Just want to say thanks and my apologies for taking so long to respond to those of you that emailed me questions regarding painting. My “Forum lurking” time has been usurped by home responsibilities. I’ll reply to the paint stripping question here.
I don’t consider myself a chemistry expert. I just share results like so many of you here do.
A modeler named Andre asked: "Which is “comparitively” better and/or safer for stripping HO shells…91% alcohol or Super Clean. Answer: BOTH and sometimes NEITHER!
He was concerned about the potential for styrene to become damaged by either of these chemical solutions.
A science professor at USF concured with findings that both products can damage styrene…under certain conditions.
91% Iso-Alcohol: “Yes, if polystyrene (and similar materials) are immersed in it over and over and over for stretches of time. Although polystyrene isn’t very soluble in isopropanol (dimethyl carbinol), prolonged exposure may cause some crazing or stiffening”.
OK, fair enough. So I would respectfully ask: How many times are you going to paint strip the same shell? Once? Twice?
Superclean: “Contains a small amount of lye, whicn can also potentially damage certain plastics immersed in the solution repeatedly over time”. That’s interesting since many of our soaps contain lye, but of course in tiny amounts. I like Superclean as it also works well, although it can take a little longer. My memory is foggy, but Superclean may be safe
That reflects my experience with 91%. Haven’t tried SuperClean. But in alcohol, I recall no issue of significance. I generally also find 91% works fast, especially if you scrub a little at the stubborn spots. Avoiding overnight soaks also tends to avoid the problems a few report, as they generally involve such prolonged soaking rather than any immediate problem.
I stripped some Athearn heavyweight cars, trying SuperClean and also denatured alcohol (primarily ethanol). I did not notice any effect on the plastic.
I did find that the 6 used cars I acquired were not consistent in how the stripping went, likely because of different production runs and not the same paint. I also did not find that one of the solvents always worked better than the other, perhps for the same reason. I noticed the caustic type SuperClean heated somewhat so was wary with it. In either case one needs to be careful and use the proper gloves, not be tempted to get ones hands wet with the ethanol as it has an effect on the skin (ditto the SuperClean with which I was most diligent).
I’d be interested to know how the denatured alcohol vs. the iso-propanol (IPA) compare in this area.
I’ve used denatured with basically the same results as 91%. My testing isn’t terribly extensive, though, but they’re close chemically. Denatured is basically the same as drinking alcohol, but treated so it’s undrinkable, but that’s just my off the cuff memory.
Locally, methanol is $7.30 qt while 91% iso is $2.58 qt. Not a hard choice if they perform equally well.
Methanol is substantially less expensive if purchased by the gallon, but still more expensive than 91% iso by the quart. I can’t find a local source of 91% iso by the gallon.
Unless you do a lot of paint stripping, consider the evaporation rate of 01% iso. Depending on your local storage enviroment, you could lose a lot to evaporation before the bottle is done.
I have had good results using 90% Isopropyl Alcohol. Never used Superclean, in fact this is the first I have heard of the stuff.
You ought to remember that the chemistry of the paint you are trying to strip isn’t all that much different from the chemistry of the plastic shell. Anything that cuts the paint, may well start in on the shell if you give it enough time. You ought to check for paint softening with a toothbrush now and them. When the paint started coming off as you scrub it, it’s time to take the shell out of the stripper. I wouldn’t leave a shell overnight in the stripper. And when the shell is all free of old paint, it wants a really good wash in hot soapy water, with a good rinse afterward to get all the stripper off. A trip thru the dishwasher does a good job in this dept.
I would be cautious about putting the shells though a dishwasher that heats its own water, such as most Bosch models. The water gets very, very hot and seems to cause cracking in some rigid plastic items.
That is what I experienced when I started putting my insulated styrene coffee mugs through the dishwasher. I no longer use the built in water heater and the problem has not reoccurred with the new replacement cups. I also do not use heated drying.
In the past, methyl hydrate was my go-to paint stripper for styrene, and it worked on most model paints - some Rivarossi colours on their passenger cars were rather resistant to it. Athearn and MDC cars often were stripped in minutes, with the paint coming off in sheets. Here’s an Athearn caboose in the stripper for only a couple of minutes:
I did, however, have two Train Miniature boxcars, a brand which stripped as readily as Athearn, each develop large, longitudinal cracks in one of their sides. I do have a lot of TM cars, though, and had problems with only those two.
Atlas locomotive shells didn’t strip well with methyl hydrate and while I found that brake fluid worked very well, it also damaged the plastic beyond recovery in a very short time.
Floquil’s ELO worked well-enough on the Rivarossi cars mentioned earlier, but I found it to be fairly labour-intensive.
Scalecoat paint is quite resistant to Methyl hydrate, though, as are many of the newer paints.
I’ve used Super Clean on several hard-to-strip cars and it’s worked well (albeit at varying rates of time), and I’ve not experienced any damage.
Lacquer thinner is my choice for stripping metal models of any type.
When using any strippers, be aware of the safety and health hazards and protect yourself accordingly. Lacquer thinner for any appreciable exposure requires a two stage respirator, as does methyl hydrate (and I use it when using isopropyl alcohol, too, as I find the smell irritating). The use of nitrile gloves is recommended for Super Clean and for methyl hydrate, as the latter is readily absorbed through the skin. Many chemical fumes are also readily absorbed through the eyes - there’s MSDS available on-line for pretty-well everything, I think…not just the various strippers, but the paint
If You are talking about Denatured alcohol, appliance fuel/marine stove fuel, it is not only undrinkable, It is Poison. I use it exclusively on stripping paint from all plastic’s…but I do not soak them in it. I pour some in a pie tin and brush it on the whole surface, within seconds, it bubbles the paint and then I use a stiffer smaller brush to brush it off with and add more if need be. Have not harmed any plastic models yet. I also use it as thinner on all Tamiya Acrylic, Vellejo, Citadel paints that I use. All metal,Pewter, white metal, I use Automotive Finish Pro #5000 Lacquer thinner medium dry, for stripping and mixing My solvent paints with…also the only thing I use to clean My air brushes with and back flush them often.
I was stripping the paint off the old rivarossi u25c so I can add the kalso upgrade. It sat in 91% alcohol for a year. Although it softened the L&N paint a toothbrush could not take off the paint. So I finally switch out the alcohol with PURPLE POWER degreaser and within15 to 30 min I was able to brush off all the paint. is purple power the same as super clean
I have been using Super Clean (Walmart- Automotive Dept) for almost a decade on a wide variety of metal, styrene and “unknown” materials. I enjoy repurposing swap meet old Athearn BB and other mfrs’s rolling stock and engines. I use Super Clean as my first choice, but as that product works relatively quickly on old paint, I rarely soak shells or parts longer than a few hours. I prefer it to 91 alcohol with very old plastic shells, as it works more gently. I will use 91 alcohol applied with a Q-tip to crevices and other difficult locations on a spot basis, but I believe the 91 alcohol will “dry out” very old plastic and create brittleness. (from experience [:D]).
Super Clean also should always be used with disposable nitrile gloves (cheap- and in hand sizes- at Harbor Freight) and I thoroughly wash cleaned shells and parts in dish detergent after removing from Super Clean solution.
Again, as others have pointed out, unless you make a mistake in a repaint effort, you will rarely- if ever- need to retreat a painted shell in Super Clean more than once.
a modeler was curious about the tub I use to paint strip my passenger cars so I’ll just answer here.
I wanted to have a “Paint Stripping Bathtub” that would be durable and that, sizewise, would not be too large so that I could pour just enough alcohol or superclean to do the job.
I took some inexpensive 1/16" mild steel plating, measured and cut it into to 3 long pieces (bottom and sides) and 2 short, pieces and welded them together with a mig welder. Worked out nicely. It’s 13 1/4" long which will easily accommodate any 85 foot long HO passenger car shell as well as most locomotives. BTW: Mild steel is generally easy to weld (compared to high strenght steels and aluminum).
Neat facet about mild steel plates is that they can be easily cut and shaped with a cut-off tool or die grinder to form weights for rolling stock (although I prefer 1/32" or thinner).
Of course untreated mild steel does rust easily, but in my case it’s of no consequence to paint stripping process. I could easily spray some Rustoleum or Zinc etc primer on the sides, but I like the bare steel look so I just quickly hit it with a grinder once a year.[:P]
i have found no stripper that works 100%, i have used dot2 brake fluid, 96% alcohol,mister clean with amonia,goo be gone,potassium hydroxide,atomic 235 and many, more found that each brand of models are different and as op said each run is different so i keep several different ones to try if want to strip somthing.the worst brand that run into for striping is accurail paint.
Into the mix I will through concentrated sodium hydroxide. Lye. Back in the '80’s, I stripped at least a dozen Rivarossi passenger cars with it. I could leave them in for days. I never noticed a reaction to lye from THAT particular plastic. The paint came off. And it was water cleanup.
If you chose to use it, wear safety glasses. Keep rinse water available, preferably running water. I got it on my hands now and then. It feels “soapy”. Rinse until it doesn’t. I never had that much reaction to it. But then my grandfather was from Krypton.
With respect to containers for soaking models to remove paint, I use empty swifter wet sheet containers (rectangular blue with a cover to prevent evaporation) and a variety of food take out containers from Boston Market or similar (also with covers).
I’m not sure about the Swifter containers, but the food ones are engineering plastic and relatively impervious to alcohol and Super Clean. I would get advice on using brake fluids in these types of containers. The Swifter containers handle a passenger car and have a raised bottom surface. I have found that I can use the same Super Clean solution twice, for separate model paint removals, before it becomes too soiled for further use.
I would just like to clarify a statement You made…
‘‘Denatured is basically the same as drinking alcohol, but treated so it’s undrinkable, but that’s just my off the cuff memory.’’
Denatured Alcohol Appliance & Marine Stove Fuel is NOT the same…It is Poison…not just merely treated so it’s undrinkable. ‘‘Flammable Liquid & Vapor. Vapors May Cause Flash Fire. May Be Fatal Or Cause Blindness If Swallowed. Vapor Harmful. Eye Irritant.’’
I have been using it for yrs. In My real boats, My friends 31 ft Teak cabin crusier for cooking and many other uses. I have been using it also for stripping painted models…works quicker than 91% alcohol without any damage to the models finish, takes longer on baked on paint, but I never soak it. I also use it for acrylic paint thinner like Tamiya, Vellejo and Citadel and more. I have also used it to take off silk screen lettering with cotton swabs, with no damage to the rest of paint, if careful.
The only time I ever soak anything will be if it’s a metal casting…then I’ll use Automotive Lacquer thinner. That is also the only solvent I’ll use for cleaning My air brushes and larger guns. Been painting many yrs.
