How To/FAQ
Ratios-- Do I need to measure by weight or by volume?
Silicone RTV’s
Our systems are formulated to achieve the best physical properties by weight. Silpak’s systems are flexible enough to mix by volume also, but you could run short of the catalyst (B side).**Exception – Platinum based R-2100 series must be mixed by weight to within 0.5%- high or low range.
Urethane Plastics & Urethane RTV’s
The balanced ratio is by weight. Various systems can end with curing problems because the density of part A and part B are different. When mixing by volume, you will need to pour the A side into the B side without scraping the container to achieve a somewhat accurate measure. Otherwise you will be short on the part A side and will need to order extra.
Epoxy
Epoxies are very sensitive to ratios, and, because of the density of the base to hardener, it can be 20% or more off if working by volume. Trying to work out volume ratios can be done but the weight but must be worked out first. An accurate scale is recommended.
Polyester Resin
This system is unique in that, typically, the catalyst is added at a minute amount, between .75 to 1.5% to the resin weight. Adding more catalyst will accelerate gel and cure time. Volumetric measurements have been generated for these types of resin. See Technical Information-- MEKP RatioChart.