What removes acrylic paint but not the varnish?

[PeteySödes]

Not actually a joke setup.... 

 

Im looking to paint a finishing segment on a part that i've already blended. Normally I just go back and correct mistakes with the base color but its not possible (feasible) in this instance.

 

Plan is to gloss varnish the surface then go to town. I have read that denatured alcohol on a swab would do the trick but wanted to confirm that it wouldn't "eat" the varnish underneath should i need to correct some lines.

 

Anyone done anything like this?

[Wispy]

i've never done this, but i recall a time i tried to use simple green to strip paint from a model only to have it do all because the paint i was trying to strip was a tamiya lacquer.

 

so theoretically, if your varnish is lacquer based, maybe you're okay? then again, i just stripped a model with simple green and it was spayed with a testor's lacquer (dull coat), so maybe not?

[Major_Gilbear]

It depends on the varnish... Something like an enamel would be too thick I think, but could work for your purposes.

 

If you use a lacquer, and you're careful with the isopropyl alcohol, you might get away with it too.

 

However something like an acrylic or a polyurethane would just come off the paint because they are just too close in terms of formulation to the paint (that's my personal experience at least, after a varnishing mishap).

 

For what you're looking at doing, I believe it's more common to use oil paints over varnish, as they can be reactivated or removed with mineral spirit.

[crd26a]

Could you go with the hairspray technique?  Sounds like you're trying to just ensure some lines that might get put over could get hit.  Let's you just use some water to soak into paint and then scrape away.  Could be worth a shot

 

https://miniarmour.net/2012/01/16/hairspray-technique-tips-tricks/ 

[Semper Fortis]

I've done it successfully but only on paint that was very fresh, like less than ten minutes. I had two layers of well cured gloss varnish down and used those really tiny cotton buds that Tamiya (?) sells. Cotton buds were just damp with alcohol and I was very gentle. (Do you sense a lack of confidence here? :) )

 

It worked well enough to let me get some free hand down on an already finished model.

 

Edited to add --- Oh, and I prayed to the Emperor and asked the intercession of St. Celestine the entire time.

[PeteySödes]

Thanks all!

I already have a layer of hairspray for the rust weathering haha. Im just painting a design over what i assume ill use is Liquitex gloss varnish. The paint would be fresh for sure since id be going slow and cleaning lines as i go.

I think ill try the alcohol with some airbrush cleaning swabs since they're so tiny. I'll definitely pray to Russ and the allfather though as you say.

[crd26a]

You could add drying retarder to the paint and have some of the swabs wet & ready to go.  Wipe it up quick before it sets and dries, the retarder just buys you time

[Major_Gilbear]

Something else to consider might be a few layers of varnish rather than just one, with a good 12+ hours of curing time between layers. That way at least if you do remove some of the varnish, it will only be the outer-most layer or two that ablate, leaving the lower layers and the paint beneath intact.