Effects of Water and Paint

[LokisTyro]

I was thinking about this for a minute and wondered if anyone had any info on it. I live in a rural area with a well. It's filtered in a couple different spots so it comes out clean to the eye. But I was wondering if there were any known effects from "contaminated" water sources. I haven't had a problem with mine, but I'm a bit curious. Are people using water-softener or treated water unknowingly ruining paint jobs?

[Ace-Garageguy]

Interesting question. I've found that cleaning models with 70% isopropyl alcohol before priming and painting pretty much eliminates any surface contamination from questionable water, mold or die lubricant, detergent or stripper residue, handling or just sitting around.

[LokisTyro]

Do you use a tack cloth as well? How do you apply the iso?

[Ace-Garageguy]

Do you use a tack cloth as well? How do you apply the iso?

I don't use a tack-cloth, even on 1:1 jobs anymore. For me, blowing the work off with clean, dry, filtered air works better.

As far as the iso goes, I use a pretty well saturated white paper towel, folded over into quarters, to wipe it on, and a clean dry one to wipe it off. Having a pretty much sterile area (wiped down with iso first) to lay the model and towels on during the procedure insures against picking up contaminants from a table, etc. I wear clean latex (non-powdered) gloves as well.

It may seem like overkill, but the hours it can save correcting fisheyes is worth a few extra minutes to me.

[64SS350]

I like to follow Lone Wolf's method, wash with mild soap, rinse completely, use airbrush to blow dry, then paint immediately after.

[Ace-Garageguy]

I like to follow Lone Wolf's method, wash with mild soap, rinse completely, use airbrush to blow dry, then paint immediately after.

I'm sure that works very well, as his results speak for themselves.

I personally prefer to thoroughly scrub my bodies with hot water, with a toothbrush and an abrasive cleaner like Comet. I find it roughens the surfaces perfectly for maximum primer adhesion and flowout (I use Duplicolor, SEM and Plasticoat automotive spraybomb primers); it also gets into the very small crevices around molded details that sanding misses entirely, and it doesn't soften the details like sanding certainly can. Then a hot water rinse, and a wash in isopropyl before primering.

I do a lot of heavy bodywork, and my models often sit for weeks waiting for the primer to fully shrink in. I've had surface contamination issues that caused massive fisheyes and took a LOT of time to correct on a couple of occasions where I failed to iso-wash a primered body that had been sitting out for some time, before painting. It's more work, but it's good insurance for me, and I wouldn't skip the step now for anything.

I got into the habit of Comet-scrubbing everything (even small parts) before primering as a result of buying and restoring rather a lot of gluebombs over the years, and noticing how paint on very old models sometimes seems to crack and pull away from crevices, indentations and areas adjacent to molded details. Paint tends to be thicker there, and so it shrinks more (as there's more there to shrink). The Comet scrub roughens these potential trouble spots nicely, and also thoroughly removes any stripper-residue (brake cleaner, Easy-Off oven cleaner, etc.) which is often left when one removes paint from a gluebomb.

I finish with an isopropyl wash, as mild soap won't remove some contaminants like silicone...which will cause horrible fisheyes if painted over.

Different methods work for different people using different materials in different situations.

Edited November 17, 2013 by Ace-Garageguy

[Art Anderson]

I like to follow Lone Wolf's method, wash with mild soap, rinse completely, use airbrush to blow dry, then paint immediately after.

I've washed body shells off with ordinary DIAL handsoap and a toothbrush for years, before painting, and also use my airbrush (without paint, of course) to blow dry the body shell.

Never have a problem with paint issues using this method.

Art

[Mike_G]

Watch out for lanolin and fragrance in 70% isopropyl alcohol- lanolin in particular can cause problems

Definitely avoid any labeled as "rubbing" alcohol, as that's normally the type with lanolin added to avoid drying out yer skin

I get the 92% stuff to be safe and as an added benefit it works great for thinning Tamiya acrylics for airbrushing

[Ace-Garageguy]

Only problem with 91% isopropyl is that it will attack some paints. If you're trying to wash something that's been sitting and gassing for a while, lets say, before shooting color over primer, or clear over color, 91% can cause you real grief.

Test, test, test.

Edited November 21, 2013 by Ace-Garageguy

[Mike_G]

Only problem with 91% isopropyl is that it will attack some paints. If you're trying to wash something that's been sitting and gassing for a while, lets say, before shooting color over primer, or clear over color, 91% can cause you real grief.

Test, test, test.

That's very true- I was referring more to bare plastic prep.