Binding mistake...

[otterly2k]

OK-- I'm working on my IV kit and routed the binding channel in the back and deepened the one in the front to accommodate the slightly thicker rosewood binding from StewMac. #

Unfortunately, I didn't measure it quite right and was too much of a nitwit to test on scrap, so I ended up routing a channel that is now deeper than the binding is thick. #

I'm assuming the way to deal with this is to build up the binding with another (thin) layer...is this right?

Also, despite the fact that I used a binding router, the edge isn't totally smooth... there are a couple of places where the line is a little wobbly. #This doesn't matter to me on the back, but it does matter on the face. #What's the best way to deal with this??

thanks in advance ...
KE

ps... now I understand better the prevalence of sunbursts.
http://www.mandolincafe.net/iB_html/non-cgi/emoticons/sad.gif

[Darryl Wolfe]

put on a contrasting thin layer of holly or similar and go on

[sunburst]

How much too thin is the binding, and how thick are the ribs?
If the binding is sitting just under the surface, you can cut/file/sand/grind the sides down 'til everything is level. The sides get a little thinner, but usually that's OK.

I smooth up the surface with files and rifflers.
You say "despite the fact that I used a binding router, the edge isn't totally smooth". Well, I say because you used a binding router, the edge isn't totally smooth. That's one of the reasons I started doing it by hand with a violin perfling cutter. A router can do a good job, but it isn't automatic.

BTW, no matter how many times someone tells us to test on scrap, we never seem to learn the lesson until something like this brings it home. Consider yourself lucky to have gotten this lesson over with early. http://www.mandolincafe.net/iB_html/non-cgi/emoticons/smile.gif

[Darren Kern]

John, you use a purfling cutter for your whole binding channel? Just trying to clarify.

[Antlurz]

How much is "A Little" too deep? Do you have calipers you can use to put real numbers to it?

Sunburst is more than likely dead on, but some hard numbers might be insightful.

Ron

[sunburst]

Darren, I cut the top and back plates undersize to start with, so that most of the binding channel is there before I start cutting. I do the rest with the perfling cutter, knives, chisels, flies,...

Ron, I don't know how thick IV ribs are, but if, for example, they are .100" thick, and the binding is sitting .040" low, you can sand the sides down to the binding and still have .060" of rib thickness.

[otterly2k]

I'll take measurements at home and try provide numbers to inform the discussion... thanks.
KE

[sunburst]

A few other thoughts:

Unless you wanted the thicker bindings, the channel could have been left like it was, and the binding thinned later. A few minutes with a scraper will thin the bindings down to the level of the sides faster and easier than thinning the sides down to the binding, and the bindings would have been the same thickness as the ones intended for the channel when all was done.

It's almost always best to cut the binding channel a little shallower than the thickness of the binding so that the bindings can be cut down flush and smooth. It also gives a little room for error, but a fairly consistent binding thickness looks much better than a binding that is thick and thin, so only a little room for error.

Testing on scrap can yield results slightly different than the actual cut. A straight square scrap can cut differently than the curved side edge of a mandolin, depending on the router set up. Another reason to keep your channel slightly shallow.

Bindings almost always require a little fudging here and there to make up for slight irregularities. Take your time, smooth everything up, add some thickness to the binding or thin the sides or whatever the fix turns out to be, and the results can still be worthy of a blonde finish. (Yes, you can "paint over" a lot of stuff with a sunburst. http://www.mandolincafe.net/iB_html/non-cgi/emoticons/wink.gif )

[Antlurz]

Ron, I don't know how thick IV ribs are, but if, for example, they are .100" thick, and the binding is sitting .040" low, you can sand the sides down to the binding and still have .060" of rib thickness.
Exactly. That's how I saw it too. I'd imagine the ribs are fairly substantial on the kits.

Ron

[Dale Ludewig]

My few thoughts:- build up, as said before. In that you're using rosewood binding and not ibi ivoroid, you'll probably be fine. If you were using ibi, letting the binding stick over the side even a little can be noticeable when you scrape it down flush. On the other hand, bringing the side thickness down to the binding is exciting. http://www.mandolincafe.net/iB_html/non-cgi/emoticons/biggrin.gif

The wobbly edge is inherent in using a router bit of any sort and that can be trued up with files and such.

Back to the side thickness, I don't know what the IV sides are. Maybe John does. But, I'd make sure I measure them and know what I knew what my tolerances were and then I would definitely use either a scraper of sandpaper on a block. There's few things more frustrating than sanding a side too thin after the mando is to this point. Just my $.02.

Carry on! http://www.mandolincafe.net/iB_html/non-cgi/emoticons/biggrin.gif

[Antlurz]

Random side ports? http://www.mandolincafe.net/iB_html/non-cgi/emoticons/tounge.gif http://www.mandolincafe.net/iB_html/non-cgi/emoticons/biggrin.gif http://www.mandolincafe.net/iB_html/non-cgi/emoticons/biggrin.gif

Ron

[otterly2k]

funny, Ron. I think I'll save that as a last resort strategy!

John... of course you're right about cutting the channel a little shallow... this whole experience is full of "DOH!!" moments. A humbling experience that renews yet again my respect for luthiers.

back soon with measurements.

[otterly2k]

Measurements-
The binding is .08" thick, and the channel I cut is about .11" (with a little bit of variation, but I think that's the deepest) leaving me with about .03" difference.

I'm thinking of either
- ordering some wood strips from LMI that are .024" and adding that to the binding... any difference beyond that could be handled by sanding the sides...

OR
-- ordering some bw purfling that's .043" and adding that to the binding (same width as the binding) and any difference remaining could be handled by sanding/scraping down the binding.

I forgot to measure the thickness of the ribs, but I'm pretty nervous about making them too thin, so I think it'd be a better strategy to build up the binding.

yes?

[sunburst]

If you like BW perfling, that's probably the easiest, most attractive solution. (A laminated wood perfling would look good too.)
.104 (.080 + .024) would look pretty wide for the trim around the face if it was all one color, and if it was a contrasting wood inner strip, it would probably look more like a fix than the perfling, which would look planned.
(I won't tell anybody...)

[otterly2k]

Yeah-- I was already leaning in that direction.

thanks for keeping my secret safe, John...now it's just between you and me and whoever is responsible for the 240+ views of this thread! #http://www.mandolincafe.net/iB_html/non-cgi/emoticons/biggrin.gif http://www.mandolincafe.net/iB_html/non-cgi/emoticons/biggrin.gif

....correction... 340+ views of the thread!