Defect in clear parts

[Timonator]

On the Tamiya porsche 1/12 935. There are lines in the clear parts that I'm not sure what to do with. On the windshield and back glass there are lines going from top to bottom right in the middle. I thought they were scratches but I  sanded and polished them and they're better but still slightly visible. The side glass' have these weird curvy lines. I  have a backup kit for extra parts just in case and the clear parts have the same lines.

[Tabbysdaddy]

That looks like swirls in the plastic from the injection molding process. I don't think I've ever seen that on clear parts before. 

[Ace-Garageguy]

Easy enough to make replacements from PET or clear styrene or acetate sheet...

[Fat Brian]

Ideally you could get replacements but I've never tried from Tamiya before. Someone is selling that parts tree on ebay right now but it'll be $70 to get it. Unfortunately that looks like a defect that won't polish out.

[1972coronet]

Since you'll likely have to find or make replacements, you may as well try coating them with Future [et al.] and see if that makes any difference.

[Timonator]

  On 9/18/2022 at 6:32 PM, Ace-Garageguy said:

Easy enough to make replacements from PET or clear styrene or acetate sheet...

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How ? What do I need for that ?

[Timonator]

  On 9/18/2022 at 7:32 PM, 1972coronet said:

Since you'll likely have to find or make replacements, you may as well try coating them with Future [et al.] and see if that makes any difference.

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I used that stuff on a paint job and it all cracked a few years later

[1972coronet]

  On 9/18/2022 at 7:43 PM, Timonator said:

I used that stuff on a paint job and it all cracked a few years later

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That stinks, man. I've used it for years with no negative effects -- but, I've always used it on 'glass', plating, and bare plastic. 

[Raoul Ross]

I'd bet if you contacted Tamiya about this they would take of it. That's the first thing I'd do.

[Ace-Garageguy]

  On 9/18/2022 at 7:57 PM, Raoul Ross said:

I'd bet if you contacted Tamiya about this they would take of it. That's the first thing I'd do.

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Best advice so far...  

[jaymcminn]

Definitely contact Tamiya. I think the 935 is either in the current catalog or recently rereleased. My 934 had a thin mold line in the windshield but nothing like that.

[Rick L]

  On 9/18/2022 at 6:13 PM, Tabbysdaddy said:

That looks like swirls in the plastic from the injection molding process. I don't think I've ever seen that on clear parts before. 

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That’s exactly what it is. It’s a result of the plastic flowing through the mold from different directions from different injectors. The plastic from one injector is colder than the other and setting up before it meets the plastic from the other injector resulting in a parting line throughout the part that unfortunately will not buff out. Bummer!

[Timonator]

I will definitely contact them but I'm trying to  get it finished for the Atlanta show.

[robdebie]

  On 9/18/2022 at 9:24 PM, Rick L said:

That’s exactly what it is. It’s a result of the plastic flowing through the mold from different directions from different injectors. The plastic from one injector is colder than the other and setting up before it meets the plastic from the other injector resulting in a parting line throughout the part that unfortunately will not buff out. Bummer!

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To add a bit: that's why the best clear parts are molded form just a single injection point per part. That of course avoids the weld lines. Take a close look at different clear part sprues / runners to see what I mean.

Rob

[Timonator]

I contacted Tamiya and they said that it must have been done on a Monday and that they would send me new ones. But I am skeptical since my old release kit and new release version both have it.