Changes to the PR-1 usage recommendation

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Changes to the PR-1 usage recommendation

Postby jmurray2112 » Fri Sep 21, 2018 5:21 pm

The original post on this topic was lost in our recent web-hosting migration. Since the original posting, I've had a fair amount of time to test our new recommended carrier for the PR-1 resin, and the results (at least for me) are pretty conclusive.
Once upon a time, our PR-1 resin was very friendly to aqueous solvents like denatured alcohol or acetone. It tolerated them well, with no swelling or application issues like surface agglomeration (little bits of hardened resin clinging to the leather surface) when the primer mixture was rubbed on. Then, about five years ago, there was an industry change to resins like this. They were originally primarily siliconized acrylics, but then the big chemical companies that produced them decided that silicones were too expensive no matter how effective they might be, and decided to mix urethanes with the acrylics instead. Then, they passed on their savings by doubling the price. Can you tell how I feel about big chemical companies? :x .
However, our cleaner is a much better carrier than alcohols or ketones. The citrus solvent in it is a oil-based solvent (organic solvent), but because the cleaner is an emulsion (combination of normally incompatible components like oil and water), the PR-1 resin interacts with it just fine, with none of the swelling or surface agglomeration described above. I do a lot of priming of unfinished veg-tan leather, and the difference between the two types of carriers is pretty dramatic, and really speeds up production because I don't have to sand or strip off the little residual bits of primer prior to finishing.
So, I recommend using either SG-4 ready made, or make your own using our cleaner and PR-1 concentrate. SG-4 is basically 3 parts cleaner to 1 part PR-1 concentrate. If you make your own, you can also load in the PR-1 (up to 35%) if you are priming a really thirsty aniline leather, or are converting a nubuck to a finished leather. Let me know if I can provide clarification or more info.

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