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PostPosted: Sat Jan 16, 2010 7:43 am 
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Old Growth Brazilian Rosewood
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Location: Ann Arbor, Michigan
First name: Hesh
Last Name: Breakstone
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Here is how I fit/floss my bridges to my guitar tops.

Set-up includes taping some 120 grit sandpaper to the guitar top with a low tack tape. Since we want the bridge to fit this top precisely and tops are not always the exact radius that we make them to be in the dish it's important to fit the bridge to the location on the top where it will be glued. As such I use tape markers to indicate on the sides of the guitar where I want to be flossing the bridge on the sand paper.

In addition it's difficult, at least for me, to always hang onto something as small as a bridge and not end up sanding my finger tips. So I use latex gloves to get a better purchase on the bridge. Of course if you are known to have any allergies to latex this is not for you....

Attachment:
DSC00732.JPG


The next step is to make pencil lines on the bottom of the bridge so that we may observe our sanding/flossing progress. Be sure to make lines near the corners of the wings in as much as this is the area that will take the longest to floss if your bridge is made with a flat bottom.

Attachment:
DSC00733.JPG


My bridges are made with a radius so in my case the wings of the bridge will sand first if the radius of the bridge is greater than the radius of this particular guitar top.

Attachment:
DSC00734.JPG


Attachment:
DSC00735.JPG


Attachment:
DSC00736.JPG


After a bit of time and flossing the bridge fits the top perfectly with all edges making wood-to-wood contact.

Attachment:
DSCN2676.jpg


Additional considerations:

1) A light scraping of the bottom of the bridge and the guitar top where the bridge will be glued just prior to gluing is advisable for a better joint.

2) Both fitting/flossing the bridge and gluing the bridge benefit from being done in a specific humidity range since the guitar top will react to changes in humidity. If you flossed the bridge to fit with the humidity in the area of 45% glue the bridge on in that range too and the great fit that you had prior when fitting will be there for you.

Thanks!


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PostPosted: Sat Jan 16, 2010 12:16 pm 
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Mahogany
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First name: mark
Last Name: warwick
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Thanks for that Hesh!

Curious though... How come it is taking material off the outside of the bridge if the top has a radius?

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PostPosted: Sat Jan 16, 2010 5:07 pm 
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Cocobolo
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[/quote]How come it is taking material off the outside of the bridge if the top has a radius?
Quote:

Quote:
My bridges are made with a radius so in my case the wings of the bridge will sand first if the radius of the bridge is greater than the radius of this particular guitar top.


That's why.

Cal

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PostPosted: Sun Jan 17, 2010 4:24 am 
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Mahogany
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First name: mark
Last Name: warwick
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Gesss sorry i don't know how i missed that caption!

Where's the egg on face smiley :oops:

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PostPosted: Sun Jan 17, 2010 8:00 am 
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Old Growth Brazilian Rosewood
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woodsworth wrote:

Where's the egg on face smiley :oops:


Sorry - I should have put it back where I found it.... :? :D


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PostPosted: Sun Jan 17, 2010 10:39 am 
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Brazilian Rosewood
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This is so important to get that perfect glue joint
at the bridge. I used to use a separate sanding block with the top radius
the same as the guitar top or so I thought. There can be a slight difference so
this way is much better. Good tute Hesh. [:Y:]

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PostPosted: Mon Jan 18, 2010 11:47 am 
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Old Growth Brazilian Rosewood
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Joined: Fri Nov 02, 2007 9:49 am
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Location: Ann Arbor, Michigan
First name: Hesh
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Thanks Dave - hey I have to floss a bridge later today and now I have something to look at to tell me how.... :D


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PostPosted: Mon Jan 18, 2010 1:15 pm 
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Hey, Hesh,

How do you get the original radius on the bridge bottom?

Joe


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PostPosted: Mon Jan 18, 2010 1:47 pm 
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Old Growth Brazilian Rosewood
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Location: Ann Arbor, Michigan
First name: Hesh
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Hi Joe - what I did was laminate some wood together, in this case 6 pieces and then sand the top of the block in a 25' radius dish after making pencil lines all over the top of the block. When the lines are gone you are good-to-go. That transfers the dish's radius to the block. Cover with self stick sandpaper and you're done!

Attachment:
DSC02706.jpg


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PostPosted: Mon Jan 18, 2010 4:22 pm 
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Something to note here is that Hesh is shaping the bottom of the bridge before he puts finish on the guitar.

It shouldn't make much difference if you do this after the finish is done (buffed out etc...) as a good finish should only be about 0.005" thick.

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PostPosted: Mon Jan 18, 2010 8:29 pm 
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Thanks, Hesh1


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PostPosted: Thu Jan 21, 2010 10:41 pm 
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Cocobolo
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Thanks Hesh, I plan to do this tomorrow so this is a great reference! I appreciate all your effort and helpful answers, as well as those I got from everyone in the thread that (i think) inspired this toot.

One thing I was going to do was trace an outline of my bridge in the proper location on the sandpaper, so that I can try to make sure and keep the bridge over the spot I am trying to match. Do you think this is a useful step?

One question - looks like you are using wax pencil - do you think that (or graphite) could have the potential to interfere wtih the glue if some remains in the pores? Just a thought.

Thanks again brutha!

adam

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