View Full Version : Not mine.....is this bad?
A mando l looked at had a crack in the heel, you can feel it with a fingernail.
How bad is this?
176367
Marty Jacobson
Apr-29-2019, 10:34pm
Repairs go like this:
Is it ugly?
Is it a structural problem (i.e. will impact playability or tone)?
Will it be expensive to fix?
If it's ugly and expensive to fix, but not structural, then leave it alone and just deal with it, like a pick mark on the top.
If it's structural, you need to fix it, because that's what makes a mandolin a mandolin instead of a sculpture- the ability to play it.
If it still plays fine, then you're in the "ugly- expensive to fix, but not structural" category.
That means it's frustrating, and impacts the value of your instrument, but doesn't necessarily reduce you enjoyment from the instrument (unless you let it).
Jeff Mando
Apr-29-2019, 10:38pm
The neck heel probably separated from the heel cap due to taking a bump -- not a crack, exactly, but a seam separation -- still ugly and a problem. Depending on the price of the mandolin, a strategically placed long screw and strap button would make it a non-issue for function -- cheap solution for a cheapo. If it is an expensive mandolin, fixing it right so it doesn't show, would be expensive.......
Larry Simonson
Apr-29-2019, 11:02pm
My guess is that the grain lines of the neck are pretty much parallel with the fingerboard and the heel has split due to drying out and and/or the constant tension of the strings trying to lift the neck.
Does not this suggest that it is wise to carve necks so its grain lines are perpendicular to the fingerboard?
ProfChris
Apr-30-2019, 5:01am
My guess is that the grain lines of the neck are pretty much parallel with the fingerboard and the heel has split due to drying out and and/or the constant tension of the strings trying to lift the neck.
Does not this suggest that it is wise to carve necks so its grain lines are perpendicular to the fingerboard?
Not unless you want a neck that is floppy! Or even snaps. The grain lines need to run along the length of the neck to make it strong enough.
You could make a two-piece heel with the lower part having grain perpendicular to the neck, but then you are glueing end grain and the joint is likely to open up.
This picture looks to me like a two piece heel where the glue joint has failed (though the wood could have split of course). Either way I'd expect the neck to be pulling forward already, and for it to get worse over time.
MikeEdgerton
Apr-30-2019, 7:26am
Can you slide a piece of paper in there? If so do it and loosen the strings. Can you pull the paper out? If not it's moving. If it's the same either way it might be ok to just leave it as is, maybe.
It may have been repaired already, and the finish not repaired.
Try the thin paper. If it slides in, it should be glued and clamped.
This is a job for someone who knows what they are doing. If the repairman doesn't get a good glue joint, it can be nearly impossible to clean out the failed glue and re-do it. This is a joint that is under very high tension, and it will not hold if there is old glue in there.
If this is an inexpensive instrument and you are thinking about buying it, you might want to pass on it and find another one.
If it's an expensive instrument, a heel crack de-values the instrument at least 10 or 20 percent and this should be taken into account. And budget for a repair even if it is not opening up now. It may open up later.
If this is a friend's instrument and they want advice, check the joint. If it's open, repair sooner rather than later. If it's not open, watch it and repair it when it opens up.
Larry Simonson
Apr-30-2019, 10:52am
ProfChris, I was not suggesting end grain butting up to the heel button on the back (I can not imagine that). There have been Cafe discussions on the merits of parallel vs. perpendicular (to the fingerboard plane) orientations of the neck grain, and my recollection was that one or the other was preferred to get the best visual curly maple figure.
Was one I was looking at, I think pass is the correct choice here for me.
Rob Roy
May-11-2019, 7:28am
The straightness of the crack looks like it was likely a laminated neck instead of a one-piece. I wouldn't gamble on it.
That is simply a glue fail in a stacked heel constructed neck, steam the slot clean, squeeze some glue in, clamp and leave 24hrs, some paint and its as good as it was new.
Steve
John Bertotti
May-12-2019, 5:52am
So just what glue would you work into that joint and how would you get it deep within? I would think hide glue would dry to quickly and be a bit thick or yellow wood glue, is it strong enough? I have seen joints fail on either side of a yellow wood glue joint but I don't know how it holds up to environmental changes. Titebond? I haven't really used it. Good topic to learn from though. Seems this could be a rather good repair to learn.
prairieschooner
May-12-2019, 8:00am
Don't take a short cut here if you proceed.
All depends on type and value of the instrument...
Simple injection of glue and clamping will likely not hold too well and fail sooner or later unless it was HHG glued and the joint is open enough so you can get enough fresh HHG in there.
I assume this is cheaper Kentucky or similar (better instruments don't use stacked heel). The neck joint is likely V slot filled with GOK glue and will be nightmare to disassemble for more thorough repair. Also the area around joint is typically flooded with that black lacquer that will crack and look ugly. So for this type of instrument the "proper" repair, IMO, would be gluing with thin CA (that can run easily into those separations and will hold better than anything on uncleaned surfaces) and adding a woodscrew to clamp it tight (of course the screw must be prepared and fitted to clamped joint before using glue, just back off screw few turns, add glue and tighten). Masking all surfaces right at the edges of the crack is MUST. Cleanup will be simple scraping the tiny ridge of dry CA glue with razor blade and buffing. I've used this on cheap guitars and it works. typically I would chip away fiingerboard wood between two frets (1/2" wide strip from one fret slot to the next using flat chisel - notice direction of grain!) right above the crack and bury head of screw inside fingerboard, after the repair glue the splinter back on top and on RW or ebony boards the repair is invisible. In case of truss rod you may use two smaller screws at an angle to bypass the rod.
On higher grade instruments I would choose more refined way depending on type of joint and how easy it would be to remove the neck etc...
Training neck removal (or other more complicated repair jobs) on low end instrument (think unpredictable construction methods) may become a nightmare and will not give you the lesson you expect (but will give you one quite different lesson :-) ) and result will not be satisfactory. Some types of repairs are not worth doing on cheaper instruments for ANY reasons.
It amazes me the use of screws in peoples repairs and construction, lutherie does not require them, clean/glue/clamp.
Steve
It amazes me the use of screws in peoples repairs and construction, lutherie does not require them, clean/glue/clamp.
Steve
Problem is that you cannot clean the separation in this case and trying to do so may make things worse (and ugly). If the neck was completely off or wide open gap I would suggest cleaning and closing with glue. But this is not the case. I've seen (and been asked to re-do) more than enough of such jobs that didn't hold when someone just glued it together.
What about bolt on necks on guitars? Bolts (and metal hardware) became part of our inventory long ago and if we want to do effective job than we need to consider all tools we were given. I wouldn't use them on instrument where they don't belong but in case of cheap import with hairline separation that cannot be cleaned easily and new (traditional) glue would not be easy to inject the bolt is the most effective way. I repaired broken biathlon training rifle with exactly this method (using one large woodscrew from IKEA furniture and strong epoxy) and the repair hes held for two years - summers and winters outside (being banged around by junior team trainees) while other two broke in the same spot (short grain of wood through "handle").
You know... REAL LUTHIERS don't use spray guns and routers and modern glues and ... the list can go on.
multidon
May-13-2019, 6:08am
Interesting thread. It’s especially interest that the comment was made by Adrian that quality instruments don’t use stacked heels. And yet I’ve seen not one but two Gibson F-9s displaying that same separation.
Interesting thread. It’s especially interest that the comment was made by Adrian that quality instruments don’t use stacked heels.
I feel quality or brand of instrument has little to do with the use of a stacked heel. Its typical of saying only a carved one piece headstock is superior to a scarfed headstock, its just not true. Its simply a choice of build.
Problem is that you cannot clean the separation in this case and trying to do so may make things worse (and ugly). If the neck was completely off or wide open gap I would suggest cleaning and closing with glue. But this is not the case. I've seen (and been asked to re-do) more than enough of such jobs that didn't hold when someone just glued it together.
I tend to have a different viewpoint on the repair to yours.
Steve
Interesting thread. It’s especially interest that the comment was made by Adrian that quality instruments don’t use stacked heels. And yet I’ve seen not one but two Gibson F-9s displaying that same separation.
I haven't seen F-9 with stacked heel, so what you saw was likely cracked wood. Of course stacked heels are typically used on classical guitars (but they have much lower string tension and the neckblock is integral part of neck heel so the gluing surface is much larger than let's say on D-18 neck) You don't see that often on higher end mandolins since the size of neck is smaller.
Ky Slim
May-13-2019, 9:30am
Do "real luthiers" ever use black permanent markers? :whistling:
multidon
May-13-2019, 5:22pm
Adrian, you are right. Now that I think about it the 2 F-9s I saw both had developed a line but it was between the neck heel and the cap. I still thought it was bad news though.
Jeff Mando
May-13-2019, 8:16pm
Do "real luthiers" ever use black permanent markers? :whistling:
I don't know about real luthiers, but a brown Sharpie is the guitar repairman's best friend............
multidon
May-13-2019, 8:47pm
I’ve heard piano techs call black Sharpies “Steinway repair kits”.
I don’t think black or brown would do any good here because it would eventually rear its ugly head again.
I don't know about real luthiers, but a brown Sharpie is the guitar repairman's best friend............
I wouldn't recommend that. at least without testing the complete procedure on scrap.
I once used it to stain a spot of missing finish on broken neck heel I glued (no screws as it was clean break easily glued with HHG) but after touch-up of crack line with lacquer (or shellac?) the spot (initially perfect match for surrounding color) turned to ugly phosphor green-yellow.
But luckily the spot was tiny and the instrument was banjo so no big deal :-)
jim simpson
May-14-2019, 2:20pm
Wouldn't the correct way to repair this (assuming it was worth enough to repair) be to remove the neck and remaining heel, then glue them together before gluing the neck back in?
Correct way is always very individual to instrument and exact level of damage. Were this expensive mandolin I would do following (I hope I won't miss any important steps)
1. examine if the break is clean (no previous glue or repair) nad/ or can be cleaned well enough without further damage to instrument
2. examine if it can be closed well enough (on expensive meaning wood- to wood with no gap whatsoever, just finish crack showing)
3. examine any problems that may have relation to the problem being fixed (it the neck root fixed tightly, was the neck angle good before break, problems with neck "hump" or loose fingerboard etc...)
If I find that I can just clean add fresh HHG, clamp tightly and all will be in good cosmetic shape, alignment and structurally sound I wouldn't do anything more. I guess this would be in 9 out of 10 cases of well built quality mandolins. Always think about the guy that may be the next to repair it after you - don't do mess.
If I find that the neck angle was not too good and the construction method allows relatively safe neck reset I would remove the neck glue it together and then reset the neck on the body (WARNING: on mandolins this is major surgery and should be done only in absolutely necessary cases as collateral damage is almost inevitable, and even most carefull work can leave some scars especially with some methods of neck joints and finishes that are impossible to touch-up)
If there are signs that the lower part of heel is not holding well (loose neck joint etc.) I would consider re-gluing it or full neck reset as well.