Seeing the Light

I can't be the only one out there to discover, too late, a little spot of glue that I missed during cleanup. When painting a chair it shows up as a spot where the paint won't stick but even worse, when working cherry it shows up as a light spot months later as the rest of the piece darkens.

I was reading the book on hide glue that I got from Tools for Working Wood and the author mentions that the glue glows under a UV light. So I went on Amazon and got a UV flashlight, and there it is.


This is the chair that my current student is working on. We don't bother to clean the glue off of the top of the seat because it will be scraped later, so it provided a perfect test case.


Apparently, the best range of nanometer is 365 for detecting a large range of light waves that fluoresce, but the 385 nm light that I got for $12 works fine.
Next I spent a minute with some warm water cleaning the surface around the joint, and sure enough, no glow.


How cool is that!
I also wanted to mention that Greg Pennington has brought my posts on handling drawknives to a new level by bending the tangs to change his knife from a bevel down to a bevel up user. Check it out. Well done Greg.

I've been spending more time on hide glue and the chair joints lately, trying to better understand some things that have been passing for assumptions. I'll be posting more on the results as they come in.