Post by G. RossEastern Red Cedar wood will lose some of it's volatile components with
time, and some of them will crystallize on the surface. Just brush
them off. Try using the brush attachment on a vacuum cleaner.
Right. And Mike said - under certain conditions, the "chemicals" will melt, then crystalize - then he comments about temps as high as 85 to 92 degree C, somewhat implying the crystalization is dependent on high temps. I think that's misleading, but he's being brief, for answering the initial question or concern of the poster.
Crystalization is not dependent on higher temps. The crystals can form at room temps. As I see/experience most of my rough cut ER cedar, once the resin is exposed to air, it will readily "crystalize". As I assume is happening, the resin, inside the wood, remains fluid, like mercury in a thermometer. Once it becomes exposed, then only certain, of the chemicals, making up the resin, will crystalize. I think, as GW says, once the volatiles of the fluid evaporate, then the remaining "solids" will crystalize or dry in crystal-like form.
In the dense wood areas, like knots and really tight grain areas, the "sap" seeps out and, often, doesn't dry completely.... it remains really gummy, somewhat hard taffy-like. That gum has to be scraped off, not sanded.
This oozing of sap can be seen on live trees, also, where there might be damage to the tree or some sort of exposure of the inner bark, allowing the sap to ooze out and hardens, begins to harden. If you've ever climbed a cedar tree, it's not uncommon to get some of this sap on yourself and it doesn't wash off easily, either.
I've done lots of projects with ER cedar, often times working outdoors in good sunlight. If you ever do a project, don't expose a planed board or your pre-finished (prepped, ready to apply finish) project to direct sunlight. Slight temps rises, slight heating, by even a little direct sunlight, will cause the resin to move (like mercury in a thermometer). You'll hear small popping sounds, as the wood heats up... it doesn't take much heating .... and you'll know it's too much, because you'll hear the popping sounds. This will be the precursor to those crystals starting to form and, if the exposure is long enough, you'll have to resand the board or project. Many times, until I learned better, I'd have to resand a project, before I learn not expose it to sunlight, that way.
Sonny