Acrylic paint on buildings

[Faavs730222]

Hi, I am having trouble with acrylic paint on my buildings. I use Tamaya acrylic paint thinned with 70 percent Alcol for airbrushing. As soon as I do the mortar lines and  rub the access of the brick color also comes of. Am I doing something wrong? Should I paint the structure with primer first? Will normal enamel primer from a can work with acrylics? Any help would be appreciated.

[Stourbridge Lion]

Faavs730222 - Welcome to trains.com!

[EM-1]

Just kind of a guess, how long are you letting the base color dry before applying the detail color?  It might be a good idea to let the paint dry at least 3 or 4 days before applying the mortar lines.  There is often a difference between a paint drying to the touch, and being fully dry.  Many paints, and glues, even the instant set CAs require at least 24 hours to fully dry or set.  Come may require more than that.  And some, like Epoxies, actually have a change in structure, a curing or setting process, as well as a drying process, taking place.

[cowman]

Welcome to the forums.

Another sort of guess here, to add to the above drying idea.

How are you applying the detail color?  If you are spraying it, again using alchol as a thinner, it may be that it is reacting, especially if it is not fully dry.  You might try just wiping on a wash, thinned with water to get your mortor color in place.

Just a thought.

Good luck,

Richard

[Jumijo]

The alcohol used in your mortar paint is attaching your brick color, and makes it easy to wipe off. Try using brick-colored red primer from a spray can for your base color. The alcohol won't affect it. At the very least, spray a coat of Dullcoat over your existing brick paint before spraying the mortar color.

[Medina1128]

Jumijo

The alcohol used in your mortar paint is attaching your brick color, and makes it easy to wipe off. Try using brick-colored red primer from a spray can for your base color. The alcohol won't affect it. At the very least, spray a coat of Dullcoat over your existing brick paint before spraying the mortar color.

I have to agree with Jumijo. If you're using acrylics, you will need to seal it with some kind of clear coat. Be advised that the clear coat  (especially if you use Testors Dullcote), it will turn kind of a chalky white if it comes in contact with alcohol. No worry, though. Another coat of Dullcote will turn turn it back to clear.

I also use primer for my base color. Make sure you get lacquer, instead of enamel. Its drying time is much shorter.

[wjstix]

Acrylics are water-based paints, so normally would be thinned with water. A little alcohol can be used but a lot can have a negative effect on the paint. Keep in mind too that unlike solvent-based paints, most acrylics come pretty much ready to spray, but sometimes may require a tiny bit of thinning with water.

It's generally a good idea to always primer anything you're going to paint. I like to use Tamiya gray primer from a spray can. It has a very fine spray and goes on (IMHO) just as smoothly as airbrushing, with a lot less work.

FWIW I generally paint a brick building's walls (before building the kit) in primer gray inside and out, and then color the raised bricks with a dark red or brown art marker.

[dknelson]

I use distilled water to thin my water based paints and I suspect the gallon I bought will last a lifetime.  I also use it as a first "cleanout" of the airbrush. 

As to the problem of the paint washing away, in addition to the possibility that the alcohol itself is weakening the paint coat, is there a chance the surface of the plastic has oils from handling? 

Dave Nelson

[Boise Nampa & Owyhee]

The ideas noted above are all good and possible......... especially with the high concentration of alcohol that you said you are using.  It is causing the fresh paint to become a solvent for the previous.  This is common in lacquer and solvent based products but not so common in acrylics.

Try "Changing the medium"...  this is a little trick I use to prevent solvent lifting.

Do you put your brick color on first or the mortar lines? ? ?  This is the Ford and Chevy pickup debate  ! !

I spray on with the cheapest gray primer I can find in a big box.   That is a solvent base and no acrylic will touch it later.  Then I dry brush on my brick colors. Note plural... I use a number of colors as bricks are seldom all one color. they vary as to where they were in the pile when fired.

If you insist on putting your mortar on last.... Don't use alcohol for a solvent in your acrylic but plain water.  Be sure your base color is REALLY dry and then flow on a really diluted wash that you don't have to rub the surface clean. Just let it flow into the mortar lines and see what you get.  Otta get it..

see ya

Bob

[leighant]

dknelson

I use distilled water...  I also use it as a first "cleanout" of the airbrush. 

Gee, I woulda thunk you would use ordinary water for the FIRST cleanout, and distilled water for the LAST clearnout, when you've got it pretty clean and want to get it get completely OK.

But maybe there's something I haven't thunk of...

[Faavs730222]

Thank you all very much for your replies. I will try your suggestions.

[modelmaker51]

It's ok to use a drop or two of alcohol to promote paint flow, but not so good to use as a thinner as it can weaken the paint. I use an 80/20 mix of water/alcohol that I keep in a used acrylic thinner bottle and then thin as needed. Be sure give the wall a couple or 3 coats of paint and let cure for a week, before using any "wiping" tecniques.