Tamiya acrylic paints not fully hardening.

[Radretireddad]

I use Tamiya acrylic paints almost exclusively because of all the benefits they offer and because I’ve been pleased with the results I’ve been getting. The problem I’m having with airbrushing the gloss paints is that they never fully dry to a hard enough finish. Handling parts that have been drying for several days still leaves finger prints or masking tape marks that have to be polished and buffed out. I’ve been thinning it with Tamiya thinner. Id be interested in finding out if anyone else has found a solution to this. Thanks.

Brian.

[Dave G.]

Try lacquer thinner. If you go to the Tamiya site, you will find suggested thinning methods/products. Lacquer thinner is listed for the purpose of a harder finish.

That said, while I've used regular lacquer thinner, I prefer Mr Leveling Thinner for it's leveling feature.

[bobss396]

My brother uses the acrylics, he likes denatured alcohol as a thinner. Do you have a dehydrator? These speed up drying times quite a bit.

[Mike 1017]

Bob is right. Sometimes I use a blow dryer.

Mike

[Radretireddad]

9 hours ago, Dave G. said:

Try lacquer thinner. If you go to the Tamiya site, you will find suggested thinning methods/products. Lacquer thinner is listed for the purpose of a harder finish.

That said, while I've used regular lacquer thinner, I prefer Mr Leveling Thinner for it's leveling feature.

Thanks, I’ll give these a try.

[Dave G.]

1 hour ago, Radretireddad said:

Thanks, I’ll give these a try.

Just for the record, Mr Leveling thinner is lacquer thinner. It has an initial retarder feature that allows the paint to flow out. But overall dry time is still good. I thin Tamiya acrylics about 1 to 1, so equal part paint to thinner. It acts a lot like shooting the LP lacquers. I've also used hardware store lacquer thinner, for me personally it's good too. But IMO, the MLT gives a result a notch above.

[Radretireddad]

24 minutes ago, Dave G. said:

Just for the record, Mr Leveling thinner is lacquer thinner. It has an initial retarder feature that allows the paint to flow out. But overall dry time is still good. I thin Tamiya acrylics about 1 to 1, so equal part paint to thinner. It acts a lot like shooting the LP lacquers. I've also used hardware store lacquer thinner, for me personally it's good too. But IMO, the MLT gives a result a notch above.

Got it! Thanks again!

[bobss396]

Years ago I took one of my brother's models to a show, he was away on business. It was a Chevy truck, all Tamiya acrylics. It was done for at least a few weeks, he placed the hood in a paper envelope. When I unpacked it at the show, the envelope printed on the hood, but it still showed well. This was before we got into dehydrators.

[Dave G.]

Just for the record, I use a dehydrator on all my model my paint jobs, using any paints from crafts paints, to Tamiya acrylic, LP lacquer, Createx, decanted enamels, Testors, etc. Even primers get a little blast from the dehydrator.

[Rich Chernosky]

I also spray a lot of water based acrylics like Tamiya.  Most acrylics will dry to the touch within 20min. But that is not curing. Curing is when the paint fully gases out. In the case of water base paint this can take upwards of two months depending on the humidity.  It will stay soft and handling will leave marks. On the plus side when they do cure out they dry rock hard...harder than most solvent base paints. There are many ways to speed the cure process up as previoulsy mentioned in this post.  Hope this explanation helps. 

[Radretireddad]

7 hours ago, Rich Chernosky said:

I also spray a lot of water based acrylics like Tamiya.  Most acrylics will dry to the touch within 20min. But that is not curing. Curing is when the paint fully gases out. In the case of water base paint this can take upwards of two months depending on the humidity.  It will stay soft and handling will leave marks. On the plus side when they do cure out they dry rock hard...harder than most solvent base paints. There are many ways to speed the cure process up as previoulsy mentioned in this post.  Hope this explanation helps. 

Yes, curing is what I’ve been referring to and what you describe is what I’ve experienced as well. I’ve found The use of Tamiya thinner helps speed up the curing process somewhat but it still takes forever to fully cure. A dehydrator is definitely on my wish list. Thanks for the clarification and advice.

[Radretireddad]

7 hours ago, Dave G. said:

Just for the record, I use a dehydrator on all my model my paint jobs, using any paints from crafts paints, to Tamiya acrylic, LP lacquer, Createx, decanted enamels, Testors, etc. Even primers get a little blast from the dehydrator.

How long have you found it takes for a dehydrator to fully cure one of your paint jobs?

[Radretireddad]

8 hours ago, bobss396 said:

Years ago I took one of my brother's models to a show, he was away on business. It was a Chevy truck, all Tamiya acrylics. It was done for at least a few weeks, he placed the hood in a paper envelope. When I unpacked it at the show, the envelope printed on the hood, but it still showed well. This was before we got into dehydrators.

Yep, I can definitely identify.

[bobss396]

In a dehydrator, I would say that 4 to 6 hours at no more than 105 F should do it. I never run mine hotter than that.

[Dave G.]

46 minutes ago, Radretireddad said:

How long have you found it takes for a dehydrator to fully cure one of your paint jobs?

With Tamiya acrylic, I give it a couple of hours. Then to be sure, a couple of days in room air. It's usually pretty hard after that. Usually 106- 108F . If I just want to be able to handle the parts, 30 minutes will do.

I can do pretty much what I want with craft paints after 30 minutes to an hour. 105f

Enamels I do six hours for decent handling and it still needs days in the air to be fully cured. Some people consider it cure coming out of the dehydrator after 10-12 hours. I'm not in a rush, I just want it to be handle-able. It's enamel I do at 110F ( I had said Tamiya at 108-110 but no, it's enamel that gets 110. In fact if I've tested the plastic I'll go 112f.

Edited August 22, 2024 by Dave G.

[Radretireddad]

5 minutes ago, Dave G. said:

With Tamiya acrylic, I give it a couple of hours. Then to be sure, a couple of days in room air. It's usually pretty hard after that. 108F . If I just want to be able to handle the parts, 30 minutes will do.

I can do pretty much what I want with craft paints after 30 minutes to an hour.

Enamels I do six hours for decent handling and it still needs days in the air to be fully cured. Some people consider it cure coming out of the dehydrator after 10-12 hours. I'm not in a rush, I just want it to be handle-able.

Cool, thanks!

[bill-e-boy]

Tamiya also have a retarding thinner and this helps with levelling of the paint finish. But as mentioned above it takes a while for Tamiya paints to harden even after being in a dehydrator. 

This is week old paint that has been in a dehydrator and then masked for under hood paint. Good thing is Tamiya paint falls off when washed down with Isoprop alcohol

 

 

 

[Bainford]

1 hour ago, bill-e-boy said:

Tamiya also have a retarding thinner and this helps with levelling of the paint finish. But as mentioned above it takes a while for Tamiya paints to harden even after being in a dehydrator. 

This is week old paint that has been in a dehydrator and then masked for under hood paint. Good thing is Tamiya paint falls off when washed down with Isoprop alcohol

 

 

 

Did you use Tamiya tape? Just curious as I have had Tamiya masking tape seriously damage two well cured lacquer paint jobs. 

[bill-e-boy]

44 minutes ago, Bainford said:

Did you use Tamiya tape?

Yup for the main part. The rest with a similar but wider tape. The top of the hood was fresh paint and the under side paint was a bit older and had no problems with the masking tape there

I have had issues in the past with foil tape adhesive eating into Tamiya paints as well when using BMF as a paint mask. You just have to be patient and let the paint harden - seems to be OK then

[bill-e-boy]

I am not bagging Tamiya paints as they have some mighty fine colours and products. But they do have some issues but when you know what they are you can work around them

[Radretireddad]

I’ve been successfully using parafilm to mask Tamiya paints. It won’t react with the paint but you have to be careful not to stretch it too thin or you’ll never be able to remove it. To remove minor fingerprints I use these foam backed buffing pads I got for about $7.00 at Hobby Lobby. They start at 3200 grit and go all the way up to 12000.

Edited August 31, 2024 by Radretireddad