MIMF

Maiden post on this forum - I have a small repair and building workshop serving players in the local district.

Had this lovely old guitar left with me with a view to getting it playable - not really a financial proposition but the owner would like to play it and happy to pay the price for the repair and a refret / neck refin. He has an excellent set of hardware to go with it.

Back of the neck has seen the wrath of a woman scorned IMHO and I attach a couple of pics of the damage. Not sure whether I should attempt to fill with saw dust / glue or file a flat and glue a fillet of mahogany. Another idea is to build it up with veneers. Aesthetics are not to important to the owner and he just wants a smooth playing surface. The damage is quite deep and almost through to the truss rod on the right side. It is heavily impregnated with sweat and oil from years of playing after the damage was inflicted.

Any ideas would be great - thanks

Sawdust and glue is not an acceptable method for anything guitar related. And using veneers would not work well either.

The best approach would be to make the surface level so that you can cleanly graft in a piece of mahogany without having any voids. This would be challenging due to the size and shape of the damage and dealing with a curved neck.

Barry Daniels wrote:Sawdust and glue is not an acceptable method for anything guitar related.

Point taken - It confirms my feelings as to why it has been sitting ignored for a month. The budget is way short of a proper job.

You are going to respray the neck anyway, and it looks like an opaque finish (can't see through it). I would smooth it with bondo or epoxy with fairing filler, and spray it. I love old Melody Makers - I have a 1962.

Brian

It's always best to fill with new wood. The marks don't appear all that deep. I'd file it back to clean wood and glue new mahogany in place with epoxy because it is the best at filling any gaps left- don't try to take the damage down all the way, it would be ok to leave a few of the deeper damage. Use epoxy, glue new wood down, shape it and re-finish.

A light sanding would remove most of the oil and sweat and filling the dings and depression with bondo ( as Brian suggested) could make a less noticeable repair than removing more wood and replacing it with another piece. Mohawk makes a wood colored bondo that can be further colored with powder stains. Graining it similar to mahogany and adding the opaque finish could make an inconspicuous cost effective repair.

Barry Daniels wrote:Sawdust and glue is not an acceptable method for anything guitar related. And using veneers would not work well either.

Interesting counterpoint to this argument that I came across while reading Fretboard Journal 38 this morning. Stephen Gilchrist, noted Anipodean mandoline luthier, was commissioned to do a deep deep repair of the first Lloyd Loar F5 mandolin that had a severely caved in top. He describes how he faired the cracks after structural repair was complete: "Gilchrist chose to fill the cracks with a mixture of (original) wood dust and glue, rather than inserting splices"

I personally often use sawdust and CA glue to fill splinters in fretboards. I use sawdust and shellac to grain fill. So I guess to me it depends on the situation.

Brian

A tiny fill is OK but a large repair will look horrible. For one thing, alphatic resin glue fills will shrink which is more noticeable in a larger repair. And there is no way to match the grain unless we are talking about ebony.

Filling a light colored wood with sawdust and glue is akin to making a filler using particle board. Why would you ever want to do that? Replacement with solid, matching wood is so much better from a strength and visual standpoint, and not by just a little bit. Can you tell I feel strongly about this

"A tiny fill is OK but a large repair will look horrible. For one thing, alphatic resin glue fills will shrink which is more noticeable in a larger repair. And there is no way to match the grain unless we are talking about ebony."

I agree that a large repair using sawdust and glue might not be the best option, but bondo could work fine. It is a relatively shallow depression with some gouges at the bottom of it. I think the neck is structurally O.K. as it is. I think leveling it and adding a wood patch would create a more noticeable repair. I have "grained" bondo to look like various wood types, mahogany being one of the easier woods to match. For an opaque finish I think not removing wood and filling with bondo is a better solution.

Clay Schaeffer wrote: I agree that a large repair using sawdust and glue might not be the best option, but bondo could work fine. It is a relatively shallow depression with some gouges at the bottom of it. I think the neck is structurally O.K. as it is. I think leveling it and adding a wood patch would create a more noticeable repair. I have "grained" bondo to look like various wood types, mahogany being one of the easier woods to match. For an opaque finish I think not removing wood and filling with bondo is a better solution.

Thanks for your advice Clay and those who have posted previously.

I am not really too keen on using a fill. I reckon that getting a nice sanded transition from the harder denser section of auto filler to the wood will be a good deal more tricky than with a glued in fillet of mahogany.

I thought of using sand paper block on a purpose built ramp to take off the dented material in a flat plane, It would be tricky to transition from the ramp back to the line of the neck but with care I think I could do a reasonable job with a round sanding rod.

Any further discussion would be appreciated on methods of doing the job with a mahogany fillet

Hi Ray,
You should use what you feel comfortable with. There is more than one way to skin a cat.
During my working career I wore a number of different hats, one of which for a couple of years, was as a furniture repairman fixing damaged furniture back to "as new" condition. As such I used a wide variety of materials and techniques to structurally repair and then hide those repairs in an expeditious and cost effective fashion. I used a number of the Mohawk products and if you are going to be doing repairs and finish touch up you may want to look into them.
If you make the repair with a wood fillet my only suggestion would be to match the grain orientation to that of the neck. Wood movement over time can sometimes cause patches to become apparent. Mahogany is one of the more stable woods so that is in your favor.

I would just look at the large voids as single individual issues. This is a nice challenge that may be worth more as a learning experience/adventure than as a money making repair. Reform the voids as minimally as you can to accept donor patches of like-grained mahogany -- they're not really deep and not really under stress. Feathering these is comparatively easy because its a continuous convex shape. Do yourself a decent photo documentation for your portfolio or facebook page. The biggest challenge I see is finish matching but this'll be far easier if you do the repair with wood.

OK, so here's a stupid question... These appear to be moderately deep scratches not significant structural damage. I'm all about wood replacement when appropriate, but why not just drop fill and re-touch the finish?

tricky to photograph and in hindsight should have taken one with a rule sitting atop the damage. At its deepest point in the right of the photo's there would be a depth of 3mm-5mm below the original line of the neck.