Vacuum Pump Build

[woodrat]

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Originally Sun Jan 24, 2010 12:36 pm

Hi Everyone, I thought that I would share a few pics of my latest bit of kit. It is an electronically controlled vacuum system that consists of a second hand Gast twin cylinder laboratory pump and some special components that can be bought through Veneersupplies.com that when cobbled together in the best Heath Robinson style gives you a very nice vacuum generator that will provide the required vacuum for any holding or veneering applications that you may have. My system is set to give 18inches of Hg (according to the supplied gauge) vacuum. My pump would only pull 19inches (again according to the supplied gauge) so I set it slightly less than that. I have used as vacuum reservoirs 400mm long 150mm diameter Vinidex pipe with a wall thickness of 4.5mm as this was the heaviest available to me but I put in an internal column in the cylinders to support the endcaps and that seems to be adequate at the moment. I know that there are a number of members that either have Vacuum holding systems or are in the process of building/acquiring ones so maybe we will see lots of good ideas involving vacuum here on the forum. Dom has already posted a great vac holding device for routing endgrafts so keep them coming. Thanks for looking.

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John

[HiString]

This is the setup I made a few years ago. Based on info from JoeWoodworker's site........pump is a Reischle-Thomas, main reservoirs are 2 X 50ltr compressor tanks, etc., etc.

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ChrisO

[Dominic]

Looks good Woodrat. Nice compact design. Did you look through all the pics of various systems people have built on the Veneer supplies web site? I got some good ideas for my system from them. I used old gas bottles for the reservoirs.

These things are so handy and having the electronic cut off and reservoir makes them more friendly to use. My system has zero leaks so I can leave it on all the time. In fact, I did not put a on/off mark on the switch and I have open a valve to see if it is on or off.

Last week I made 8 x 600mm disks of 16mm mdf laminated onto 21mm ply (glued up in vac bag) ready to make various sized radius dishes in the jig I posted for use in a brace clamping jig.
I am betting we will see heaps of cool vac ideas coming over the next year as others get set up and start thinking about uses.

Vac things I have been thinking about.

Brace clamping jig
Head plate and rear head plate press
Fretboard gluing press
Side laminating press
Holding jig for fretboard while doing radiusing etc
Fretboard binding clamp
Also many uses for clamping instead of toggle clamps for machining parts etc.

Good luck with your system Woody
Cheers
Dom

[Allen]

Those systems look great. I'm looking forward to getting mine up and running. And seeing some innovative ideas on it's uses.

[woodrat]

Thanks Dom, Yes I took my lead from the EVS system that Joe Woodworker designed but went for slightly bigger buffers because I could get 150mm pipe at the local Reece Plumbing store. I would like to know how accurate the gauge is though. I think that I have adequate vacuum as Robbie O'Brien said on his video that 15-25 in Hg should be adequate for most lutherie applications. Mine will pull 18 or 19 on the gauge...
Yes Allen...I'm looking forward to seeing the different configurations that people come up with and some their fiendishly clever applications...consider all ideas pre-stolen!

Cheers

John Very Happy Very Happy

[schrammguitars]

I've been using Joe's system for about 5+ years. Mine easily pulls 30Hg.

This is a great system for lutherie: http://joewoodworker.com/veneering/EVS/concept.htm

[Allen]

Micheal Connor and I were just chatting on the telephone a few minutes ago and were discussing if you could use hide glue with a vacuum press. Joe Woodworkers site says no to hide glue and vacuum veneering, but what about gluing on bridges and braces?

[Kim]

My take on that advice would be that the very common assumption made by many people in the USA when discussing HHG, that everyone else lives in an area with sub zero winters, has struck again Allen. With the ambient of tropical Cairns, my guess is you should be fine.

Cheers

Kim

[Allen]

You may very well have it nutted out Kim.

It's really left me puzzled. I'm sure I read somewhere it was because it could not dry through evaporation in a vacuum, but unless I totally off base, PVA's dry in the same manner don't they? At least initially. Don't know the chemistry involved after the initial loss of moisture I must admit.

How about anyone actually having tried it yet with a Yes or No?

[schrammguitars]

I use titebond all the time in my vacuum clamp. Haven't tried hide glue yet. I would imagine it would be fine.

[Kim]

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Prepare yourselves for immediate disintegration Earthlings!

Well i finished putting my system together today. The pumps is a second hand Thomas and, if you wait a while for the last .5 to register on the gauge, it can juuuuust pull 25"Hg. I have it set at the recommended 21"Hg and it gets there quickly and with little effort. Best of all my system has held 21"Hg for the last 2 hrs without loss so that means no leaks .

I've wanted to build one of these for the last couple of years if for no other reason than they look like an "eranium pu36 explosive space modulator" and i have always want one of them in case i get the urge to destroy the world.

I followed the plans from the Joe Woodworker site and found the project to be simple and fun to make. The one hurdle i hit was with the size or class of the PVC pipe. The plans, drawn up for the USA market, call for 30" of "Schedule 40 or 80" PVC pipe with matching endcaps. Here in AU we don't have that rating system so it was a little confusing. Instead we have a PN or Pressure Number rating. With a little research i worked out the or equivalent is PN18 or PN12 and that stuff can be Xie unless you get lucky and find a place to trade for a carton of beer as i managed to.

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Anyhow a bit more research revealed that 30"Hg is actually only 1 BAR of pressure or just over 14psi. So there remains a big question over the need to go so robust with the PVC in the first place. For anyone else thinking of venturing down this track, i remain confident that PN9 PVC will be more than adequate to make reservoirs for these vacuum units.

I see that John has used 150mm drain pipe with an internal bracing and it appears to have worked out very well for him so that is certainly a good option and as i found, is no more work than using the more substantial domed endcaps which fit the higher PN rated pipe.

You see the high pressure rated fittings are quite thick as they are all made to the highest PN18 specs allowing one size fits all PN classes. On the face of it this would seem to be a good thing. But when you go to assemble the parts supplied with the JWW EVS kit, you soon discover that the main manifold components, that is those brass fittings which join together to mate the two PVC reservoirs side by side to act as one, are too short to reach from centre to centre on the end caps DAMHIKT

Anyhow sitting half way between "look before you leap" and "there's more than one way to skin a cat" is this solution. The holes where drilled and tapped into the centre of two of the end caps. (A note on this, the Joe Woodworker kit comes with all NPT (National Pipe Tapper) threaded fittings. Either buy the correct 1/4" NPT tap from JWW when you by the kit or if you only have a 1/4" BSPT (British Standard Pipe Tapper) tap, then that will work OK.) Drilling the holes off centre will not work too well as the two endcaps need to be screwed onto two "T" pieces on the manifold and the oscillation as you attempt to screw them into place would cause them to jam upon each other.

Once the fittings were tapped, i screwed a 3/8" barb supplied with the kit into the endcap and chucked it into the drill press. Using a chisel, and a spirit level as a tool rest, I turned the fittings down to size. This does not effect strength that much because the domed end remains untouched and most of the sides of the caps will be supported by the pipe once it's glued in place.

As you can see the finish off the chisel is quite brutal...

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This is where a "Mill Cut" file comes into it's own. You can see it in the above image, it's like a rasp but each tooth is cut at an angle from one side of the file to the other. The mill cut file makes short work of the ridges and leaves a finish ready for sanding like this...

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Then it's just a matter of holding some 80 grit and then 120 grit cloth backed abrasive against the spinning cap and you end up with a finish like this.

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And a mess like this..

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That job done it was just a simple matter of sanding a flat facet into the other two endcaps so the reservoirs would sit parallel, and then following the simple plan. You will note i used some paint to tart things up...no wallet was damaged in this production. The crappy 'jarrah' stained polyurethane used on the ply was left over from a little fix up i done for my mother around 5 years ago. It was lumpy but effective The Hammer tec blue came from the last can of a dozen i bought at a disposal auction over ten years ago...lasted well that stuff...OK i paid $8 for a spray can of red. Why? Because i felt anything with the core function of this machine should be equipped with a stick of bright red lip stick

So here she is............meet Phylis

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That gauge needs topping up with glycerin....maybe 'Nitro'-glycerin

Where's the Kaboom???There's suppose to be an Earth shattering KABOOM!!!

Cheers

Kim

[Dominic]

Allen wrote:
You may very well have it nutted out Kim.

It's really left me puzzled. I'm sure I read somewhere it was because it could not dry through evaporation in a vacuum, but unless I totally off base, PVA's dry in the same manner don't they? At least initially. Don't know the chemistry involved after the initial loss of moisture I must admit.

How about anyone actually having tried it yet with a Yes or No?



Nice set up Kim. Now for some jigs.

Allen, in the Charles Fox article I sent Kim he mentions that the vacuum helps take the moisture out of the glue quickly and PVA glues set faster. Makes sense. See no problems using other water based glues. Polyurethane would be a problem as it sets with water contact.
For bridges the clamp acts so quickly I recon you would have more time to glue on a bridge with HHG than with other clamp setups. I use two pins through the outside holes, push the bridge on, place bridge clamp on and turn tap. Bingo.

Cheers
Dom

[Allen]

Thanks Dom for that.

Kim, that looks great. And I really like the hammertone on the large tanks. Very professional look to the whole setup

[woodrat]

Hi Kim, Your pump looks great...very professional...I didnt spend so much time on presentation...
.....anyway your pump looks pretty much like mine capacity wise and will pull 25 when I can barely get 19. Do you think that there may be something wrong with the gauge or is my pump a whimp? Sad Any way at least 18 0r 19inchs of HG is adequate for our purposes....I'd just like more ...than just adequate.

John

[Dennis Leahy]

If anyone is interested in dying wood, that is another use for the vacuum. This mostly from hearsay (reading on the 'net), but evidently dying wood veneers in a vacuum gets the dye in deeper than dying in the same amount of pressure. Think: purflings, maybe other accent veneers such as layers on a headstock, and I plan to experiment to see if that also means bindings.

One type of dye I've begun to experiment with is ferrous acetate (steel wool dissolved in vinegar), which has a reaction to tannin in wood to change it anywhere from grayish-brownish to black. (American Walnut goes black - I'm sure there are other species with a high natural tannin content.) For wood you want to turn black that does not have much natural tannin content, you can paint on (or, I assume, vacuum infuse in) a tea made from the bark of a tree with very high tannin content (such as "quebracho" bark powder, sold by taxidermy and leather tanning outfits.)

Dennis

[Allen]

woodrat wrote:
....I'd just like more ...than just adequate.

John


Oh don't we all John.

[Kim]

Nice one Allen.

Yes John, it would appear that not all pumps are created equal with some pulling more inches than others. It is difficult to tell if your "just adequate" reading is the pump or the gauge, though i would not let that be a concerned as it appears you do have enough to get the job done and i have been reliably informed that it is all about how you use what you have got that really matters and one can make up for any short comings with elevated enthusiasm. Wink

A couple of things i would suggest, places like Super Cheap Autos etc sell vacuum gauges as part of those nasty Asian tune up kits. Few people use them now days as they are old tec, so they seem to gather in herds now days at local flea markets and swap meets were they are then sold cheaply to other old tec things that have seen better days. You could maybe use one of these carby vacuum gauges to check the accuracy of your JWW gauge, but i suspect you will find that not to be the problem. There could also be an effect on the reading because of your very manly reservoirs...but i cannot figure how this should change anything as it does not seem logical as to my way of thinking, 21"Hg should remain constant despite the volume of the vacuum. (Good name for a rock band right there, Volume of the Vacuum Cool )

To me there seems more potential for a 2nd hand pump to be a bit worn causing a reduction in the "Hg it can pull at the check valve which sits between it and the reservoir. Once the pump has reached it's threshold, it will then 'run on' at that point pulling the same air out of the line, as the vacuum already in the reservoir then pulls it back again. I suspect that as the rings in the pump were to wear more, that threshold of "Hg would reduce accordingly until the pump can no longer pull the "Hg required to be in a workable range. The good new is however that I would imagine these things would be quite cheap and easy to rebuild back to new condition giving one the bragging rights of a young bull in regards to how many inches they can now pull.....if only life were so simple for us all. Sad

Dennis, great tip on the wood dying, thank you, I like the steel wool vinegar dye idea, this may work well on cheese wood to make black purflings.

Cheer

Kim

[Dennis Leahy]

Kim wrote:
Dennis, great tip on the wood dying, thank you, I like the steel wool vinegar dye idea, this may work well on cheese wood to make black purflings.

Cheer

Kim

There was a company that made a product called "Ebon-x" a number of years ago, that produced an Ebony "substitute" (well, it was black wood) from American Walnut, and a chemical process in a vacuum. They could supply 3/4" thick boards that were black through-and-through.

Now, Walnut has enough tannin naturally that it needs no coaxing to turn black with the ferrous acetate. I'm convinced it will be easy to make a batch of binding blanks (say, approximately 1/4" thick x 2" wide x 34" long), in a PVC tube with ferrous acetate under vacuum pressure. That would allow the wood strip to be stickered and dried, and then sanded down to 3/16" thick, glue a few veneers on one face, and saw out binding strips.

I've just started experimenting, but Osage Orange needs the high tannin tea dip to be able to go black under the ferrous acetate, and I'd guess the same of Cheesewood. (Seems to me the high tannin woods are probably all a rich brown or reddish brown color naturally, though that's just a guess.) Based on hardness and density of Cheesewood, it would certainly be closer to real ebony, but for ease of bending and the fact that you would not need to do the tannin tea step, I think Walnut might be ideal. Of course in Oz, you may want to look at something else. I found this note: "Most imported Malaysian / Indonesian / New Guinea Hardwood timbers, Merbau, Kwila, Kapur, Belian, Balau, Kempas & some Australian timbers have a high content of Tannin..."

Sorry for the sort-of-hijack of the thread, but is is related. More info in a thread on the Luthier Community: http://www.luthiercom.org/phpBB3/viewto ... =25&t=1330 see especially the links off the first post.

Dennis

{edit} Oh, Kim said "purflings" and I went off on "bindings"... damn flashbacks!

[Kim]

From what you say Dennis, Jarrah should work well as it blackens deeply if wet PVA glue comes into contact with metal clamps. If so this could work out very well for anyone who has a cube and a half of the stuff stacked on the shop floor

Cheers

Kim

[jeffhigh]

Ok you have convinced me to have a go at this vacuum lark.
I have a pump on the way and initially want to do a bridge clamp.
Dont really want to go with the LMI version for usage a few times a year.
any hints for homemade as cheap as possible?

[Kim]

Hi Jeff,

Some great instructions for DYI are available at the Joe Woodworker Veneer.com site. Joe has some great tips and clear explanation of what the various parts of these vacuum systems do, and why they are necessary.

Below is a link to the instructions on Joe's site that a few of us have been using but I recommend perusing Joe's site carefully to get a good understanding of the principal and uses for this great tool. Joe does list all the bits for anyone wanting to put their own kit together but as some of the components are not 'off the shelf' it makes sense to just buy one of Joe's kits which come with most everything you will need. These instructions are focused on building an Electric Vacuum System with one of Joe's kits, but can also be used by anyone who wants to do the run around and source all the bits themselves.

http://www.joewoodworker.com/veneering/EVS/concept.htm


Cheers

Kim

[Pete Brown]

OK, vacuum for dummies...

I know I must be missing something obvious here - I'm not that dumb! LMI sell a vacuum valve that can be used in conjunction with a compressor and Robbie O'Brien makes reference to it on the video demonstrating LMI's vacuum bridge clamp. It all looks and sounds simple, with minimal requirements - no big deal at all.

Please educate me on the need for these fancy rigs (geez, I hope I'm not the only one wondering!)

[jeffhigh]

I may go with something simpler to start with
like this
http://www.seabreeze.com.au/Articles/Wi ... 93413.aspx
but I would not want to be running a pump of compressor continually.

[Dennis Leahy]

Pete Brown wrote:
OK, vacuum for dummies...

I know I must be missing something obvious here - I'm not that dumb! LMI sell a vacuum valve that can be used in conjunction with a compressor and Robbie O'Brien makes reference to it on the video demonstrating LMI's vacuum bridge clamp. It all looks and sounds simple, with minimal requirements - no big deal at all.

Please educate me on the need for these fancy rigs (geez, I hope I'm not the only one wondering!)

I think there are times when you need to hold a vacuum for a long time, and for that, the extra vacuum cylinders are great. But to glue on a bridge only takes maybe 20 minutes of running the vacuum pump, so I think no big deal. I suppose if the power ever went out in the middle of vacuuming, I'd be really pissed that I do not have a vacuum cylinder.

For simplicity, and cheap... I got putty and bagging film and a vacuum valve from FiberGlast.com.

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[Allen]

Pete Brown wrote:
OK, vacuum for dummies...

I know I must be missing something obvious here - I'm not that dumb! LMI sell a vacuum valve that can be used in conjunction with a compressor and Robbie O'Brien makes reference to it on the video demonstrating LMI's vacuum bridge clamp. It all looks and sounds simple, with minimal requirements - no big deal at all.

Please educate me on the need for these fancy rigs (geez, I hope I'm not the only one wondering!)


Using a venturi valve certainly will work Pete, but it does mean that your compressor is going to be going full tilt for the entire glueing session. If you've got a turbine, like we do at work, (then you're far to rich to be a lutheir) and it never stops, then perhaps not a big deal, but one of those small shop piston compressors isn't going to be much fun listening to for hours on end.

You can just use a standard vacuum pump without the reservoirs and save some cash, but the benefit of the system like many of us are putting together makes going down that route well worth it if you do indeed plan on using it for many tasks, and perhaps on a daily basis.