vacuum for vacuum table

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MadRussian
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vacuum for vacuum table

Post by MadRussian »

Long overdue but better late than never.
I'm starting to build a vacuum table of my profiler. Table is big enough to profile 2 skis at the same time.
What size of vacuum and how many needed for the table?
I built a small test vacuum box about 6 inches wide and 20 inches long using 1 small shop vacuum I have iirc 2 hp 5g not provide enough suction. Also all shop vac created equal? Will vac overheat if all holes in the table covered?
I have not failed. I've just found 10,000 ways that won't work.
Thomas A. Edison
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MontuckyMadman
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Post by MontuckyMadman »

sammer wrote: I'm still a tang on top guy.
MadRussian
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Post by MadRussian »

I saw that video. I have biger vacuums and not enough suction
I have not failed. I've just found 10,000 ways that won't work.
Thomas A. Edison
gav wa
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Post by gav wa »

I use one old house dyson vacuum and get heaps of hold down.
Use small holes not a channel and use the mdf with coated faces like used in cupboards. The plain mdf is very porous and loses vacuum out all the sides.
knightsofnii
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Post by knightsofnii »

I built one similar to Donek, except for the underneath chamber, i routered it all out.

But i guess if you have no cnc, then use his method, you could do it that way, then drill all those holes with a hand drill!!! hah that's a ton of work
but you dont have to be laser precise with the holes.

A layer of pegboard over mdf as a template for your holes?

Anyway, I didn't cnc my hole depths enough, and had to go back and finish out the holes with a hand drill, over 1600 holes, it took a couple nites.


I've been using a shopvac. it says 5hp, but i think its a lie, its a 2" hose, one hose into the center of the vac table.

Best way to get the best suction is to make sure there's no leaks, masking tape and cardboard goes a long way to cover the excess holes and seal around the edges of stuff.

once you have it all together, use your profiler, with just flat profile rails, and skin the entire thing to deck it nice and flat, that way your surface is flat to your router bridge, then put your profile rails on, then good luck!

Oh and I dont know how well it would work with router bridge. But I've been using Whiteside 2 flute spiral DOWNCUT bits. Like RD2100 1/2".
I figure if it's ejecting chips downward, then it's pushing down on the workpiece as well, instead of pulling. Give that a shot.
Doug
gav wa
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Post by gav wa »

yeah a negative cutter tooth angle will produce downward pressure.
Another way is to use a cutter with a positive entry angle, like a 45 degree cutter, you also get other benefits too, like increase surface finish quality and feed speed.
MadRussian
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Post by MadRussian »

My table already build. I'm only adding vacuum.
Tabletop is 1/8" metal plate with frame below so vacuum table will be 8 individual vac chambers connected together with PVC pipe. To start I will make 5 chambers to see how it works before going further.

Table is not set up to use spoilboard..
Router bit Whiteside 1.5" straight
previously I used double-faced tape to secure core with mixed results.
I have not failed. I've just found 10,000 ways that won't work.
Thomas A. Edison
amidnightproject
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Post by amidnightproject »

I'm currently using a Rigid shopvac. I'm going to try to secure a few household vacuume cleaners to take apart and try however so I can get some more hold down.

The rigid works rather well. Every once in awhile my bit will pull up a core on the finishing path near the tips. I started using thing 3m VHB at the ends for a little extra 'insurance'
MadRussian
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Post by MadRussian »

Almost finished.
I have three shop vacuums different denominations under 5 hp. Looks like 2 produce enough suction to hold 1 core in place.Tip/tale section not enough suction I did holes 1" distance there. In the middle I did tighter about 5/8 to 3/4 distance will be adding more holes in Tip/tale section tomorrow.
First test results promising.
I have not failed. I've just found 10,000 ways that won't work.
Thomas A. Edison
MadRussian
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Post by MadRussian »

amidnightproject wrote:I'm currently using a Rigid shopvac. I'm going to try to secure a few household vacuume cleaners to take apart and try however so I can get some more hold down.

The rigid works rather well. Every once in awhile my bit will pull up a core on the finishing path near the tips. I started using thing 3m VHB at the ends for a little extra 'insurance'
Looks to me shop vacuums produce only so much suction. Couple of vacuums connected to the table can compensate for air going through but do not necessarily increase suction.

Do you put double-faced tape around perimetor of the ski or only at the tips?
I have not failed. I've just found 10,000 ways that won't work.
Thomas A. Edison
amidnightproject
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Post by amidnightproject »

MadRussian wrote:
Looks to me shop vacuums produce only so much suction. Couple of vacuums connected to the table can compensate for air going through but do not necessarily increase suction.

Do you put double-faced tape around perimetor of the ski or only at the tips?
Only at the tips. You are correct though, a shopvac will only produce so much. It works, but it's not the best option. I can't lift any of my pieces off my table when the vac is on. Part of the reason my tips were pulling off the table is because of heat and I use an upcut bit. Thin wood and warping + upward pulling motion = chunks out of the end of your core. no bueno!
sammer
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Post by sammer »

Leave a couple inches of core blank past where you are cutting.
It will stop the ends from lifting.
Cut it off after.
My $.02

sam
You don't even have a legit signature, nothing to reveal who you are and what you do...

Best of luck to you. (uneva)
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chrismp
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Post by chrismp »

More holes in the tip/tail area. Dismantle the shopvac and hook up the hose directly to the motor. Only profile your core where your actual ski shape will be and leave the rest as is. Then cut off the flash with a jigsaw.

That's how I do it. Never had a core lift off the machine. Mind you, I have a vacuum table that's 2,6 x 1,2m driven by three vacuum motors.
amidnightproject
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Post by amidnightproject »

chrismp wrote:More holes in the tip/tail area. Dismantle the shopvac and hook up the hose directly to the motor. Only profile your core where your actual ski shape will be and leave the rest as is. Then cut off the flash with a jigsaw.

That's how I do it. Never had a core lift off the machine. Mind you, I have a vacuum table that's 2,6 x 1,2m driven by three vacuum motors.
Yea! I remember you telling me about yours in my thread. I still need to do some dismantling of the extra shopvac I've got to do some testing!

I'd leave extra material but I don't really have room for it. I profile my cores with sidewall attached and already shaped to spec.

Image

I did punch extra holes in the vac grid where the core sits and it helped quite a bit. I profiled a few cores without tape. It just made me super nervous the whole time.
knightsofnii
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Post by knightsofnii »

Is that the "roughing" step prior to doing the full taper?


For me, the combo of decent vacuum plus a spiral 2 flute downcut bit, like a Whiteside RD2100, works really well :).

My bigger issue is skinning the deck and getting it so flat that both sides of core are within tolerance. My vac table has been thinned out and I think i need to rebuild one with 1.25" MDF.
Doug
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