Any advice on improving vacuum on sys-vac?

[Jesse Cloud]

Is there any guidance for how strong the vacuum needs to be for different applications?  My vacuum gauge generally shows in the middle of the red area, but the workpiece seems firm and doesn't move when sanding or edge routing - so I'm hoping its ok.  I noticed that in the Festool Germany video the gauge shows near the top of the red area.

Any tips for what one can do to improve the hold?  I suspect much of my problem comes from the elevation here, about 5,600 ft above sea level.

I have the standard Festool setup.  I'm using it on both sheet goods and hardwood.  Melamine gets the best vac, good plywood next, then hardwood, and MDF works very poorly.

Thanks in advance for any help.

 

[Nat X]

Painter's tape is the usual answer.

 

[semenza]

Painter's tape is the usual answer.

[member=41196]Nat X[/member]      Maybe a little more detail  [huh]

Seth

 

[Michael Kellough]

Is there any guidance for how strong the vacuum needs to be for different applications?  My vacuum gauge generally shows in the middle of the red area, but the workpiece seems firm and doesn't move when sanding or edge routing - so I'm hoping its ok.  I noticed that in the Festool Germany video the gauge shows near the top of the red area.

Any tips for what one can do to improve the hold?  I suspect much of my problem comes from the elevation here, about 5,600 ft above sea level.

I have the standard Festool setup.  I'm using it on both sheet goods and hardwood.  Melamine gets the best vac, good plywood next, then hardwood, and MDF works very poorly.

Thanks in advance for any help.

I don't know how to outwit physics but compared to sea level the maximum pressure the air can exert on your work is 19% less. I think your only option is to increase the size (square inches) of the sucker. @5600 feet PSIA is 11.95 compared to 14.7 at sea level.

PS  I don't know what the "red zone" signifies.

 

[GarryMartin]

Painter's tape is the usual answer.

[member=41196]Nat X[/member]      Maybe a little more detail  [huh]

Generally the lower vacuum is because the material is in some way porous. Applying painters/masking tape to the material around the clamp area decreases the porosity and so improves the vacuum. Clearly you're then reliant on the holding power of the masking tape though, so use carefully depending on the operation.

 

[Michael Kellough]

Is there any guidance for how strong the vacuum needs to be for different applications?  My vacuum gauge generally shows in the middle of the red area, but the workpiece seems firm and doesn't move when sanding or edge routing - so I'm hoping its ok.  I noticed that in the Festool Germany video the gauge shows near the top of the red area.

Any tips for what one can do to improve the hold?  I suspect much of my problem comes from the elevation here, about 5,600 ft above sea level.

I have the standard Festool setup.  I'm using it on both sheet goods and hardwood.  Melamine gets the best vac, good plywood next, then hardwood, and MDF works very poorly.

Thanks in advance for any help.

This can sometimes be an advantage.

I had to edge route a dozen smallish MDF pieces and set the whole stack on the sucker and even the top piece was held well enough while I ran a small router/round-over bit around the perimeter. Just slid them off one after the other as the routing progressed. This would not work at all on non-porous stock.

 

[Jesse Cloud]

Is there any guidance for how strong the vacuum needs to be for different applications?  My vacuum gauge generally shows in the middle of the red area, but the workpiece seems firm and doesn't move when sanding or edge routing - so I'm hoping its ok.  I noticed that in the Festool Germany video the gauge shows near the top of the red area.

Any tips for what one can do to improve the hold?  I suspect much of my problem comes from the elevation here, about 5,600 ft above sea level.

I have the standard Festool setup.  I'm using it on both sheet goods and hardwood.  Melamine gets the best vac, good plywood next, then hardwood, and MDF works very poorly.

Thanks in advance for any help.

I don't know how to outwit physics but compared to sea level the maximum pressure the air can exert on your work is 19% less. I think your only option is to increase the size (square inches) of the sucker. @5600 feet PSIA is 11.95 compared to 14.7 at sea level.

PS  I don't know what the "red zone" signifies.

Thanks Michael.  I'll show this to my wife as further proof that we should move to the beach!  [big grin] [big grin]

 

[junk731]

Jesse to go a little further MDF is porous and allows vacuum through, I believe this is one of the reasons its used as spoil boards on commercial CNC machines.

John