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SYSTEM THREE FAQs

FAQ from the System Three website:

My epoxy resin is taking too long to cure. How can I speed it up?
The only way to speed the cure of our epoxy resin products, once they've been applied, is to heat the room or the area that your project is in. Every 18°F increase in temperature cuts the time it takes for the resin to cure in half.

I made a small batch and after a week it has not cured. What happened?
It is difficult to measure a batch of resin and hardener less than three fluid ounces by volume. If you need to make a small batch, measure it by weight. System Three offers a small digital scale perfect for this use.

I made a large batch and found a few areas that are still sticky after most of the surface is cured hard. What happened?
The material was probably not thoroughly mixed and unmixed material was scraped from the container onto the surface. When mixing always be sure to mix from the bottom to the top and scrape the sides of the container and the stick. Experienced users dump and scrape the mixed material from the first container into a second and then mix again. This totally avoids the problem described above.

I made a large batch and found a few areas that are still sticky after most of the surface is cured hard. Can I fix it?
Yes. First, scrape off what you can. Then pour or wipe a suitable solvent on the surface. Wear a respirator or provide proper ventilation when working with solvents. Wipe or scrub the resin surface. This will remove residual uncured resin but won't harm any cured resin. Sand the underlying cured resin and apply a fresh coat properly measured and thoroughly mixed. Note: Over bare wood the fresh coat of resin will need to be worked into the wood with a stiff-bristle brush to mix any residual uncured material into the fresh material. This will ensure that the fresh coat will adhere properly to the wood.

 

MIXING – Further comments from Mike Doolin:

  1. The epoxy is very sensitive to mix ratio, and it's hard to get it right when measuring by volume in small quantities. The best thing is to measure by weight with a triple-beam-balance gram scale. The mix ratio of resin to hardener is 100:44 for SB112, 100:43 for Clear Coat. Thoroughly mix the epoxy first, then add the thickener.

    I use two paper Dixie cups, one inside the other to keep the epoxy from soaking through to my fingers. I first weigh the empty cups, which turns out to be 3.5 grams for the particular cups I use. Then I squirt in 10 grams of epoxy resin, which makes 13.5 grams. Finally I squirt in 4.4 grams of hardener, bringing the total weight to 17.9 grams (and making the mix ratio 100:44). I mix this really thoroughly, scraping the bottom and sides and the stirring stick, and turning the cup around frequently. I spend a good 20-30 seconds stirring the stuff, making sure there isn't any unmixed epoxy in the corners or on the stick. Then I add the thickener and stir it in just until it's all wetted.

    This makes enough epoxy to cover a whole guitar if you work fast, with lots left over after scraping it all off. Remember, the idea is to leave none on the surface, just in the pores. I wipe the corners with an alcohol wetted rag to make sure there's no build-up there.

  2. The epoxy is also somewhat sensitive to temperature. It cures better at 70 degrees or higher. After application, hang the guitar in a warm room to cure. It should be hard but very slightly tacky after 6 hours, no longer tacky after 24.