Lighthouse or gast?

[changrudy]

Hi all,

I recently put together my vac table with one of the lighthouse motors for my 32" buddy. I get about 8" hg with this setup but to cut smaller parts, 2" x 3.5", I am not getting enough vacuum due to the small area. From the posts that I've read, adding another vac motor would get me to about 10" hg. I'm not through cutting the part and I'm tired of routing the tabs off each time. Will one of those gast vacuum pumps, with 1.2 or 3 cfm with 26" hg the more logical choice?

Thanks in advance,

Rudy

[Brady Watson]

The high Hg/low CFM pumps are only good if you have *zero* leakage. An Ova Da Hump Valve (http://www.talkshopbot.com/forum/showthread.php?t=11813&page=2) may help, but the Vacuum Film Technique (http://www.talkshopbot.com/forum/showthread.php?t=11481) is probably more suited to what you are doing.

In regards to vacuum, it matters more how you use the vacuum setup you have than how powerful the pump is. You can go pretty far with a single Lighthouse or Fein T3 vac...

-B

[changrudy]

Hi Brady

I've read your vacuum film technique and couldn't completely understand it. Would you have to do the whole procedure each time you cut a new set of parts?

Is it not possible to achieve zero leakage with proper all-star adhesive gasketing and a flat plenum? From what I understand of the ova the hump design is that the fein would flatten the work piece to get the proper sealing, but I would be cutting 1/2" hardwood planks. I will plane them flat beforehand to ensure proper sealing.

Thanks,
Rudy

[Brady Watson]

If you are not going to be cutting through the part, then you can either use AllStar or just make up a BradyVac II in the form of a puck that the plank will fit on. Dimensional lumber and thick pieces that don't have a lot of surface area are tough to hold with vacuum many times - but that is where the hi Hg/low CFM pump will work - as long as you don't have leaks. The OTH valve in conjunction with a Fein or LH vac will give you some insurance if you suddenly spring a leak.

Yes - Vacuum Film is for one-offs or lots of small parts and thinner materials.

I missed the part in your 1st post about not cutting all the way through...AllStar 'Spoilboard Cover' would probably be a good choice. Mike can help you to decide what thickness for your application - you don't want it too thick.

-B