I remain extremely sceptical that using one will solve this specific problem, not least because no intelligible explanation has been given as to how it is possible for the use of an airbrush to solve this problem.
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Re: Oxcott [Thames valley 1989/Network SouthEast]
« Reply #229 on: April 17, 2020, 02:17:06 PM »
You’re talking about microns of thickness. An aerosol is a blunt instrument and isn’t just pure pigment, there’s other “stuff” you’re spraying onto the model. You could say the same with brush painting. If you needed x microns of coverage regardless of application then you’d get the same result brush painting as spraying.

There’s a reason no professional resprayer worth their salt uses aerosols for detail work.

If I may turn it around you’ve been told it numerous times on RMWeb and here, why do you still think an aerosol is just as good?

To answer your question, because I have not had a clear and satisfactory explanation of the basis on which an airbrush is superior for the specific applications that I have in mind.

I am afraid that I still do not follow the explanation. To my understanding, the paint in an aerosol can and the paint in a tin (for either hand brushing or airbrushing) consists of broadly three components: (1) pigment; (2) thinner/solvent; and (3) additives, such as matting/flatting agent. When applied to the surface, the thinner/solvent evaporates, leaving the pigment (and possibly some of the additives - I am not sure whether the matting agent works by remaining in the pigment layer or evaporating).

To cover a black area with yellow paint, a certain thickness of pigment is required, as the yellow pigment (in particular) is slightly translucent. That thickness of pigment is so great that it will leave a visible ridge if there is a hard line between the painted and unpainted area. It is difficult to see how it is possible for the method of application to alter these basic physics.

The only way of mitigating this effect is to have a gradual transition between the over-painted and the factory painted area. This can be achieved with hand brushing. On a much larger model, it could possibly be achieved by very skilful use of an airbrush, but I doubt that this is realistically possible in N gauge (and if it is, the skill level required would be beyond what is realistically achievable for me).

For my understanding, the reasons that people especially serious about painting often use an airbrush are:

(1) more control is possible, giving more ability to influence subtly the finished effect and also to spray in specific areas, which is useful for weathering and freehand painting;
(2) a greater range of paints are available for use with airbrushes than with aerosol cans; and
(3) less paint is wasted because the airbrush tends to spray a narrower area.

Of those things, only (1) is potentially relevant to this issue, and, as described above, it is not clear from the information that I have that this would make any difference to the particular issue that I am having.

The issue is not that the aerosol can makes a very thick layer: it does not. Each individual coat of the aerosol paint (at least, the Railmatch paint that I am using) is extremely thin. However, because it is so thin, a very large number of coats are needed to cover the black of the underlying plastic exposed by modifications to the model. There is still no explanation of why this number of coats would need to be any fewer with an airbrush. It is very doubtful that there would need to be any fewer coats.

Thus, whilst airbrushes no doubt do have significant advantages in some very specific ways, I remain extremely sceptical that using one will solve this specific problem, not least because no intelligible explanation has been given as to how it is possible for the use of an airbrush to solve this problem.

In which case, it's probably best that you carry-on doing what you're doing and accept that it isn't to the standard that you'd like, and we quit going around in circles.

As Nick has pointed out, you've gone through this before and people have offered you help and explanations, but because in your mind you can't see how something might work, then it's advice you're not willing to accept.  It must be very frustrating for those trying to help you do a better job.

It must also be frustrating for them to witness the amount of time and effort you've committed into your trackwork, computer control, motive power, rolling stock, etc., only for you not to at least get yourself an double action airbrush and and actually try it!  In the grand scheme of things, it's not that expensive.

You've commented in another thread about the paint on the side of your rails being thick and peeling off. Prime the rails and use an airbrush properly to apply your colouring, and then varnish over the top, and I guarantee you wouldn't have that problem. and it would be quicker, solving another issue you raise there.

Whilst I would and have used an aerosol for modelling work (Gresley BG sides - sprayed from about 15 -18 inches) I absolutely would not use anything other than and airbrush for the precision type of work you are trying to do with the dominos on the front of your 47s, or instance.  The paint droplet size and properties from an aerosol are very different to that from a low pressure, air-propelled modelling airbrush.  I don't imagine you will believe that, but it is true.

Finally, with regards overpainting black with yellow, I would prime it first with white or even better yellow primer, for reasons that were explained on your RMWeb thread. 

Scott.

(PLEASE NOTE: Unless where obviously posting on behalf of the NGS, all posts and views are my own and not connected/endorsed by the Society.)

Anxiety is a lot like a toddler. It never stops talking, tells you you’re wrong about everything, and wakes you up at 3am.

I get nervous about just about everything. Sometimes I literally don’t know why I’m anxious. I just am and no-one seems to understand that.

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Re: Oxcott [Thames valley 1989/Network SouthEast]
« Reply #230 on: April 17, 2020, 02:17:59 PM »
Are you spraying yellow onto black plastic? If so it doesn't mater if you're using an airbrush, aerosol or paint brush, you'll always struggle to get a decent finish without needing a thick layer of paint.

Use a white primer on top of the black plastic. I use a bog standard one from Halfords. Primer is the one paint I'll normally use from an aerosol. The Halfords ones are good quality and cover well without hiding surface detail.

Once you're got the primer down, you can start on yellow. I've found that yellows from Phoenix and Railmatch don't cover well. Humbrol yellows cover a lot better - I've starting using "Trainer Yellow" (24?) as an undercoat before using Phoenix paints to give the correct shade of yellow.



Steven B.

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Re: Oxcott [Thames valley 1989/Network SouthEast]
« Reply #231 on: April 17, 2020, 04:02:26 PM »
Thank you both for your replies.

Scott - you give the entirely unfair impression in your post that I am unthinkingly refusing to accept a clear explanation. That is not true. Rather, I am not accepting explanations in so far as they are not logically sufficient to support the claimed conclusion.

I am willing to change my mind if there be a sufficiently complete explanation of the reasoning, but not otherwise. There has not so far been a sufficiently complete explanation of the reasoning, for the reasons that I have set out very clearly in my responses.

You refer to the paint droplet size and properties being different in an airbrush to an aerosol, for instance, but you do not state how they are different or what specific consequences that this difference has to the particular application in question. I cannot sensibly make any decision without this information.

I have already acknowledged that an airbrush is superior for some types of work, but I still have not had any intelligible explanation of specifically why it is superior for the specific type of work under discussion here, for the reasons that I have set out exhaustively already. I do not understand why a reply insisting that an airbrush is superior for the specific type of work that I am trying to do has not specifically and fully engaged with those reasons.

Indeed, as Steven helpfully sets out, for this specific problem, an airbrush is unlikely to make any difference.

Steven - this is very interesting and very helpful, thank you. I did prime the ends of the class 121 with I believe Tamiya grey primer, but I am not sure that I used enough coats as the shade of yellow was still different where the black had been compared with where it had not been. How many coats of primer do you suggest? Or do you think that one coat would have sufficed if I had used white?

Can I clarify - do you suggest primer then Humbrol yellow then Railmatch or Phoenix yellow?

In any event, thank you again: this is most helpful.
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Re: Oxcott [Thames valley 1989/Network SouthEast]
« Reply #232 on: April 17, 2020, 04:28:13 PM »
Thank you both for your replies.

Scott - you give the entirely unfair impression in your post that I am unthinkingly refusing to accept a clear explanation. That is not true. Rather, I am not accepting explanations in so far as they are not logically sufficient to support the claimed conclusion.

I am willing to change my mind if there be a sufficiently complete explanation of the reasoning, but not otherwise. There has not so far been a sufficiently complete explanation of the reasoning, for the reasons that I have set out very clearly in my responses.

In other words, having asked for advice and/or help for a problem, you are further insisting on the advisor to comprehensively prove something before you will consider it, rather than taking those suggestions and trying them out yourself. Why not try the advice given and see if it works for you?

Indeed, as Steven helpfully sets out, for this specific problem, an airbrush is unlikely to make any difference.

Now who is being unfair? The problems you have been having with your dominos are not restricted to coverage (but please note I gave the same advice as Steven with regards a primer coverage of the black background - As did someone else on your RMWeb thread a while ago) but you also highlighted a problem with build up of paint around where the masking tape edges were.

The combination of a good primer and airbrushing of the top coat WILL make a difference to both coverage AND the paint build-up. Ditto the side of your rails.

I hope you find a solution that is acceptable to you, and soon.

Scott.
(PLEASE NOTE: Unless where obviously posting on behalf of the NGS, all posts and views are my own and not connected/endorsed by the Society.)

Anxiety is a lot like a toddler. It never stops talking, tells you you’re wrong about everything, and wakes you up at 3am.

I get nervous about just about everything. Sometimes I literally don’t know why I’m anxious. I just am and no-one seems to understand that.

Offline exmouthcraig

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Re: Oxcott [Thames valley 1989/Network SouthEast]
« Reply #233 on: April 17, 2020, 04:49:19 PM »
Its ALL a question of scale.

Rattle cans are brilliant for MASSIVE work pieces like A CAR

IF rattle cans were so good WHY does every car paint shop use a compressor and spray gun??? Oh yeah because its BETTER.

This is the same drama your having on something that's 6 inches long.

YOU CANNOT PAINT AN N GAUGE MODEL WITH A RATTLE CAN.

If all these people HERE and OVER THERE are telling you this why not listen. But clearly until ICI get involved you wont believe anything your told.

I'm not being funny but for £150 you can get a more then satisfactory airbrush and compressor and some paints and PRACTICE let's me honest buying Railmatch rattle cans at £6 a pop wont take you long to of blown that much money on them to get your inferior finish.

I cant see Bachmann Dapol or Revolution masking and spraying their 2 colour models with rattle cans.

Sledgehammer and Nut spring to mind.

No one is obviously giving you the answer you want even though they all say the same so accept the help or quit asking pointless questions you already know your answer too.

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Re: Oxcott [Thames valley 1989/Network SouthEast]
« Reply #234 on: April 17, 2020, 05:07:29 PM »
Steven - this is very interesting and very helpful, thank you. I did prime the ends of the class 121 with I believe Tamiya grey primer, but I am not sure that I used enough coats as the shade of yellow was still different where the black had been compared with where it had not been. How many coats of primer do you suggest? Or do you think that one coat would have sufficed if I had used white?

Can I clarify - do you suggest primer then Humbrol yellow then Railmatch or Phoenix yellow?

Yes, spray white primer on the bare plastic. Use several light passes until the black plastic has been replaced by white paint. Once this has dried (at least 24 hours, if not longer), then you can apply the yellow. It's up to you if you go for Humbrol yellow as an undercoat to the Railmatch/Phoenix shade. You may find the Humbrol shade to be close enough to warning panel yellow to not need the "Rail yellow" coat. If you do undercoat then again, leave the paint at least a day to dry before painting over the top.

I do agree with the comments about avoiding aerosols - except for primer as I've mentioned. Due to the pressure of gas in the can they output a lot of paint in a short amount of time. Even at a distance you'll get a faster build up of thick paint than you would with get from an air-brush. If you avoid runs you still end up with a layer of paint that's thicker than you can achieve with either an air-brush or even a paint brush.

There are ways of getting a better finish than you're getting with an aerosol rather than jumping straight to an air-brush. Take a look at some of Gareth Collier's work (either in the Journal, RMWeb or here - @thebrighton https://www.ngaugeforum.co.uk/SMFN/index.php?topic=18674.0). I believe he paints all his models with well thinned paint and a good quality paint-brush. The standard he achieves is superb. Perhaps it's worth testing and practising a few techniques on a sheet of plasticard or scrap model?


Steven B

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Re: Oxcott [Thames valley 1989/Network SouthEast]
« Reply #235 on: April 17, 2020, 05:23:01 PM »
These replies (Steven's excepted) are becoming increasingly inappropriate and belligerent. It is totally inappropriate under literally any circumstances whatsoever aside from an actual emergency, which this is not, to respond to reasoning with aggression. Ever.

I will not be persuaded by people typing in all capitals or insisting that they be treated as an authority. I will be persuaded by a logically complete explanation. I will make my own decisions based on the available information. I will not defer unthinkingly to others, especially those who refuse to give a clear and complete explanation of the basis of their recommendation.

Indeed, the more that people are resistant to answering the basic questions that I have been asking and making the incomplete explanation complete, and the more that people resort to aggression rather than to clear explanation, the more sceptical that I and any other rational person will be of whether such people really have sufficient understanding to be giving advice in the first place. The more that people use aggression in response to reason, the less that I (and anyone else rational) will trust them - and for very good reason.

In short: I will not do something merely because somebody tells me that it is the best thing to do. I will do something if somebody can make me understand why it is the best thing to do. I remain open to considering that in respect of an airbrush or anything else, but there has been so far no attempt at all to respond to my legitimate questions about this.

Frankly, it is totally bizarre and positively disturbing that people should be so invested in whether I accept a recommendation of which I am legitimately sceptical because of the incompleteness of the explanation as to become aggressive.

Can we please return to a reasoned calm discussion of the delights of railway modelling?

On the topic of which - thank you, Steven, for the helpful reply. I will investigate the thinned paint/brush techniques to which you refer. Do you recommend also that the primer coats be applied in this way?

I should note that the actual thickness of the coats with aerosol cans does not appear to be the issue, as, as stated above, I need a very large number of coats (circa 7) to cover the black, at least without priming with white, which I have not tried yet. The Railmatch aerosols are very heavily thinned, more than Phoenix aerosols, I think. Having said that, I have had very good results from Phoenix aerosols on 1:76 scale 3d printed models:

3d printed articulation in action by James Petts, on Flickr

3d printed articulation in action by James Petts, on Flickr

In any event, the point is rather that enough layers of pigment, however applied, to cover the black appears to be so thick as to leave a visible line if masked. If fewer layers can be used by using a suitable primer, and a good finish achieved by brushing thinned enamels, then this might be the way forward, as brushing will remove the need for masking, allowing the paint to be blended with the factory finish.

As for testing the technique on plastic sheet, would Plastikard with some spots of black paint added be a good way of testing coverage over black by using white primer and yellow overcoat? How many coats in total (i.e. of all layers) do you imagine are likely to be needed to get good coverage with this technique?
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Re: Oxcott [Thames valley 1989/Network SouthEast]
« Reply #236 on: April 17, 2020, 06:48:24 PM »
I am a big admirer of the work being done in the creation of this layout, the attention to detail and the era / stock choice.

I have absolutely no desire to enter the debate ref spraying and the options available.

I would however like to show the thread / layout owner this photo of my first (and so far only) loco respray. This was done entirely using rattle cans and brush painting. IMHO it is reasonable (I am happy with it), but will invest in an airbrush at some point, if only to learn a new skill.



I will continue to follow this great project.

Kind regards

Skyline2uk



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Re: Oxcott [Thames valley 1989/Network SouthEast]
« Reply #237 on: April 17, 2020, 06:51:45 PM »
Skyline - thank you: it is interesting to see your respray efforts. That is quite impressive!
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Re: Oxcott [Thames valley 1989/Network SouthEast]
« Reply #238 on: April 17, 2020, 06:54:18 PM »
Skyline - thank you: it is interesting to see your respray efforts. That is quite impressive!

Very kind of you, and your overall layout and methodical approach is impressive to me  :thumbsup:


Skyline2uk

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Re: Oxcott [Thames valley 1989/Network SouthEast]
« Reply #239 on: April 17, 2020, 07:55:38 PM »

On the topic of which - thank you, Steven, for the helpful reply. I will investigate the thinned paint/brush techniques to which you refer. Do you recommend also that the primer coats be applied in this way?

As for testing the technique on plastic sheet, would Plastikard with some spots of black paint added be a good way of testing coverage over black by using white primer and yellow overcoat? How many coats in total (i.e. of all layers) do you imagine are likely to be needed to get good coverage with this technique?

I've found that using a good quality primer (such a Halfords) means you can spray directly on the model.

As for your test, yes paint some black, or use black plastic.

It is perfectly possible to get a decent repaint using  aerosols just as it's possible to get a poor finish with an air-brush. I've managed both ends of the scale with all three methods. I've never found Railmatch or Phoenix very good. Both clog nozzles and aren't really suited to smaller scales. Games Workshop and Humbrol's acrylics are fantastic and work well even in N.

If I get chance I'll find and photo some models painted with each method to compare them. Personally, I now only use aerosols for primer and final varnishing, perfering brushes of the hairy or airy variety for most other jobs.

Steven B

 

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