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cag_200

De-yelowing white plastic?

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hi

I am looking for an easy way to deyellow some sprue parts of a Esci 1/48 Bell 206AB. Is there a way to turn the plastic to bright white again?

Besides Biotex I used soda, bleach (small dosis), Dasty and oxygene actif (some wondercure for curtains :)/>/>)

All without effect (soaking took 12 hours).

Now I did searched on youtube and read some on forums and hydrogen peroxide/UV would do the tric but hard to realize for me.

Did anyone used a different approach?

- Which white paint would be best to use (2nd option). I know Humbrol still tends to yellow when aging.

Tamiya gloss?

sopje_zpsnphco28w.jpg

Rgds,

Duncan

Edited by cag_200

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If the parts are clean (i.e. grease free), I would simply prime it in white and they use your favorite white color. Haven't used acrylics long enough to give you a tip there. You might try automotive colors, as they are not supposed to yellow.

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Thanks Guys

To Andrew: does commandant M3 helps? Vinegar?

As for the sprue part, I cut a piece in lenght and noticed the same coloring inside, so its the polymer. Cheap plastic.

- the use of Slika hair bleach which contains peroxide could do magic (?)

I could try this on the 1/32 MPC kit...

Anyway Italeri will release a new 1/48 Bell 206, hopefully this one comes with white sprues like the 1/72 does.

AB206B_zpsqk7i5x2v.jpg

Edited by cag_200

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Can you explain why you want to "de-yellow" white plastic? Are you not going to paint it? Confused.....

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hi, Habu

yes, I prefer to keep the white and finish it with clear.

I never liked the grey plastic in kits.

Specially when it comes to USN planes/helo's.

I use Revell/Humbrol white and this yellows, even the new cans do over in time.

The Esci kit I got from ebay was yellowed due to its age, this is why I try to brighten it.

Here the Swissheli snap-tite kit is left as (white plastic).

Heli_1_zps8cqxbli2.jpg

Think I switch to Tamiya white paint.

Edited by cag_200

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Medium gray plastic is very useful when building a kit: it's a lot easier to see if parts are well aligned and smooth. Polished white instead hides a lot of issues that can then turn out when paint is applied.

Anyway, for areas that need to stay white, most enamels tend to turn yellow to some degree with age.... it should be something related to UV light (same problem for clearcoats).

Acrylics should all be immune to the problem, so I suggest you to try gunze (now mr hobby) or tamiya.

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Ok.. thats why grey is used. Thanks Yuri, i did not know.

I will try gunze (or mr hobby) / tamiya.

Will emaille paint go on top of acrylics? Just.. asking :crying2:

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Ok.. thats why grey is used. Thanks Yuri, i did not know.

I will try gunze (or mr hobby) / tamiya.

Will emaille paint go on top of acrylics? Just.. asking :crying2:/>

Yes and no. Usually if a paint is well cured there shouldn't by any problem coating one brand with another.... but you never know.... better try it first on some scrap plastic.

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What about Revell aqua colors? Anyone used this?

Edited by cag_200

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Hi Duncan

Dipping into my chemistry background, if the white plastic has discolored in the kit, there is no practical way to remove this color and convert the plastic to a brilliant white color. The colored material is most likely part of the polymer (styrene) that makes up the sprue and there would be no reasonable way to remove this color without making the plastic parts unusable. The same thing goes with vacuformed clear canopy parts. I wish it was not so as I have a few kits with yellowed vacuform canopies but such is chemistry!

Have fun modeling

Mike

(a somewhat polymer chemist by day.....)

:cheers:/>

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.. me too ..

Just bought some Slika hair bleach with 12 % peroxide to try out but this will not do the job as i am convinced the polymers cannot be de-colored.

So just a new layer of white paint it is!

Edited by cag_200

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Enamels yellow because of the oil in them. Look at an older bottle of MM enamel. When everything separates, the oil on the top is almost brown. That's why enamels yellow. Someone mentioned "car paint." That would be lacquer. It won't yellow. Good luck.

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Someone mentioned "car paint." That would be lacquer.

Not necessarily. The world of automotive paint is incredibly convoluted, but today, "lacquers" are more the exception than the rule.

IMO, the simplest alternative would be Tamiya's TS-26 Pure White spray paint. It won't yellow, dries quickly and is pretty easy to get a good gloss surface, and it's available at most hobby shops around the world. Either apply directly or decant and airbrush, depending on your personal preferences.

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