Using White Glue Instead of Epoxy

This Instructable I will fill a void in a wooden guitar neck with white glue instead of epoxy or a glue/sawdust mixture. It’s an experiment to see how it sets up, sands and takes finish.

Elmers white glue
Sandpaper
Masking tape
Wood stain

When I was carving this guitar neck a void opened up and got bigger and bigger as I proceeded with the shaping process. I couldn’t see how deep it was but it was big enough that it needed to be filled with something. I’ve always wondered how pure white glue would hold up on it’s own so I decided to give it a try and record the process to show others before they try the same thing.

Here is a link to a video that shows the whole process.

First I created a dam around the hole with masking tape. Then I just squeezed white glue into the hole until it overflowed the edges. I let the glue dry overnight. I was surprised when every morning I check the hole and the glue was gone! Either the hole had much more area hidden from view or the glue was just losing lots of volume as it dried.
I had to repeat the fill/let dry cycle at least 7-8 times before the entire void was filled and the glue was hard and dry. Actually many more times than I originally thought I would have to do that.

The glue dries very hard and I found it hard to sand by hand so most of the initial sanding was done on the bench sander with 80 grit. I was fairly impressed with the smoothness of the glue surface. However there were 3 or 4 very noticeable depressions that appeared after that sanding and those needed to be filled with more glue so back to the glue/dry cycle again!

I used an Ebony wood stain on the guitar neck and covered the glue fill with it too. I found the glue patch became darker with each coat of stain but not to dark. Also any pinholes in the glue collected stain and dryed to show as small dark spots. I should have taken more care with my finish sanding of the glue patch to eliminate all holes or depressions. The glue patch actually appears hard and smooth and more importantly feels hard as the wood that surrounds it and is just as smooth too. Also no discernible “edge” where wood meets glue. When I’m playing this guitar I cannot feel where the patch is.

Overall I would say using pure white glue to fill a void in a wood project was a successful move.
Some things to consider though;
1- Doesn’t stain hardly at all. Perhaps adding colouring to the glue might work?
2- Lots of volume loss when drying. Not a one shot solution for void repair many applications are required.
3- Sanding is labor intensive and every imperfection shows especially after staining.

These drawbacks are not too different from those encountered with any wood filler product though so I would give this experience a positive mark!
Thanks for reading this instructable! Check out the video for more visual information and have fun!