MIMF

I found an old neck that I made several years ago and I'd like to use it for project I'm working on. The neck is a little thinner than I like (.80 @ 1st fret), so I'd like to build up the thickness to .83. I plan to finish the neck to match the body color, so I don't need an invisible method. I'm assuming that my water-based lacquer finish will not add .03. Is this a correct assumption? My first thought was Bondo. Any thoughts on this method? Any other ways to add a little more thickness to this neck? Any help will be greatly appreciated!

What about replacing the fingerboard with a thicker one??
(Bondo??....really??)
WB finish would probably end up .005" or less

Dave, consider gluing a layer of veneer between neck and fingerboard.
Patrick

Another vote for a layer or two of veneer between the fretboard and neck; also adds some visual interest!

yep...good solution.

If the neck is fully constructed and you do not want to remove the f-board just build up the thickness with epoxy, fiberglass or you could add a layer of Carbon fiber cloth or some other cloth to it and epoxy it on. That would add the thickness and strenght to the neck.

I like my necks to be .75" at the first fret. Is there a reason the .03" would make all the difference to you? You could wrap the back of the neck with a layer or two of veneer but you would want to have a pretty straight neck shaft and I can't imagine how you would blend that in at the ends without resorting to the aforementioned Bondo.

Removing a fretboard is too easy to resort to these other methods.

I agree with the "pop the fingerboard off and lay some veneer" school of thought. Other methods would be more time consuming.

I really appreciate everyone for taking the time to respond to my question. (Mario, it is good to have your voice and experience back on the forum). I re-measured the neck and I'm getting .81 at the first and .84 at the 12th. I can live with that. (I'm sure, that in a blindfold test, I wouldn't be able to tell the difference of 2 or 3 hundredths). Even though it is now a moot point, I thought of Bondo for a two reasons. 1) I've worked with it many times. 2) It goes on easily and is easy to sand. Although I get the feeling that using Bondo on a guitar was sacrilege to some, I not sure I see the difference between Bondo and other synthetic materials used in guitar construction and finishing. Epoxy as a pore filler comes to mind. Obviously, Bondo could only be used under an opaque finish. If anyone else has an opinion on the use of Bondo, I'd love to hear it.

I once used Bondo to fill a mis-rout in the body of an electric that was receiving an opaque finish. Worked fine for that.

For .03 I doubt I'd go through the hassle of changing your thickness.