Vac Puck #001--Don't laugh:)

[scottp55]

Dad bought small 3CFM Chinese vac pump a year ago and never got excited as every time I plugged it in...I could smell oil within a minute.
He finally got around to buying a little blue thing he said would capture the oil, and I got it last week...and it seemed to work.
No more excuses.
Had little pieces of live edge Curly 8/4 that were cut offs from legs on a dovetailed/wedged Rosewood slab side table, and decided to make little bowls/trays out of them,but one was a bandit to clamp, soo my first test subject.
Got the wrong type tubing(.5+" OD), wanted to see if I needed vac surge reservoir,wanted to see if oil leaked once pump got worked,and wanted a rough idea of how much hold down a 4.5X1.75" puck with a Thick gasket would give me for other slab cutoffs that are twisted/warped up to an 1/16+" in that distance.
Only puck material choice at hand was 5/4 NICE hardwood, or a 2X4 scrap...so 2X4SPF it was(think Spruce).
Only Thick(.375") gasket hanging around was Ace Hardware closed cell soft stuff.
Just used the whole 20' of hose to simulate air evac of a larger jig to see if I needed reservoir.
WAY overthought it(typical), and just winged the design on the fly, so PLEASE suggest changes!
3 coats unwaxed shellac, and just forced tubing in with HouseholdGoop which was open vs. silicone which wasn't.
NOW I see why you guys like Vac so much!!!:)
Sucked it right down and started with .01" pass with 1.25 Mortising bit at 2IPS and progressed up to .04" passes at 2.4 and it still didn't budge.
Then I grabbed a 5' section of Indian Rosewood with a 3/32" bow in 4", and just stuck the tip on the puck.
THEN decided to put a gallon of latex paint on it like a balance beam...Puck was wedged FIRMLY with threaded insert holding triangle down.....and the wedge let go before the puck did!
Sooo... I threw a a Shopfox clamp on it with a wedge....THAT lifted off before the puck let go!
Tossed a Rockler on the left side of the puck then:)
Center of paint can got about 36"(center of can) before suction let go(and the Rosewood is pretty heavy by itself). Think the soft foam with the bowed Rosewood was the reason.

Anyways...I'M SOLD!!!:)
Need to get smaller OD hose/gauge fitting/ and a few valves and quick connects.
Pump got too hot to touch, and going to stick it inside my MakerCrate, so going to make a small heat shield for it to rest on and where it's right up against the ply. If I had always had that little oil recovery unit...I'd KICK myself for procrastinating so long!!
Long winded for such a simple Gommy set up, but thought I'd post.
Next step is to machine a cover gasket setup from AllStar Adhesives out of HDPE for 1.4" buttons (with cover gasket so buttonholes can be drilled) so I can FINALLY get away from carpet tape? Fingers crossed!
scott

[scottp55]

Oh...Rosewood test. Amazed I didn't wind up with a gallon of paint on the floor! :)
Next one will have counterbored holes for Fastenal connection bolts to catch a threaded insert.
Will add a little piece of filter medium to the puck intake also.

[scottp55]

Just an aside.
I was wondering if the pump was supposed to get that hot.
Dad responded in an e-mail;
"With wood, unfortunately, there is a water content that is the misery of vacuum. Not only is there a lot of it in wood, it's the one gas that the pump does a **** job pumping. Water is like a rubber band, the pump sucks on it on the vacuum side but when the pump tries to toss it out into atmospheric pressure the water has gone from a gas to a liquid, goes no place, and rides back into the vacuum and when it hits the vacuum goes back into a gas.

One trick the pump people can do is keep the pump temperature close to the boiling of water so it can't get back to a liquid when in the pump. This could explain your hot pump."

So maybe they're DESIGNED to get that hot?
No idea of actual temp- but can only touch it for a split second.
Normal?
Just a pic of the oil recovery filter and pump plate. I was worried about the "Replace every 30 days", but Dad said they were often used in a caustic environment, BUT for this use..it actually should last for years. NOT cheap...think about $50. Just a REALLY tight pressure fit by adding Teflon pipe tape.
Had a piece of paper towel over the outlet for over an hour, and paper towel wasn't even discolored....so it must be working:)
Out to test on .25" more porous woods/unplaned wood/and some warped S2S stuff.

[Burkhardt]

It is probably just that type of pump. While the vacuum will suck the water out of the wood I never noticed it to be substantial. The vapor pressure of water at room temperature is something like 2 or 3 kPa or 28"Hg so it will never boil with such a pump.

I would invest in an oil-less refurbished GAST pump for maybe $150.

[gbradley]

Scott

Nice that you came over to the dark side:)! The Gast pump I used got hot running the vac base and circles.

[MogulTx]

I have a Welch Allyn that is used for greater vacuum and large volumes. It gets pretty hot. Check out your compressor head when it is running. Same approximate principle. And they get HOT! That's why they have so many fins to dissipate the heat. Don't get it too confined. Better to have it being cooled by a fan or shop air circulation.

[scottp55]

Thanks all!
G. Dad bought pump over a year ago, I'll recommend a Gast for the other Desktop up North. Will use this one until it dies OR causes problems. Don't have any money myself, so I use whatever I have, and scrounge a lot. Dad was president of AVS for over a decade, so on Vac I defer to him as I only know what I read. Dad STILL doesn't understand wood though.
G, How hot does Gast get if run for 8 hours+ a day? George?

George,
Yep:) Pretty difficult as only way I can figure hold down in my head is to picture a gallon and a half of milk on every square inch! AND then try to picture cutting force from my limited experience:) Pretty sure I'll make every mistake in the book.
Was that a Gast you were running at Shopbot Camp and lugged Desktop rig up the stairs?
I remember you talking over the pump, and kind of remember how loud it was. Only reference I have, and shop is fairly quiet and I'd like to keep it that way.
IF I rig 3 cover caskets for 4X24X.25" button blanks and switch them on 1 by 1, do you think that little 3cfm pump can hack it? (3/4" HDPE for jig)

Thanks Monty,
MY MakerCrate has the front open for wheelchair that TJ and Bill made for me, and back panel is open also. Pump will probably live on right hand ledge of Crate towards the rear so I don't cook my feet by mistake as I can't feel them(cooked foot once by having toe of boot in the heating vent of van from Atlanta to Richmond---T'waren't pretty:).
Got an old heat shield for a Pony Jotul I'll bolt into Crate and salvage a cooling fan from defunct computer if needed. GOOD point though as Kirk has an unmodified MakerCrate and will maybe have to leave pump out OR remove his 2 panels and add a fan even if he goes Gast?

[Burkhardt]

....G, How hot does Gast get if run for 8 hours+ a day?.... Hm, don't run it that long often, usually 2-3 hours max. But these pumps are made for continuous duty. I have my vacuum system for about 2 or 3 years now without problem (actually a Thomsen pump but looks exactly like many Gast pumps). At some point they will surely wear out but refurbished ones are really inexpensive. I have a dual rocker piston pump similar to the one below. They are rather quiet. Of course you hear it purring along but not like the roots blower air raid siren that I built at one point. The spindle/bit is way louder than the pump.

With a solid clean piece of wood I can easily hold down a few hundred square inches. However, leakage through a small crack or loose knot can kill the vacuum. The minimum size I like to use is maybe 3-4 square inches. Below that you have to use a small bit and light cut or may move the part. I guess for a large button it should be o.k. with some experimentation.

http://www.gastmfg.com/product_images/75R-TW.jpg

[scottp55]

Thanks G.
Used puck for sanding today and Liking it:)