Anyone used vacuum jigs

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simso
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Anyone used vacuum jigs

Post by simso » Tue Dec 20, 2011 10:01 pm

Hey folks, just a simple question, Im old school, glues / clamps / cauls etc,

Was browsing LMI's stuff becuase I need some more heat blankets, but I noticed there range of clamping sets that work via vacuum, apparently you can fit an acoustic bridge and string it up 40 minutes later due to the fact you used a vacuum method for clamping, anyone used these, are they that good.
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Re: Anyone used vacuum jigs

Post by Dominic » Tue Dec 20, 2011 11:06 pm

Hey Steve, I use vac for bridge and brace gluing, and I have a set up for holdng the body of a guitar for working on the bindings. Once you it you will wonder how you ever did without it. Happy to give morte details if required. I'll take some pics if you esnt.

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Re: Anyone used vacuum jigs

Post by simso » Wed Dec 21, 2011 12:30 am

That would be greatly appreciated, Ive never ever used vacuum for guitar work, so this is a whole new field for me of which I have zero knowledge, the downside I can see so far is you cannot visually confirm that the bridge is in the right spot whilst it is under vacuum, also you need to be running a vac pump or a compressor for 40 minutes.

I can see huge advantages for clamping uke bridges, Im always paranoid about applying too much pressure and cracking the back or top as you cannot get directly under the bridge in most situations. But again, visual confirmation the bridge is in the right spot is missing.
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Re: Anyone used vacuum jigs

Post by Kim » Wed Dec 21, 2011 12:59 am

A few images lost from a hack and trash event we had a while back, but text is in tact so this topic may be helpful...vacuum is good.

viewtopic.php?f=24&t=2328

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Nick
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Re: Anyone used vacuum jigs

Post by Nick » Wed Dec 21, 2011 6:19 am

I've switched to a vacuum bridge clamping system (The LMI one) and would never go back Steve, after mucking around with clamps & trying to manoeuvre them to get the bridge clamped down whilst not marking the top :roll: the vacuum is just sooooooo much quicker & hassle free. To overcome your apprehension about having the bridge in the correct place, it's just a matter of positioning the bridge (with glue applied) in the right spot then a couple of bits of masking tape just to keep it there while you put the jig on it. The beauty of the system is that the frame doesn't contact the bridge & the rubber diaphragm sits above it so there's no contact with it and no chance of knocking the bridge out of position. Then once the vacuum is applied the diaphragm pulls straight down onto the bridge, evenly & quickly so there's no tendency for the bridge to want to kick off sideways or skew. Ten minutes later you release the vacuum, lift the jig, remove squeeze out then re-apply the clamp, no mess no fuss :wink: . Not sure about the "string it up 40 minutes later" claim though, I must admit I've never tried it but I still like to let it sit overnight.
You only need a simple diaphragm type vacuum pump which makes no more noise than one of those portable tyre pump type things that people buy from Supercheap & keep in the boot & plus it's only running for 30-40 minutes.
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Re: Anyone used vacuum jigs

Post by jeffhigh » Wed Dec 21, 2011 7:44 am

I use two 2mm plastic pins in the saddle slot to locate the bridge (side dot material)
Locate the bridge in position, drill through slot into the soundboard, pull off the bridge, install the pin, a drop of thin CA to secure the pin, trim so only 2.5mm protrudes, HHG to bridge and soundboard, slip onto pins, apply vacuum fixture and turn on.
Easily clamped within 20 seconds of glue application.
Run for ten minutes , pull off and clean around with damp cloth then clamp for another ten.
Havent done this on a bridge reglue yet, you would have to block the existing pinholes from the inside, Tape?

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Re: Anyone used vacuum jigs

Post by simso » Wed Dec 21, 2011 10:22 am

Wow, it's more commonly in use than I had anticipated, placed an order just then for the unit, definetly look forward to giving it a go.

I understand that it pulls the top up and the bridge down, but I would not have envisioned it being better than having a clamp on the bridge and a caul underneath.

I did not realise you would be able to tape it down as well and then vacuum clamp, that's good to know.

Appreciate the input folks
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Re: Anyone used vacuum jigs

Post by kiwigeo » Wed Dec 21, 2011 10:51 am

Vacuum sucks
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Re: Anyone used vacuum jigs

Post by Nick » Wed Dec 21, 2011 11:23 am

simso wrote:Wow, it's more commonly in use than I had anticipated, placed an order just then for the unit, definetly look forward to giving it a go.

I understand that it pulls the top up and the bridge down, but I would not have envisioned it being better than having a clamp on the bridge and a caul underneath.

I did not realise you would be able to tape it down as well and then vacuum clamp, that's good to know.

Appreciate the input folks
Here's a link to Robbie O'Brien's video on the LMI bridge clamp & other Vacuum uses ( I won't post the actual video because it's already posted in Robbie's "Tips du jour" in the tutes section). Robbie uses the tape method for classicals & a form of Jeff's pin method using the actual bridge pins for steel stringers but I've found the tape method can work on both styles, I guess the pin method is double insurance against getting the placement wrong if you are at all unsure.
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Re: Anyone used vacuum jigs

Post by Dominic » Wed Dec 21, 2011 12:20 pm

Steve, I have built a system with a buffer tanks and gauges that maintain the preset-vac in the tank. So my pump hardly runs when doing a bridge. Bit like a compressor. There are kits you can get with foot switches along with detailed plans at Joewoodworker.com. I love this sytem, very easy to use. I have the pump behind my workshop wall and have plumbed lines inside with a vac gauge so I can check pressure. Very good system.
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Re: Anyone used vacuum jigs

Post by jeffhigh » Wed Dec 21, 2011 1:44 pm

If you watch Robbie's video be aware that his bridge clamping force estimates are high(about 3 times) due to using the total area of the fixture rather than the area of the bridge.
Still plenty but as always you should have a perfect fit rather than trying to deform the bridge into contact.

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Re: Anyone used vacuum jigs

Post by Dominic » Wed Dec 21, 2011 5:29 pm

Jeff, I noticed that. Its a weird (actually just plain wrong) way to quote clamping pressure.

It should quoted as kg/m2 or gms/mm2 or something like that before being applied to the bridge. The point is though that a decent pump should pull around 25Hg max to create ample even pressure for gluing a bridge.
Steve, I also drill the two outside string holes and use plastic pins the locate the bridge. But on the last 2 classical I just taped the wings down and then carefully pulled the vac and it didn't budge. It’s less precarious than you think.

Charles Fox talks about its many uses in a GAL article from a few years ago. For braces it is more consistent than go bars and you can pre-shape the braces before gluing even feathering the ends down to nothing and the vac will apply even pressure where a go bar would not work in that situation. Many other uses.

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Re: Anyone used vacuum jigs

Post by kiwinoz62 » Wed Dec 21, 2011 6:05 pm

Hi everyone,

Has anyone used the compressor vacuum valve? as a vacuum unit.
Seems a cheaper alternative, if it does actually work.

Interested in any feedback.
cheers wayne . . .

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Re: Anyone used vacuum jigs

Post by Richard » Wed Dec 21, 2011 6:30 pm

The compressor vacuum (venturi) valve from LMI does work quite well. I used it for a dozen or so guitars when I first got into vacuum clamping.

I was using a small cheap (Supercheap Auto) compressor to drive it; it ran almost constantly so I'd tend to set the bridge and run inside the house to get away from the noise.

I've got the valve sitting collecting dust if anyone wants to go down this route; I'd be happy to part with it for much less than LMI's $150 asking price.

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Re: Anyone used vacuum jigs

Post by Nick » Wed Dec 21, 2011 6:37 pm

kiwinoz62 wrote:Hi everyone,

Has anyone used the compressor vacuum valve? as a vacuum unit.
Seems a cheaper alternative, if it does actually work.

Interested in any feedback.
I haven't used one of those air type valves Wayne but I work in a Chemistry department & when I first started there were these little glass units hanging off the cold water taps everywhere. I asked what they were & I was told they were a vacuum generator, the lab equivalent to these valves. They work on a simple venturi principle similar to the Carburettor on a car. I was suprised by just how much vacuum was developed even with a small flow of water through the venturi. I'm guessing these air units would be the same, not sure, but I would guess there would be a limitation such as only being able to use it on one piece of equipment at a time as compared to a full on vac pump i.e The amount of vacuum pressure would be good but it's ability to pump down a large piece (such as a vacuum 'buffer' tank that Dom speaks about) or several pieces of gear at once would be poor.
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Re: Anyone used vacuum jigs

Post by kiwinoz62 » Wed Dec 21, 2011 7:02 pm

Hi Richard,
PM sent. . .
cheers wayne . . .

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Re: Anyone used vacuum jigs

Post by jeffhigh » Wed Dec 21, 2011 7:03 pm

I'm Just using an air conditioning compressor to draw vacuum with nothing but a filter and a guage between it and the fixture.
I only use it for 20 minutes at a time for bridge clamping or I would go with the sort of setup that Dom is using.
Only cost about $120 on the bay.

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Re: Anyone used vacuum jigs

Post by simso » Wed Dec 21, 2011 8:31 pm

Very interested in links to purchase a vacuum generator or instructions to make a basic one.

I went down the path of buying LMI's convertor unit for compressor to vacuum, so Ill be able to use all there gear straight away, but from the out pooring thumbs up for this, I guess Im going to move into the 21st century for repairs, so should really get myself a vacuum pump unit, does anyone have links to buy it now units available in australia.
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Re: Anyone used vacuum jigs

Post by Dominic » Wed Dec 21, 2011 10:15 pm

simso wrote:Very interested in links to purchase a vacuum generator or instructions to make a basic one.

I went down the path of buying LMI's convertor unit for compressor to vacuum, so Ill be able to use all there gear straight away, but from the out pooring thumbs up for this, I guess Im going to move into the 21st century for repairs, so should really get myself a vacuum pump unit, does anyone have links to buy it now units available in australia.
http://www.veneersupplies.com/products/ ... s-Kit.html
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Re: Anyone used vacuum jigs

Post by Kim » Wed Dec 21, 2011 11:00 pm

If you check the link to the topic I provided earlier in this thread it has examples of the Joe Woodworker units, links to the products, discussion about construction and tips to watch for in the kits conversion from Yank to Aussie PVC construction.

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Re: Anyone used vacuum jigs

Post by simso » Wed Dec 21, 2011 11:04 pm

Okay, Ive been doing some reading and research, so now I have a few questions.

If you purchase a vacuum pump, why do you need cylinders to be attached, or are they being used as a header tank for vacuum, would not just the vacuum pump by itself work fine.

Has anyone that uses this vacuum method made a tool that allows the clamping of fretboards, I want it personally for violin fingerboards and cellos and so forth, that would be sensational if I could use vacuum for clamping them on some how

Very interested, and my mind is travelling at a million miles an hour with ideas
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Re: Anyone used vacuum jigs

Post by Kim » Wed Dec 21, 2011 11:19 pm

simso wrote:Okay, Ive been doing some reading and research, so now I have a few questions.

If you purchase a vacuum pump, why do you need cylinders to be attached, or are they being used as a header tank for vacuum, would not just the vacuum pump by itself work fine.
Mate if you read the info at the link provided above the answer to what you ask is all there for you, all you need do is click and read.

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Re: Anyone used vacuum jigs

Post by simso » Wed Dec 21, 2011 11:41 pm

Thanks kim, I actually read the whole 3 pages the first time you linked it up, but I had no understanding or concept of vacuum clamping so it was humbo jumbo, that being said I just reread the whole three pages again,

Im still kind of am guessing the extra tanks are not necessary but are advisable, there used for a head of vacuum ""yes"". So something like the LMI tool that works on compressed air flowing would not have a vacuum tank between the tool and the clamping hood.

The link to the other webpages I followed as well, for the free plans, but on there website it saids click for free plans but does not bring those plans up either.

I could not find any references for clamping jigs for fingerboards.
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Re: Anyone used vacuum jigs

Post by Kim » Thu Dec 22, 2011 2:21 am

So you missed this bit then mate...
Indeed as Allen said a well made system with reservoir makes the unit more efficient and flexible. When gluing, the reserved vacuum will evacuate air instantly and bring the membrane quickly into contact with the work piece without any need to wait and hope nothing moves. This feature is very handy if you have a large project in a big vacuum bag.

Another plus is that you have a head of vacuum to provide instant grip when vacuum clamping, you can clamp and release and clamp again as fast as you like because only the vacuum in the lines need to replaced between cycles and as you have a vacuum control switch monitoring the reserve, the available vacuum remains constant. This also mean that the pump itself only needs to run when the reservoir requires topping up, saving wear and tear and reducing shop noise.

Speaking of wear and tear, the system includes a mac valve, (the small blue box on my system) which works in conjunction with a check valve (inline brass fitting) and a small 'free air' tank (the small red cylinder on my system). These components work together to save a great deal of load on the vacuum pump when it needs to restart each time the Hg drops by providing 'free air' which is air at normal atmospheric pressure, thereby allowing the pump to reach full speed instantly instead of fighting against any vacuum which remains in reserve.

So these fancy looking systems do actually have a function over and above a standard vacuum pump with direct connection to the work piece insomuch that they make working with vacuum more reliable and efficient. They reduce wear on the vacuum pump. They increase the flexibility of the tool and they reduce noise and power consumption.
:D

That pretty much some up the only benefits of a vacuum reservoir and mac valve linked to a small 'free air' tank over a straight vacuum system Steve. Instant evatiation even of a quite large volume of air, less wear on the vacuum pump as it only needs to evacuate the air line from one operation to the next, no load rerstart for the pump when vacuum drops below set levels.

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Re: Anyone used vacuum jigs

Post by jeffhigh » Thu Dec 22, 2011 7:57 am

I use the pump without tanks and it works fine for the limited usage I give it, evacuates air quickly etc, but for the amount of usage you are looking at it would be worth adding the tanks and valves etc.
Never heard of a setup for gluing on fretboards, I dont think that would work, you either need to cover one object and seal it to another(as in the LMI bridge clamp) or enclose both objects together in a bag, and if you did that with a hollow instrument it would implode.

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