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Building ain't fixing - - - bridge department
http://www.luthiersforum.com/forum/viewtopic.php?f=10137&t=55581
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Author:  joshnothing [ Sat Mar 18, 2023 6:19 am ]
Post subject:  Re: Building ain't fixing - - - bridge department

Image

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Image

Author:  Hesh [ Sat Mar 18, 2023 8:05 am ]
Post subject:  Re: Building ain't fixing - - - bridge department

SteveSmith wrote:
Hey Hesh, unfortunately I didn’t get a photo of Dave’s bridge gluing setup.


Understand the next time I do one I will get a shot. What you are doing is the same thing, very cool.

Author:  Hesh [ Sat Mar 18, 2023 8:06 am ]
Post subject:  Re: Building ain't fixing - - - bridge department

Looks great Josh that's basically what we do too only we waste masking tape and stretch it across the guitar three times :)

Author:  Smylight [ Sat Mar 18, 2023 8:33 pm ]
Post subject:  Re: Building ain't fixing - - - bridge department

Thanks Josh and Hesh. I suddenly remembered having seen similar pics of the tape trick right here some time ago. I must have filed those in the wrong department of my aging brain. Thanks again guys, like any repair person I do a lot of bridge reglues, so any improvement to the process is worth a lot to me.


Pierre
Guitares Torvisse

Author:  Hesh [ Sun Mar 19, 2023 3:32 am ]
Post subject:  Re: Building ain't fixing - - - bridge department

You bet Pierre happy to share, always.

One thing not shown in the pic above that we do and that is helpful is I make a well of sorts for the bridge with two layers of masking tape on the full three sides, front and two sides.

I make the well by positioning the bridge in a dry run in the exact location that I want it, snugging the clamps and then laying down two layers of masking tape on the three sides indicated. Then I loosen the clamps and remove the bridge, the clamps are still in place as per the rigging, blocks, tape, whatever.

So now after heating the bridge for 10 seconds in a 600 watt microwave and after applying a layer of HHG to the bridge bottom and the bridge patch I slap that puppy down in it's prepositioned well and you can feel it click into place and then I snug the clamps.

I wait abut 2 - 3 minutes and then remove the tape and when I do the squeeze-out snot comes up on three sides clean as a whistle. I follow-up with paper towel and hot water from the glue bath and clean up the trailing edge where there was no tape and the squeeze out is present and hit the other three sides too for any errant glue.

They I hang it for 24 hours, remove the clamps, drill and ream the pin holes, clean out the saddle slot and make sure it's bottom is level and then put it all back together again and set it up properly.

We charge a goodly amount for a proper bridge reglue but we do much more too. We are super careful to not damage finish on the removal too. When all is said and done we believe that our reglue is vastly superior to a factory bridge gluing for a number of reasons. 1) HHG is superior to what the big two use. 2) We expand the wood to wood footprint, more gluing area. 3). We refine the fit and do not rely on the clamps to distort the bridge shape and make it fit. We fit bridges to stay down with only light finger pressure and then we clamp and use HHG.

Additionally we rabbit the bridge perimeter approx .003" deep (depending on finish thickness) and approx .010" inward. This pocketed bridge glue is also what Collings and even Taylor do or have done at times. It's an extra step but the beauty is the finish and the bridge intersection is clean as can be with no glue line showing. It also makes future repairs likely to be easier and more serviceable since we did not go to the perimeter of the bridge which would force all others who come after us to do the same thing.

Author:  joshnothing [ Sun Mar 19, 2023 6:14 am ]
Post subject:  Re: Building ain't fixing - - - bridge department

I also usually follow Hesh’s procedure with a well of tape - in those pics I have only a few scraps for location because the finish on this guitar was over 0.030” thick (!) and so it did a great job of securely locating the bridge on its own :D

Author:  Smylight [ Sun Mar 19, 2023 7:59 am ]
Post subject:  Building ain't fixing - - - bridge department

Hesh wrote:
You bet Pierre happy to share, always.

(…)

Additionally we rabbit the bridge perimeter approx .003" deep (depending on finish thickness) and approx .010" inward.


This bit is particularly interesting to me. What king of jig do you use, because I suspect you do, organized fellow that you are… ;-)

Thanks Hesh!


Pierre
Guitares Torvisse

Author:  Hesh [ Sun Mar 19, 2023 1:02 pm ]
Post subject:  Re: Building ain't fixing - - - bridge department

Pierre I'll get some pics of it the next time I'm there. It's a Dremel on a Stew Mac router base with some mods. Make fast work of rabbiting the bridge.

Author:  phavriluk [ Sun Mar 19, 2023 11:06 pm ]
Post subject:  Re: Building ain't fixing - - - bridge department

I can see how a bridge can be installed right quick using HHG when clamps that can be prepositioned and clamped in place before gluing are used. No such luck in my cave. I didn't know these clamps even existed.

Author:  Hesh [ Mon Mar 20, 2023 5:14 am ]
Post subject:  Re: Building ain't fixing - - - bridge department

phavriluk wrote:
I can see how a bridge can be installed right quick using HHG when clamps that can be prepositioned and clamped in place before gluing are used. No such luck in my cave. I didn't know these clamps even existed.


Were you vacuum clamping then?

I don't know what it is and I can't prove a thing but we see a goodly percentage of bridge lifts with pinless bridges including from some of the biggest names in the business at times.

Wondering if some of the other repair folks here have noticed this too, Josh, Chris, Woodie, Dan and many others who do repairs professionally?

As such we've speculated as guitar repair people do when working in close proximity why it is that we see or seem to see more pinless lifts than pinned lifts. To be clear I am not sure this is true, I am a data guy but I never thought to keep data on bridge lifts and who was doing it.

But in our speculation vacuum clamping was and is suspect because of less clamping force and the entire operation being visually obscured you can't easily see if something is untoward or perhaps part of a wing is not all the way down.

Anyway speculation from me so no worries.

Author:  joshnothing [ Mon Mar 20, 2023 5:51 am ]
Post subject:  Re: Building ain't fixing - - - bridge department

I’ve always thought pinless bridges bore more of the force from string tension directly on the glue line between bridge and top, vs a pinned bridge where the strings, anchored against the plate, are yanking on the whole assembly - bridge, soundboard, plate, x brace arms etc.

It’s hard to say if I see more failures on pinless bridges because the main brand I see fail - Takamines - also often feature the ‘palathetic’ pickup system which requires a large rout through
top and bridge plate for the honkin huge transducer assembly. This same design is used in modern Maton guitars (pinned bridges) which suffer routinely from bridge lifts. So it’s hard to lay the blame solely on the pinless bridge…

Author:  Smylight [ Mon Mar 20, 2023 9:22 am ]
Post subject:  Re: Building ain't fixing - - - bridge department

phavriluk wrote:
I can see how a bridge can be installed right quick using HHG when clamps that can be prepositioned and clamped in place before gluing are used. No such luck in my cave. I didn't know these clamps even existed.

They're at StewMac. Worth every penny IMHO.


Pierre
Guitares Torvisse

Author:  Smylight [ Mon Mar 20, 2023 9:25 am ]
Post subject:  Re: Building ain't fixing - - - bridge department

joshnothing wrote:
I’ve always thought pinless bridges bore more of the force from string tension directly on the glue line between bridge and top, vs a pinned bridge where the strings, anchored against the plate, are yanking on the whole assembly - bridge, soundboard, plate, x brace arms etc.

It’s hard to say if I see more failures on pinless bridges because the main brand I see fail - Takamines - also often feature the ‘palathetic’ pickup system which requires a large rout through
top and bridge plate for the honkin huge transducer assembly. This same design is used in modern Maton guitars (pinned bridges) which suffer routinely from bridge lifts. So it’s hard to lay the blame solely on the pinless bridge…

Same experience here. Taks mostly it seems, but as they are very popular round here they might be over-represented.


Pierre
Guitares Torvisse

Author:  Hesh [ Mon Mar 20, 2023 9:39 am ]
Post subject:  Re: Building ain't fixing - - - bridge department

Peter the Ibex clamp and the Stew Mac bridge gluing caul are great to use and have too. You can drill a dimple in the caul that matches the ball end on the clamp when you pull the nylon white thing off the clamp, that's what we did and do.

The first one I recall suggesting drilling the dimple since I like to give attribution on the OLF was Colin Symonds. Hope he's doing great have not heard from him in a decade or so.

Author:  phavriluk [ Mon Mar 20, 2023 9:19 pm ]
Post subject:  Re: Building ain't fixing - - - bridge department

I just saw a suggestion that the clamps I was amazed to see are sold by StewMac. While they may be 'worth every penny', three of these clamps is more than a thousand pennies. That's a lot for this amateur builder to absorb for single-purpose tools that won't get used but once a project. I can't tool up for a professional shop in order to do hobby-intensity building.

edits: I just looked up the current prices on the clamps I mentioned above. Same price today (apples to apples) as the StewMac clamps. I'm living in the past. I bought those Ibex copies on sale, it must be, from Grizzly for less than ten bucks each. I couldn't afford them today.

Moving along to my pinless bridge, the guitar gods solved part of my problem for me. The bridge departed the guitar two days ago sometime while the guitar was in the case. Near as I can tell, the string tension exceeded the peel strength of the Titebond. At any rate, it was easy to scrape the soundboard down to smooth bare wood. I made a new pinned bridge and the Titebond Extend is drying. Tomorrow morning I'll slot the bridge and see about setting the string height.

I haven't forgotten climbing the HHG learning curve, but this problem wanted a solution and I had the resources in hand to respond to the need. My new coffee warmer came in the mail today, too.

Hesh asked if I was using vacuum clamping. Nope. Three Shop Fox knockoffs of Ibex clamps I bought from Grizzly.

I learned today that ebony likes to chip at the edges of bridge pin holes.

Author:  joshnothing [ Tue Mar 21, 2023 4:49 am ]
Post subject:  Re: Building ain't fixing - - - bridge department

Yes, it can be an expensive hobby in terms of tools and materials. I was forced to turn pro when I realised there was no other way to justify the expense :D

Author:  SteveSmith [ Tue Mar 21, 2023 6:16 am ]
Post subject:  Re: Building ain't fixing - - - bridge department

joshnothing wrote:
Yes, it can be an expensive hobby in terms of tools and materials. I was forced to turn pro when I realised there was no other way to justify the expense :D

That’s why I started doing repairs and setups too :)

Steve

Author:  Hesh [ Tue Mar 21, 2023 7:30 am ]
Post subject:  Re: Building ain't fixing - - - bridge department

Yeah same here there was so much $$$ going out the door it was sell drugs or become a professional Luthier. Anyone wanna buy some drugs :) They won't make your guitar sound or look better but you may think so..... :)

Author:  phavriluk [ Tue Mar 21, 2023 4:19 pm ]
Post subject:  Re: Building ain't fixing - - - bridge department

All done. Reset the neck, too. Plays nice.

Author:  flemsmith [ Thu Jun 15, 2023 6:29 pm ]
Post subject:  Re: Building ain't fixing - - - bridge department

So happy to run across this thread with all the detail and pix. My second guitar needs repair for the delam problem where I didn't understand I needed to seal with shellac before lacquer over glue joints plus I did such a sloppy job on the bridge I pulled it off. It's a cedar top, and coupla small hunks of wood came off with it. If I'm not asking too basic questions:
1. Does a pinned bridge mean you use the two 3/16" recesses outside the 6 pin thru holes to mount permanent studs thru the bridge plate? Not clear to me how I would accurately locate them now. Make little pointed studs to press into the cedar while using the thru pins for temporary bridge location?
2. No idea how to deal with the gaps left from the removal cedar wood. Routing just the few thou depth freaks me out, as I have little idea how to make an idiot proof routing template, especially with a 25' radius top. I doubt that just filling the gaps with HHG would work...?!
On the good side, I have a good bit of time, cause I've started on the shellac/lacquer issue which won't be quick and learning to do HHG would be a big improvement over what I've been doing for bridge process. I always wondered what those clamps were for with the extra screw heads. Sorry to take up time with such beginner questions. Roy

Author:  joshnothing [ Thu Jun 15, 2023 7:24 pm ]
Post subject:  Re: Building ain't fixing - - - bridge department

In this thread I have been using “pinned bridge” to refer to a conventional steel string acoustic guitar which makes use of six bridge pins.


Sent from my iPhone using Tapatalk

Author:  joshnothing [ Thu Jun 15, 2023 7:31 pm ]
Post subject:  Re: Building ain't fixing - - - bridge department

To reglue a bridge, there are several methods of locating it such that it does not skate around when clamping.

Some use locator pins, studs, spikes or the like but in my view these are unnecessary and a roadblock making future bridge removal slightly more difficult. I use the simple expedient of dry clamping the bridge in desired final position and building up a “dam” of masking tape several pieces thick on the sides and front edge. These little walls of tape positively locate the bridge and prevent any movement during clamping.

Image

I have also seen people use cam clamps or magnets in the same location as this tape to provide positive location. Whatever is convenient.

Author:  bobgramann [ Thu Jun 15, 2023 7:43 pm ]
Post subject:  Re: Building ain't fixing - - - bridge department

StewMac sells some tapered hdpe or teflon (whichever, they’re slippery and glue won’t stick to them) plugs that you can put in the outer peg holes to locate the bridge. I use them both for original assembly and for reglues. Once, they’re seated I cut off the protruding tops so they pins are transparent to the clamps and cauls.

If you can, remove the cedar escaped parts from the bottom of the bridge and glue them back in. Use a piece of plexiglass or Lexan for a caul. If you can’t recover the orginal, make new filler parts from cedar scraps. Use HHG. After the glue is dry, you can and the footprint level with a small sanding block. Then refit the bridge to the top. If you’re good, you can make the fit perfect. If you’re not good, you’ll get more practice when you replace it the next time.

Good luck. I wish I didn’t have so much practice doing this.

Author:  flemsmith [ Fri Jun 16, 2023 10:01 am ]
Post subject:  Re: Building ain't fixing - - - bridge department

thanks for those inputs, much appreciated. Roy

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