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Modeling in General: Advice on...
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Gunze clear trouble?
magnusf
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Stockholm, Sweden
Member Since: May 02, 2006
entire network: 1,953 Posts
KitMaker Network: 16 Posts
Posted: Monday, July 16, 2007 - 12:28 AM UTC
Hello out there!

I am in the middle of a Tomcat project for the Tomcat group build (follow link in the avatar if you haven't been there yet!) and things are progressing just fine. However...

For some reason I decided to use Gunze acrylic clear, mostly because of all the good things I have heard aboout it. It went on without too much trouble (I have never been a fan of gloss coats, it is one of these things that I just have to do without enjoying it...).

Now, more than a month later, it is still soft. If I lift the model and hold it for a minute or two, I will get finger prints in the finish. Even the cotton gloves I use for handling the model will leave marks. I can polish the marks out using Micro Mesh but this is annoying!

Any suggestions? I used water to thin the mixture with a few drops of Tamiya acrylic thinner to break the surface tension when spraying. BTW, I did a test using just water and that is just the same. The surface is a bit rougher but it is sticky as well.

Is there anybody out there except me who has had this kind of problem?

Regards

Magnus
ws48
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South Carolina, United States
Member Since: January 30, 2004
entire network: 247 Posts
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Posted: Monday, July 16, 2007 - 01:52 AM UTC
Magnus,

With the exception of lacquer, model paint cures by oxidation. From initial setup to full cure takes 30 days. Since you have reached the 30 day mark it probably means that the cure is as good as it is going to get. You could try a different clear such as Model Master Acryl but there is small risk of the final coat mud cracking if the Gunze is still curing. I would try a small area first. This is a long shot but before spraying another coat of clear try spraying a wet coat of isopropyl alcohol. It may open up the film enough to give additional cure.

Hope this helps,
Don
ws48
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South Carolina, United States
Member Since: January 30, 2004
entire network: 247 Posts
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Posted: Monday, July 16, 2007 - 02:25 AM UTC
Magnus,

Just a follow up to my last post. I have had similar issues with Tamiya gloss colors. They tend to take 72 hours or more to dry to state where they can be handled safely without printing and still I have to be careful. Tamiya flat colors are just the opposite. They dry too fast. If I need to brush I have to use a retarder.

Not a solution to your problem but maybe helpful information.

Don
magnusf
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Stockholm, Sweden
Member Since: May 02, 2006
entire network: 1,953 Posts
KitMaker Network: 16 Posts
Posted: Monday, July 16, 2007 - 05:43 AM UTC
Hi Don!

I'll try spraying Isopropanol on my test specimen (an old Hawker Tempest) and see what happens.

Also, I was hanging out at the local plastic pusher's this afternoon and got the advice to try to thin the clear with either Tamiya thinner or pure Isopropanol, avoiding the water. If this works it will at least solve the issue for future projects and I'll have to live with a sticky Tomcat!

I'll report progress when I have tried it out!

Regards

Magnus
magnusf
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Stockholm, Sweden
Member Since: May 02, 2006
entire network: 1,953 Posts
KitMaker Network: 16 Posts
Posted: Tuesday, July 17, 2007 - 08:21 AM UTC
Don, you were right!

I tried shooting Gunze gloss clear thinned with three different solvents:

1) Water. Still sticky/soft 24 hours later
2) Tamiya acrylic thinner: Still sticky/soft 24 hours later but less so than the first mixture
3) Isopropyl alcohol: Rock solid!

I also tried to spray the sticky finish with alcohol (which was a lot easier said than done since it evaporates at an impressive rate) but that didn't help much. So I'll live with my sticky Tomcat and learn from this for the future!

Regards

Magnus
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