Painting brass models?

Hi,
I've painted plastic models before, but I have a recently-acquired brass caboose that I'm planning to paint in the UP yellow-and-red scheme. I'm using
water-based acrylic paints, and I was wondering if there is any special preparations/techniques I need to use when painting brass? Any advice would be appreciated.
Cheers, Danny B
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Danny B wrote:

Brass will absorb skin oils and such, which means that preparation is most important.
-- absolutely clean - use solvents, detergents, and clean water. Handle with museum-style cotton gloves, which you should change for fresh ones at least once during this process. -- use a solvent based undercoat designed for brass - acrylics will not bond well with brass, if they bond at all. Bake the undercoat. -- some people advise sand-blasting before painting, to create a "tooth" for the paint to adhere to. -- last time I painted brass, I used a solvent based paint, baked on at about 120C. But even so, some of the paint flaked off later - I wasn't careful enough in handling the shell after cleaning, and/or the ordinary dish-washing detergent I used didn't get the grease and oil off properly, and/or I didn't use an undercoat. So learn from my mistakes. ;-)
HTH
--


Wolf

"Don't believe everything you think." (Maxine)
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Wolf wrote:

As Wolf said, surface prep is everything in getting paint to stick to metal. First off, is the caboose bare brass or does it have a clear lacquer coat to prevent tarnishing? Net rumor has it that any such lacquer coat should be stripped off. I'd do some checking on that, look for a Kalmback how-to-do-it book, or google for "brass model paint". Assuming you do strip a lacquer coat, do a thorough job and get it all. Then run the model thru the dishwasher. The hot water and detergent will do a good degreasing job. Remove any non metallic parts which won't stand water before you do it. Then try to pickle the metal with a mild acid. Vinegar is strong enough. It should make the shiny brass go sort of matte finish. Then give it another trip thru the dishwasher. At this point don't touch the metal with your fingers, the finger prints will make the paint fail to stick.
Then do a prime coat. Use real automobile primer from the auto parts store. This stuff is specially made to stick to auto body metal, which is a little greasy, a little rusty and hasn't had the good surface prep that you have just done. It has the best stick-to-metal qualities that money can buy. Choose your color. Red primer makes a red finish coat cover well, light gray primer makes a yellow finish coat cover better. I assume you are going to paint the entire caboose one color (the base color) and then mask off and spray on the second color over the first. Pick a primer color to go well with your base finish color. Spray the primer just right, not so wet it runs and drips, but not totally dry either. You want a hint of wetness in the prime coat right after spraying. Just a hint, not a drippy runny wet. When spraying, push the button BEFORE the spray is pointed at the model, wave the paint spray down the length of the car in an even sweep right off the other end. Don't release the button until the spray has moved clean off the other end of the car. Let the primer dry good and hard. At least over night, a couple of days is better. It dries better on a warm dry sunny day. Once you have a good prime coat dry, it will paint like just like plastic, so you can do the finish coats just the way you always do them.
Good luck
David Starr
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Wolf wrote:

Would that also work for high temp paints for copper or brass boilers?
Dan, U.S. Air Force, retired
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Dan wrote:

[...]
I should think so, but have no experience with such paint.
--


Wolf

"Don't believe everything you think." (Maxine)
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Danny:
I'm a bit puzzled. You posed the same question three months ago and received, IMHO, some very good replies. Were any problems encountered when following those suggestions? If so, could you share them with us? Learning of any possible mishap might save some of us from falling into the same trap. Thank you.
Jerry
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@hotmail.com wrote:

This topic could probably start a religious war. But in spite of all the techniques tried over the years the best, and one favored by almost all the Pro Painters (a dying breed so it seems) is to clean the Brass thoroughly in Lacquer Thinner or Acetone followed by a warm soapy wash/scrub and rinse. Noe of this is new or exciting mind you. The real magic is in paint selection and curing. I would strongly urge you to locate some of the old Scalecoat and apply thinned, light coats letting them set up a bit before putting on a heavier finish coat and then while still wet bake the painted model for a few hours. Make certain that the oven doesn't cycle too high obviously but the paint job because extremely hard and durable. And a nice gloss finish that takes decals well.
I just can't imagine painting Brass with non Lacquer Base paints. Did it once and experienced a lot of peeling from masking tape (low tack). Stripped and did the Scalecoat thing and voila... problem solved.
Regards
Bill
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
That completely slipped my mind. I received the model from the US just before University started, and with the workload I haven't actually had a chance to paint it yet. I've only just finished exams now, hence the accidental reposting.
== Quote from " snipped-for-privacy@hotmail.com" ( snipped-for-privacy@hotmail.com)'s article

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.