Painting Brass Key S4 - to strip or not to strip?

[nickelplate759]

I have an old Key S4 in my "to be resurrected" inventory.  It was never painted, still in it's factory clear coat, which seems to be in good condition.
Has anyone tried painting over the clear coat rather than stripping and priming?  How did it turn out?


[edited title to make this more generic to brass models]

[mark.hinds]

I assume you're talking brass, covered in factory-applied clear lacquer?  I have a large number of Hallmark/Key/etc. brass locomotive models from the 1980s, including a Key S4, and those which I worked on, I first stripped by soaking in acetone.  Reason was to allow soldered modifications, and to eliminate the useless extra layer of paint, which presumably would have made the etched detail less visible.  FWIW, as I am not directly answering your question. 

MH

[nickelplate759]

Yes, it's brass, with factory lacquer.  What I'm wondering is - does the lacquer make a decent primer (it's certainly bonded well to the brass - no flaking or oxidation under it), or should I strip it and reprime?  I'm not going to solder it, or, as you point out, the answer is easy - you HAVE to strip it.

[robert3985]

On ALL of my brass engines that needed to be either painted or repainted, I stripped them.  The factory clear lacquer I can't trust.  I also never use a primer on brass engines or cars...just plain old Scalecoat II on brass that's been thoroughly de-greased and de-linted.

Photo (1) - N-scale Hallmark brass "U.P. Welded Caboose" in pure stock form:


Photo (2) - Hallmark "U.P. Welded Caboose" after stripping, modifying and soldering on more prototypically proportioned parts:


Photo (3) - N-scale U.P. CA-8 as received in 1964, painted with Scalecoat II enamel, without primer:


Also, I bake my brass paint jobs in my little toaster oven with an oven thermometer on a clean piece of 1X4 clear pine, making sure to never get above 175 deg F.

As you can see from the photos, the original paint on this particular model was more than merely "clear", but was an actual brass paint color.  I also paint the interiors of my brass models so that there is no "natural" brass showing anywhere other than where electrical connections need to be made.

I like to use as few coats of paint as possible, so getting rid of the original lacquer lets me use one less layer, and also have ultimate control of the paint job.

Cheerio!
Bob Gilmore

[up1950s]

When I was in HO about 1975 era I used to strip my brass , prime , and bake them on a 1968 ishTappan stove that had a plate warmer on top ,. Got them too hot to touch but never harm to solder and paint .

[peteski]

Harvest Gold (and Avocado): the "stainless steel" appliance finish of the of the '60s!
Yuck! 

[up1950s]

Harvest Gold (and Avocado): the "stainless steel" appliance finish of the of the '60s!
Yuck! 

Ours was a copper browinsh .

[wvgca]

on -most- it's recommended to strip off the clear before painting .. paint preparation could involve 'pickling' or a soda blast treatment ..,
the old clear coat usually was not consistent in depth, and details -could- be lost or de-emphasized with the additional clear before paint layers ..
it depends on the condition of the clear and the assumed depth of it ...

[SP-Wolf]

Well - I went against convention.
I painted over the factory clear coat. I use Tru-Color. Before painting on the black - I sprayed the model with Tru-Color's thinner. My thinking: first to clean the model - second was to give the paint some bite. 

The results:
Hallmark DS-4-4-1000


Hallmark S-12


Thanks,
Wolf

[JMaurer1]

I am a stripper...

Occasionally I wouldn't strip (back in my HO days) and I had trouble later when the factory clear would decide to stop sticking. The base clear also makes the railings 'bigger' since there is already a coat of paint. Also, stripping removes any oil (as in finger or lubricating oil). This becomes a MUCH BIGGER problem if you are using water solvable paint since oil and water...

[robert3985]

on -most- it's recommended to strip off the clear before painting .. paint preparation could involve 'pickling' or a soda blast treatment ..,
the old clear coat usually was not consistent in depth, and details -could- be lost or de-emphasized with the additional clear before paint layers ..
it depends on the condition of the clear and the assumed depth of it ...

I toss my disassembled brass models into my ultrasonic cleaner with ultrasonic divestment solution (very stinky), which strips them and gets rid of any brass oxidation at the same time. This takes from 45 mins to 1hr 15mins...sometimes for really thick paint, a bit longer. I then carefully pluck and peel the softened old paint from them, then rinse them two or three times in the hottest water my tap will produce, then let them air dry so that any parts that may have come loose don't shoot across the room if I "helped" the drying process with compressed air.  If I'm in a hurry, I'll use a 1500W hair dryer, which will still blow the small parts that come loose, but only onto the white towel I put on my drawing table to catch them.

For de-greasing after cleaning up the model, adding, subtracting or modifying parts, I put on my Nitrile gloves, and give them a first cleaning with several shots of Brakleen in my garage, then clean them with a stiff artist's brush and Bestine in my spray booth.  This gets them totally de-greased and ready to paint.  If I have to wait a few days before I paint them, I hang the parts in my spray booth with its doors closed to prevent dust and lint from settling on them.

That's the complete pre-paint process I go through getting my brass models ready for paint.

Cheerio!
Bob Gilmore

[nickelplate759]

Well, I finally got around to moving forward to this.  After much debating, I stripped the lacquer with acetone.   It will get a coat of Scalecoat II in the morning, then a nice rest in a warm oven for an hour or so.

After that, I get the fun of figuring out how it goes back together!  It's been apart so long I don't really remember.

[peteski]

  It's been apart so long I don't really remember.

And I thought I was the only one having this type of a problem. Some of my half-completed projects are over 20 years old! 

[wvgca]

i -think- you will be happier with the slightly increased detail of one less coat of paint ...admittedly it a lot of extra work, but in my opinion, worth it ..

[nickelplate759]

Well, after drying overnight after an Acetone bath, I see that not ALL the lacquer was removed.  The truck sideframes are fine, as is the shell, but the frame has a lot of (now discolored) lacquer still left.  Maybe it had a heavier coat?    Gonna try again with Acetone and see what happens.