Painting Unitrack rails with acrylics

[kuro68000]

Hi everyone.

 

I am trying to paint my Unitrack with Tamiya acrylic paints (XF-64 Red Brown and Nato Brown) but am having trouble making it take to the metal. Instead of forming a coat it thins out and looks very liquidy. I have not thinned it or anything like that, this is straight from a brand new bottle. The rails are nice and clean.

 

Can anyone suggest what am I doing wrong? The books I have don't seem to suggest doing anything special (my Japanese is far from perfect, especially reading...) I know you can get primers but the only one Tamiya seem to do is a spray can which seems to be designed for use on whole models and would need a lot of masking for rails.

 

I'm sure it's something really basic >_< While I'm here has anyone used Mitsubishi (Uni) paint pens? One book I have suggests using them as a quick way to paint rails, but my local shops don't have brown ones or I would have tried it.

[David]

An acrylic primer, specifically a metal primer would probably help. Acrylic primer in general can help get a more even stick the first time coat, and with metal I think the metal primer is supposed to help seal it against corrosion as well. I don't have any first hand experience using acrylics, I have the oil based markers.

 

Edit: when you say the rail is clean, is it just already clean or did you specifically clean it just before painting? You should clean it with something like rail cleaning fluid or alcohol to ensure that you are not trapping in any grease or other compounds that will be sealed in and corrode the metal. If it's old you might even lightly sand to ensure any oxidised metal is removed.

[Bernard]

Just to add another element that you might have thought of....I recommend putting a thin coat of oil on just the rail head applying it with a Q-tip....after you paint the rails, take your fingernail and run it across the rail head and any access paint will come off.

[westfalen]

I use Floquil paint pens.

 

http://www.testors.com/product/141256/F3801/_/Track_Pack_-_3-Pack_Marker_Set

[CaptOblivious]

In my experience, acrylic on metal requires a primer coat. Hit your local hobby sore and pick up some 'Citadel' black primer. Good stuff.

[kuro68000]

So I should probably use some primer, after cleaning the track and applying a little bit of oil to the top. All the primers are sprays though so I guess everyone just uses loads of masking tape? Or spray the whole thing (rails, sleepers/ties and base) then re-paint the parts to the right colour individually?

 

westfalen, those ones are not available in the UK but they seem very similar to the Uni ones. They say they are oil based which I find interesting because all the info I have says use either acrylic or enamel paint. The results look good, I really want to try them.

 

Thanks for all the helpful hints!

[KenS]

I haven't airbrushed Unitrack, but masking tape is the answer for protecting the rest of it.  I used that method on HO flex track when I didn't want the ties the same color as the rail. You'll likely get some overspray near the rail, but if you mask carefully that's probably going to be small enough to ignore.  The other thing is switches.  On those I'd recommend masking off the points and the hinges, and brush-painting those carefully, to avoid interfering with their free motion.

 

The other thing to worry about with sectional track is the electrical contact on the joiners.  If you spray over assembled track with joiners you should still have a good joint, unless you happen to spray too close and the paint runs or there's a gap at a loose joiner.

 

You probably need to remove the Unijoiners and do something to avoid painting the bases of the rails at the end where those will attach.  You could attach some sacrificial joiners and remove them promptly after painting to check for any leakage, or you could clean the base with a fine-point swab (sold for electronics use) soaked in thinner immediately after spraying each coat.

 

But Bernard's oil tip might also work here (I've never tried it, but it seems like it would work to mask the rail base), although I don't know that you could use it to paint assembled Unitrack as there's no way to remove the oil, which might itself cause contact problems.

 

I'm planning to use the Floquil Track Marker pens myself. Airbrushing sectional track just seems too hard to do well.

[kuro68000]

Okay, I have been experimenting with different paints and would like some feedback. All the above were stirred vigorously for at least 1 minute.

 

Tamiya Acrylic Flat (XF-64) Very watery and runny, does not seem to adhere well to metal or plastic. Somewhat translucent. Designed for spraying?

 

RailMatch Acrylic Took well to both metal rails and plastic. Easy to apply and gives a nice matte finish.

 

Revell Aqua Color acrylic Similar to RailMatch, worked well on metal and plastic, a bit thick perhaps for fine detail and needed a lot of stirring when first opened.

 

Humbrol Enamel A bit watery but not as bad as the Tamiya acrylics, took to the rails but needs two or three coats.

 

Citadel (Games Workshop) unknown paint Similar to RailMatch, goes on easily with no priming and produces a solid colour.

 

Generic artist's oil paint Worked surprisingly well and was very easy to mix (didn't try mixing the others). Extremely cheap.

 

Generic artist's acrylic Similar to the Tamiya acrylic, too watery to work well.

 

KenS, I have been looking at airbrushing and it seems to work well enough, but as you say afterwards you have to re-paint the ties if you don't want them to be the same colour. All the Japanese videos and blogs I checked just spray the whole bit of Unitrack, so the base and ties get coloured too. Sometimes they then re-do the ties, other times they just ballast around them. My observation though is that Japanese rails tend to have a very light colour rust because it is mixed with light dust from the ballast, and the ties are concrete:

 

 

You can see the varying levels of rust colour, partly dependent on age I imagine. Now, if you brush or spray the colour all over you get this kind of effect:

 

 

(Left: brushed on, right: airbrushed on)

 

It looks okay with lots of ballasting, but I think I would still want to paint the ties grey. The default black colour is more like old wood... Not sure what Kato was thinking there. I suppose one option is to spray the ties with grey first, then mask them with one long strip of tape and spray the rails rust colour. Fill the gaps between ties with ballast. Might be tricky on curves etc, and of course turnouts are always going to be problematic to spray. I'd love to hear from people who have sprayed their rails on how easy it is to do that sort of thing.

 

The Japanese method seems to be to paint and then clean the top of the rail with sandpaper, rather than try to wipe the paint off while still wet. One thing I will say is that wiping is difficult to do without removing more than just the paint on the very top of the rail.

[kuro68000]

PS. I ordered a Uni POSCA pen, will report how well it works. I also ordered a Uni paint marker.

 

One other benefit of sanding the rails: they lose the gold tint and go back to silver.

[KenS]

Heavily-used track will tend to have a rust color to the ballast between and adjacent to the rails.  This varies depending on the level of use and the environment (more rain probably means cleaner ballast).  I've seen this effect in photos of Japan and in person on U.S. rails.  But at the same time, heavily-used rail tends to have a grayer rust color on the side of the rail itself, rather than a reddish one, as any loose flakes of rust get vibrated off, leaving a more lightly-oxidized rail.

 

There's enough variation that you can probably find a prototype for just about any mix of colors, and I've seen models with the whole rail/ballast/tie structure airbrushed one color, varying from gray-black to orange-red.  My own preference would be a gray to dark red on the rails, heavy enough to be opaque, and a lighter red lightly dusted on the ballast and ties (except on lightly used track), allowing the original colors to show through.  But I'll admit even on my old HO layout I never did that.  I just airburshed the rails a rust-red color (masking off the ties), and then ballasted with pristine dark gray ballast.  And right now, my Unitrack is entirely unpainted.

 

What I've been thinking of for my Unitrack is the Floquil pens for the rail sides, and some kind of ink wash for the ties, just to take off the plastic shine and darken it a bit.  I had been thinking black ink for the wash, but perhaps some kind brown ink would get me closer to the rusty look.

[kuro68000]

I think you are right KenS. My experience is mostly with well used railways in Japan, where the rails actually seem relatively clean all things considered. Next time I will take more photos of the rails.

 

 

They look more dusty than anything, except in that one shot where the rust is very clear. I suppose it is a combination of regular use and regular maintenance/replacement. I took some shots of a few layouts last time I was there too:

 

 

(airbrushed)

 

 

(painted with a marker, hard to see)

 

I think the latter one looks better. I asked a Japanese friend what he would suggest and his answer was to master the art of airbrushing. Spray the ties grey and then you can then either do the rails with a marker and airbrush to blend or you can just airbrush with a very narrow spray for each rail.

[brill27mcb]

In days of old (at least in the U.S.) the whole track structure would turn uniformly brown, because the dust worn off of cast iron brake shoes would settle over everything and then rust. In more modern times the brake shoes are no longer made of cast iron, and that affects the coloration of the track. So go by photos from the correct time period.

 

Rich K.

[kuro68000]

Right, pens arrived and I did lots of test painting. Here are the results.

 

 

 

These are the same bit of track, with camera flash on and off respectively. The second image is more representative of what it looks like in real life, but the first one shows the unevenness. The closest rail to the camera has been painted first with a Uni POSCA brown pen (medium size then fine to fill in the bits the larger tip can't reach) and then brushed with RailMatch dark rust.

 

The pens are a bit light in colour but do give a quick and easy full coverage. The additional brushed on paint darkens them a bit and gives also allows spreading some onto the surrounding ties and base. I found that brushing paint on alone it was hard to get full coverage on the rails, hence the use of pens as well. You can see where I experimented with doing the ties grey, and it looks a bit rubbish. Too light I think, but might be better with some ballast to surround them.

 

The result is okay, a bit uneven but looks all right from a distance. In real life the rust seems to be fairly uniform. It is reasonably quick to do too. I still want to try an airbrush though. Although many people just airbrush the whole thing and then rely on ballast to add some contrast I think it might be possible to do the rails and the ties different colours. Either the rails will be done with a very narrow spray so the ties are left alone, or maybe the rust colour could be done first and then black/grey down the middle between the rails and light colour ballast on top. I think masking might give a harsh edge but it is also worth a try. Could be tricky on curves though, and points/turnouts are always difficult with any kind of spray but I could always do them with a brush.

[kuro68000]

Right, airbrush arrived and used for the first time! I got an AS18-2 compressor and BD-181 double action airbrush from eBay. I have not owned one before so can't make comparisons, but reviews are generally good and I am quite happy with the quality. I suffer from arthritis so I'm not terrible dexterous but I found it fairly easy to use.

 

The control on the airbrush seems to have pretty much two settings: off and on. You can do low airflow with some effort but basically it is all or nothing. The backwards/forwards movement to control the paint is quite nice though, plenty of range and it starts slowly. I can see it being good for weathering. The screw at the end which limits how far you can pull back is very handy because with a bit of experimentation you can get it in the right place and then effortlessly blast through mass spraying stuff at just the right level without the need to hold the trigger perfectly in place.

 

The compressor seems okay, no stutter that I could see, quiet and compact. The pressure setting knob has no markings and you have to turn it several times to make a small change, so the only way to do it is to experiment until it is right. The gauge is helpful and, and I found that around 1.5kg/cm² (20psi) was ideal.

 

Right, on to the painting.

 

 

This bit of track was painted using just the airbrush, focussed on the rails but covering the area around them too. It doesn't look too bad at all. I wanted to try doing just the rails though:

 

 

 

These two are of the same bit of track, one with and one without the flash. The first one looks more like the real colour, the second one shows the detail better. All were done with Tamiya XF64 Red Brown. I will clean the tops of the rails tomorrow.

 

I used masking take to limit the spray to the rails. It was not difficult at all and I found that I didn't need to be terribly careful about placing the tape. This way the colour of the sleepers is maintained, since being made of wood or concrete they would not rust. I might actually go for a bit more overspray next time. I need to add some ballast and see what it looks like. The uneven nature of the track bed ensures that the edge of the spray is not a harsh straight line, plus it should be covered with ballast anyway.

 

So far this is by far the best result. The pictures make it look a bit uneven but it isn't visible to my eyes. The only issue I can see is that the Tamiya paints really don't brush on well at all, so when it comes to switches it might be hard to apply without jamming them.

[Martijn Meerts]

Tamiya acrylics should be thinned if you just use a paintbrush. The paint dries REALLY fast (it's already drying on the brush) which makes it difficult to paint with. Something to increase the drying time would work as well.

 

The disadvantage of thinning it, is of course that you'll likely need more than 1 coat of paint.

[kuro68000]

So what do you use unthinned Tamiya paint for? What I mean is, why not just thin it 1:1 at the factory since that is what you need for spraying and brushing on?

[Martijn Meerts]

Well, Tamiya seems to think their paint is ready to be used without thinning :)

 

I've used it without thinning with some success, but you need to be really careful, and it only really works on small bits and pieces.

[inobu]

The smaller the scale the thinner the paint. Thick paint covers the detail especially when brushed. The airbrush atomizes the paint into small specks a few micron thick which is thin enough to cover the surface yet keep the detail visible. The peak shape of the ballast on the unitrack makes it harder to weather. As KenS suggested a mask will help to control the areas you want to paint.

 

The top track piece has the transition zone you want. That is where the thinnest coat or over spray is. You want your main spray to be that thin. 

 

[smg id=1366]

 

You want the mist of tint the ballast not paint it. 

[inobu]

Mojo,

 

Being that you went out and bought the full setup  I guess you mean business (that's the way to do it). Here are a few tips that can make things a little easier for you.

 

As Kens stated a mask is key in controlling paint coverage, thinning is important to place the optimum mist of the spray onto the track. Remember more air less paint. Means push down and pull back lightly on the brush. Some brushes have a setting that will only allow the trigger to go back so far. You can use that to maintain a consistent flow it your brush has it.

 

Here is what you can do. Three light passes. One to get the general area and the next two along the rail. That give the transition look.

 

Here is how you can control your hand and maintain a consistent flow. The image in the upper right shows the mask that acts as a flap that blocks the over spray.

Use the ruler to guide, rest the brush and slide it across in one pass, the only thing you have to focus on is the speed that you move your hand.

 

[smg id=1367]

 

The biggest factor that everyone misses with N-Scale, the size. In real life you would be spraying the track with a 1.5" hose. Your airbrush is .2mm to you but it is 1.5" to the N Scale track. As you can see it is really big so keep that in mind and spray real light.

 

Hope this helps, you are doing a good job already.

 

Inobu

 

 

 

 

 

 

 

[kuro68000]

Martijn Meerts: I see :) Since I am starting from scratch I don't have any spare paint pots to use for mixing, and I read somewhere that mixed paint doesn't last more than a few weeks either. Is that true?

 

Fortunately I picked up loads of scrap track to practice on.

 

inobu: Thanks for the advice, I will give the ruler and masking method a try. You are right about the overspray, but I would need to partially spray the ballast too I think. I'm not sure what to go for at this point, I could take the easier option of lots of overspray so it looks like the image you framed in the first post which might be a good idea as it is my first effort and there is a lot of track to do. On the other hand I think some colour variation would look good. I suppose I should start by overspraying the track and the adding ballast to see how that comes out.

 

The book with the layout I am making (I will post it tomorrow if I remember) suggests using chalk to dust the ballast around the rails, and it does look very good in the photos. They have gone for a southern Japan rural look which is dry and dusty. Making the chalk stick is the tricky part of course. It is an odd bit of modelling really - the chalk looks great but they painted the rails with a brush rather than an airbrush and they look very uneven in all the close-up shots.

 

I will try your technique out!

[Martijn Meerts]

Mojo, as long as you keep the paint in a decent, airtight container, you should be able to keep it as long as non-thinned paint.

 

For my father's layout, we used Humbrol enamel paint to rust the track. That stuff doesn't need to be thinned and it generally covers better than acrylic paints. The disadvantage is of course that it's a solvent based paint.

[quinntopia]

So far this is by far the best result. The pictures make it look a bit uneven but it isn't visible to my eyes. The only issue I can see is that the Tamiya paints really don't brush on well at all, so when it comes to switches it might be hard to apply without jamming them.

 

Mojo, I used the same paint with the air brush method you describe.  The airbrush was the hands down winner for me in terms of getting the job done.  I tried one of those sponge-roller painters specifically designed for this task and couldn't get it to work.  I also found that the sponge-roller was not real great at getting in behind some of the tie plates where the original steel rail would still appear.  An airbrush took care of all of this with little problem.    I skipped past the brush on step altogether.

 

In terms of coverage, I gave my paint just a drop of thinner for, as Martjin has noted, their paint doesn't need much thinner!  I did need to make two or three passes to get a nice solid and consistent coverage. 

 

Masking the ballast is a REALLY good idea too....a couple of slips of the hand as you paint the rails around the curve will result in a really unsightly over spray that won't look good .  The Tamiya cleans up pretty easily, but an once of prevention is worth a ton or something! 

[keitaro]

So I painted some test track. The vermin brown which I have left over from years of  (lord of the rings) modeling does not work well at all. It ruins contact with rails I thought it may be thick as I could use a tissue to rub it off. I tried wattered down so it was really runny same issue.

 

I may try a pen as I only want the track painted.

 

I was also going to try left over flesh wash from citadel paints. As it's a dark rusty color and runny and oily but realized it needs priming.

[KenS]

Any paint will insulate the rails.  If you can't paint just the side, you'll need to either clean it later (with an abrasive block like a "bright boy"), or wipe the top while the paint's still wet (I used this approach on my old HO layout: after airbrushing, I wiped the top of the rail with a paper towel lightly dampened with thinner).

[keitaro]

so you can't keep the top painted at all? as i had it as thin as i could get it and it would still jerk. pictures i've seen this done too look all coloured and work fine