Which paint?

[Ray_W]

1 minute ago, John McNamara said:

I was sold Tamiya Laquer thinner, retarder type, by my LMS. Same as in your link.

 

John

 

Difficult to work this out. Everything seems good if the plastic and surfaces were clean. I doubt the problem is the plastic. Only question mark I have is the primer. My understanding was always that Tamiya White Primer 87044 was a lacquer based product and I have used it with confidence. I expect no compatibility issue. Is there a reaction going on with their new lacquer range? I do not know. I do know it can go on dusty, but again with micromesh polishing and effective cleaning it should again be no issue. Those LP products should also mix like a charm. Frankly it is baffling.

 

Sorry I am not of more help. 

 

In terms of cleaning prior to painting cleaning I use a bath with a small amount of dish washing liquid and brush with a soft toothbrush. I then rinse the model extremely well and ensure only my gloved left hand touches it after that. I am not a fan of gloves and only use them at this painting stage.  After giving the undercoat or subsequent coats a rub down I go through the same wash regime. I have a hair dryer handy to assist with the drying process. I do not drown the model with usually a high level of detail already incorporated. I have not found the need to use alcohol cleaners. 

 

Ray

 

 

[John McNamara]

4 minutes ago, Ray_W said:

 

Difficult to work this out. Everything seems good if the plastic and surfaces were clean. I doubt the problem is the plastic. Only question mark I have is the primer. My understanding was always that Tamiya White Primer 87044 was a lacquer based product and I have used it with confidence. I expect no compatibility issue. Is there a reaction going on with their new lacquer range? I do not know. I do know it can go on dusty, but again with micromesh polishing and effective cleaning it should again be no issue. Those LP products should also mix like a charm. Frankly it is baffling.

 

Sorry I am not of more help. 

 

In terms of cleaning prior to painting cleaning I use a bath with a small amount of dish washing liquid and brush with a soft toothbrush. I then rinse the model extremely well and ensure only my gloved left hand touches it after that. I am not a fan of gloves and only use them at this painting stage.  After giving the undercoat or subsequent coats a rub down I go through the same wash regime. I have a hair dryer handy to assist with the drying process. I do not drown the model with usually a high level of detail already incorporated. I have not found the need to use alcohol cleaners. 

 

Ray

 

 

Hi Ray, what is even more baffling is that the blue areas have not lifted at all!  I used the micro mesh with warm water and a drop of detergent. I rinsed them under the tap afterwards. I am coming to the conclusion that the red is to blame. As mentioned it alone had very low viscosity, It alone came off with the primer. Perhaps its a bad batch but were the red is, the adhesion was almost none existant. Before adding the red, the primer seemed perfectly stable.I scraped away the red and prinmer under it last night, reprimed it and then put a couple coats of blue over the top. this morning it looks fine.

 

John

[dromia]

Paint fragility and lift is one of the many reasons why I regard these "acrylics" as a failed paint and will not use them.

 

However just a thought as to the surface finish perhaps it has been made just too smooth, as these "acrylics" just seem to form a sheath over the surface rather than biting into or adhering too like proper paint does then perhaps it needs something to key into and hold onto.

 

Maybe an experiment with a slightly rougher surface may be in order, personally I rarely go beyond 800 grit in my surface preparation. Not the micro mesh grit numbering as it is meaningless as a comparator being just a marketing con they just made up their grit numbers to make their stuff seem finer than it actually is,

[John McNamara]

1 hour ago, dromia said:

Paint fragility and lift is one of the many reasons why I regard these "acrylics" as a failed paint and will not use them.

 

However just a thought as to the surface finish perhaps it has been made just too smooth, as these "acrylics" just seem to form a sheath over the surface rather than biting into or adhering too like proper paint does then perhaps it needs something to key into and hold onto.

 

Maybe an experiment with a slightly rougher surface may be in order, personally I rarely go beyond 800 grit in my surface preparation. Not the micro mesh grit numbering as it is meaningless as a comparator being just a marketing con they just made up their grit numbers to make their stuff seem finer than it actually is,

You may well be right. But I have only ever use Scotchbrite pads and the like to de-gloss the surface prior to painting.  I always use them with wet soapy water and this ensure no clogging, and washing away any realse agent or grease.  On a plastic model even they may be a bit course. My experience on other paints is that sometimes you need an etch primer in order to get good adhesion. I have never known enamels to have this problem and rarley needed a primer although some underpinning is sometimes required with translucent colours.

Composite materials and certain plastics do shrug off paint and need the etch primer. My RC models are mostly of composite construction or finish, and these get this treatment. I have then overpainted with 1K base colour, 2K colour, cellulose, model enamels etc.  and always had good adhesion. Its very important because RC models get stressed in flight when pulling high G and the paint, if not adhered properly, can just crack or flake off. So, I wonder if we could use etch primer on plastic models? I suspect it may be too agressive.

 

John

Edited December 14, 2020 by John McNamara

[dogsbody]

9 hours ago, John McNamara said:

Hi Chris,

Yeah, that's a whole different level of cold! You would probably find a cold British winter posively balmy.

 

John

 

Wait a month or so, when the real cold weather starts. Then we'll wish it was only -27C!

 

 

 

Chris

[John McNamara]

Hi Guys, I think that the mystery is solved. After claening up the red area on the wing and repriming, I added red from a new jar I got from my LMS yesterday. Exactly the same label, but very different viscosity and a very different result.  I need to redo the rear canopy as I just cannot hand paint these acyrilics.  So I will lift the canopy off, paint it inside with white, then mask the clear area, refix and spay in the blue surround. The canopy frame between the canopy also needs attention with a touch more blue. I am going to cover it with Tamiya Gloss Clear laquer before adding the transfers. I am hoping that the white stripes have the opacity needed. I would like to buff it prior to the clear coat but I am worried about the fragility of this paint, so I think I will leave it and hope for the best. I will know to use a gloss primer in future.

John

[Ray_W]

2 minutes ago, John McNamara said:

I think that the mystery is solved.

 

That's great news John. 

 

10 minutes ago, John McNamara said:

I would like to buff it prior to the clear coat but I am worried about the fragility of this paint

 

Your call if you do not trust the finish. If it was me, I would be carefully testing the buffing on some section. My trick with this type of thing is to leave it overnight, thinking it will do. This is a great test because usually I get up next morning, clear head, and think darn it, I am going to fix it - remove the irritation. 

 

Like my F4U earlier this year - all but done and still not happy so sanded off what was the irritation in the sprayed markings and fixed a couple of other areas while about it.

 

 

Re-sprayed and glad I did. 

 

 

You always learn the best skills when things go wrong. I am sure this is the same with your RC experience - the sure-fire pursuit for learning how to fix things. 

 

Ray

[John McNamara]

19 hours ago, Ray_W said:

 

That's great news John. 

 

 

Your call if you do not trust the finish. If it was me, I would be carefully testing the buffing on some section. My trick with this type of thing is to leave it overnight, thinking it will do. This is a great test because usually I get up next morning, clear head, and think darn it, I am going to fix it - remove the irritation. 

 

Like my F4U earlier this year - all but done and still not happy so sanded off what was the irritation in the sprayed markings and fixed a couple of other areas while about it.

 

 

Re-sprayed and glad I did. 

 

 

You always learn the best skills when things go wrong. I am sure this is the same with your RC experience - the sure-fire pursuit for learning how to fix things. 

 

Ray

Hi Ray, Yes, you are right. We learn by our mistakes.  In RC the mistakes tend to have a more spectacular outcome, if your building or flying skills are not up to the mark. Nice Corsair BTW. Which kit is it from? Once the Fouga is finished I would like to finish my Corsair, but I have been waiting 5 weeks for a set of HGW seat belts to arrive.  Mine will have a very dirty, weather beaten appearance. My good lady has bought me a new airbrush for Christmas to replace my well worn Badger 155. I can't wait to try it.

John

[Ray_W]

8 minutes ago, John McNamara said:

Which kit is it from?

 

Hi John,

 

Thanks for the kind comments. It is the Tamiya 1/48 kit built for the F4U STGB earlier this year. Full build is here:

 

https://www.britmodeller.com/forums/index.php?/topic/235075763-vmf-512-f4u-id-tamiya-148-finished/

 

Have fun with the new airbrush. My favorite bit of kit. 

 

Ray