Paint Stripping help.

[x600]

On the mission to paint a D&H SD70ace, I procured a Kato UP for a good price and figured it would be just as easy as any of the more complex heritage schemes. I was partly right, as a short soak in 91% alcohol cleanly removed the grey, and the yellow underneath, plus the red numbers and stripes.

What it didn't touch is the big flag, the UP shield, "Building America", and all the little safety labels.

 I tried a few of the usual plastic safe fluids like brake fluid, and non-acetone nail polish remover.
Not even any color on the q-tip. Even tried a very, very small touch of acetone. No joy.
I normally would paint over some lettering, but this printing, like the stipes on the flag, are so thick you can actually feel them, and it will stand out even if I use satin instead of gloss.

 SO.... my question is: WTF will remove this print without using some exotic liquid unobtainium????

Oh, and it's been soaking in 91% for almost 24 hrs. Not even a budge.

Thanks in Advance!!!


Greg O.

[nickelplate759]

Greg,
My favorite stripper is Scalecoat Washaway  (https://scalecoat.com/), but I don't know if it will touch this either.

Only other idea I can think of is a small sandblaster, maybe with baking soda.

[Jesse6669]

Ironically the prototype's flags are shamefully flaking or burning off.   Maybe try diesel smoke and brake dust?     
But beyond what you've already tried, you might go with 99% ISO and a longer soak--maybe a bit of toothbrush scrubbing to cut into the surface and re-soak?  Or that Scalecoat stuff if you can find it.

[kornellred]

The abrasive blasting idea is probably the best idea proferred so far, as long as you have a suitable air compressor the abrasive gun is cheap.  And the baking soda is next to nothing.

I was going to suggest scratching up the surface of the flag with a fiberglass brush so that whatever solvent you might use can undermine the paint or decal the flags are made of and soften them up for removal.

It will be interesting to discover the method that eventually works for you.








the

[x600]

Thanks for the replies. The decision I made was based on pure thriftyness. (Cheap) Since I don't plan on stripping too many more engines in what's left of my lifetime, $30 + shipping for a bottle of something that may or may not work, verses $30 free shipping for a cool looking air eraser that I might use again for blasting the rust off of my....... wheelbarrow, yeh , wheelbarrow, made economic sense.
 Mr.  Amazon should fling it on my porch tomorrow, so I'll test it on some junk, then the Flag and post the results.

Greg O.

[ednadolski]

I can get those off using the soft plastic-bristle roatary brush tip in a dremel, with the shell in a bath of the 91% alcohol.   An ultrasonic cleaner might work too.

Sometimes I will let it soak in the alcohol for a couple of days first.  If non of that works, then gently scraping w/a curved scalpel blade or some fine grit (say 600-800) could perhaps get it done.

Ed

[x600]

That is something I can try, thanks Ed. So I let it soak in 91% over night and hit it with several of the
different brushes I had for the Dremel. I also had some polishing tips and tried them. Still didn't even make a dent or change the color one bit. I originally thought about sanding or scraping, but the flag is right over the doors and I didn't want to damage any of the details. I have a fresh box of baking soda, so I'll just wait for the air eraser and hopefully, that will do the trick.

Greg O.

[x600]

As promised, the Amazon truck stopped by on a lovely Sunday morning and dropped off this beautiful plastic thingamabob.


It came with 2 bottles of black sand which I thought might be a little strong for what I needed, but it looks like it might be a good cinder ballast. 
 I set up my stuff outside, loaded the hopper with baking soda, and tried it out on another shell before I hit the Flag. The nozzle is a little large for what I needed but I decided not to go to the hardware store to find a smaller fitting. It worked well, but a lot of the baking soda was wasted in the breeze. This probably balanced the ph in that area of the yard. I was able to clean the flag and shield off quite nicely
 but I was surprised that the shield actually had a buildup of material under the paint, like 3d printing.
Also a few of the letters in "Building America" and the stripes in the flag looked like they were molded in the body.

You can see part of the shields and a few letters. I was able to remove more of it on the other side, but ran out of baking soda. I think I can sand this off enough to hide.
The stripes in the flag also left some remnants but it was starting to hit the details a bit.



We'll see if the paint will cover and not ghost through.
Thanks for the input and for riding along.

Greg O.

[peteski]

Looks like the blasting actually etched (ate into) the surface of the plastic shell.

I wonder if the flag, instead of the old Tampo printing method, was printed using an ink jet and UV-cured ink?  Similar to what MTL uses to decorate many of their cars nowadays. I would have recommended trying Naphtha or "Purple Power" degreaser.  Those might have removed the paint used on the flag. 

[ednadolski]

Looks like the blasting actually etched (ate into) the surface plastic shell.

Not sure if that could be fixed with putty?   If not tho, please PM me... I am not sure, but I may (if I can find it) have one of those shells (stripped)  from an old project that you could have as a replacement.

Ed

[x600]

It did etch into the detail a little bit. In my exuberance to get it done, I didn't wait until I could put together some kind of smaller nozzle on the air eraser. It was like swatting a fly with a 12g shotgun.
when the work got a bit finer it was hard to focus the stream of powder. The damage is just on the one side and is minor after a some touch up with a new chisel blade and fine sanding.
 Ed, thanks for the offer of a shell, I may take you up on it. I'm going to go ahead and paint this one and hope for the best.  If it's not up to my saleable standard, maybe I could trade for something you need.


Greg O.

[Rivet Miscounter]

I would have recommended trying Naphtha or "Purple Power" degreaser.  Those might have removed the paint used on the flag.

Purple Power has been my recommendation since someone (maybe you?) recommended it to me 20 years ago.   Seems lately every time I have recommend it I get somebody telling me I'm wrong...so I've stopped suggesting it.   But yeah it has worked for me quite well when IPA doesn't cut it.

I guess I deserve it...I've cautioned people about using brake cleaner for decades now and there are still those who swear by it too.   After I had a stripped-by-brake-cleaner MDC bathtub gon pretty much turn to dust in my hands when I was in high school, I decided that probably wasn't a good idea.  Plus brake cleaner is just nasty stuff in general.  Purple Power probably is nasty too but at least I've never had it sap the 'lastic out of the plastic.

[peteski]

Yes, it could have been me who recommended Purple Power as it is one of the go-to strippers in my other hobby (automotive model car kits). We usually call it "purple pond", like in "I dunked the (car) body in the purple pond". If you have few spare hours, there is a huge thread about plastic safe paint strippers: https://www.modelcarsmag.com/forums/topic/83153-paint-strippers-what-to-use/

Originally there was only Castrol Super Clean (CSC) purple colored heavy-duty degreaser/cleaner. It worked well for stripping many (but not all) types of model paints. Later other companies started producing similar products calling them "Purple Power" or similar.  All of these are Lye based, and so is the original formula Easy-Off oven cleaner. Other Lye-based hobby stripping solutions have been produced by cottage industry over the years.  Lye is a nasty caustic chemical which attacks most paints, but it seems totally safe on polystyrene or ABS plastics.

Other hobby strippers like Foquil/Testors are glycol based, and they also do a decent job stripping hobby paints, but they can sometimes slightly attack the plastic surface.  DOT3 brake fluid is also glycol-based and some used it for stripping paint from plastic.

Problem is that there are many different formulations of plastic and different ways to apply the stripper.  Some older plastics can be affected by glycol-based strippers. Also if someone just dunks the entire object into the stripper, it can be more affected than if someone just brushed the stripper solution on the model. Then the temperature also makes difference too.  The warmer is the stripping solution, the more aggressive it seems to become. That is why some modelers have no problems using DOT3 brake fluid, while others experience damage to the plastic being stripped.

Then there is also Scalecoat Wash Away Paint remover. I'm not entirely sure what it has for active ingredients, but in my experience it can also slightly affect some of the plastic itself.  I have about alf a dozen of various stripping solutions. Usually one of them gives me the desired results.

Here are some related TRW threads:
https://www.therailwire.net/forum/index.php?topic=27613
https://www.therailwire.net/forum/index.php?topic=32998
https://www.therailwire.net/forum/index.php?topic=50854
https://www.therailwire.net/forum/index.php?topic=58707
https://www.therailwire.net/forum/index.php?topic=44744 Pine Sol
https://www.therailwire.net/forum/index.php?topic=28652
https://www.therailwire.net/forum/index.php?topic=32998
https://www.therailwire.net/forum/index.php?topic=37251
https://www.therailwire.net/forum/index.php?topic=45508

[Chris333]

I remember using Easy-Off oven cleaner to strip chrome off of model car parts. Damn that was like 35 years ago...

[OrangeAnon]

Unfortunately a bit late for Greg, but hopefully in time for anyone else running into this problem in the future. I came across this same issue when stripping a Promontory museum car in my quest for a Gordon Zimmerman #5659 Baggage Car. After the isopropyl alcohol soak and scrubbing off what I could with a toothbrush, I noticed that the flag print was kind of puckering along the bottom edge. So I very carefully, so as to not scratch the plastic, slipped the tip of a blade under and wouldn't you know it, the print just started peeling off, some chunks bigger than others.



The result after carefully peeling off what didn't come off in the initial scrub:



Another soak to get the remaining yellow and it's stripped to my satisfaction.