Re: fast epoxy

Posted by LeeG on Mar 10, 2005

My thoughts come from the perspective of a first time builder who's spent $800 for a kit and more for materials and isn't familiar with the nature of curing epoxy in a range of conditions and doesn't have a constant 72degree shop space where a heater is cooking 24/7. In the garages I've built things the temps could vary 30degrees from ceiling to concrete floor or night to day. Opening the garage door could drop the temps and slow the cure rate like moving rising bread from the top of a book shelf to the cold kitchen counter. By the time a beginner makes it to sanding the last fill coat and glueing on hatch ribs and coaming they know a LOT more than they did at the beginning. But being able to move scarfed panels around to wire up the hull in "24hrs at room temperature" is not the same situation when the coaming is clamped on and removed in 24hrs where the temps in those 24hrs could have dropped 10 degrees overnight and the tension is significantly greater. Same with hatch ribs. From a beginners perspective "room temperature" is a range,, until you've used a particular epoxy in a range of temps you really don't know the consequences of a warm 75degree "room temperature" or nice 65 degree working "room temperature" or a cool 60degree "room temperature". The range is "room temperature" but the direction "let cure 24hrs" is specific. How epoxy cures is specific to temp and time. So if Shuswap is expecting to budget the construction time it's kind of risky to assume a 24hr cure time is sufficient when the consequences might be a damaged part needing replacement or reconstruction and you don't have a pile of spare coamings, hatches or extra days for the varnish/paint to harden. It's easy to negotiate reality when the goal is clear and the nature of the task is new. If a beginner builder "has to" get the coaming/hatches on and finished in 24hrs because they're expecting to varnish and get outfitted in two weeks time it sure would be a shame to glue the coaming,hatch ribs, clamp it, remove the clamps in 24hrs and find it pulling away because: temps were in the 60's, peception of what is room temp can vary to body type. 2.dipped sometime by a few degrees in that 24hrs,,overnight? 3.the pumps had a burb so the ratio was more like 1.6:1 and not 2:1.

I know this sounds picky but given how slow MAS slow cure is compared to the average slow cure epoxy it's possible to cut corners with "room temperature" in 24hrs where builder has a deadline. Having an extra couple weeks for Brightsides to harden is a nice cushion,,knowing that some joints are cured HARD is one less unknown if the consequence is starting over.

In Response to: Re: fast epoxy by terry on Mar 10, 2005