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I'm struggling with when and how to fill some small gaps between the binding (wood) and the top and back on a current build. In the past I've waited until the finish stage, and tried to drop fill with thickened lacquer. I've bought some lacquer sticks, and can do it that way, but I'm wondering if there's a better way, such as filling now, before any shellac or pore fill.

Any advice, pro's and con's, etc., would be greatly appreciated!

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Ken Mitchell
Durham, NC

Different ways with different materials from filling in with dust and epoxy, to heating on pipe or bending iron, don't want to do some types of material with heat due to is will flash away in fire. What material did you use for purfeling and adhesive? If wood I would heat the area and push in until no gap. Or fill fill in epoxy with dust. why doing gap filling at time of finish? I may be wrong and have been a bunch, but do most of this work in pre finish prep.

If you could send some pics it would help .

If you have a small gap that you can close when pushing on the binding then all you need to do is apply some glue and clamp or tie the box in that area!

Mike

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Mike Collins

If you could send some pics it would help .

If you have a small gap that you can close when pushing on the binding then all you need to do is apply some glue and clamp or tie the box in that area!

Mike

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Mike Collins

Ken,

Search around in the archives and you'll find a tutorial posted by Hesh describing his technique.

Basically he smooshes some Titebond into the gap and then sands the adjacent area with 200
grit sandpaper, allowing the resulting dust to form a layer on top of the gluey gap. Very quick
and reasonably effective, especially if the back wood is dark.

I've used this approach on a Myrtle-backed ukulele and it filled the gap well, but due to the light colored wood, ended up being somewhat visible.

Eric

Stan / Mike,

Thanks for the input. Heating and regluing / clamping makes a lot of sense. And yes, doing this before the finish stage makes sense as well, as it will surely save time and effort (I've done it later on in the process, and it's a lot of work!).

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Ken Mitchell
Durham, NC

let us know how it goes!

Binding can be very frustrating at times!
It's one of those tasks that has daunted me in the past-now I love to do it!!!
I fit mine dry and then only glue one side at a time!!!!
45 minutes later I do the other-that way I can concentrate in a smaller area .
And my joints come out perfect!!!!
I still use waterbase glues-I can't stand the smell of C.A.

Mike

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Mike Collins

Michael, what is the waterbase glue you can use for bindings?

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Walter Lay
"It's taken me so long, but now that I know
I can see. All that I do or say, is all I ever will be"
- Billy Joe Shaver

I use Titebond 3 now because I use a waterbase finish .
Once # 3 is dry it does not shrink & show a glue line!

But any of the ones mentioned will work great!
it's the fit of the materials that's crucial!!

Mike

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Mike Collins

Eric,

Thanks for the tip about just using Titebond. I'm doing that right now, and it's working well!

Todd, I'm using LMI tape for the most part, with a caul and clamp in the waist area. I think the issue is that I'm just now getting up to speed on bending sides and wood binding, and not getting the binding exactly right is the issue. Plus there was some twisting in the binding that I tried to get out, but not all would come out. I was hoping to just pull it up snug, and for the most part, it worked. The gaps are not huge, just noticeable. But it's looking better as we speak...

Thanks everyone!

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Ken Mitchell
Durham, NC

Ken,

Thank Hesh, he's the one who put the effort into doing a tutorial on this.

Another tip I've picked up here is to slightly break the sharp corner of the inside
edge of the binding with a pass or two with sandpaper (the corner that ends up being
invisible). I think this allows a better fit even with the mild twisting that
the binding is forced into due to the radius.

Haven't tried it yet, but plan to.

Eric

Just a quick point regarding binding, something I've discovered.
Often with wood bindings especially, they seem to fit better one way than the other, if not, I take a card scraper or sandpaper to the inside bottom corner (of the binding) and radius the sharp corner a bit, this allows for a slightly deeper seat and a tighter joint, usually.
I always dry fit and make sure the gaps close. Tacking an end with CA and progressively gluing and holding for a few seconds to insure a tight joint, I usually add tape every so often just to hold the previous area, but I avoid taping and wicking glue as it usually requires more clean up and additional glue etc.. I seal the top first with shellac or egg whites and have no problems there after. When I route my channels, I try to leave the bit of fuzz created from a straight cut bit and just pull it up out of the way, scraping the excess off after binding, in the direction of the fibers lays them back down closer and tighter. I've done this several different ways and with different glues, but find that CA is best, for me. I rarely have to fill any gaps in the resulting joint, the whole process takes a little longer, but turns out cleaner and tighter in my opinion. But this is just my way and may not be for others. HTH

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Nehemiah Covey
www.coveysacoustics.com

Thanks Eric my friend!

Ken here is the toot that I did for a very simple, fast way to fill small gaps.

It's important to note the direction that you sand and if you do the light colored tops will get filled with light colored top dust and the bindings will get filled with binding dust. If you are really careful with the direction that you sand even thin b/w/b purflings will not show that there was ever a gap. The trick is to sand along the gap, not across it and this helps prevent different colored dust from migrating and showing when complete.

The entire fix can be completed in 30 seconds.

I agree that the best way to deal with gaps is to avoid them completely but that is not always possible. Some of the greats like Somogy, Fox, Klepper, and Hodges probably never get gaps but for the rest of us a quick, permanent, solution that is compatible with finish is a good thing to have.

Link to toot: http://luthiersforum.3element.com/forum/forum_posts.asp?TID=11580&KW=tutorial#forumTop

That's a great tutorial, Hesh! The photography is excellent.

I've been working a couple of hours this afternoon filling some gaps similar to the one shown in your tutorial. They are filling in pretty well, so far. This will save me HOURS of time that I previously spent fillin gaps by drop filling with lacquer

Thanks again to all who responded. It's amazing to be able to get an answer in just a few minutes, and try it out right away - nothing beats this forum!

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Ken Mitchell
Durham, NC

I rarely get any gaps these days either but I also have a preference for very thick, wood bindings.

I install my binding at .090 and doubt if more then .010 is scraped off. I most certainly could install thinner bindings or even p*astic..... but I like the look of thick wood.

I wish that I was as perfect as some of you guys who never get any gaps...... but this is not my reality nor was the questions asking how perfect some of you are and in all honesty I suspect nearly everyone gets a gap once in a while.

Be real AND helpful please........

Todd we may be in violent agreement here......

Excellence and perfection are all good things, in context, but the original question was "filling gaps in binding/purfling." Gaps happen and to agree with you gaps are often caused but a binding methodology that does not cut it..... I also agree that offering a methodology that would provide better results next time is a real plus as well.

But in the context of the original question - how to fill a gap IMHO an on target answer does not include statements from others that they are above having this problem. Again that is not helpful in my view and since the alternate method for achieving gapless binding was not offered along with the proclamation of personal perfection no one has benefited from the best-practice, do-it-better-next-time thinking here either have they? At least not yet.

I most certainly would love to be in a position to proclaim to the world that gaps don't happen on my guitars and in fact they very rarely do anymore either. But the truth is that I do get a gap once in a while and I suspect that most everyone does too and having a method or methods to fix resulting gaps is not a bad club to have in the bag.

It depends on the size of the gap and the wood that you're working with. Darker woods are easier to fill using dust and CA or titebond but light colored woods are very very hard to achieve good results. Paul Woolson instilled something in me a couple of years ago... if a repair can't be invisible (and he was specifically talking about filling gaps) then redo it.

So you really need to determine whether the filled gap is acceptable, otherwise the best fill is to remove the binding purfling and redo it.

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"There's really no wrong way, as long as the results are what's desired." Charles Fox

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That should be "otherwise the best fix is to remove the binding purfling and redo it."

I should also add that there's been good advise for filling gaps already, just make sure that the fix is acceptable.

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My Facebook Guitar Page

"There's really no wrong way, as long as the results are what's desired." Charles Fox

"We have to constantly remind ourselves what we're doing....No Luthier is putting a man on the moon!" Harry Fleishman

"Generosity is always different in the eye of the person who didn't receive anything, but who wanted some." Waddy Thomson

I’m afraid I must include myself in the group that still gets a tiny gap here and there when gluing up bindings. So, in following up on the secondary line of discussion in this thread – avoiding the gaps to begin with, can you guys offer a few “zero gap” tips and specific clamping methods that you’ve developed that might improve our results. Here’s what I do. I glue the binding on with LMI glue by the way.

• Try to ensure very accurate binding bends. Leave them overnight in the bender to ensure the geometry is completely set.
• Leave the binding ledges very slightly undersized so the bindings and purflings sit just proud of the tops and sides once they are glued up.
• Check all binding ledges with a binding/purfling scrap before gluing. File and sand any ledge irregularities.
• Dry fit for final check
• Always install bindings on the side of the guitar opposite me in order to get maximum leverage when pulling the tape tight (I use LMI brown tape).
• Use the soft rubber end of a screw driver handle to help press the bindings tightly into their channels when taping (pressing down and inward on the outside corner).
• Use fiber reinforced strapping tape at the waist to allow for increased taping pressure.

This gives me good results but there is usually a hairline gap or 2 to remind me I still have plenty of room for improvement.

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Doug Mills
Chicago, Illinois

I'm no pro by any stretch, but I've had very good results with my bindings to not get gaps. Tare out of wood is a different story and one that should be "fixed" differently then gaps.

The last 3 guitars I've bound I've had no gap issues and I don't remember the 3 before that. Maybe I'm lucky but I spend a lot of time to make sure I eliminate the possibility.

The first thing is to make sure the binding channel is cut properly, either slightly undersized to the binding or bag on.

Next thing is to make sure your bindings are bent to match the body. Work at them on the pipe till they are as perfectly fitting as you can get them. I think this is really the biggest step in eliminating gaps.

Next, make sure the bottom inside edge of the binding is relieved (break the corner with sandpaper or a scraper) so there's no chance it can be forced to tilt out of the channel causing a gap.

Now, I use CA to glue in my bindings so everything is taped in place first. I can check everything before applying any glue to make sure there are no gaps. I also use 3M fibre strapping tape for ALL of the binding. It doesn't stretch and takes a lot of force to cut it against the outer edge of the binding so you can really pull on it hard if you need to (waist and the compound curve back bindings on Florentines as Todd has already mentioned). If more force is needed to pull in the bindings then they are not shaped property and more work on the pipe is needed. I'm always surprised to see people using clamps at the waist during the binding stage. That's a lot of force that IMO shouldn't be needed if the bindings are bent properly and accurately.

There are 3 reasons I've chosen to use CA to glue in my bindings.

1st - There is no swelling of the wood or fibre paper using CA glue. AR or PVA glues swell the wood and sometimes after it is cured, it can shrink back (which can cause a gap to appear).

2nd - I can pre-fit everything, making sure it's perfect and then leave it in place to add the glue. If you pre-fit with any other type of glue, you have to remove the tape, even if it's in sections which just adds time and the possibility that a gap can happen that wasn't there during your pre-fit.

3rd - It's less messy

This gets me great results that I'm very happy with.

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My Facebook Guitar Page

"There's really no wrong way, as long as the results are what's desired." Charles Fox

"We have to constantly remind ourselves what we're doing....No Luthier is putting a man on the moon!" Harry Fleishman

"Generosity is always different in the eye of the person who didn't receive anything, but who wanted some." Waddy Thomson

OK since we are back on topic my electronic tether will permit me to participate again.......

Here are two links to a toot that "we all" did, I say we all because much of the value is in the additions that other posters made here in this binding tutorial. I learned some new tips from the comments of others - Thanks again folks!

This method, pretty standard as it goes, works for me and BTW, not to be a jerk here but this one resulted in no gaps either........

http://luthiersforum.3element.com/forum/forum_posts.asp?TID=14410&KW=Installing+Binding%2FPurfings#forumTop

http://luthiersforum.3element.com/forum/forum_posts.asp?TID=14411&KW=Installing+Binding%2FPurfings#forumTop%22

Ok, we all have our recipe for how to do this and get it "right". I am with the group that says route it off and do it again if it is still visible... but if you can hide it with an invisible fill then all the better.

Preventing gaps.

Unlike Hesh who likes 'em thick... I like 'em thin. I find thinning the bindings out to .06" gives you lots of flexibility to pull the bindings into the channels and really get things tight

I have given up on CA glue. Lots of reasons. I use LMI white. And I find one advantage to these water based glues is they swell everything a bit thus making tiny gaps almost non existant.

(I still tack the purfling miters with CA though before I bind)

Fixing gaps.

When gaps do appear... in dark woods I cut a tiny sliver of the same wood in the same direction as the original grain and stuff it into the gap and tack it with just a weeeeeeeee bit of super glue. Then I use just 1/2 drop of CA and some sanding and that usually cleans it right up. I like this over just dust and CA because it preserves the grain structure, but again... it is best to have no gaps.

In light woods I see no real option but to do it again, or to take a heat gun and try to soften that spot and move the bindings, but has a hit or miss success rate with me.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com