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GAC Specialty Polymers

14 thoughts on “GAC Specialty Polymers”

  1. Can the GAC 100 be thinned with Airbrush Medium or High Flow Medium to be used in a spray solution for airbrushing? I plan on sealing Ampersand Hardbord before I gesso it.

    • Hi Josh –

      GAC 100 can be sprayed. We would recommend blending with GOLDEN Airbrush Medium, starting at 2 parts GAC 100 to 1 part Airbrush Medium. When faster drying is required, replace the Airbrush Medium with GOLDEN High Flow Medium. We have also recently updated our recommendation around protecting fro Support Induced Discoloration and recognize that while GAC 100 still works for most normal applications, just as it has in the past, that Gloss Medium does have the edge for more extreme applications, such as thick applications of gels or pouring. Depending on your own processes, you can decide which works best for you. Again, for ‘normal’ painting, GAC 100 should be more than fine.

  2. For the GAC 200 it says that it helps improve adhesion on non porous surfaces – but not glass or tile. I was wondering if it would work on top of epoxy resin. I wanted to paint over a resin painting and was considering using GAC 100 or 200 to provide a clear coat over the resin that I could then paint on top of (possibly with oils). Do you think this would work?

    • Hello Jeszika,

      Thanks for your comment. Resin is a pretty tight coating, so in order to have good adhesion we recommend a light scuffing or sanding and a good cleaning to create opportunities for mechanical adhesion and remove and oils that could be on the surface. We recommend testing though just in case to be sure you achieve good adhesion. You are correct the acrylics including GAC 200 have poor adhesion to glass and glazed ceramic tiles, but GAC200 has a harder film when it dries. So if applied thinly it is harder to chip off or pick at, so it can hold up better. You would be creating a pretty complex sandwich of materials as you are describing and it is not something we have tested. You could reach out to the resin manufacturer and inquire about adhesion of oils to the resin direct and see if it can accept them and cut out the acrylic step. Let us know if you have more questions at help@goldenpaints.com

      Will It Stick? Simple Adhesion Testing In Your Studio



  3. I’m planning to to seal MDF partical board before painting with acrylics. Would GAC 100/200 be a good medium for this purpose?



  4. Hello,

    Can I use GAC 800 as a regular fluid gloss medium or just an extender like (GAC 100) for my heavy body paint with brushes? I don’t do pouring art but I have a GAC 800 and don’t know what to do with it. Also can it be used with a little retarder if applied in thin brushstroke layers?

    Thank you

    • Hello DJ, yes, you can use GAC 800 and also GAC 100 as a painting medium with your Heavy Body paints. The GAC 800 dries slightly milky, therefore it might not be the best choice for very translucent glazes, but if you mix in at least 5-10% paint into the GAC 800, the hazy color of the GAC 800 shouldn’t be noticable. It should be fine to add retarder as well.
      Best, Mirjam

  5. I am painting on top on non traditional surfaces such as cotton fabrics and lycra. Generally, I would use GAC 400 to begin the priming process, but my local store was out. I started priming with Matte Medium, but I wanted to know if I can apply GAC 100 over the matte. Eventually oil paint will be applied to the painting (after acrylic under paintings) I am curious, will the 100 be harmful over layers of matte medium? Or does 100 always have to be the initial layer?

    • Hi Jonathan, Thank you for your questions. GAC 400 is a fabric stiffener for natural fibers. This could be replaced by GAC 200 if trying to stiffen the cotton, as this is one dries to the hardest film. The GAC 400 does not however, block oil penetration. Three coats of an acrylic medium like Matte Medium, GAC 100, or acrylic paint should be sufficient to block the oil penetration. It is fine to apply the GAC 100 on top of Matte Medium, but may not be necessary if you had a total of three coats with the Matte Medium nd Acrylic paint. Please allow the acrylics to dry for three days before applying the oil paint. We hope this is helpful and if you have any further questions, please feel free to email us at help@goldenpaints.com.

    • Hello Dj, yes, the GAC 100 will be sufficient, at least for some pigments. The mineral pigments, such as natural earth pigments, wet out easily and it should be fine to mix those into a paste with water and then add GAC 100, or add GAC 100 straight away. Synthetic organic pigments, such as quinacridones or benzimedazolone pigments don’t readily mix with water and you will likely need a wetting agent to create a pigment paste with water before being able to create a good paint with GAC 100. In our Pigment ID Chart you can sort colors by their chemical category – organic (carbon based) or mineral based. When making your own acrylic paint one quickly overloads the paint with pigment which leads to mud cracking during drying. We therefore recommend keeping detailed notes of the amounts of pigment water and binder, in order to find the right ratios. Take a look at our article Just Make Paint for more detailed instructions.

  6. I am wanting to paint a old leather recliner chairw/nailheads. I stripped the dark color off w/acetone. It is a carmel colour & I want it a creme colour. what to do/use?

    • Hi Bobbi,
      Difficult to say how resilient acrylics on a leather chair will be. We have never tested anything that would get that much flexing and potential surface abrasion. Here is an article about painting leather with acrylics. It has some good tips and test results that should steer you in the right direction. Painting on Leather with Acrylics: https://justpaint.org/painting-on-leather-with-acrylics/
      We hope this helps!! Good luck!


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