| Home | Articles | CP reprints |

SAFE-T-POXY WORKING TEMPERATURE
(From CP23, Page 6, January, 1980)

     Builder feedback has indicated some difficulty using the Safe-T-Poxy in cold climates. Typical situations are where most EZs are built in garages that are difficult to heat in the winter. Problems are where the builder will heat up the room/garage (air only) and go directly to work but the epoxy, glass, parts, tools etc are still cold—soaked. In use, cold epoxy wets slow and greatly extends the time to wet the cloth properly.
     The Safe-T-Poxy has a higher viscosity than the previous resins, thus requiring a higher working temperature to use, especially on the larger lay-ups. The high viscosity was selected for the Safe-T-Poxy to eliminate the tendency of the previous material to bleed-out (inducing air in the lay— up during cure).
     If you are building in a cold garage in the winter you can still use the new Safe-T-Poxy if you take the following precautions:
     (1) Warm the resin and hardner evenly to 85-90 degrees F prior to mixing. Don t try to hurry this. We use a light bulb under the ratio pump 3-4 hours prior to use, or keep your resin jugs in a cabinet with a light bulb inside.
     (2) Its important to have everything thoroughly warm prior to starting to work. This also cannot be rushed. It takes time to get the parts (wings, foam blocks, etc) up to a stable temperature through Out. If you are starting from a very cold garage the warming process could take 4 hours or more. Don't think just because the air is warm that all the material is warm.
     (3) Use an electric hair dryer to warm the area as you work, being carefull not to over -heat the part or epoxy. When, due to cool temperatures, a part is slow to wet out, a few quick passes with a hair dryer will greatly speed the lay-up time. Do not use a hair dryer to heat a cup of epoxy. This can give local hot spots and ruin pot life.
     What shop temperature is satisfactory? That has a lot to do with the size of the job. Small jobs can be worked to as low as 65 degrees F but the working time will be excessive. It will also be more difficult to remove excess epoxy, resulting in a heavier part. On large lay-ups like the fuselage, wings, etc, where there is a lot of epoxy to drag around, 77 degrees F should be considered the minimum. That’s epoxy pre-warmed to 85-90 degrees F and all parts, glass, foam, tools, table - - everything up to 77 degrees for 4 hours then go to work. Those temperatures are minimums -add 5 to 10 degrees F and your working time will be greatly reduced and parts built lighter. Optimum working temperature range for the current Safe-T-Poxy is 85 -95 degrees F. We realize that this is higher than desired, thus we are now working with the formulator, testing improvements. These will be incorporated -however, by the time the pipeline is filled the cold season will be over.
     Safe-T-Poxy is sold in 1-1/2 gallon kits. The price is the same per gallon as the previous resin.