post fitting question...

[Mat Roop]

I have heard of wetting the bottom of fitted bridges to soften the wood and create a better fit.....

... and so the question is ... what is the  general concensus of wetting the ends of a sound post before inserting after final ajustments?? 

Do pros do that? ... I have always done mine dry. 

Could this possibly create a softness that could create a slight indent in the top... and that would cause difficulty if future ajustments were needed?

Thoughts?? ... Thanks! Mat

 

[Brad Dorsey]

My understanding is that the purpose of

21 minutes ago, Mat Roop said:

...what is the  general concensus [sic] of wetting the ends of a sound post before inserting after final ajustments [sic]??...Could this possibly create a softness that could create a slight indent in the top..?...

I was taught to moisten the post ends before making cuts to fit them, because wetting will make the end grain easier to cut.  I don't think enough moisture remains in the post ends to cause an indentation in the top.

[Blank face]

7 hours ago, Mat Roop said:

I have heard of wetting the bottom of fitted bridges to soften the wood and create a better fit.....

The question is, what is softened with this method, the bridge or the belly wood and varnish.

[JacksonMaberry]

On 11/1/2022 at 1:57 AM, Blank face said:

The question is, what is softened with this method, the bridge or the belly wood and varnish.

I would hope that the varnish would not be affected by a little water, but we all know that some varnishes are! It's a shame.

[Gary M]

For what it is worth, The "Pros" who taught me do moisten the soundpost ends but not the bridge feet.

 

[Blank face]

There are some "old pro's tricks" being quite questionable. The simple consideration is, what might give in: The hard endgrain of the soundpost or the soft quarter grain of the belly?

And BTW, shouldn't be used rabbit pee for moistening?

[Torbjörn Zethelius]

I was taught to wet the ends but now I think it's a bad idea.

[Davide Sora]

9 hours ago, Gary M said:

For what it is worth, The "Pros" who taught me do moisten the soundpost ends but not the bridge feet.

 

The ends of the soundpost are wetted to be able to cut them better with the knife, but then they are allowed to dry perfectly before inserting the soundpost (at least that's what I do). Another usefulness of wetting the ends of the soundpost just after cutting them is to make the surface homogeneously opaque for the raised grain effect, so that the compressed shiny contact points are better seen, without confusing them with the areas already rendered quite shiny from the cut of the knife.

No wetting is required or suggested on bridge feet (they are not endgrain like soundpost). To think that by wetting it is possible to remedy an imperfect fit is definitely inappropriate, this also applies to the soundpost.

[Strad O Various Jr.]

one thing about wetting and by this I assume licking the ends of the post, is that wetted posts fit a bit tighter than unwetted ones,. For me if the post fits fine in the correct position I don't wet it, I only wet it if its a bit of a loose fit and I want it to be a bit tighter or further in from the outside of the bridge foot, but you have to be careful, sometimes when the post dries out it becomes looser again and might fall over.

[Blank face]

Wood, especially softwood, expands by wetting and shrinks when drying again, and as mentioned the fibres stand up. Therefore it's now wonder that a post seems to fit more close when licked, but gets loose again after drying.

The problem is that it usually doesn't come back to the original volume but often to a slightly larger and irregular shape. Therefore a post which had a more or less good fit, or a wood insert or replacement, a peg or whatelse won't fit like before.

For this reason I'm preferring the carefull use of fine sand paper (800, 1000) to get an opaque surface to see contact points at a post or peg.

[Brad Dorsey]

6 minutes ago, Blank face said:

…I'm preferring the carefull use of fine sand paper (800, 1000) to get an opaque surface to see contact points at a post…

I’m curious how you hold the post at a constant angle to the sand paper while doing this.  Do you use some fixture as an aid?

[Blank face]

16 minutes ago, Brad Dorsey said:

I’m curious how you hold the post at a constant angle to the sand paper while doing this.  Do you use some fixture as an aid?

As I wrote, carefully. If it's necessary to explain what this means and how to do, I can't.

[Blank face]

Surprise. I didn't know that I can hold a post, a sandpaper, a phone and make a photo all at the same time.

[JacksonMaberry]

33 minutes ago, Blank face said:

Surprise. I didn't know that I can hold a post, a sandpaper, a phone and make a photo all at the same time.

Please share the address of the surgeon you went to for the third arm surgery! That would be "handy"

[stringcheese]

It may help to understand how wood moves with moisture changes. When wood gains or loses bound moisture it expands and contracts primarily across the grain, not along the grain. So moistening the ends of the post changes the length very little. I moisten the post ends slightly when making the initial (larger) cuts, but I prefer to make the final cuts dry. It's just easier to cut end grain that way. The bridge feet are a different matter though. They are cross grain. After I have fit the feet as closely as possible, but before doing the final fitting, I moisten the feet slightly then put the bridge in place with a couple of strings to hold it and apply a bit of pressure. Then I leave it sit for a few hours. The wood expands, then compresses, correcting some microscopic variation that you can't actually see.

[JacksonMaberry]

https://youtu.be/X0k04hjdYuQ

 

Maybe @David Burgess' sawzall bridge approach isn't too far off - I'd imagine the linear friction welded fit of a bridge to a top would be unimpeachable. Would make future adjustments difficult however.

[Blank face]

4 hours ago, JacksonMaberry said:

Please share the address of the surgeon you went to for the third arm surgery! That would be "handy"

it's probably not surgery but long year training of holding a kid, singing, preparing food and calling customers/students at the same time. Or doing this while standing on your head or a single foot.

[JacksonMaberry]

Haha, well nice job!

[GoPractice]

7 hours ago, Davide Sora said:

The ends of the soundpost are wetted to be able to cut them better with the knife, but then they are allowed to dry perfectly before inserting the soundpost (at least that's what I do). Another usefulness of wetting the ends of the soundpost just after cutting them is to make the surface homogeneously opaque for the raised grain effect, so that the compressed shiny contact points are better seen, without confusing them with the areas already rendered quite shiny from the cut of the knife.

 ( ... ) 

My apologies to Maestro Sora, but this might be worthy of a second look... 

 

 ( dramatic pause ) No really. 

A master once grabbed a knife on my bench and then cut an onion skin off a crappy post.

He did moisten. A kiss, a baccio? a touch.

The moisture helps in the cut. 164 - 165 degrees off the grain? The integrity of the cut matters as much as how soggy the wood might be.

 Not sure that we are relying on spit, water, to make the fit better. For my own instruments, I rarely care how the post fits, but for friends, I fit, then play, then play the next day. Posts do settle ( just my opinion. )

There are so many angry an righteous players that storm back to shop complaining the instrument is not the same. I would argue it is for the better. But that little bit water will likely not be the difference.  

 

 

 

[GoPractice]

As for sandpaper, it works great, like a scraper blade that I have used. But for general buffing, I have an old brush with very stiff bristles used for cleaning phono styli that can buff, pre- burnish a post.

[Blank face]

48 minutes ago, JacksonMaberry said:

Haha, well nice job!

If it wasn't for pride and honor, a tripod or a stand can do the job, too.

[Davide Sora]

3 hours ago, GoPractice said:

 But that little bit water will likely not be the difference. 

Indeed.
I prefer to let the soundpost dry well before inserting it, in addition to the reasons I mentioned to better identify the contact points, also because the wet surfaces would cause too much friction, making the feeling of tension unreliable.

Obviously, even without being moistened, the soundpost will need some time to settle, but the main culprits are the archings that deform and settle, soundpost compression will likely not be the culprit. 

[Nick Allen]

I've been licking soundpost ends and immediately installing them into instruments for a couple of years now. I have never encountered a problem from the tiny bit of moisture on the ends. Or from bridge feet for that matter. I lick both just to make them substantially easier to cut. 

[JacksonMaberry]

28 minutes ago, Nick Allen said:

I've been licking soundpost ends and immediately installing them into instruments for a couple of years now. I have never encountered a problem from the tiny bit of moisture on the ends. Or from bridge feet for that matter. I lick both just to make them substantially easier to cut. 

I lick as many parts of the instrument as possible to see how it tastes 

[Nick Allen]

1 minute ago, JacksonMaberry said:

I lick as many parts of the instrument as possible to see how it tastes 

How else would you know how it sounds?