How do you paint your engines ?

[Gas_mantle]

Hi,

I'm just wondering how others go about painting their models to get a good even finish ?

I have a small airbrush set up that seems to work great some days but not so good on other days so the last engine I painted I had a go at brush painting with Humbrol enamel, that seemed ok but there are a few spots that the finish isn't great so I thought about trying car body work spray cans this time.

Any thoughts on using spray cans ? is it easy to get a good even coverage without runs ?

What about buying better quality paint than Humbrol and brushing again ?

The engine I'm building is intended to run on steam so I'd like something that with withstand a bit of heat 

Thanks.

[Ye-Ole Steam Dude]

Hi Gas_mantle,

I am no expert but I have found that the primer is a key. I use Krylon "Cover Maxx", Ultimate Coverage primer and have not found any better.

Two coats of the primer with a fine sand paper between each coat ( like 1000 grit ).

The finish coat I use Krylon "ColorMaster" with 2 to as many as 4 coats. Again, fine paper sanding between coats.

Hope this will help.

Have a great day,
Thomas

[Jasonb]

I do airbrush some of mine if I want a particular colour or finish, usually use Precision Paints enamels and their primers.

But mostly I use spray cans as they are convinient. bare steel or iron will get Halfords grey primer, aluminium, brass, bronze, etc I use an etch primer for usually U-Pol Acid8, for sand cast iron and some fabrications I use a filler primer such as U-Pol's High5 followed by the grey. Halfords colour more often than not topped off with a clear coat as they gives a deeper glossy look, fuel proof one for the IC engines.

Several light coats applied without getting too close will avoid runs.

this post shows my prep work

http://www.modelenginemaker.com/index.php/topic,4863.msg97803.html#msg97803

[simplyloco]

Taking my cue from Chris Vine's excellent book 'How NOT to paint a Locomotive', I made a miniature spray booth out of a plastic closable crate, complete with extractor vent and rear filter panel. I fitted a winding mechanism, essential when using thin spray paints, as it is then possible to turn the work as it is drying thus preventing runs. I also stole my other half's spare cake decorating turntable...
It works and it cost very little!
John

DSC01041 by inkaboat, on Flickr

[Mcgyver]

great thread topic. Its an area I wish knew more about so am hoping for lots good advice

[steam guy willy]

As with hand filling i use brush painting ....i suspend all the parts onto threaded rod or bike spokes .  I use sable hair brushes and use primers first. When you paint it is better to do the detailed mouldings first and then the large flat parts last. when you use the brush you always brush off the edges never onto a corner. it is best after charging the brush to start a little bit further on from the last painted part and work back slightly. When i paint the parts ,to stop any dust being disturbed i do it when i get up ,or after spending time away in cafes etc .Also as you dont want any clothing fibres to adhere to the surfaces one can do it naked !!! with thin rubber gloves and a hair cap....hope this is not too much info....I also have a lightweight card box that a put over the newly painted parts.....

[Rustkolector]

This question comes up from time to time, and my vote is still for a finish called Gun Kote. I build IC engines that accumulate a lot of oil at times, and I like to run them a lot. I wanted a no worry paint finish that could tolerate a harsh solvent like brake cleaner as well as heat. I tried many paints and finally decided on Gun Kote, and I have been very happy with it. It is a single part heat curing finish (bake 1 hr @ 325F or 2 hr @ 250F - toaster oven) that fixes the paint to the surface so well that it can only be removed by grit blasting. Preparation is #125 AL oxide grit blast which I normally do anyway to hide fine machining marks. No primer is used. I use an inexpensive air brush to apply Gun Kote at very low pressure. It goes on in thin coats so runs are easily avoided. It can also be applied wet or dry spraying to simulate smooth and cast surfaces. Gun Kote is available in a wide spectrum of colors with most colors available in gloss, satin, and flat. The advantages of Gun Kote are that it doesn't chip or peal, it adheres to all metals equally well even tough ones like brass and aluminum, it goes on very thin and doesn't hide detail or cause assembly interference problems, it is very heat tolerant, and I haven't found a solvent that effects it in any way. I suppose some would say that powder coating has many of the same attributes, but it cures at 400F which is only about 20F degrees below the melting point of 4% silver solder which many of us use on detail parts. That's too close for my comfort.
Jeff

[Jasonb]

I have a feeling there is something in Gun Kote which means it is not sold in the UK, Brownell's UK site does not list it.

[Gas_mantle]

Thanks for the replies, it sounds very much like I need to start using a primer which up till now I haven't bothered with.

I'm not convinced my little airbrush set up is consistent enough for what I want, it's also difficult to get the right mix of thinners so that subsequent coats are all of the same shade.

I like the idea of making a spraying box from a plastic crate 

[Jasonb]

A lot of airbrushes put on too thin a coat for our robust requirements and need the paint thinned a lot which does not help with runs. Unless you have a heavy duty nozzle on the airbrush it will not cope that well with the coarse pigments found in enamel paints. Some of the small guns are better in this respect.

Thinning will not alter the shade of the paint, what you are likely seeing is the base metal colour affecting the finish shade as the paint film is too thin. This is another good reason to use the right primer as it will give a uniform base otherwise you risk a part made from say cast iron looking darker than one made of aluminium even though they have been painted with the same colour coat

[RayW]

I have used both spray cans and brush applied paints in the past. Like Jason, I have used Halfords auto spray paints, but a word of caution, as mentioned on my Otto thread, shades of the same colour can vary from can to can.
For brushing paint, I generally use coach enamels from specialist paint suppliers such as auto paint factors, or companies who produce paints specifically for the vintage market.
My local auto paint supplier will mix whatever colour you require and will also put some of the paint into a spray can, at extra cost. This means that you are assured of identical colour matching on both sprayed and brush painted components. If you have purchased paint from, say, one of the specialist vintage paint suppliers, they will also put some of that into a spray can for you.

[steam guy willy]

Also you can use a 'Tack cloth' to remove dust before painting..........

[bent]

Wow, you guys really know your paint.  I'll be the heretic here, as I'm not a painter, just a bodger:

The last painted bit I did (iron base casting for PMR #3) I took the time to chamfer all the sharp corners and mask the machined areas.  Then set it on a cardboard box just outside the garage door, and started spraying light coats of "Hammerite" paint (the kind advertised not to require primer).  First coat went on looking like a tint, but I let it dry for an hour per the can instructions, and then put the next coat on.  And so on, for about 4 or 5 coats.  Then waited a day, flopped it on its side and hit the bottom with a couple of coats.  Came out looking pretty good.

Aluminum, brass - why paint?  Both are pretty corrosion resistant in the raw.

(Ducking and running)

[Stuart]

My problem with paint is I put it on inside out and it looks like a rough casting

The shiny finish is always on the inside and the side that should be on the casting is outside

It never looks any good  and makes me  and  then I  and feel like 

But hey I woke up this morning and hope to do tomorrow 

Stuart 

[b.lindsey]

Don't discount even the water based acrylic paints for airbrush use. I have found they hold up well and there are primer colors too for the base layer. Most are ready for use in airbrushes and clean up with warm water and soap is a snap.

Bill

[Rustkolector]

Gas_mantle,
Sorry, I did not realize you were in the UK. KG Industries Gun Kote protective coatings are not currently sold in the UK according to their website although Viking Arms in Harrogate does appear to distribute other KG Industries products. You might want to try some of the other baking gun coatings offered by Brownell's in the UK. They are all pretty tough coatings.
Jeff

[Gas_mantle]

Gas_mantle,
Sorry, I did not realize you were in the UK. KG Industries Gun Kote protective coatings are not currently sold in the UK
Jeff

No probs Jeff, thanks for your help and to everyone else who offered advice.

It kinda sounds like I'll get some improvement just by starting to use a primer 

[ddmckee54]

The thing that a lot of people do not realize is that most paints are not designed to stick to bare metal, they don't have enough of the proper binders.  Paints are usually designed to stick to primers, the primers are designed to stick to the bare metal.

Don

[Gas_mantle]

Thanks Don, I hadn't really thought too much about primers still I started asking questions here.

The next question is what kind of black paint do I need to paint a small boiler - the one I have is wood cladded but I want to paint the fire hole door and the base.

[Jasonb]

Stove paint works well, the Thermacure has not burnt of my flame licker

[Gas_mantle]

I've just ordered a few odds from Maidstone Engineering and thought about adding this to my order :-

http://www.maidstone-engineering.com/paint/paint-spray-brush/aerosol-black-matt-heat-proof-400m-for-use-on-boilers-up-to-650deg-c

At the moment I'm still figuring out what to make as a boiler base ring so don't need to paint just yet but it looks like the kinda stuff I need.

[ddmckee54]

Look like it's good up to 650°C so temperature shouldn't be much of an issue.  If you want a color other than matt black try looking for exhaust manifold/brake caliper paint.  Those paints are usually rated to the same temperature.  You'll also find listings for BBQ paint, but that will usually just be matt black so not much help there on different colors.  650°C puts you real close to the melting point of aluminum so that should handle normal boiler firebox operating temperatures.

Don