Question regarding clear styrene and IPA

[Lemosteam]

I picked up a couple of older Bachmann shorty coaches with the passenger silloehettes painted on the inside of the clear “glass”.

I want to clean off the images without ruining the inside surface. Will IPA work or will it cloud the surface?

[peteski]

In my experiencing Isopropanol 99% or 91% will be safe on clear polystyrene.  But I also want to mention that using Naphtha on clear polystyrene might dull it slightly. Not actually crazing - it just gets slightly cloudy.

The items in question are various jewel boxes (from multiple manufacturers). When I take price and other stickers I first tried Naphtha and noticed the clouding. But IPA does not have that effect.

However if you rub that window "glass" hard with a piece of paper towel moistened with IPA, paper is slightly abrasive ant might also cause some dulling.

[nkalanaga]

Another household chemical that will remove sticker residue is WD-40.  It also works for road tar on vehicles, without damaging the paint.

[robert3985]

I use Bestine (Heptane) to remove sticker residue.  I haven't noticed clouding on anything.  I apply it with an old artist's paintbrush and wipe with a micro-fiber cloth.

Of course I use Bestine for many other de-greasing and de-waxing purposes, so I always have at least a couple of medium sized cans of it around.

As far as IPA being clear Styrene compatible...I've never actually used it on clear Styrene as the windows always get removed before I strip a shell.  I would think that brushing, like with a soft toothbrush or paper towel to help remove the paint would be more damaging than the IPA on clear window Styrene.

Cheerio!
Bob Gilmore

[Lemosteam]

This is not sticker residue. It’s paint, but I cannot soak the whole roof as I want to leave the original paint on the roof.

Now if you look closely, the clear styrene was masked with a matte clear, and the heads are tamped on that. Hmm.

[Lemosteam]

Trying this method:

[davefoxx]

@Lemosteam,

If you scratch that clear styrene, you can polish it with progressively finer sanding sticks.  I think I used 400, 800, 1000, 1500, and 2000 grit in my set to polish clear styrene windows in locomotives and automobiles.

Hope this helps,
DFF

[peteski]

John, put a strip of Saran wrap over the wet paper strip to slow down evaporation of alcohol.  That beats adding the alcohol ever few minutes.

Also, since the roof looks generic black, it should be a cinch to repaint. I think it would be easier to just strip the entire piece. You could also then use a stronger plastic-safe Lye-based paint stripper like Castrol Super Clean or the generic Purple Stuff.  I guess Simple Green and concentrated LA Awesome are supposed to work and be plastic-safe.

I also use NOVUS line of products to remove scratches and polish plastic.

The other alternative would be to cut out the thick plastic "windows" just below the roof line and replace them with a strip of evergreen 0.010" clear styrene for more in-scale appearance and transparency. The Con-Cor cars have a similar design and that's is just what I did in this observation car.

[Jimbo]

@Lemosteam,

If you scratch that clear styrene, you can polish it with progressively finer sanding sticks.  I think I used 400, 800, 1000, 1500, and 2000 grit in my set to polish clear styrene windows in locomotives and automobiles.

Hope this helps,
DFF

One other thing to consider:  sometimes these stamped silhouettes will leave impressions on the surface.  If this is the case, then polishing is the best option.

Let me know how it works out; I have this same project to do.

Jim

[Lemosteam]

It worked perfectly. No imprint, 20 minute soak, lightly rubbing the tissue did not mar the surface, and in fact the matte coating was not touched by the ipa, so I left it.

Yes Pete, I ended up repainting with Tamiya TS-6. I’ll share pics here and on the WU. Also, the IPA never fully evaporated so the tide stayed wet as I was rubbing the heads off.

Thanks for all the feedback.

[Lemosteam]

@Lemosteam,

If you scratch that clear styrene, you can polish it with progressively finer sanding sticks.  I think I used 400, 800, 1000, 1500, and 2000 grit in my set to polish clear styrene windows in locomotives and automobiles.

Hope this helps,
DFF

Tamiya makes an assortment pack from 600 up to 8000 grit for that sort of thing. I’ll see how they look in the shell, but I might be OK with the matte finish.

[peteski]

Is it possible that the matte surface is just directly in the plastic surface finish (not applied as paint)?

[Lemosteam]

Possible, but not likely as there are shiny areas surrounding the patch. 

Here is how they look now

[peteski]

So  it does appear  to be some sort of coating. I still think that cutting the glass area out and replacing it with thin clear styrene would be something to consider.

[Lemosteam]

Here are the finished cars, and the set I added them to: