I've examined more than a few 19th and early 20th century bridges that had shellac on them. I've examined even more that did not.

I've done it both ways and have not noticed any difference in them either way.

Vibration is transmitted through the feet anyway, so one would assume applying a finish on the sides and leaving the bottoms of the feet sanded clean would have no impact on sound.

quote:

---

Originally posted by Bart Veerman

I don't recall seeing posts on this topic for a long time. Here's a neat one I do remember from forever ago:

https://www.banjohangout.org/archive/72653/1

I'm curious, how do people think about the "yes/no bridge-finish" thing these days and are any of the boutique  bridge makers doing it?

My own thinking about it is posted somewheres on my website (yup, still works):

https://banjobridge.com

 

---

I agree with Scott Zimmerman's (desert rose) assessment in the archived thread.

Not necessary in my opinion.

Historically, I have never put finish on bridges but I have stained them.

Why? I am asking myself and I have never really thought about it that much.   It's because when I started making banjos a long time ago in a galaxy far away, I was told that finish would inhibit the bridge's ability to transmit sound. Who told me that?—can't remember. One of those bits of "musical instrument conventional wisdom" I have since advanced beyond, so my not finishing bridges is some combination of laziness and path dependence.

I will say this—when setting up a banjo I tweak the bridge a lot and finish on it would interfere with that process, so I'll "say" that's why I don't finish them—it gets in the way of shaving and tweaking.

Really, I see no reason why you couldn't shellac or even spray lacquer on a bridge.  I wouldn't soak them in oil.

Watco oil. Looks cool; I doubt it affects sound. I learned it years ago from a violin/fiddle guy.

For those who have tried it, once the finish is dried, is the weight the same?

Three types of "finishes" so far -- oil, shellac/varnish, stain.  Discussion in the referenced link mixes them up.

Oil and stain seem like they are for cosmetic purposes.

Shellac/varnish seems intended for sealing the surface from air and vapor penetration.

Would these three types of finishes have different effects on the sound of the bridge, compared to nothing at all?  Would any of these three types have no effect on the sound?

This is an issue of immense importance. While we are at it perhaps we can determine how many angels could dance on the head of a banjo. Let's see, umm, 20 angels on the head of a pin, 11 inch head...Wow, 549,213.3 angels.

OK, I confess I wouldn't think there would be any noticeable difference, BUT, I have always wondered why the inside of guitars aren't sealed, particularly classical guitars. Back to my hole in the ground. banjered

quote:

---

Originally posted by Alex Z

Three types of "finishes" so far -- oil, shellac/varnish, stain.  Discussion in the referenced link mixes them up.

Oil and stain seem like they are for cosmetic purposes.

Shellac/varnish seems intended for sealing the surface from air and vapor penetration.

Would these three types of finishes have different effects on the sound of the bridge, compared to nothing at all?  Would any of these three types have no effect on the sound?

---

i don't believe any of them would have any discernable affect on the sound—the bridge doesn't produce a sound, only transfers the energy of the strings to the head. finish wouldn't saturate into the wood far enough to damp it unless you impregnated it with oil in a pressure chamber or something like that.

The poly finishes used on guitar tops nowadays to make them "mirror shiny" often weigh more than the spruce, but I don't think any thoughtful builder would do that to a banjo bridge. If they did, it would certainly make it weigh more and probably change the way it worked in some way.  

A lot of speculation:

one would assume

not necessary

see no reason

doubt it affects the sound

wouldn't think there would be any noticeable difference

don't believe

And one experience:

I've done it both ways and have not noticed any difference in them either way.

Spanish rosewood classical guitars are often finished on the inside.  Rarely on steel string.  Current makers of steel-string guitars cite the following reasons for not finishing:  doesn't prevent the wood from absorbing moisture - only slows it, future repairs might be more difficult since cracks are generally repaired from the inside, not economic for large-scale manufacturing.  

The variation in moisture absorbed by guitars does affect the tone and the geometry throughout the seasons of the year.   So the question of the effect of sealing or not is a practical question.

Looking at it from another angle...if finishing/staining bridges made any improvements, it seems it would be a standard for banjo builders.

quote:

---

Originally posted by OldNavyGuy

Looking at it from another angle...if finishing/staining bridges made any improvements, it seems it would be a standard for banjo builders.

---

Agreed! 

I would do a blind comparison and post it, except that nobody would listen to it, so it would be a waste of time—as John Boulding, previously on this forum, said you'd be stepping into the tarpit of subjectivity.

@OldNavyGuy - you're totally correct, there's absolutely no need to finish a bridge
@Ken Levan - yup, the huge tarpit of subjectivity for sure

I never ever made any kinds of promise that finishing would result in any kind of performance improvement or that it would make a bridge moisture proof.

I did, however, gleefully comment that an oil finish would make a bridge look awesome. @Ken Levan - you've gone to great lengths and spend a huge amount of time and effort to banjo your banjos look awesome - would the 30 seconds of time it takes to make your unfinished furniture type of bridge look matchingly awesome with a tiny splash of oil???

People spend hundreds upon hundreds of dollars on beautiful inlays, multiple coats of plastic wood finish, the right kind of metal plating and who knows what else. "Bridges though, who gives a hoot - people don't deserve them looking awesome!" Yeah, seriously eh...???

Come on you guys, get with the program and stop aiming to score the Statler & Waldorf grump award!

Read some more of my comments about the topic here:

https://banjobridge.com/myths.htm

I have treated bridges with fingerboard oil and it visually enhances the grain of the bridge. While it's not necessary, it does look nice and doesn’t seem to affect the performance in any fashion. It amounts to a personal preference decision.

I find the grain stands out fine when I polish the bare wood with a Dremel "red stone".

Another way to look at it -

There are 3785 ml in a gallon, there are 20 drops in a ml, so there are 75,700 drops in a gallon.

If you took one drop of 1 pound cut shellac and rubbed it into a bridge and let the alcohol evaporate it would leave 0.0059 grams of shellac on the bridge or about 6 milligrams.

A 2 gram bridge would them weigh 2.006 grams after finishing and would increase the weight of the bridge by 0.3%.

If I did the math right anyway. Feel free to check it.

Most scales used by bridge makers probably don't even read accurately at that level unless they are capable and calibrated.

I think from now on I'll shellac my bridges cause they will look pretty and I'll wait till someone can measure the difference in tone.    Isn't math fun?

quote:

---

Originally posted by RBuddy

A 2 gram bridge would them weigh 2.006 grams after finishing and would increase the weight of the bridge by 0.3%.
 

---

Would that apply to all wood types used for bridges?

Just kidding...

Me too Jim, but for the record I think the math was correct. Sometimes my old days in a lab decades ago come out when you least expect it.

Cheers