MRP crazing plastic?

[Woody V]

Primer necessary with MRP?

That's a big fat no. The solvent used in hobby grade lacquer paint does not attack styrene, period. If it did, why are people, including myself, using it to strip lacquer paints from their models.
This is a fact and you can prove it yourself by putting a piece of styrene in a jar of Mr. Color thinner (leveling or otherwise) let it sit for a day and see what happens. But don't try this with the lacquer thinner sold in hardware store because it's not the same thing.

Edited April 8, 2023 by Woody V

[quang]

To each his own chemistry.
I’ve been using primer since 1980. They called it DuPont Lucite then.
Nowadays I always put a coat of Mr. Surfacer 1200 diluted with hardware store lacquer thinner prior to painting. Not a single mishap with lacquer paints: Gunze, Tamiya, AK, Hataka.
I steer away from MRP because I hate paying extra for someone else to thin the paint for me. 

 

[Woody V]

4 hours ago, quang said:

To each his own chemistry.
I’ve been using primer since 1980. They called it DuPont Lucite then.
Nowadays I always put a coat of Mr. Surfacer 1200 diluted with hardware store lacquer thinner prior to painting. Not a single mishap with lacquer paints: Gunze, Tamiya, AK, Hataka.
I steer away from MRP because I hate paying extra for someone else to thin the paint for me. 

 

That makes sense because you’re not mixing chemistries and whenever I need a consistent color over mixed materials I prime too and with hardware store lacquer thinner. 
 

So you and I are essentially on the same page, except that you do not NEED a primer. It’s a matter of personal preference. 

Edited April 8, 2023 by Woody V

[quang]

99.9% of my builds have mixed components. I guess that would explain my addiction to primer 

[Rick Griewski]

On 4/7/2023 at 6:13 PM, LSP_Kevin said:

 

I wouldn't bother, personally. Just give it a light sand/polish, and go over it with some decent primer.

 

Kev

Agree

000 steel wool with a gentle hand.  It also looks to me you have paint dust.  The will will rub it off and may not need any further treatment. 

[LSP_K2]

On 4/10/2023 at 5:56 AM, Rick Griewski said:

Agree

000 steel wool with a gentle hand.  It also looks to me you have paint dust.  The will will rub it off and may not need any further treatment. 

 

I may give that a whirl. I'd like to salvage the kit, if at all possible. I just completely and utterly destroyed a 1:48 Tamiya Ki-61, and I'm getting just a bit tired of throwing away good money.

[kensar]

I am using MRP paints for the first time on a Hobby Boss TA-152 and I am seeing this.  My impression is that the MRP paints are thinned too much to spray them closely onto a surface and the thinner does not evaporate quickly enough.  This gives the paint pigments time to conglomerate into the 'rough' surface before the thinner does evaporate.  I'm calling it 'weathering'.  Try spraying from a greater distance, giving the thinner more time to evaporate before reaching the surface and see if you get different results.

 

Just a theory.

[LSP_K2]

I'm trying to resolve this issue right now, using primer over the sanded surface. Wish me luck.

[Cheetah11]

10 hours ago, LSP_K2 said:

I'm trying to resolve this issue right now, using primer over the sanded surface. Wish me luck.

 

Hi Kevin, I have had similar issues with lacquer paint (Tamiya and Mr Hobby) on my Kitty Hawk Mirage 2000 and Tamiya Spitfire. It seems to be worse when using the retarding thinners. I think it might be the specific type of plastic in the above kits which react with the thinners as the combination of above paint worked fine on other kits. I ended up priming with Tamiya primer and then using non retarding thinner.

Nick

 

Edited August 27, 2023 by Cheetah11

[Maxim61]

Looks to me as if the thinner has evaporated before the paint had a chance to lay down or you sprayed from a too far away distance.. I would be spraying closer at a lower pressure or I would add some retarder to slow the paint down from flashing off to fast. Hope you get it fixed. I have never been an MRP fan.

[LSP_K2]

9 hours ago, Maxim61 said:

 I have never been an MRP fan.

 

I started off hating the stuff too, but have really become a fan. I sprayed a Luftwaffe subject with RLM 76, and it's smooth as glass, takes tape well (with no damage) and looks just great.

[LSP_K2]

On 4/8/2023 at 5:55 AM, quang said:

I steer away from MRP because I hate paying extra for someone else to thin the paint for me. 

 

I like them for the colors themselves, which to my eye, just really look good. I've seen examples of four or five RLM colors from different hobby paint suppliers, say RLM 75, side by side, and all look different from one another. I've had limited experience with Tamiya and Gunze lacquer paints, but am very happy with the results so far from those that I have used.

 

While I love my Tamiya acrylics, I really don't like to use them on the outsides of a model very much, as they are so prone to getting easily scratched up.

[LSP_K2]

My experiments thus far have told me that from now on I'll be using a primer underneath all of the MRP paints.