Acoustic Guitar Construction

Response from O'Brien:
Dave has asked about using hide glue for antiquing. If you want to give your guitar a look of being about 20 years old you can use the hide glue as a sizing technique. This makes the guitar, especially the top look as though it has been exposed to ultra violet light giving it a "warmer" older look.

I received this response from Patrick Edwards, the man who came up with the Old Brown Glue, a ready to use formulation of hide glue, that gives a bit longer open time than HHG. I'd asked him about pore filling properties of HHG vs OBG.

"Dave

These are very good questions.

Using hot hide glue to size wood has been a method used by woodworkers
for centuries. Not all woodworkers do this. The hot glue must be
very thin. It acts to fill the pores on open grain wood and provides
a more dense surface for sanding and scraping. I do not do it.

Liquid hide glue does not work in this manner, as it takes much longer
to set and the loss of moisture will affect the dimensions of the wood.

I would not use liquid hide glue under a French polish either. When
you put a hard (shellac) surface film over a softer (OBG) surface, you
will get crazing. "craquelure"

When I do hammer veneering, I prep the substrate with a toothing
plane, working the surface in two directions at an angle to the
grain. I do not size it with hot glue. If you size it with hot glue
first and let that glue set you will probably have an uneven surface
to apply the veneer, which will create problems for uniform adhesion.
I know you say he uses a cabinet scraper, but why the extra effort
when a toothing plane on fresh wood is the normal method?

We use hot hide glue and liquid OBG in the shop every day. Each has
its purpose.

Patrick"

Not sure I understand why I would ever want to make anything brand new look old? I get toner for color and warmth, but not the intentional aged appearance.

I do agee that liquid hide glue has a great deal of water so it does not seem it would be suitable as a filler.

BTW scraper blades are used around the world to level finish materials -- so I don't understand the "difficult comment" -- I believe true Japan lacquer technique is done totally with scrapers --- I use scrapers instead of sandpaper when ever possible.

I think HHG to fill pores would work but it would still take multiple coats since it does contain a lot of water.
I wish I could watch those videos from work but I can not. Although that wood working dude from PBS is amazing. Not a Norm Abrams, but who is really?