Hello all,

As a novice rod builder (but have a career in the epoxy coatings industry), I was wondering if anybody does any post-cure for their epoxy finishes. Standard epoxies (modified Bis-A) typically reach about 80-90% cure with ambient temperatures. Driving the reaction to 100% (or very close to it) usually requires an additional high temperature cure for a few hours after the epoxy has reached the 80-90% cure. Does anybody do this, and how do they do it? I have a large industrial oven at my work that i stick my finished rods in there at 120*F for half of a work day, and sometimes i just put the rod outside on a hot Southern California summer day. any input would be appreciated. thank you.

It's not necessary. At 72F most of the epoxies sold for use as thread wrap coatings will set in about 2 to 3 hours and reach a tack-free cure in about 24 to 72 hours. For any given 20F deviation, down or up, you will double or halve the set and cure times.

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Without getting scientific, because I am not an epoxy formulator;) I think it is not a bad idea. We are in Texas where our cars sit in the sun and get to be about 120F on many days in the summer. While we aren't really concerned so much about the "final 10%" we do need to speed the cure time so that we can wet our lines. We let the rod rotate at room temp for a few hours and then put it in a hot car to kick it off faster. It works great. People have sent us many pics over the years of custom hot boxes with heat lamps. Our 4X machines that are wall mounted lend themselves well to a hot box design.

Flex Coat Company
Professional Rod Building Supplies
www.flexcoat.com

i also know that people that go out fishing will have the rod in the sun for long enough to hit that last cure state. was just wondering if i was doing an extra step that isn't necessary. thanks for input!

If you're pressed for time, there's nothing wrong with using mild heat such as mentioned to speed the cure. If not, a couple to three days at room temperature are enough.

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The post cure process will improve the mechanical properties as well as the temperature resistance of most epoxies. Therefore post curing the epoxy at a temperature higher than the material will see in use is beneficial.

Depending on the epoxy used post curing should be initiated between 12 hours or before full cure at room temperature, this is important because after the epoxy FULLY cures at room temperature, post curing will have no additional effect on the materials properties.
GENERALLY recommended cure temperature for RIGID materials is 175 degrees F for 8 to 24 hours.

GENERALLY recommended cure temperature for FLEXIBLE materials is 140 degrees F for 8 to 24 hours.

These recommendations are NOT GOSPEL and varies for different materials and epoxies..

My personal preference is that the post cure is not necessary but it is important to make sure the epoxy is fully cured before the rod is placed in service.

Vincent,
You brought-up a good point about post curing epoxy, one which I have mentioned numerous times on this site without any response. John DeMartini offered the best reply to your question, especially the first paragraph, and I totally agree. Is post curing epoxy required for rod building = no; is it better = yes; is it required for structural composites = indeed.

Mark Talmo
FISHING IS NOT AN ESCAPE FROM LIFE BUT RATHER A DEEPER IMMERSION INTO IT!!! BUILDING YOUR OWN SIMPLY ENHANCES THE EXPERIENCE.