We've never wanted to go this route and we already have commercial/lab quality vacuum pumps in our shop that we use for the Collin's Saddle Mill. We've also made our own vacuum fixtures and stock gasket material but never saw the need to clamp bridge on this way.
I suppose that if one is a builder only and repetitively does the same process with some sort of registration pins or method to glue on bridges and can resolve the issue of cleaning up squeeze out and preventing skating cool more power to ya.
In the repair world lining up and matching where a bridge has to be located because of finish issues, etc. requires one to see what they hell they just did after the clamps are in place so we have a shot at getting it right. Vacuum clamping for bridge reglues blocks one's view and I wouldn't like this at all.
Also in the repair world irregular and deformed tops are standard fare on older instruments. This requires at times creative clamping in areas such as the wings where more clamping horse power is required. This is not available with vacuum clamping either.....
Our primary vacuum pump is the quietest that I have ever heard but still I would not want to have to hear that thing for long periods of time either.
With all of this said what you plan on doing will dictate if vacuum clamping is right for you. If you are building with methodologies that are repetitive and you get it all down to a procedure that works with vacuum clamping I can see this as one way to go. I don't see any advantages though..... But if your world includes repairing and lots of variation my preference would be conventional clamping and all the variance in camps, locations, shapes and quantities that will silently.... do their jobs while our glue cures. Being able to clean up squeeze out AND recheck final location without it being a leap of faith would likely keep me from atrial fibrillation as well.
We have a commercial repair shop making my measure different than folks who are not doing repair work on a professional basis. The question that I ultimately ask myself when considering different methods and tooling is will it improve the quality of our work and the value to our customers and/or make us more money. If it's a triple no, and it is in this instance for us, it's a no go.
Thanks very much for that.you make some very good points.
I've yet to perform my first bridge re glue so was intrigued when I came across this vacuum system.
How about heating blankets to help remove a bridge?What are your thoughts on those?
Happy to help Mark and welcome to the trade if you're new at this.
We prefer a 250 watt heat lamp for softening the glue under bridges and fret board extensions. We also make and use cardboard protective shields lined with heavy duty foil, reflective side out to protect the instrument. Heat lamps should never be left unattended and I typically only heat for perhaps 30 seconds at a time before testing the glue with my pallet knives.
Blankets require contact to work via conduction where heat lamps don't have to have physical contact with the irregular shapes that bridges and fret board extensions with frets installed represent.
We also use metal cauls dedicated for use with cartridge heaters for bridge plate removals.
Thanks. I've been doing setup work for a long time and am now slowly delving into structural work. I want to do things right so I appreciate craftsman such as yourself and the many other people on this site.
That's another great tip regarding the heat lamp.The heating blanket appealed to me because the bridge heater iron method makes me a little nervous.
Everyone's got so many different ways of doing things. No doubt the circumstances of the job also dictates 'the best approach'. Checked out your web site. Very cool vids! Love the 'guitar bench control'.
Do you ever use this type of bridge clamp:
I'm not Hesh, but I have that type. It works ok but a couple things I've found. The screws that push down on the wings can dig in the bridge, so you'll want to put a couple scraps of wood under them. The threads that go through the bridge can gunk up with glue and be a little hard to back out if you use too much glue. Otherwise, it's ok.
I don't use mine anymore. I prefer to use the long reach clamps and a caul underneath. I can undo the center clamp and have access to all the bridge pin holes after it's all dry. This way I can drill out the pin holes all the way through while the outside clamps are still in place, holding the caul underneath real tight. With the caul in place, there is a backup when drilling and I get less drill bit blow out (chipping).
I see.Would some machinist wax on the threads minimize the glue problem?
No we don't don't like those clamps and here's why.
We use HHG and want the clamps in place and snugged down in under 15 seconds. We have a method of pre placement of the clamps that permits us to easily have everything in place and snugged down with the bridge located in a masking tape well of sorts. This can all be done in under 10 seconds once we are set-up for it in advance. It takes the drama out of working with short open time HHG.
Thanks for the compliments on our site. I created the site and Dave created the videos which by the way get lots of viewers and that generates some business. We teach fretting and set-up methodologies to other Luthiers and so far our students have come from three continents. Our classes are targeted at best practices that create billable hours and make both Luthier and client very happy.
Yes, very similar. We make a bit more stout "well" with masking tape, I often use two layers so that when skating on HHG I can feel a definite snap into place when the bridge falls into the well.
The key to the method is the prepositioned and tape secured clamp with the bridge plate caul (not shown) already in place inside the box. We may do this with multiple clamps too if the top deformation is such that it warrants multiple clamps or wing clamps.
We only tape on three sides as well so that we can get a visual of how well the thing is in the finish pocket.
I'll add that we also score and remove the finish to very close to the bridge perimeter but not to it and then rabbit the bridge about .005" inward and .003" deep or what ever the film thickness measures. Collings, RIP Bill....., does this too on new instruments. We can feel the bridge doe into the pocket.
The SM caul requires some awareness that snugging down the wings past a certain point lifts the middle..... but after you get a feel for it it's workable. Our caul is modified with a dimple for the ball of the IBEX clamp to fit in, we remove the white nylon end that comes on it.
I use hot water from the HHG pot, paper towels (Bounty Select-a-size in white only....) and wooden toothpicks for clean-up.
Yes I watched your video. Very good.
Thanks Hesh I've learnt a great deal!
If I was in the USA I'd come and study with you.
And thanks Glen H too.
It's a real privilege to learn from true craftsmen!
You are very welcome my friend!