The science of lacquer leveling thinner

[CasualModel98]

I have been using Mr.Color Leveling Thinner for lacquer paint for a while and they are not cheap. So I started to look around for cheaper alternatives. Let me share some findings here.

This is not for acrylics as they have their own water based formulation. It is more for lacquer paint.

All lacquer paint have to be thinned with some form of organic solvent or alcohol derivatives. The problem is that many of these solvent have a high evaporation rate that dries when the paint leaves the AB.

Thus the manufacturers actually use slower evaporating solvents as their thinner or to mix with their thinners to create Leveling thinners. Leveling thinners must have two properties in that they dissolve lacquer (duh) and that they have a slower evaporation rate to give time for the paint to level out before drying. However it cannot take too long as nobody wants to "watch paint dry". So the evaporation rate must be slow enough and yet faster than water.

 

How do you measure evaporation rate? The industry generally benchmark it to Butyl Acetate with an evaporation rate of 1.

I quote from the Business Dictionary, "Chemicals with evaporation rate of 3.0 (three time the evaporation of normal butyl acetate), such as acetone (5.6), hexane (8.3), or methyl ethyl ketone or MEK (3.8) are classified as 'fast evaporating.' Chemicals with evaporation rate between 0.8 and 3.0, such as ethyl alcohol (1.4) or VM&P naphtha (1.4) are classified as 'medium evaporating.' And chemicals with evaporation rate less than 0.8, such as water (0.3), mineral spirit (0.1), or xylene (0.6) are classified as 'slow evaporating'."
 

With that in mind I took a look at Mr.Color Thinner.  Its composition is about:

10% of 2 Pentanone 4 Hydroxy 4 Methy (0.085, evap rate slower than water but only 10% in mixture)

10-30% 2-Propanol (1.0 medium evap rate)

10-30% Isobutyl alcohol (0.6 slow evap rate)

10-30% 2 Pentanone 4 Methyl (1.6 medium evap rate)

10% ethanol 2 Butoxy (0.08 slower than water)

If you average out the evap rate by percentage mix then overall evap rate of Mr. Thinner is about 1.

 

 

I can't find the composition of Mr.Leveling Thinner online so I cannot measure the average evaporation rate.  

 

However I found the composition of a lacquer leveling thinner for use in general painting. Here is their composition.

Sunnyside brand Lacquer Retarder

Xylene (0.7) 100ppm

Ethyl Benzene (0.8) 100ppm

Butyl Acetate (1.0) 150ppm

Butyl Alcohol (0.4) 50ppm

2 Butoxy Ethanol (0.079) 20ppm

So you can see it has an average evap rate of 0.8, compared to water evap rate of 0.3.

 

I can't find the composition for Tamiya Lacquer Thinner but it has Methyl Isobutyl Ketone with evap of 1.6, quite fast.

 

Mineral spirits depending on the composition is 0.13.

Xylene is 0.7.

 

Typical lacquer thinner from the hardware store is about 75% Toulene (1.9) and 25% Acetone (6.3) so quite fast evaporating. When I use this to thin my paint, the paint dries in the air and gives me a rough finish.

However lacquer thinners works the best for dissolving lacquer paint and allowing us to spray it thin and smooth.

 

This is the reason why manufacturers have a mixture of solvents good at dissolving lacquer with slow evaporating solvents as you see above.

 

I am going to try getting my hands on some xylene and mixing it to the lacquer thinner to slow down the evap rate and increase the leveling effect. I am still waiting for my xylene to arrive. Perhaps this can be my cheap source of leveling thinner, or at least a cheap composition I can use to wash my AB and painting tools.

 

NOTE that all the chemicals here are toxic to humans. So please use the proper safeguards like well ventilated space, masks, etc.

 

 

I found these articles to be very useful for understanding solvents.

https://thefinishingstore.com/blogs/news/127179715-understanding-solvents-part-iii-laquer-thinner

https://www.nytimes.com/1996/10/27/nyregion/how-to-use-and-apply-the-many-varieties-of-solvents.html

 

[Steve Noble]

As I only use the Mr Color levelling thinner to thin the actual paint, I don't use much. I buy the large bottle and it lasts a very long time, maybe 5 or 6 models. For cleaning I use a cheap gun wash thinner from the car paints store, £5 for a large 5 litre can. If something works well and is compatible with the paints I don't mind paying for it. Mixing solvents and trying to make my own thinner has never worked for me, so I tend to stick to the proper stuff..

[Jamie @ Sovereign Hobbies]

On 6/28/2019 at 4:49 AM, CasualModel98 said:

However I found the composition of a lacquer leveling thinner for use in general painting. Here is their composition.

Sunnyside brand Lacquer Retarder

Xylene (0.7) 100ppm

Ethyl Benzene (0.8) 100ppm

Butyl Acetate (1.0) 150ppm

Butyl Alcohol (0.4) 50ppm

2 Butoxy Ethanol (0.079) 20ppm

So you can see it has an average evap rate of 0.8, compared to water evap rate of 0.3.

 

I am going to try getting my hands on some xylene and mixing it to the lacquer thinner to slow down the evap rate and increase the leveling effect. I am still waiting for my xylene to arrive. Perhaps this can be my cheap source of leveling thinner, or at least a cheap composition I can use to wash my AB and painting tools.

 

I notice that the composition quoted for the Sunnyside brand is in units of PPM, so that really begs the question "what is the rest of it?" Obviously 420 parts per million doesn't add up to a million. Infact the above, if the units are correct, accounts for 0.00042% of the total liquid volume and as such will be almost entirely inconsequential to the net evaporation rate - you could add 0.00042% of virtually anything to 99.99958% toluene and to 99.99958% mineral spirits and each would more or less retain its own evaporation rate. Hence adding Xylene yourself is going to require some very hefty batch sizes for you to safely add a measurable quantity of that chemical. I'm sure you're aware already but xylene is one of the key chemicals in plastic cement used for model making. It not only dissolves paint but styrene plastics too. I suspect the units are off though.

 

Your last points about toxicity are valid though, but it still makes me chuckle that so many consumers' brains are jammed in the simplistic "acrylic good / enamel bad" mantra given that almost all of the lacquer paints are marketed as acrylic lacquers, so when they ask "someone please recommend me an acrylic match for x,y or z" they get recommendations for everything from Lifecolor to MRP with hardly anyone stopping to question what sorts of behaviours or attributes the person asking the question actually wants.

 

Lastly, given that so many people who now dislike enamel do so because of drying times, it's also worth noting that almost all of them have only ever experienced using the stuff with mineral spirits (white spirit in the UK) as thinner. It's the use of household thinners with very slow evaporation rates which result in painfully slow drying times. That can actually be useful for making washes etc though.

 

 

[azureglo]

This I gotta see, I am a devout follower of the Sacred Levelling Thinner and this is exactly the kind of stuff that floats my boat: Keep us posted and heed your own safety advice, it's hard to post updates from the next life!

 

Anil

[CasualModel98]

Yes, xylene does dissolve plastic. Note that the industrial lacquer thinners are probably meant to thin lacquer for painting furniture or non-plastics. So the high xylene content is fine for them but may not work for plastic models.

 

Anyway I plan to keep using Mr.Color for the paint and to make a cheaper concoction to clean my AB and brushes, etc. 

 

Further information to consider is that ketones, esters and glycol ethers are active solvents for lacquer. Lacquer does not require a lot of active solvents to dissolve so most manufacturers add less expensive Toluene or Xylene, or alcohols to make up the bulk.  Mr.Color thinner above is made up of about 50% active lacquer solvent and 50% alcohol.

 

The "additional" solvents must evaporate faster than the lacquer solvents so that the lacquer solvents have time to level out before evaporating leaving a smooth layer of lacquer. Otherwise you will get the appearance of whitish residue on the paint. 

 

Still waiting for my xylene supply, will test out and update later.

[CasualModel98]

By the way I also saw a video that you can dissolve your styrene leftovers in xylene to form a soft piece of styrene block that you can use for scratch building or cast into a mold. Let me also experiment with that later on.

[CasualModel98]

Some forum mentioned using Klean Strip to thin lacquers. Here are the ingredients.

Again about half active lacquer solvents and half other solvents to make up the volume.

 

Methanol {Methyl alcohol; Carbinol; Wood alcohol} 25.0 -35.0 %

Acetone {2-Propanone} 20.0 -30.0 %

Petroleum Hydrocarbon Mixture (Alkanes and Cycloalkanes) 20.0 -30.0 %

Acetic acid, ethyl ester {Ethyl acetate} <15.0 %

Toluene {Benzene, Methyl-; Toluol} < 5.0 %

Ethanol, 2-Butoxy- {Ethylene glycol n-butyl ether, (a glycol ether)} < 5.0 %

[azureglo]

http://www.mr-hobby.com/en/itemDetail.php?iId=160

5 hours ago, CasualModel98 said:

Some forum mentioned using Klean Strip to thin lacquers. Here are the ingredients.

Again about half active lacquer solvents and half other solvents to make up the volume.

 

Methanol {Methyl alcohol; Carbinol; Wood alcohol} 25.0 -35.0 %

Acetone {2-Propanone} 20.0 -30.0 %

Petroleum Hydrocarbon Mixture (Alkanes and Cycloalkanes) 20.0 -30.0 %

Acetic acid, ethyl ester {Ethyl acetate} <15.0 %

Toluene {Benzene, Methyl-; Toluol} < 5.0 %

Ethanol, 2-Butoxy- {Ethylene glycol n-butyl ether, (a glycol ether)} < 5.0 %

While your experiment, are you aware of Mr Hobby Retarder, woodworkers lacquer retarder and urethane reducers? I've thought of trying the Mr Retarder with standard cellulose thinner ( which I buy in 25 litre drums for £30 in the UK) and this will prompt me to give it a go and report back. Unless you hear of very loud explosions in North Hampshire,UK,  in which case I'll contact you in your dreams...

 

Anil 

 

[CasualModel98]

19 hours ago, azureglo said:

http://www.mr-hobby.com/en/itemDetail.php?iId=160

While your experiment, are you aware of Mr Hobby Retarder, woodworkers lacquer retarder and urethane reducers? I've thought of trying the Mr Retarder with standard cellulose thinner ( which I buy in 25 litre drums for £30 in the UK) and this will prompt me to give it a go and report back. Unless you hear of very loud explosions in North Hampshire,UK,  in which case I'll contact you in your dreams...

 

Anil 

 

Go ahead and look forward to your interesting outcome as well.  I don't have these in my local hardware stores.

Standard cellulose thinners works great for thinning but they dry too fast. So adding Retarder may do the trick.

What are the chemicals inside Mr.Retarder and the thinner you are using?

[CasualModel98]

Finally got my supply of Xylene and Acetone. Each cost me about 5 quid for a 3.5L tin.

I tested it compared to MrColor Leveling Thinner and here are some photos.

 

This first photo is spraying with the original Mr.Color Leveling Thinner and with pure Xylene.

You can see the nice smooth finish of Mr.Color. However the Xylene started to eat the plastic. 

 

I also sprayed with pure Acetone. Just to try out. Here is the effect. FOr some strange reason the blue is more vibrant and distinct with the Acetone compared to Mr.Color. I checked my dilution and its all the same 1:1 dilution. There is a little sign of etching by the Acetone though but it leaves a smooth coat and the color comes out darker.

 

 

[CasualModel98]

The earlier test was with a Hasegawa F-15E leftover kit. I think the plastic was from a softer material. I tried it on an old kit from Tamiya (but manufactured by Italeri I think). The plastic here felt much harder than those newer kits. This is a 20 year old kit. I sprayed Mr.Color silver as well as blue.

 

You can see the Xylene and Acetone works well as leveling thinner.  Both retain the shine of the paint and levels out well. However the same effect was seen in that Acetone and Xylene produces a darker blue than the original Leveling Thinner.  Maybe this has to do with the reaction of lacquer paint with the solvents. 

The older plastic don;t seem to show any etching or damage by the solvent. No sign either from Xylene or Acetone.

 

When I tried to mix the Acetone with methylated spirit to spray, the effect is not good. The paint loses its shine/gloss.

 

[CasualModel98]

One other thing I noted was that Xylene does not dissolve lacquer as well as Acetone but is hotter on plastics than Acetone.

Both Xylene and Acetone also takes a little bit longer to dry.

 

I will run other tests over the next few days. I think I am comfortable with mixing this cheap Acetone with Mr.Leveling Thinner to extend the volume.

 

 

[CasualModel98]

Since I am less impressed with Xylene as a solvent, I was thinking of other uses.

I had a tube of dried out Tamiya basic putty. I used xylene to revive it and it seems to work. Adding more xylene makes it more malleable to be spread out. Once it hardened, it can be sanded quite smoothly and not cumbly. Top circle.

 

Bottom circle. I also melted some sprues in the xylene and used it as a filler. After an hour of soaking the sprues all melted. After 8 hours of airing to let the Xylene evaporate, the resultant mixture is a gooey substance that can be applied as a putty to fill gaps.  I will let you know how well it works later on after it has hardened.  Melted sprue takes a while to harden as you need the xylene to totally evaporate from the gooey mixture.

 

 

The dried putty can be revived and used again and it sands smooth and hard, not crumbly.

 

[ixlr8nz]

Very interesting thread! There is a lot of great info and tests here and it actually leads to even more questions.  I was just wondering if the tests carried out are on bare plastic or with primer? Acetone is known to be fast evaporating, but also melts plastic, so interesting to see your results how it performed as a thinner. Just wondering was the paint applied light or heavy to get that result?

 

Also I have used Mr Levelling thinner as a paint stripper which does not attack the plastic (in my case just a small area). There is unlikely to be Acetone in MLT.

 

In terms of Acetone allowing more vibrancy to colours compared to other thinners, this would be quite useful in painting racing cars and bikes.

 

Also has anyone tried the Tamiya Lacquer Retarder (small blue top bottle). I wonder if you had say 1 litre of regular lacquer thinner, how much Tamiya Lacquer Retarder would need to be added to make the result the equivalent of either Tamiya or Mr Color's levelling thinners?

 

Btw I have noticed with Tamiyas LP clear colours, regular Lacquer thinner works better than MLT as you get less chance of running which is better for building up colours faster.

 

Sorry for all the questions, but very interesting.

[Steve Noble]

Whilst I admire your resolution to test all these things, I still prefer to use the proper Mr Color levelling thinner. I put a lot of effort into my models and the paint finish is the final step. I wouldn't want to risk a sub standard finish by using a home brew thinner and ruining all my preparation work. It's made by the manufacturer of the paint to work with their paint..