Gentleman,
I need your help.

Yesterday evening I have made the pin-wash (burned umber Windsor/Newton oil+ terpentin) on my actual model, a M3A1 Scout Car from Hobby-Boss.
I got something from the pin-wash to the plastic windscreen, which created a milky surface.
I thought, no problem, its plastic, so I tried to clean this now slightly dried pin-wash with a bit of clean terpentine on a brush.
But nothing improves, the screen is milky as before.

So, before I start some experiments and maybe destroy the screen, any ideas how to clean the plastic wind screen ?

Thanks in advance.


Erich

I'm afraid that your turpentine has damaged the clear plastic

If the turpentine has damaged the plastic, you could try polishing it out. There are plastic polishes available for exactly this sort of job - I got some from Hannants a few years back. Be warned it takes a fair amount of polishing, and if the damage is more than skin-deep it may not work anyway. Can you hide the damage with a spray of "dirt", as often seen on in-service windscreens?

I knew somebody in college who smoked so much that the insides of her car windows looked like they had frost! There were tiny "port-holes" in the windscreen and side window where she rubbed them to see out...

Tom

F..., so I have to become 48 years old to "learn" that terpentine destroy my clear plastic windscreen, unbelieveable.

Mauro, Thanks for your KO information. Even its not what I expected.

Tom, the idea is good to integrate it as a "dusty windscreen", but I suppose my milky area would means too much dust.
So I wil llook what I can save...

Thanks,
Erich

When you originally said "milky", I was thinking you had some of the umber wash on the screen.

However, I am sure if you look at it closely, you may even see some crazing or cracking from the solvent. If you leave plastics in turpentine, I am sure they will soften and maybe even dissolve partially. Now imagine your clear glass, the surface would very easily get hurt from the washes.

I would recommend if possible, making new wind shields. If you have any plastic containers laying around (you know the ones electronics come it that are impossible to open at Christmas), you could fashion new shields. I find that material is less sensitive to super glues and solvents.

Never use turpentine for models. It is too heavy and harsh, and as you can see, it damages plastic. Always use odorless mineral spirits (white spirit) for your washes and weathering.

Thanks for all of your inputs.

In fact it was white spirit, not pure terpentine, which I used for the pinwash.

So I have tried something yesterday evening and discovered following:

First: The pin-wash has created something like a "hard" cover on the Hobby-Boss windscreen, around 3-4 mm wide from the outside to the middle of the screen, with an flat, milky look.
I discovered this after moving the peak of a toothstick over the pinwash area and got a clear scratch, means I was able to scrub away the pin-wash layer a bit.

As I have cannibalized a cheap Zvedzda M3A1, to use the canvas, I have now even put some pinwash on the Zvedzda windscreen. I wanted to reproduce my problem, happened on the Hobby Boss part.

But the Zvedzda windscreen was something unimpressed from the pinwash, only a light shadow was the result on the clear plastic. So seems to be different from the material Hobby-Boss is using.
Then I put some theeth-paste on a wooden thootstick and started to polish the milky area on the Zvezda windscreen for testing and it improves the situation.

So I have done the same on the Hobby-Boss windscreen, with the result is, that I could reduce the "milky" area so much, that it is ok for a partially dust covered windscreen.

Again, thanks to all for your inputs.

Erich

amen. ruined a 3 week project once. still makes me sick.