Replies

1. 
   Lilshaver | May 22, 2004 04:24am | #1

   I use a venturi pump that has some kind of cfm capacity, but what is it??? It doesn't matter to me.....the pump will evacuate my 5x10 bag in relatively short order. If I'm in a real hurry, I simply stuff the sucking end of a shop vac into the bag and remove most of the air. Then quickly seal and turn on the pump. No problem. Buy what you can afford.

   By the way: I wouldn't get the venturi system again. It works well in my shop where there is a big air compressor, but recently I had to use it in a clients home. It's awkward having to transport an air compressor. Fortunately I only had to use my small laminating bag.

2. 
   migraine | May 22, 2004 07:17pm | #2

   After using a press for the past 10+ years, I would recommend a rotary vein pump(oil-less) and a controller.  My favorite is the (electric)controller is from Quality Vak and I believe it runs around $250-$300.  Get the larger of the two.   Use a check valve to keep the from running back through the line, if the pump should turn off.  Any kink of tank can be used a resevoir so the pump does not cycle on a off(compressor tank, or an old well bladder tank works get and you can usually get these free if you live in an area that has wells).  You can buy a oil-less pump from any Graingers

   You can make a vinyl bag with plain old patio vinyl and a tube of vinyl adhesive.  just run a hose in one end, and clamp around it.  Two sticks and a few 2"spring clamps work for both ends.  You don't even need the thick stuff.

   I would recommend you try out the above bag method before you start investing in pre made bags.  I eventually bought a complete roll of a softer vinyl and have made a countless number of bags for various applications

   One step up from the bag would to make a steel or aluminum frame and mount the sheet of vinyl to it .  This frame/vinyl then seals to the table you are working on.  MUCH easier to work with.

3. 
   ScottPost | May 22, 2004 08:07pm | #3

   I have the small continuous running unit from http://www.vacupress.com which is probably the same thing you're looking at. I've had it for about 6 months and it completely suits my needs. The small CFM worried me too, but it pulls down plenty fast and, in fact, a faster pump would just make a glue up more hectic since you've have less time to realign anything that slipped.

1. 
   theRev | May 24, 2004 02:52am | #9

   I've got the same set up and am pleased with it. When I'm doing a larger project , needing to get a larger volume of air out initially, I just use my shop vac and its hose to pull most the air out quickly, then plug the bag hose into the pump, and there ya go. Beats waiting around for five minutes watching the glue set up while the small pump takes its time.

   scott

4. 
   KeithNewton | May 22, 2004 08:16pm | #4

   Hey Ktmguy, I have 3 vacuum pumps out in my shop. I almost never use the rotary vane because of the noise. It is loud enough to make me crazy, or crazier. The other two are old refrigiration compressors from walk-in coolers, and I have 2 air-compressors that can be converted in a pinch if I needed it. You may already own a vacuum pump without knowing it.

   If your air-compressor is the standard piston-type with oil in a crank-case,( The oil-less type don't work) and if the intake filter screws on with standard pipe threads.

   Here is what you do to test it. Take your air filter off, and get whatever plumbing fittings that you need to connect a air hose to that end. Then plug or close off the intake. (If you have a vacuum pressure guage you may want to tie that in so you can see how many inches of Hg. you are drawing. For each 2' of Hg. you get 1 psi of pressure on the outside of the bag.)

   The first time through, I would recomend disconnecting the airline between the pump and the tank to make sure no oil is being sucked around the rings. After that just open the drain plug , or stick a male quick-coupleing in the line out. Just open the tank so that you dont satisfy the tank pressure switch.

   Now turn it on, and let it run. You should only hear the hum of the motor after the air is evacuuated from the system. The pump is going to run the whole time, but if you are pulling 28" of mercury that is only -14 lbs. psi., so the motor isn't doing a lot of work. After about 10 minuts of running time, I usually turn it off and feel of the motor and pump for heat, and peace of mind. If there is more heat than I want to feel in hot weather, I sometimes set a small fan to blow across the pump and motor.

   You can make your own bags from almost any plastic film,(I usually use vinly which I buy from a upholstry supply shop.) and two sided carpet tape, and a little wad of rope caulk. I bagged some stair parts once which were 22' long and 2' wide and 2' thick. When things get that big you have to glue up the parts on top of the open bag, then seal it up around the parts. I have been thinking about holding a week-end workshop if you are interested. To see some of my work go to http://www.treetales.com.

   Vacuum bagging is one of the best skills that a good craftsman can add to his bag-o-tricks, pardon the pun, to becoming the best that he or che can be.

   Cheers, Keith

1. 
   migraine | May 23, 2004 06:59pm | #5

   Very, very nice work you have done.

5. 
   sharp | May 23, 2004 07:32pm | #6

   i just bought the vacupress 5cfm with big poly bag.

   ive only used it twice so far, but it really sucks the air faster than i expected.

   When leaving an item clamped for a long period the unit rarely turns on. ( 1 time in 10 hours)

   its quiet too.

   good luck

6. 
   10fingers | May 23, 2004 07:39pm | #7

   If you wish to build your own system to save some money, check out http://WWW.surpluscenter.com for vacuum pumps and other related parts.  Look throught what they offer, it is some interesting stuff.

1. 
   mitch | May 23, 2004 07:57pm | #8

   while we're on the subject, i have two new unused reserve tanks from Woodworker's Supply.  i bought them for another application and ended up changing my mind and using a different set-up.  "reservoir tank ####'y, item no. 826-489" on http://www.woodworker.com  they're $39.99 ea. new.  any offers?  not very heavy so shipping shouldn't be much.

   m

2. 
   ktmguy | May 27, 2004 06:29am | #10

   Thank you to all who took the time to answer my post. http://www.surpluscenter.com is a great place for parts. If you want to make you own Vac press http://www.joewoodworker.com has good instructions and odd parts (vacuum switches, bag material, etc)

1. 
   user-5880422 | May 27, 2004 06:53pm | #11

   The http://www.joewoodworker.com site has excellent info and resources for vacuum press construction.