[CAUT] Epoxy the bridge cap

Mark Cramer cramer at brandonu.ca
Wed Apr 22 16:13:23 PDT 2009


Yes... after all, isn't that the industry standard?! ;>)

Actually I've tried the natural maple, and like the look of that too, but as
Shawn Hoar says "ya gotta have fun when yer workin!" 

I should correct a typo from my last post... meant to say "so I will try his
(David Love) and Ron's suggestion of driving the pins dry and CA-ing them
after.

Cheers man!
Mark

-----Original Message-----
From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of Alan
McCoy
Sent: April 22, 2009 5:16 PM
To: College and University Technicians <caut at ptg.org>
Subject: Re: [CAUT] Epoxy the bridge cap

So are you saying that you'll sacrifice function for what ... vanity??! :)
For me, I'll go with the naked good looks of rock maple.

Alan


> From: Mark Cramer <Cramer at brandonu.ca>
> Reply-To: "College and University Technicians <caut at ptg.org>"
<caut at ptg.org>
> Date: Wed, 22 Apr 2009 15:44:43 -0500
> To: "College and University Technicians <caut at ptg.org>" <caut at ptg.org>
> Subject: [CAUT] Epoxy the bridge cap
> 
> Great,
> 
> For anyone else curious about Bill's method, here's an excerpt from my
> notes:
> 
> . Ream the holes to an up-size if necessary, then vacuum again.
> 
> . Apply one bead of epoxy in each hole, swabbing as you go, one octave
> at a time.
> 
> . Dip each pin in epoxy before installing, then after two octaves, set
> pins to full depth.
> 
> . Brush excess epoxy into notches with an acid brush, rinse it in
> lacquer thinner, then scrub the bridge top, cleaning the brush after every
> couple unisons.
> 
> As we know, the thinner evaporates almost immediately, and the remaining
> surface looks like bare but polished, pore-filled maple.
> 
> Nonetheless, I'm really intrigued by David's idea; staining the cap (for
my
> own vanity sake, if nothing else :>) so have mixed up a dark mahogany dye
> for this one. I won't be able to go the epoxy route, because the lacquer
> thinner would remove my dye, so will his and Ron's suggestion of driving
the
> pins dry and CA-ing them after.
> 
> Mark
> 
>   
> 
> 
> Hi Mark,
> 
> Thanks for the suggestion. I like the idea in concept. I have some of this
> bridge stock left over so I will drill some holes, apply the clear coat
and
> then apply the thinner chaser. Then after a week or so I'll cut the stock
in
> half to see what kind of penetration there is.
> 
> I have often used the Spurlock method for bridge pins, but I wanted to try
> the clear coat because I would prefer not to use the epoxy while driving
the
> pins - an extra step I'd like to avoid. I haven't tried the
Nossman/Fandrich
> style cap as I haven't built a power notcher so I don't need a "driving
> fluid". The caps I have used are a 4- or 5-ply laminated maple.
> 
> Alan
> 
> 
>> From: Mark Cramer <Cramer at brandonu.ca>
>> Reply-To: "College and University Technicians <caut at ptg.org>"
> <caut at ptg.org>
>> Date: Tue, 21 Apr 2009 18:12:19 -0500
>> To: "College and University Technicians <caut at ptg.org>" <caut at ptg.org>
>> Subject: Re: [CAUT] install bridge pins?
>> 
>> David mentioned sanding the epoxy coating. I've never done this, nor left
>> anything on the surface Alan.
>> 
>> After surplus is brushed into the notches, I rinse and clean the
remainder
>> with lacquer thinner, and it soaks in like an oil finish. That's the
> surface
>> I was trying to describe... nothing between the wood and strings.
>> 
>> As for the barrier to moisture, I'm obviously relying on the initial
> coating
>> to penetrate as deep as it can (for about 10 to 15 minutes), then chasing
> it
>> with the thinned coat, which really dissolves and evaporates quite
> quickly.
>> 
>> Again, it's not a layer on top, I don't really want that, the saturation
> of
>> the wood itself is all I'm after. If you haven't tried this method, I
hope
>> you will, and let me know what you think.
>> 
>> Thanks,
>> Mark    
>>    
>>  
>> 
>> -----Original Message-----
>> From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of
Alan
>> McCoy
>> Sent: April 21, 2009 5:52 PM
>> To: College and University Technicians <caut at ptg.org>
>> Subject: Re: [CAUT] install bridge pins?
>> 
>> Hi Folks,
>> 
>> Last job I coated the new bridges and caps with System 3 Clear Coat, a
>> penetrating epoxy. Letting it flow into the holes as it would. Rationale
>> being to seal the bridges as much as possible. This was done after
> drilling
>> and notching. I put the pins in dry. First one I've done with Clear Coat.
>> You can watch as the epoxy penetrates. It does not penetrate maple as it
>> does spruce, needless to say. But it does penetrate some. The hope is
that
>> it reinforces the surface fibers for strength as well as form a humidity
>> barrier for the bridge as a whole. The jury is still out about longevity.
>> The only thing I don't like about it is the glossy finish as I'd prefer
> less
>> shine. (Holes were drilled deeper and pins were not seated or filed. No
>> lubricant used.)
>> 
>> Alan McCoy
>> 
>> 
>>> From: Mark Cramer <Cramer at brandonu.ca>
>>> Reply-To: "College and University Technicians <caut at ptg.org>"
>> <caut at ptg.org>
>>> Date: Tue, 21 Apr 2009 14:03:52 -0500
>>> To: "College and University Technicians <caut at ptg.org>" <caut at ptg.org>
>>> Subject: Re: [CAUT] install bridge pins?
>>> 
>>> Yeah, that's what I'm chewing on at the moment Jim. I'm drilling a new
>> cap,
>>> and have pretty much decided to drive the pins "dry" on this one,
> followed
>>> by a drop of CA at each pin.
>>> 
>>>  
>>> 
>>> A year or so ago I did a test to see whether CA, or epoxy (via a heated
>>> bridge-pin) penetrated the bridge cap better. After drying, I pulled the
>>> pins then sliced through the holes on a table saw. For the life of me, I
>>> can't remember the winner!?
>>> 
>>>  
>>> 
>>> I did this at the Banff shop, so maybe Bert can help out. I've really
got
>> to
>>> look into those memory enhancing drinks!
>>> 
>>>  
>>> 
>>> Any case, Ron Nossaman's suggestion was/is  that only the surface
> matters,
>>> so the depth (both went several mm) issue would be a moot point.
>>> 
>>>  
>>> 
>>> When a valid idea comes along, I think it's important to get some
> examples
>>> in place in a hurry, after all it takes a few years of seasonal cycling
>>> before any kind of responsible conclusions can be made.
>>> 
>>>  
>>> 
>>> Mark
>>> 
>>>    
>>> 
>>>  
>>> 
>>>   _____  
>>> 
>>> From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of
Jim
>>> Busby
>>> Sent: April 21, 2009 12:34 PM
>>> To: caut at ptg.org
>>> Subject: Re: [CAUT] install bridge pins?
>>> 
>>>  
>>> 
>>> I don't know if this has been said or not, but the Nossaman method of
>>> drilling the pin deeper than normal and using a laminated cap is
> extremely
>>> effective in keeping the top of the hole firm (laminated). Using CA glue
>> and
>>> filling the hole may negate the advantage of the deeper hole by filling
>> it,
>>> allowing the bottom of the pin to touch bottom, which has some negative
>>> effects.
>>> 
>>>  
>>> 
>>> Jim Busby
>>> 
>>>  
>>> 
>> 
>> 
>> 
>> 
>> 
> 
> 
> 
> 
> 







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