Methods for Removing Factory Paint off Plastic Models?

I have a set of Atlas O Alco C-630's that I want to paint up in a fantasy SP&S "Spokane Portland and Seattle" colors "Green and Yellow" (I know that SP&S didn't have C-630's)

I have everything to paint these professionally but I've only stripped paint off brass/die cast items. I've only painted plastic models that did not have paint on them originally.

Anyways I wanted to pick your guys brains on stripping paint off plastics. I believe these are an ABS type of plastic. I've heard of Spray on Oven Cleaner working, Simple Green.... Bake Fluid??

What methods have worked for you guys?

Thanks!

 

Original Post

I do not try and strip paint from plastics.....there is no need. use the factory finish as your substrate. first thoroughly wash the piece with warm soapy water. let completely dry. next, any heralds emblems, or road numbers you want to vanish, use fine sandpaper (600 or finer) to blend out into the original finish. then scuff the entire piece with gray scotchbrite. depending on the amount of different levels of colors piled on top of each other, will determine how much blending you have to do....the trick is not to break paint. if you do its not the end of the world, you will just have to use primer to build the area back up. then repeat the blend process with the fine paper. At this point, depending on your choice of refinish color, you can use a quality model primer or a sealer to prep for your new finish......I'm sure AMC Dave will hop on here too, and some of the other fellas too that have turned out beautiful models.....again, no need to strip....if you are not careful, you can wind up with a hot mess quick!..

The Water Level Route.......You Can Sleep

Hi Bruk

brake fluid works but its slow, media blasting is nice but not often available

I have used 'super clean'  foaming tough task cleaner degreaser in purple spray bottle from auto parts stores

it works good at removing the pad printed lettering without removing all paint at least on some chineese Bachmann cars I did

If the factory graphics are not too heavily applied you could prime it lightly and topcoat from there

Good luck and be patient

Dave

 

I've stripped multiple Atlas loco shells using just 91% isopropyl alcohol.  Available at most any drug store or walmart pharmacy.  Relatively inexpensive too.  I let shells sit for a day or two.  It doesn't take long.  Rinse and use a toothbrush or similar to get into the nooks and crannies.  It's my preferred method as it's relatively benign with respect to odor and cleanup.

It did not work on the diecast frame though.   I don't know if it's different paint, or simply better adhesion.   Even after soaking for an extended amount of time, the paint wouldn't come off.  I used the spray on Citrustrip, bought at Home Depot, to strip the frame.  Again, I was looking for a safer alternative since I was doing this work in my apartment.  If I had a shop, I probably would have tried something more aggressive.

You cannot use the 70% type alcohol.  Only the 91% type.  The paint lifted right off in most areas.  The corners were more stubborn.  

013011

Jim

 

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I used Easy-Off (for ovens) on my Weaver GP38-2 plastic shell.  It worked great.  Actually, I use that to strip all of my diecast now too because it worked so well.  I tried the alcohol route, let it sit for a while and nothing.  Someone suggested the Easy-Off, but I was too scared to use it.... at first.  Wish I would've listened because it would've save me a bunch of time!

Here is my thread documenting the process.

Stripping, Detailing, and Repainting Project

-Mike

Mechanical Designer

Big Train has it. 91% Alcohol. Its cheap and works great over night. I just stripped (4) ALCO C424/425's from Erie Lackawanna paint.. worked great over night sitting in the alcohol. Also, use a scrub brush with plastic bristles to scrub the paints off..  Dan 

You can order 99% Isopropyl Alcohol from on-line places.  Here it is on Amazon: 99% Isopropyl Alcohol (2-pack).  It will be the most effective, and I like it as it evaporates quickly when I use it for cleaning.

Bruk posted:
big train posted:

You cannot use the 70% type alcohol.  Only the 91% type.  

What about anything higher than 91%, would that work? Curious because I have access to IPA at work

I don't think it's a problem to use something with a higher content, if you have convenient access to it.  70% and 91% are the two types most easily acquired at the local drug or grocery store.  Between those two the 91% is the way to go.  I did briefly look into buying from a supplier so that I could get a bigger volume, by the gallon.  It can take a lot of alcohol to fill the size tub needed for an O scale loco or car.  You can get a funny look or two when you checkout with 20 small bottles at the store.  

For the tub, I just used a plastic storage container.  But another good idea is a wallpaper hanger glue trough.  It's the right shape for O scale type stock.  But no lid, so I would cover it with plastic wrap or similar to prevent evaporation.

It would appear that 99% costs about 4 times as much as 91%, based on GRJ's link, but if you have it at work then that's not an issue.

Jim

mjrodg3n88 posted:

I used Easy-Off (for ovens) on my Weaver GP38-2 plastic shell.  It worked great.  Actually, I use that to strip all of my diecast now too because it worked so well.  I tried the alcohol route, let it sit for a while and nothing.  Someone suggested the Easy-Off, but I was too scared to use it.... at first.  Wish I would've listened because it would've save me a bunch of time!

I tried the 91% alcohol on some Weaver Centerflow hoppers.  On some, the paint came off in sheets almost immediately.  On others, the paint didn't budge even after and extended bath, soaking upwards of a week.  So maybe they had used different paint formulations at different times?  The project went on hold so I never got around to testing anything different on the stubborn Weaver shells.

If the alcohol doesn't dent the paint, EZ-Off oven cleaner is my next choice.  I always use oven cleaner on diecast paint, whatever they use seems impervious to alcohol as previously mentioned.

HARMONYARDS, above: "I do not try and strip paint from plastics.....there is no need. use the factory finish as your substrate....."

I concur. There certainly are pieces that just need to lose a lot of complicated, showy  and hard-to-sand-off graphics actually stripped from them, but when you can skip it using the methods suggested (I use similar tactics), you are ahead of the game.

To quote (roughly) a repaint article from Model Railroader a number of years back: "you will never find a better primer coat than a factory paint job". 

Use it if you can, I'd say.

I just removed a coat of bad weathering and all the lettering on a lionel scale PS1 boxcar with the super clean product.  it left the silver base color untouched. I sprayed on super clean and wrapped it in few sheets of paper towels wet with more of same  and to control evaporation   wrapped it in a plastic bag. 8  hours later unwanted graphics and weathering came off easily with soft brushing and warm water.

No noxious oven cleaner smells

rubber gloves were needed as with any high power soap

D500 posted:

HARMONYARDS, above: "I do not try and strip paint from plastics.....there is no need. use the factory finish as your substrate....."

I concur. There certainly are pieces that just need to lose a lot of complicated, showy  and hard-to-sand-off graphics actually stripped from them, but when you can skip it using the methods suggested (I use similar tactics), you are ahead of the game.

To quote (roughly) a repaint article from Model Railroader a number of years back: "you will never find a better primer coat than a factory paint job". 

Use it if you can, I'd say.

I agree that the original paint is the best base coat but when you start adding more layers of paint on top of that the details in the car body start to fill up with paint. Lines are not sharp anymore but rounded.

 My disclaimer: test everything yourself first....you know the drills

 I've soaked plastic models (not trains, Revell, Monogram, Tamaya, etc). in Castrol's "purple degreaser"(Super Clean?) to remove botched paint jobs in the past (usually on Testors paint). It worked well, rubbed off with a toothbrush. The plastic did soften some initially. Letting it sit for a few days they seemed fine and are still around today. I even cleaned a 30yr old model my uncle started as a kid and repainted it. It did seem to soften some detail SLIGHTLY. Nothing compared to a coat of paint though.

It doesn't desolve the paint so much as penetrates under it and breaks the very thin bond layer away. Paint comes off like a thick waterslide decal.

I noticed the same thing with oven cleaner. Very fine detail change on models.

Could be the same active ingredients. Oven cleaner degreases well too. Both require gloves, but short term exposure isn't painful with them either. Both pune the skin then, dry your skin out as moisture dissipates. 

   Dont use "the purple" on some alloys or aluminum, it can cause changes in the metal and the end result looked kinda like the beginning of Zinc pest, to discoloration. (I tried it on some thick Magn./Alum. alloy and Alum. ) Bottle warns against it too.

Simple Green was reported to melt FT here years ago and I have no reason to doubt him. But others have claimed to use it on plastics without issue.

I've had citrus cleaners gum up plastic pretty good too; but these days who knows whats in a product like that anyhow detailers

..feel lucky?  

Soda blasting?

 

Edit: Who.is missing or used the word "detailers"?......after two weeks of no issues, looks like Google has issued another great update to rid the world of mistake free text.

"Still trying to not shoot my eye out"

 

"Nursing insomnia one railcar at a time"

My aroma therapy? Smoke Pellets.

 





Adriatic posted:

    Dont use "the purple" on some alloys or aluminum, it can cause changes in the metal and the end result looked kinda like the beginning of Zinc pest, to discoloration. (I tried it on some thick Magn./Alum. alloy and Alum. ) Bottle warns against it too.

I've used "Royal Purple" probably the same stuff to clean some aluminum and chrome on a hot engine once....that was a huge mistake. Never again will I use that to clean polished metals.

Micro-marks sells a tinny airbrush media blaster, maybe in the future if I start stripping down more body shells ill go that route.

I have used brake fluid for years with great results. It takes a little time, needs a little encouragement with a toothbrush, but just as importantly, when the brake fluid gets mixed with paint that has been removed be sure to replace the fluid with fresh. As the brake fluid gets contaminated with the removed paint it loses it's ability to continue to loosen paint. I would recommend practicing on a discarded piece to familiarize yourself with the process.

owner, operator of The Cuyahoga Valley Short Line Railroad,

TTOS#8836

milnyc posted:

I have used Scalecoat II Wash Away paint stripper for over 20 years with good results. You can get direct from the manufacturer here: http://www.minutemanscalemodel.../product-p/10568.htm

Walthers also has it as do many good hobby shops.

I've been using Scalecoat II for about thirty years and always had excellent results. The problem I found with leaving the old paint on is that you don't know how the new paint will chemically re-act to it. 

That's a great point Paul (even with non-train stuff, "the best prime job being old paint" assumes compatability and i.e., a painters abilty to I.D. the topcoat correctly)

"Still trying to not shoot my eye out"

 

"Nursing insomnia one railcar at a time"

My aroma therapy? Smoke Pellets.

 





I have been using a dilute solution of lye, sodium hydroxide, for many years to strip plastic, since the late 60s at least.  I keep it in a 6 gal. bucket with a snap on lid. If I am not mistaken sodium hydroxide is the active ingredient in oven cleaner as well.  The stronger you mix it the faster it will remove the paint. However if you mix it too strong it will generate so much heat that it melts the plastic.  I used to use Red Devil lye but it was removed from store shelves several years ago as it was also useful in the production of crack cocaine so now you have to buy drain cleaner. At this moment I am using COMSTAR Commercial Lye that says on the bottle for drain cleaning and paint removal. If you use drain cleaner buy the type that DOES NOT have little metal flakes in it. Lye has an infinite shelf life and a pound will last me ten years, give or take.  Depending on the dilution you can strip one layer of paint off at a time, especially silver paint. For some reason I find a lot of old trains that someone decided would look better silver. With a weak solution I have been able to remove silver paint leaving the original paint and decals intact.  Lye will also remove chrome plating from plastic. A lot of old Flyer plastic passenger cars have chrome plating that is mostly worn away. The lye will finish it off.  I tie a nylon or polypropylene string to the car and lower it into my bucket leaving most things overnight then use a nylon bristle brush to scrub it the next day. Repeat till all the original paint is gone.  The main reason I like to remove the original finish before applying new paint is you can apply your new finish much thinner if you do not have to cover the old graphics.  I have used the lye solution as strong as eight oz. of crystals per gal and as weak as one.  Just depends on how fast you want to get the paint off and how much heat your plastic can stand.  I would start off rather weak about two oz. per gal.  and add a little more lye till it strips at a rate you like. Also remember the weaker the safer should you get it on yourself. I usually don't wear goggles as my solution is quite weak but should you opt for a speedier mix get yourself a good pair of goggles that seal around the edges. If you keep your hands in it for any length of time it will make your skin raw and chapped. A little lotion on your hands before you start is a good precaution. Or gloves, though I don't like to wear them as I seem to be more likely to splash or drop something if I am wearing gloves.

Update:

Well I decided to go the 91% Alcohol route. I bought 16 - 32oz. bottles at wallyworld (Walmart) for $1.50 each. I put one set of parts (one stripped C630 body/frame) in there today at 1pm (9/21/17). When I get home it would have soaked for 11 hours. The green paint on the shell was already starting to come off when I was moving things around for good placement in the container so my hopes for success are high. I bought a can of "EASY-OFF Oven Cleaner to try on the enamel based paint that is painted on the hand rails (if the 91% doesn't work)

JohnActon posted:

EasyOff is sodium Hydroxide and will attack metal parts.

I have also heard this.  I remembered a few days after I posted about EasyOff, that I used that for the Weaver plastic,  but  used a spray paint stripper from Home Depot for the metal and thats actually what I use for my diecast repaints now.  The Easy Off was perfect for the Weaver shell though and caused no damage.

Bruk posted:

Update:

Well I decided to go the 91% Alcohol route. I bought 16 - 32oz. bottles at wallyworld (Walmart) for $1.50 each. I put one set of parts (one stripped C630 body/frame) in there today at 1pm (9/21/17). When I get home it would have soaked for 11 hours. The green paint on the shell was already starting to come off when I was moving things around for good placement in the container so my hopes for success are high. I bought a can of "EASY-OFF Oven Cleaner to try on the enamel based paint that is painted on the hand rails (if the 91% doesn't work)

If you had used brake fluid, it would have been done 10 hrs. ago.

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