Tamiya paint cracking; cause?

[Ace-Garageguy]

One more thing. I'm not trying to be a "know it all" here or bust anyone's chops.

I'm just trying to save some guys unnecessary grief, because this topic comes up so frequently.

There are 2 SIMPLE rules to follow if you want to avoid paint problems on models.

1) Spend a few bucks and only use compatible products from one product line, from one manufacturer.

Or 2), if you decide you want to ignore rule 1, TEST thoroughly BEFORE you commit to painting a model, and test on the plastic the model you're trying to paint is made from. Spoons and sprue don't always tell you what you need to know.

TEST on the underside of hoods, inside body shells, or the topside of frames, or the parts of interior tubs that won't ever be seen.

Edited November 13, 2023 by Ace-Garageguy

[bobthehobbyguy]

Solid advice.

Rule 1 is the safest. If you're going to use Tamiya. Use the same type throughout the process. If a paint job goes south you are wasting time and money. This goes for any other modeling paint brand. Unless you are building lots of model in a year it isn't going to be that expensive.

Rule 2 the risk is even if you test there is still a risk if you don't paint the model under the same conditions as the testing that there will be an issue.

Painting is a process. First off prepping is important. Then you have the paint process which takes time. Don't rush the painting process. The better you do the better the model will come out. And the build will be enjoyable.

[bobss396]

My go-to primer was Duplicolor up until maybe 6 months ago. It is still a good primer, I don't like how the cans spray when they empty out. Yes, I do clean the nozzles. I have used Tristar aunto body primers, a great barrier but I wind up having to do the nozzle cleaning thing too often.

Now I'm liking Mr. Hobby primers and Tamiya Fine Surface products. Not cheap but less work in the end. They go on MUCH smoother and I can paint "lacquers" over them.

Auto touch-up paints are not as nearly as hot as they were 20 years ago. They are considerably less volatile due to environmental regulations. I have to shoot some over bare plastic and see if they still craze.

I have guys in my club who seek out the cheapest primers possible. Rustoleum, Ace Hardware, Home Depot and so on. Then they wind up with mixed results and wonder why. There were a couple cheapos I liked, Bright Beauty (also has a great clear lacquer) from parts stores and Bondo brand.

[gman]

18 hours ago, Ace-Garageguy said:

No.

Lacquers "cure" by evaporation of the solvents in them.

Everything else you wrote is fine, but the above isn't.

Lacquer solvents do indeed penetrate into some plastic substrates, some more than others, they definitely penetrate into any previous coats of material, and subsequent coats of material can indeed retard the evaporation of solvents in underlying coats...which can result in a surface that squirms around or expands unpredictably when topcoats are applied, leading to cracking or wrinkling that looks like the effect of lacquer shot over enamel.

But as Duplicolor primers are, in general, much more solvent-resistant than any hobby primers, properly applied and aged Duplicolor primers should be fine under any hobby paint.

Still, TESTING of any material combination you want to use ON PLASTIC THAT'S THE SAME AS THE MODEL YOU'RE TRYING TO PAINT, and applied and aged exactly the same way, is imperative to avoid problems like the OP had.

 

 

 

What I am referring to with the statement "chemically bonding" to previous coats is that re-wetting, one coat of lacquer over another where the solvents activate the previous coat will then behave as one thicker coat rather than multiples.

When you polish a paint job that consists of multiple coats of lacquer, it tends to be more homogenous (should you polish through one coat into the next) compared to polishing over multiple coats of enamel. Enamels never truly cure beyond the top skin of the paint layer, and wet sanding or polishing through the topmost layer can sometimes look like an archeological dig compared to using the same process on a lacquer paint job- changes in color as you go through that top skin into the uncured portion of enamel layers closer to the base styrene. 

To be clear, I am not trying to be difficult or nitpick either. I like Duplicolor primers and paints and have used them under enamels (which I only use rarely now), under Duplicolor paint, and under Tamiya paint as well. All without issues. While sticking to a one product primer/basecoat/clearcoat system is much more predictable, I also use Tamiya and Gunze lacquer primers when the top coats are not going to contain hotter automotive solvents. If you prefer not using the word "cure" in relation to lacquers, that is fine...perhaps it would be better to say that all of the solvents have had a chance to evaporate or gas out rather than "cure." 

Many years ago when I didn't know any better, I shot Duplicolor Wimbledon White straight over bare AMT styrene (no primer) on a '32 Ford. As you can expect, that didn't work out well and it caused a bunch of texture to poke out of the styrene resulting in a ruined finish. I resigned that body in the parts bin. I came across that body and pulled it out after a decade or so, and was surprised to see most of that texture had disappeared- I broke out some polish and had at it, and was able to level any remaining texture into what would be considered an acceptable paint job without cutting through the Duplicolor. In about the same time period, I had a similar failed paint experiment shooting Duplicolor over un-primed Revell styrene on a '29 Roadster pickup. This attempt also polished out after many years, even though it didn't have as much texture as it did blush to a dead flat finish. While adding more lacquer to either body would have had the solvents wet and reactivate the mess caused by reaction from the styrene, those original coats of Duplicolor had certainly become stable over time and did not react to the mild solvents in the polishing compound. I have learned since the early 80's and always use a suitable primer under automotive lacquer.

About 12 years ago, I primed the then-new Revell '50 Olds in Duplicolor black primer (two mist coats and one heavier coat). This kit uses the reformulated styrene that is more sensitive to lacquer than vintage styrene. After a few days (when I could no longer smell solvent in the primer and it had settled into not having any texture) I dusted on a few mist coats of Duplicolor base coat followed by one wetter coat and again got some horrible texture from solvents leaching down to the styrene. This too eventually settled down and was polished into something acceptable, though I burned through the color coat in a few areas. If I had a do-over, I would have let that primer gas out for a few weeks before spraying color. The point being, technique is every bit as important as using compatible products from one manufacturer's paint range. I really miss the old Plastikote lacquer primer, as I never had any adverse effects with that under automotive lacquer, hobby lacquers or enamels. 

[Claude Thibodeau]

Hi!

I've used Tamya lacquer countless times (clear or candies) over Testor's One coat, to no ill effect. However, once, I got this wrinkling using just one coat of TS-13 Tamya's clear over a fully cured coat of Tamya's own (!?!) acrylic flat white. I was surprised, as it never happened before, and never ever since. 

Of course, most of us know that if you use TS-13 clear to your satisfaction on a part, let it cure a few days, and try to coat it AGAIN with said TS-13 within 30 days... you will likely have crazing. Many magazine writers wrote about that, and I saw it once on a project. 

CT

[Ace-Garageguy]

36 minutes ago, gman said:

If you prefer not using the word "cure" in relation to lacquers, that is fine...perhaps it would be better to say that all of the solvents have had a chance to evaporate or gas out rather than "cure." 

It's not so much "prefer" as it is what's correct.

36 minutes ago, gman said:

When you polish a paint job that consists of multiple coats of lacquer, it tends to be more homogenous (should you polish through one coat into the next) compared to polishing over multiple coats of enamel. Enamels never truly cure beyond the top skin of the paint layer, and wet sanding or polishing through the topmost layer can sometimes look like an archeological dig compared to using the same process on a lacquer paint job- changes in color as you go through that top skin into the uncured portion of enamel layers closer to the base styrene. 

Exactly...and one of the reasons touching up real-car lacquer jobs (many factories used acrylic lacquer also) was so easy, as opposed to repairing enamel work. Did I mention I've been in the real-car repair/refinish/restoration/race prep business for well over 5 decades?

36 minutes ago, gman said:

...About 12 years ago, I primed the then-new Revell '50 Olds in Duplicolor black primer (two mist coats and one heavier coat). This kit uses the reformulated styrene that is more sensitive to lacquer than vintage styrene. After a few days (when I could no longer smell solvent in the primer and it had settled into not having any texture) I dusted on a few mist coats of Duplicolor base coat followed by one wetter coat and again got some horrible texture from solvents leaching down to the styrene. This too eventually settled down and was polished into something acceptable, though I burned through the color coat in a few areas. If I had a do-over, I would have let that primer gas out for a few weeks before spraying color. The point being, technique is every bit as important as using compatible products from one manufacturer's paint range. enamels...

Same kit, Duplicolor sandable gray primer, plastic crazed and significant swelling over the "peak" and emblem on the hood after they were sanded flat, allowed to dry thoroughly, and repeatedly re-primered and sanded until it was stable, then shot with Duplicolor color, as-shot, no clear, no color-sanding or polishing.

"Acceptable"? Well, it's better than 99% of what I see on models, and illustrates that technique...including a thorough understanding of the materials and their limitations...is essential to produce "acceptable" results.

Edited November 14, 2023 by Ace-Garageguy

[restoman]

12 minutes ago, gman said:

What I am referring to with the statement "chemically bonding" to previous coats is that re-wetting, one coat of lacquer over another where the solvents activate the previous coat will then behave as one thicker coat rather than multiples.

When you polish a paint job that consists of multiple coats of lacquer, it tends to be more homogenous (should you polish through one coat into the next) compared to polishing over multiple coats of enamel. Enamels never truly cure beyond the top skin of the paint layer, and wet sanding or polishing through the topmost layer can sometimes look like an archeological dig compared to using the same process on a lacquer paint job- changes in color as you go through that top skin into the uncured portion of enamel layers closer to the base styrene. 

To be clear, I am not trying to be difficult or nitpick either. I like Duplicolor primers and paints and have used them under enamels (which I only use rarely now), under Duplicolor paint, and under Tamiya paint as well. All without issues. While sticking to a one product primer/basecoat/clearcoat system is much more predictable, I also use Tamiya and Gunze lacquer primers when the top coats are not going to contain hotter automotive solvents. If you prefer not using the word "cure" in relation to lacquers, that is fine...perhaps it would be better to say that all of the solvents have had a chance to evaporate or gas out rather than "cure." 

 

Archeological dig... I like that!

But actually, enamels appear that way due to the nature of enamels: the resin content is much higher than lacquer, allowing more resin to migrate to the top as drying/curing occurs. The resin does contain some colour, but not as much throughout the film build. The differences noted - the archeological dig - is just a result of exposing that film, like skimming the cream of the top of fresh milk. 

Old enamels do indeed cure, though not nearly as effectively as catalyzed products, but it takes a loonng time.

Same thing happens with modern base/clear systems when burning through the protective clear while wet sanding...

I hope I'm not stepping on toes here, just spouting off my over-abundance of knowledge of out-dated technologies.

[Ace-Garageguy]

5 hours ago, restoman said:

But actually, enamels appear that way due to the nature of enamels: the resin content is much higher than lacquer, allowing more resin to migrate to the top as drying/curing occurs. The resin does contain some colour, but not as much throughout the film build. The differences noted - the archeological dig - is just a result of exposing that film, like skimming the cream of the top of fresh milk. 

Old enamels do indeed cure, though not nearly as effectively as catalyzed products, but it takes a loonng time.

Same thing happens with modern base/clear systems when burning through the protective clear while wet sanding...

I hope I'm not stepping on toes here, just spouting off my over-abundance of knowledge of out-dated technologies.

Exactly...but people who haven't spent a lifetime working with refinish materials for a living, where getting it wrong costs you not only frustration but A LOT OF MONEY, don't always believe that real-world experience has any value, and that internet advice is often useless...or just flat wrong.

"Sensitive substrates" have been the bane of anyone involved in the real-car repair or refinish business since the beginning, and we've dealt with...and overcome through understanding...every paint problem known to man.

Edited November 14, 2023 by Ace-Garageguy

[gman]

24 minutes ago, Ace-Garageguy said:

It's not so much "prefer" as it is what's correct.

Exactly...and one of the reasons touching up real-car lacquer jobs (many factories used acrylic lacquer also) was so easy, as opposed to repairing enamel work. Did I mention I've been in the real-car repair/refinish/restoration/race prep business for well over 5 decades?

Same kit, Duplicolor sandable gray primer, plastic crazed and significant swelling over the "peak" and emblem on the hood after they were sanded flat, allowed to dry thoroughly, and repeatedly re-primered and sanded until it was stable, then shot with Duplicolor color, as-shot, no clear, no color-sanding or polishing.

"Acceptable"? Well, it's better than 99% of what I see on models, and illustrates that technique...including a thorough understanding of the materials and their limitations...is essential to produce "acceptable" results.

I wasn't referring to your work when I said "acceptable." That green looks great. I do not doubt your credentials, and I do admire your work and your posts, do appreciate what you have to say.

I shot mine with a Duplicolor metallic brown over black primer, and my finish is what I was referring to as acceptable (as opposed to optimum). If my finish turned out like the hood on yours, I would have wrapped up the build at that point rather than shelving it. When I get around to it, mine will need additional colour coats and some paint correction.

The statement I was making in my initial post in this thread is that there was likely still too much solvent in OP's primer which was trapped under the Testors and Tamiya he shot over top of it. Intention wise, I was trying to help the OP but I'll refrain from further posts in this thread as my intent isn't to argue with anyone.

[Ace-Garageguy]

1 minute ago, gman said:

...I'll refrain from further posts in this thread as my intent isn't to argue with anyone.

Please don't feel that way. You've imparted some useful information, and opened up the scope of the discussion.

My intent isn't to "argue" either, but to add as much valid insight as seems appropriate.

Anyone reading through this entire thread will probably learn a lot.  

[Ace-Garageguy]

Here's a little more insight into "hot" primers and the like.

I tried to shoot this Ferrari 250 GTO with hot Duplicolor self-etching primer. It crazed horribly on the hood, but rather than stopping there, I shot the whole thing, like an idiot.

A lot of people would have tossed it at that point, but as it's a fairly expensive kit, I decided to save it...knowing I had a very good chance, based on previous experience.

It has morphed into this...

The lesson here is simply "don't give up". Most everything can be saved, one way or another.

BUT...thinking through what you're doing (and benefiting from other people's mistakes they share here) BEFORE you make a mess that's hard to fix is smarter.  

EDIT: Another thought...fixing paint or crazing problems is far, far easier on models that don't have fine surface details like emblems, script, etc. So THINK before you spray.

Edited November 14, 2023 by Ace-Garageguy

[bobthehobbyguy]

4 hours ago, Claude Thibodeau said:

Hi!

I've used Tamya lacquer countless times (clear or candies) over Testor's One coat, to no ill effect. However, once, I got this wrinkling using just one coat of TS-13 Tamya's clear over a fully cured coat of Tamya's own (!?!) acrylic flat white. I was surprised, as it never happened before, and never ever since. 

Of course, most of us know that if you use TS-13 clear to your satisfaction on a part, let it cure a few days, and try to coat it AGAIN with said TS-13 within 30 days... you will likely have crazing. Many magazine writers wrote about that, and I saw it once on a project. 

CT

Yup even when you stay within one brand and type, things can go haywire. However that is often the exception to the rule.

When you start mixing types and brands the oppornities for disaster goes up significantly. 

[Roadrunner]

On 11/13/2023 at 5:07 PM, Ace-Garageguy said:

Or 2), if you decide you want to ignore rule 1, TEST thoroughly BEFORE you commit to painting a model, and test on the plastic the model you're trying to paint is made from. Spoons and sprue don't always tell you what you need to know.

TEST on the underside of hoods, inside body shells, or the topside of frames, or the parts of interior tubs that won't ever be seen.

Of all the great advice which has been offered here, and I appreciate all of it, this really strikes home. I use the spoons just to check various paints to achieve a color I like, but ever gave a second though to compatibility issues, as such. So, I intend to try a combination that already worked on a spoon, but try it again on a couple of parts from the same kit (Revell '32 Ford Sedan), that I know I'll never use otherwise, so thanks very much for that thought. I'll post the results here in a few days.

[Ace-Garageguy]

43 minutes ago, Roadrunner said:

Of all the great advice which has been offered here, and I appreciate all of it, this really strikes home. I use the spoons just to check various paints to achieve a color I like, but ever gave a second though to compatibility issues, as such. So, I intend to try a combination that already worked on a spoon, but try it again on a couple of parts from the same kit (Revell '32 Ford Sedan), that I know I'll never use otherwise, so thanks very much for that thought. I'll post the results here in a few days.

In that vein, here's something a lot of modelers don't seem to be aware of.

Besides the "styrene" your spoons are possibly made of being very different (again, possibly) from the kit "styrene", they may not even be polystyrene at all.

A lot of plastic spoons are made from polypropylene, which can react very differently to solvents. 

Adhesion can be an issue with polypropylene, and adhesion promoters are often required to get paint to stick to it in the real world.

https://www.smsdistributors.com/products/sem-plastic-adhesion-promoter

What this means to the modeler is that, simply because of its surface properties that manifest as solvent resistance, some primers may not stick, and when hit with topcoats, everything can squirm and crack just like the OP's example.

Again, this is part of the reason I continually harp on the idea of testing on the plastic the particular model you're working on is made of.

And remember that not every issue of the same kit is necessarily made of the same "styrene" blend.

Edited November 15, 2023 by Ace-Garageguy

[Dave G.]

10 hours ago, Roadrunner said:

Of all the great advice which has been offered here, and I appreciate all of it, this really strikes home. I use the spoons just to check various paints to achieve a color I like, but ever gave a second though to compatibility issues, as such. So, I intend to try a combination that already worked on a spoon, but try it again on a couple of parts from the same kit (Revell '32 Ford Sedan), that I know I'll never use otherwise, so thanks very much for that thought. I'll post the results here in a few days.

I use the amber prescription bottles ( God knows I build up a collection of empties fast enough !), primer is a must for a couple of reasons to include that the amber color bothers the color output/rendition. But more than that I learned some time ago that tape pull tests will fail much easier on those bottles, as well as scratch tests compared to kit plastic. As Ace mentioned, I too use extra hoods or inside of body shells etc for my final tests.

[bobss396]

3 hours ago, Dave G. said:

I use the amber prescription bottles ( God knows I build up a collection of empties fast enough !), primer is a must for a couple of reasons to include that the amber color bothers the color output/rendition. But more than that I learned some time ago that tape pull tests will fail much easier on those bottles, as well as scratch tests compared to kit plastic. As Ace mentioned, I too use extra hoods or inside of body shells etc for my final tests.

I have a few of those bottles too for some reason... I mainly store parts in then on ongoing projects. I will have to squirt some sample paints on them. I also have a good supply of leftover kit pieces I use to experiment on. I have been doing that for many years.

[Ace-Garageguy]

4 hours ago, Dave G. said:

I use the amber prescription bottles ( God knows I build up a collection of empties fast enough !), primer is a must for a couple of reasons to include that the amber color bothers the color output/rendition. But more than that I learned some time ago that tape pull tests will fail much easier on those bottles, as well as scratch tests compared to kit plastic. As Ace mentioned, I too use extra hoods or inside of body shells etc for my final tests.

 

1 hour ago, bobss396 said:

I have a few of those bottles too for some reason... I mainly store parts in then on ongoing projects. I will have to squirt some sample paints on them. I also have a good supply of leftover kit pieces I use to experiment on. I have been doing that for many years.

Most prescription, vitamin, other pill bottles, and many soda and water bottles are PETE...polyethylene terephthalate...another plastic very different from polystyrene, and that also has a surface that paints don't like to stick to (as Dave G. noticed).

I have and still do recommend using primered soda bottles for practice spray painting. For finding the sweet-spot between dry-spray or excessive orange peel and running the paint off on the ground, they're a great alternative to model car bodies. And because they're similar in size to model cars, they make it possible to develop good overlap technique, to avoid streaks and blotchiness in metallics.

HOWEVER...they will tell you little about paint compatibility, as the relatively poor adhesion of primers can lead to squirming, cracking, and wrinkling when topcoated, again similar to the OP's example.

EDIT: Highly aggressive "self etching" automotive primers (that would pretty much ruin a styrene kit body) might be useful for preparing soda bottles for painting practice, but I haven't tested them for that application.

Edited November 15, 2023 by Ace-Garageguy

[bobthehobbyguy]

 

16 hours ago, Ace-Garageguy said:

In that vein, here's something a lot of modelers don't seem to be aware of.

Besides the "styrene" your spoons are possibly made of being very different (again, possibly) from the kit "styrene", they may not even be polystyrene at all.

A lot of plastic spoons are made from polypropylene, which can react very differently to solvents. 

Adhesion can be an issue with polypropylene, and adhesion promoters are often required to get paint to stick to it in the real world.

https://www.smsdistributors.com/products/sem-plastic-adhesion-promoter

What this means to the modeler is that, simply because of its surface properties that manifest as solvent resistance, some primers may not stick, and when hit with topcoats, everything can squirm and crack just like the OP's example.

Again, this is part of the reason I continually harp on the idea of testing on the plastic the particular model you're working on is made of.

And remember that not every issue of the same kit is necessarily made of the same "styrene" blend.

Interesting information. So the only real information you can get from spoons is testing colors. Paint compatibility and plastic compatibility have to be determined on the actual kit plastic itself.

This has been a very informative thread and I've learned a lot from it.

[Roadrunner]

And the (expedited) result. Tamiya white primer, Testors diamond dust, Tamiya clear blue & Testors clear. No issues at all, thank goodness. I'm very comfortable now with proceeding.

[peteski]

Surfaces used for paint compatibility testing:

Yes, plastic spoons can be made from various plastic resins (yes all plastics are resins).  With the recycling push all over the world, you can easily tell what you are buying.  Look for the recycling symbol on the spoon packaging.  #6 is Polystyrene (which is as close to the kit's plastic as possible). If it is not #6, don't buy it.

Bottles are usually soft plastic (soft drinks, medicine, etc). Again, they should all have the recycling symbol.  They will likely not be polystyrene, but are still useful for testing paint combinations to see what the finish will look like.  Soft  drinks bottles are usually PET (#1 or 2), and medicine bottles are Polyropylene (#5).

Recycling symbol is your friend!

[Dave G.]

15 hours ago, peteski said:

Surfaces used for paint compatibility testing:

Yes, plastic spoons can be made from various plastic resins (yes all plastics are resins).  With the recycling push all over the world, you can easily tell what you are buying.  Look for the recycling symbol on the spoon packaging.  #6 is Polystyrene (which is as close to the kit's plastic as possible). If it is not #6, don't buy it.

Bottles are usually soft plastic (soft drinks, medicine, etc). Again, they should all have the recycling symbol.  They will likely not be polystyrene, but are still useful for testing paint combinations to see what the finish will look like.  Soft  drinks bottles are usually PET (#1 or 2), and medicine bottles are Polyropylene (#5).

Recycling symbol is your friend!

This post runs on a bit but it's good info I believe:

That's a great chart ! My amber prescription bottles are indeed pp #5.

But here is an interesting fact for all, on the pp bottles, Stynylrez primer sticks best, better even than Mr Surfacer, both in terms of scratch and tape pull tests to pp #5, I've conducted. But on model plastic the roles are pretty equal if not leaning slightly toward the Mr product.. Here is an even better observation, Tamiya LP lacquer sprayed directly onto each surface with no primer fails badly on pp #5 but sticks like iron to styrene model kit plastic ( shouldn't be a surprise since it's formulated for kit plastic).  The only reason I see for the primer on the model plastic is color control, surface evenness  prep etc. Not so much adhesion.  And it's nearly the same result for Tamiya X series acrylics. Waterborne acrylics however need the primer to stick and with primer do very well at it. Without primer the stuff could flake off and has for many people unknowing of that fact.

Anyway I have no qualms about using Mr Primer/Mr Surfacer or Stynylrez on models. Either is sufficient, however Stynylrez is both primer and sealer. That can have advantages when needing a sealer.

Some folks may not know this, Mr Surfacer is not really a lacquer primer. Read the label sometime ! It's a very good primer though.

Another tidbit: you can thin Stynylrez with hardware store medium dry lacquer thinner, close to 50/50 and in so doing you will get a crazy smooth satin finish from it. I learned that over in the FSM forums, so of course had to do it. Beautiful result. I use it on frames and water hoses etc as color coat in the black Stynylrez. And as a further note, Klean Strip brand hardware store lacquer thinner comes in two formulas now, labelled at the top of the front of the can. Fast dry and Medium dry.

[Dpate]

On 11/16/2023 at 8:07 AM, Dave G. said:

This post runs on a bit but it's good info I believe:

That's a great chart ! My amber prescription bottles are indeed pp #5.

But here is an interesting fact for all, on the pp bottles, Stynylrez primer sticks best, better even than Mr Surfacer, both in terms of scratch and tape pull tests to pp #5, I've conducted. But on model plastic the roles are pretty equal if not leaning slightly toward the Mr product.. Here is an even better observation, Tamiya LP lacquer sprayed directly onto each surface with no primer fails badly on pp #5 but sticks like iron to styrene model kit plastic ( shouldn't be a surprise since it's formulated for kit plastic).  The only reason I see for the primer on the model plastic is color control, surface evenness  prep etc. Not so much adhesion.  And it's nearly the same result for Tamiya X series acrylics. Waterborne acrylics however need the primer to stick and with primer do very well at it. Without primer the stuff could flake off and has for many people unknowing of that fact.

Anyway I have no qualms about using Mr Primer/Mr Surfacer or Stynylrez on models. Either is sufficient, however Stynylrez is both primer and sealer. That can have advantages when needing a sealer.

Some folks may not know this, Mr Surfacer is not really a lacquer primer. Read the label sometime ! It's a very good primer though.

Another tidbit: you can thin Stynylrez with hardware store medium dry lacquer thinner, close to 50/50 and in so doing you will get a crazy smooth satin finish from it. I learned that over in the FSM forums, so of course had to do it. Beautiful result. I use it on frames and water hoses etc as color coat in the black Stynylrez. And as a further note, Klean Strip brand hardware store lacquer thinner comes in two formulas now, labelled at the top of the front of the can. Fast dry and Medium dry.

Yeah surfacer's carrier is lacquer based.  

[Dave G.]

11 hours ago, Dpate said:

Yeah surfacer's carrier is lacquer based.  

 The label of the spray can for Mr Surfacer 1000  says this: Product name : Synthetic Resin Paint.

Material:  Acrylic synthetic resin, organic solvent, pigment.

Edited November 18, 2023 by Dave G.

[peteski]

44 minutes ago, Dave G. said:

 The label of the spray can for Mr Surfacer 1000  says this: Product name : Synthetic Resin Paint.

Material:  Acrylic synthetic resin, organic solvent, pigment.

Well, today's lacquers aren't made from beetles - they use synthetic resins.  That is where this generalization modelers use that anything "acrylic" is automatically water-based and an enamel is not helpful.

[Dave G.]

2 hours ago, peteski said:

Well, today's lacquers aren't made from beetles - they use synthetic resins.  That is where this generalization modelers use that anything "acrylic" is automatically water-based and an enamel is not helpful.

True lacquer to me is made from cellulose, IE nitrocellulose lacquer. Yes today it's synthetic, true. And there is acrylic lacquer, I just never thought of it that way for primers.

The beetle thing sometimes called lacquer over seas ( mostly Asia) is actually what we see in our stores here as Shellac. It's made from the secretion of the lac bug.  That stuff coats tree limbs and is flaked off. Take that and mix it with alcohol, it melts into the liquid and you have shellac. I have never known of any model primers or paints made from this, though it makes a good stain sealer, so I guess in that sense you could call it primer or at least sealer.

Edited November 18, 2023 by Dave G.