Painting Etched Brass Details

[C855B]

I'm at the point on the grand C855B project to start cutting bits from the etched fret of details. With only a couple of exceptions they are Harbor Mist Gray, so I plan to spray the entire fret as a unit and touch-up as needed.

My concern at the moment is a heads-up from @MRLX1020 that Tru-Color does not adhere well to brass, that he had instances of paint lifting with the masking tape. I won't need to mask the details, but I am concerned about handling. So it needs to be right, but the final coat has to be Tru-Color to match the rest of the model.

So the process I envision at the moment, advice taken from previous TRW threads about painting brass:

• Wash with alcohol, lacquer thinner or acetone to degrease.
• Sandblast or vinegar etch.
• Scalecoat I as a primer.
• Topcoat with True-Color.

Anybody see any problem with this before I... uhhhhh... paint myself into a corner? 

[Santa Fe Guy]

Looks like you have it covered Mike.
Rod.

[bbussey]

Tru-Color is similar to Accu-Paint. What I've done in the past is bake the brass parts prior to masking each color. Never had a problem with paint adhesion.

This CN sleeper has brass sides that were painted/baked and decaled prior to assembly with the ALM core kit components (which also were painted before assembly).

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[C855B]

^^^ Oooo... good point. I will do that. Even have an oven in the art studio for things like this. (No risk of spousal displeasure using the kitchen range!)

Concerns with the two-paint process is my experience with Scalecoat has it going on a little thick, and some of what I'm painting are grilles that will be one-too-many coats away from filling-in. If I can use the Tru-Color without the intermediate step, that's wonderful. Thanks!

[peteski]

It is always a good idea to test a new painting technique (and adhesion) on a scrap piece of the photoetched fret.

[C855B]

Without saying, Pete. I just finished rummaging through project scraps for something to verify the process.

[C855B]

Went from testing to production in short order. Specific testing with sprue scraps revealed the biggest contributor to finish durability was sandblasting. Debatable whether baking would do any good. I did, but while waiting I surfed around and read a couple of posts in other forii that claimed Tru-Color is a lacquer and not an enamel (sounds reasonable), but that baking only benefits enamels such as Scalecoat. Hmm.

Anyway, I'm happy with the result. There will be touch-ups from tooling such as bending handrails, but by and large this was a success.

[narrowminded]

Thanks for posting this.  

Did you use a true sandblaster or a small pencil unit like the Badger?  And then, the pressure and the abrasive?  That would complete the information nicely.

[C855B]

Paasche Air Eraser with AEX (fast) grit. As to pressure, I was distracted by something when I intended to adjust the regulator to recommended (35-40 psi), so it was inadvertently left at 100 psi from using an impact wrench. However, I was very pleased with the ease and consistency of the "cut", so I will be erring on the high side in the future.

[peteski]

Good to know!

Tru-Color is a lacquer as it can easily be redissolved (and can even be reused) after it is dry. When enamels dry and harden (by a chemical reaction), they cannot ever be brought back into usable liquid state. PAin stripper or lacquer thinner will wrinkle them so theycan be removed, but the enamel will remain undissolved.

[bbussey]

There also are reports of baking being a benefit for laquers and acrylics.  I've baked Accu-Paint on brass in the past, which has been far more durable than not baking.

[coosvalley]

Not sure of the truth of this , but I heard Accu-paint(and thus Tru Color) is actually an ink.......

A lacquer ink?

[peteski]

Not sure of the truth of this , but I heard Accu-paint(and thus Tru Color) is actually an ink.......

A lacquer ink?

I have also heard that George Bishop (proprietor of SMP Industries which manufactured Accu Paints) used to buy some sort of ink in large 5 gallon containers and pour it into the small bottles to be sold as Accu Paint. So I heard the same rumor. But I'm sure that whoever makes the Accu Paint and Tru Color is guarding the source of their paints.   

BUt I don't think it is the ink we think of (for printing newspapers or magazines). It is likely some specialty ink used maybe for Tampo priting or for printing some weather resitand items.  But since it can be redissolved it fits the definition of a lacquer.