Paint Thinner home brew for a noob!

[DarkCobra47]

I would prefer to make my own Thinner, obviously to save on cost a little. Everyone I've seen uses 99.9% IPA. However, they are cutting it down with water to around 30-33%. 

 

Question: Can I use 91% Iso Alcohol or does it have to be 99.9%?

[Bertie McBoatface]

The missing 8.9% would have been replaced with water so, yes. just add 21 to 24% more water to get to the same mix as 'Everyone you've seen'. What paint are you intending to thin with your homebrew, I wonder. They are all different in their formulation some very much so. I recommend experimenting before using your mix on a model.

 

Welcome to Britmodeller. 

[Casey]

IPA is not a thinner for everything, some paints will happily turn into gooey gloop.

 

If you make your own thinner, add a tiny bit of retarder and flow improver. It helps a lot!

[DarkCobra47]

Thanks Bertie! I didn't think I was crazy.... 🤣 Appreciate you my friend and thanks for the welcome, feels good to be here! 

 

I currently have Vallejo Model Color. There are so many these days! Used to be easy.... Testor.... LOL!! I need to grow my paint collection for sure. Totally planned on adding some retarder and improver. Once it's mixed the testing starts! Thanks Casey! Appreciate your experienced advise my friend! 

Edited January 6, 2023 by DarkCobra47

[Casey]

2 minutes ago, DarkCobra47 said:

I currently have Vallejo Model Color. There are so many these days! Used to be easy.... Testor....

Vallejo has a great thinner, I actually use it for a lot of purposes. Another good acrylic thinner I have is from... army painter - it is an mix of acrylic medium so it can thin paints more than usual IPA.

 

Interestingly, with a lot paints you can do decent with just distilled water and flow improver/retarter.

[ColonelKrypton]

Home brew thinners is a common subject found throughout online hobby medias.

 

It is understandable from an economy point of view but in reality it is false economy.  As you read the various forum postings on problems encountered with painting and airbrushing the common thread is users mixing different products and creating some incompatibility or other problematic application condition.

 

The first most important question to ask is - What is the intended purpose of the thinner?  For cleaning brushes, airbrushes (and so on) then a general purpose isopropanol alcohol be it 99% or 91%  or a stronger lacquer thinner for tough jobs are quite adequate choices.

 

Manufactures will often specify thinning of no more than perhaps 10 to 20% thinner to paint.  All paints generally speaking are composed of three primary ingredients - pigment (the colour), binder (acrylic polymer resin in acrylic paints) and carrier. The acrylic polymer resin is what provides the actual paint coating and the carrier is the solvent into which everything is mixed which eventually evaporates leaving behind the pigment and acrylic polymer resin. Over thinning the paint with more than the recommended amount of thinner can cause the paint to break down and cause problems with adhesion and other poor coating properties.

 

If the goal is to use something to thin the paint for better brushing or airbrushing properties then using the manufactures own thinner product is always a good choice. A large bottle may seem a bit pricey but a little will go a long way if used only for thinning.

 

There are two commonly found hobby acrylics and these include art art and craft products as well - water based acrylics ( i.e Vallejo, AK Interactive acrylics, Liquitex, Golden, etc)  and non-water based acrylics ( Tamiya Acrylics ). Water based acrylics can usually be intermixed freely but do test before using. Tamiya acrylics cannot be freely mixed with water based acrylics. Too many have learned the hard way that you cannot use Tamiya X-20a acrylic thinner ( a mix of water, alcohol and retarder) with the like of Vallejo; you will end up with no end of problems and likely a globby mess. 

 

In my experience, a better choice for reducing ( just another fancy name for thinning a paint ) a water based acrylic for brushing or spraying is to use one of the airbrush mediums. Liquitex, Golden, Vallejo, and Army painter have these products; Liquitex and Golden can be found in larger 4 and 8 ounce bottles and are good value for your dollar. Remember you will only use a little and a little goes a long way. These airbrush mediums are composed of primarily water, acrylic polymer resin, and retarder ( typically propylene glycol ).

 

Which brings me to another point regarding thinners, retarders and flow improvers. You will find that in these water based acrylic paint lines ( such as Vallejo ) that their thinners, retarders, and flow improvers are little more than water and retarder in somewhat different proportions.  If you are planning to use a retarder then it should not be necessary to use a flow improver as well. And, if you were to use one the airbrush mediums then you shouldn't need to add either retarder or flow improvers although depending on you local conditions ( i.e. very low humidity and/or high temperatures) a wee bit more retarder might be beneficial.

 

Vallejo airbrush cleaner is chemically very similar to their thinner ( mostly water and propylene glycol ) just in different proportions. I have found that the Vallejo airbrush cleaner to work a bit better than their thinner. 

 

My apologizes for being a bit long winded. I am not a chemist just a long time hobbyist and maker that has expended much time in exploring and experimenting, and reading through many hundreds of safety data sheets of the various products in order to gain a better understanding of the subject. I am still learning ( ancora imparo - Michelangelo )

 

cheers, Graham

 

 

[DarkCobra47]

@ColonelKrypton thanks for that in depth, informative, and thought provoking information. I do really appreciate all of it. Getting back in to modeling is very daunting because of all of the advances in models, paints, tools, and glues/cements. 

[ColonelKrypton]

59 minutes ago, DarkCobra47 said:

Getting back in to modeling is very daunting because of all of the advances in models, paints, tools, and glues/cements. 

 

Agreed. Even for those that have been in the hobby for many years are discovering some of their old familiar materials disappearing and being replaced with an ever growing and bewildering array of new products. 

 

Sometime too much choice is no better than too little choice.

 

cheers, Graham

 

[rayprit]

Couple of money saving tips here :-