7mm Corwen Road

[LarryG]

Back onto spraying equipment again. The airbrush was a toy. Sweeping statement I know, but for my job it was. The spray was so fine, it was taking ages to build up a good finish on a coach side. I gave up by the time I reached the underframe and used a Halfords matt black aerosol. Then I went indoors and ordered a Fiac Kite Mini Gravity Gun with 1.omm nozzle. It arrived next morning! Thanks Precision Paints for the suggestion.

While the airbrush demanded over 40 psi, I am back using 25psi which doesn't force paint under masking tape! Spraygun on right...


A coach was sprayed in a fraction of the time this morning and with a glass-like finish...

 

[Rob R]

Larry, I think you need to try 5.5mm scale. A perfect compromise?

Why compromise?

The no compromise answer is S.

Rob

 

[LarryG]

Lock-down is not much different from working from home for much of my life, ie: winter for working indoors and summer days for travelling. The latter hasn't happed for most of us for a year now, but things are looking up. We have a lot of travelling to catch up on, some of it to see relatives of our generation, so 4mm/OO out-of-boxes suits me while making buildings and coaches will feed my modelling habit.

 

[Mike Garwood]

Hi Larry

I'm interested in your chice of needle size for your new airgun. I have an Asturo with a 0.3mm needle. I only dilute the celly at 4:1 going over the top of a primer. Usually, Halfords grey. I've always sprayed at 20 psi.
3 / 5 passes on a model and it's covered. Before I go in for the finishing pass. I have always thought that the more passes the deeper the colour and that the finer the spray the better the chance of a good finish.
But looking at your picture of the finished side I have to say I'm begining to doubt my airgun. I was wondering what size needle you used in your old De Viblis?

Mike

 

[J_F_S]

I hope Larry will not mind a slight side-step on airbrushes.

About 20 years ago I was completing the overhaul of my Fowler ploughing engine and wanted to paint it as close as I could to when it left the works.



Elaborate lining like this done 'traditionally' is well beyond me and professionals charge a mint because it takes forever. So I decided to do it using modern clear-over-base automotive refinishing paints - which means spraying it.

I did the lining by 'differential masking' - ie having got a glass-smooth finish with the primer coats, spray the yellow first, then put a 3mm tape over it then spray the red and put a 6mm tape over it, then spray the brown and put a broad tape over it then spray the black all over everything. Finally, pull off all the masking, and over-spray the lot with two coats of clear lacquer. Needless to say everything was done before assembling it all.

But here is the relevance to this thread:- ALL of the lining, including the brown (which is 2" wide in places) and the white for the registration number was done with this:-


.. which is about the simplest single-action air brush about and which was bought from Kings Cross model shop in 1974! (as well as a lot of wear and tear, you can see the quick-fit connecter to plug it into my 13cfm compressor!) Prior to this job, the biggest thing it, (and I) had sprayed was a 4mm GW 28XX! The primer coats, the black and the lacquer coats were all done with an HVLP touch-up gun which looks similar to Larry's.

What did I learn from this?

Firstly, even a simple tool like this can actually shift a LOT of paint - so long as you do not want extremely fine control of exactly where it will land.

Second, the quality and viscosity of the paint is extremely important - the polyester base coat I used came with precise dilution instructions and a not-inexpensive grade of thinners. It went on like glass and was dry immediately (like an extremely good quality cellulose) and had the added bonus that if I made a b*lls of it, it would wipe off with a thinners soaked rag - no matter how long it had been on. Pity it is no good for models because it needs over-lacquering!
Third, practice is the most important ingredient. I used a LOT of paint just gaining experience and finding the limitations (and unnexpected capabilities) of the equipment.
The above photo shows the job after 18 years of mud, muck and abuse and I don't think it looks too bad. (BTW that is not me driving!)

Oxford die-cast do a 4mm scale model of my engine - Oxford Diecast Fowler BB1 Ploughing Engine No.15337 Louisa - but the paint job is rubbish ... and I was not consulted in advance!!!

I should of course add that I now own a more expensive air brush for painting my 4mm models! It will be a long time before it has as much paint through it as the Badger! But I think I would have the confidence to still use the badger for bigger jobs - if I could find a replacement for the bent needle and the lost large-capacity jar!

Although I said that the polyester base coat is not suitable for models, I have got some of my "cellulose" model paints from the same refinishing dealership - it is a while since though, as a litre lasts some time ... they can, of course, mix any colour and what always amuses me is that when I ask for 'black' they offer me about 200 swatches to choose from...

Hope that is of some interest,

Best wishes,
Howard.

 

[Heather Kay]

if I could find a replacement for the bent needle and the lost large-capacity jar!

Squires used to stock an almost complete range of Badger spares. I think they’ve recently had issues with importing from the US, though.

 

[LarryG]

Hi Larry

I'm interested in your chice of needle size for your new airgun. I have an Asturo with a 0.3mm needle. I only dilute the celly at 4:1 going over the top of a primer. Usually, Halfords grey. I've always sprayed at 20 psi.
3 / 5 passes on a model and it's covered. Before I go in for the finishing pass. I have always thought that the more passes the deeper the colour and that the finer the spray the better the chance of a good finish.
But looking at your picture of the finished side I have to say I'm begining to doubt my airgun. I was wondering what size needle you used in your old De Viblis?

Mike

It's a P5013 Kite Mini as per this link. https://www.sitebox.ltd.uk/docs/wilkinsonstar/pdf/P-5013.pdf

1mm fluid nozzle, needle and cap. I set the gun up so that it is using far less air than it would wide open. Like my old DeVilbis, is uses more paint than an airbrush, but it puts more on in one go as well. I usually spray two coats with 5 minutes between each. The first three coaches of a batch of four were done with the airbrush while the fourth was done with the spraygun. Not only is the paint surface like glass on the latter, but the carmine is noticeably darker because the gun is putting on more paint in two coats than the airbrush was in 3 to 4 coats.

The airbrush will be useful for weathering track and other odd jobs around the layout. Alan Brackenborough put me onto a DeVilbis Type MP spraygun in the late 1960's. It had three nozzle/needle & cap sizes originally but I ended up using the intermediate size (1mm) for everything from GEM's N Gauge exhibits to Pete Waterman's Gauge One locos.

Cellulose dilution depends on the thinness of the cellulose. My Matt Black is somewhat thicker than 50/50 to cover in one coat. But dilution is an instinct a lot like my mother-in-law throwing handfulls of ingredients into a bowl to make the best Parkin and rag-puddings in the land!

 

[Richard]

I've found all this information about spraying very helpful. I was going to buy a new airbrush to replace my old Badger, but I'm now minded to opt for the P5013 instead.

As a matter of interest, what size compressor are you using?

The link recommends a 2 hp compressor for the Kite, but that's a rather larger compressor than is found in most homes. I'm assuming that the 2 hp is required for continuous usage rather than the lower air volume required by most modellers.

 

[Mike Garwood]

Thanks Larry - that's useful.

Mike

 

[LarryG]

Hi Richard,

My replacement for the old commercial compressor and separate air container was a DHL-TC-620X Sparmax 620X Twin Piston compressor invoice total £248.59 from Everythingairbrush.com. Spraygunshop.com.

A quick Google will tell you if it meets with your air requirements. It feeds the Kite spraygun alright at the current settings. The factory setting on the spraygun delivered lots of air and paint before I altered everything. At some settings using lots of air, I rather suspect the compressor would have a job keeping up certain air pressures. Same with a spraygun with a larger than 1mm nozzle. When it was feeding my old DeVilbis (badly leaking air), the pressure dropped from 25 to 15psi as soon as I started spraying. I simply set the latest spraygun to delivery much as the Devilbis did when it was working properly. The compressor kicks in now and then to maintain working pressure so I am working well within its limits at 25 psi.

The Kite spraygun I bought is also available with an 0.8 nozzle. For comparison, the Sparmax GP-850 has a 0.5 nozzle, which for me simply wasn't big enough, hence going for a 1mm. Whether you are spraying 4mm, 7mm or 10mm scale models, the Kite will be just the job.

 

[Richard]

Thanks Larry,

Funnily enough I was given a similar compressor some years ago, so that should be no problem. My big compressor in the garage with the 50 litre tank will just need a filter fitted to it if I need a bit more reserve.

However, the silent ones are a bit more forgiving on the ears.