Vac Table Top Surface

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joejinky
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Vac Table Top Surface

Post by joejinky »

Hi,

I am converting my 5x10 Samson 510 table from a plasma table to a router table. I have a LOT more fun with a router than with a plasma cutter.

I have removed the steel grates and crossed the steel frame with oak 1x4's, notched on the sides to set down onto the frame. Then a sheet of 1/2" high quality plywood, some spacer strips to create an air cavity, and then ... the top?

I hear that regular MDF (Particle Board) works for a vac table, but I looked at the stuff in the big box stores. I cannot imagine that anything can be sucked against that surface from a vacuum chamber on the other side. Am I wrong?

What do you suggest I use for the top surface, and for a vac pump? Would a "shop vac" be enough, or do I need to get something more powerful?

Joe
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Adrian
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Re: Vac Table Top Surface

Post by Adrian »

When using MDF you surface both sides to remove the compressed layer. It's the middle part that a vacuum works through. The lightweight grades work best.

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Rcnewcomb
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Re: Vac Table Top Surface

Post by Rcnewcomb »

- Randall Newcomb
10 fingers in, 10 fingers out
another good day in the shop

joejinky
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Re: Vac Table Top Surface

Post by joejinky »

Adrian wrote:
Mon Mar 09, 2020 9:45 pm
When using MDF you surface both sides to remove the compressed layer. It's the middle part that a vacuum works through. The lightweight grades work best.
So if I buy 3/4" particle board, I have to route down both chocolate cookie sides about 1/8" to get to the creamy center of the OREO?

Is there another material that will work as a porous board surface?

Joe
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scotttarnor
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Re: Vac Table Top Surface

Post by scotttarnor »

You could look at this article also.
http://cncshark.com/downloads/vacuumtable.pdf
Scott T

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Rcnewcomb
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Re: Vac Table Top Surface

Post by Rcnewcomb »

Is there another material that will work as a porous board surface
Trupan Ultralight MDF

TRUPAN Ultralight MDF is produced from fresh Radiata Pine fiber that originates in ARAUCO’s PEFC-certified plantation forests in Chile. The quality and consistency of the raw materials used in the manufacturing process gives TRUPAN Ultralight a light, uniform color. TRUPAN Ultralight panels have an average density of 32 lb/ft3 with 220 grit sanding achieving an ultra light and smooth surface.

Trupan Ultralight MDF provides a smooth, flawless surface and a consistent density profile. It is an ideal choice for millwork and lamination applications where finished product weight is a concern. TRUPAN Ultralight is ideal for a wide variety of furniture and decorative applications.

Average density of 32 lb/ft3
- Randall Newcomb
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joejinky
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Re: Vac Table Top Surface

Post by joejinky »

Thanks! I am going to try to buy a few sheets of that material!

I wonder if it is cheaper to just drive to Fort Worth from Franklin, KY., or if I could save a few bucks by having it shipped. They make 5x12 FOOT panels, so I wonder what that will cost to ship?

Joe
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Rcnewcomb
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Re: Vac Table Top Surface

Post by Rcnewcomb »

I wonder if it is cheaper to just drive to Fort Worth from Franklin, KY
Lots of distributors for Trupan -- should be something closer to your location. Sometimes even the Big Box stores have it.
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Re: Vac Table Top Surface

Post by joejinky »

I actually thought about using simple pegboard. I would lay the material to be routed onto the pegboard, and cover the entire pegboard surface (exposed holes) with long strips of vinyl, which would cut off the air flow through them. I have a huge pallet of 18"x30" vinyl flooring tiles that could be used. Do you think that would work? In this way, no "pods" need to be designed. No valves or hoses need to be plumbed. Just a large 5x10 vac chamber with a stiff frame and a pegboard top.

I would just lay down the piece to be routed, and cover the rest of the holes with the vinyl sheets. Maybe I am missing something, but I *THINK* that would work...

Joe
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joejinky
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Re: Vac Table Top Surface

Post by joejinky »

Rcnewcomb wrote:
Tue Mar 10, 2020 12:56 am
I wonder if it is cheaper to just drive to Fort Worth from Franklin, KY
Lots of distributors for Trupan -- should be something closer to your location. Sometimes even the Big Box stores have it.
I will start making some calls. The price is reasonable, considering the SIZE of the piece. 5x12 = 60 sq. ft., which is basically two 4x8 sheets (64 sq.ft.)

. For $68.00 per 5x12 sheet, that is fantastic!

Joe
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Re: Vac Table Top Surface

Post by Rcnewcomb »

I would lay the material to be routed onto the pegboard, and cover the entire pegboard surface (exposed holes) with long strips of vinyl, which would cut off the air flow through them.
The problem I see with that is when you cut through the board and expose the holes you will lose a lot of your vacuum. Using LDF/MDF doesn't cause the large changes in air flow when you cut through.

I remember how astonished I was the first time we hooked up our vac system and had air pulling through 3/4" MDF.
There was another guy who stuck himself to his spoilboard because part of his shirt was between the spoilboard and the plywood sheet when the vacuum activated. Fortunately the CNC was not cutting.

We ran production for 5 years using a ShopVac system. For some smaller pieces we had vacuum pucks connected to a GAST pump. Not having to worry about crashing into clamps and screws is great.

Full disclosure:
- Special consideration is needed for cutting very small parts. They may not be held in place and disappear into the dust foot.
- Another downside of a vacuum system is spoilboard fires will be sucked into the plenum.
SpoilboardFire.jpg
- Randall Newcomb
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Re: Vac Table Top Surface

Post by joejinky »

Rcnewcomb wrote:
Tue Mar 10, 2020 1:28 am
The problem I see with that is when you cut through the board and expose the holes you will lose a lot of your vacuum. Using LDF/MDF doesn't cause the large changes in air flow when you cut through.
So what if I used pegboard on top of the Trupan? Would I get a good hold at the pegboard holes, but still have minimal vac loss when those hoes were exposed? It seems it would be easier to close off the pegboard holes than the entire surface of Trupan.
Not having to worry about crashing into clamps and screws is great.
THAT is my goal.

Joe
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joejinky
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Re: Vac Table Top Surface

Post by joejinky »

Thinking outside of the box ... :roll:

WHAT IF I were to use thicker pegboard for the top surface.

1. Set material onto pegboard.

2. Turn on Vac System.

3. Hand scatter over remainder of pegboard with 3/8" plastic balls that settle into open holes and plug air loss.

4. Cut material.

5. Turn vac off.

6. Remove material.

7. Squeegee plastic balls into side tray around vac table for re-use.

Joe
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Re: Vac Table Top Surface

Post by Mikehell »

A vacuum table can be great, or it can be a useless pain in the butt. Depends on what you are cutting, and the quality of your vacuum table. I find it really only works for full sheets. If you cut smaller pieces, it's typically useless, and you end up screwing the material down to the spoilboard anyway.

One problem I've had is with a vacuum table that didn't suck the MDF down evenly, causing low spots. So, just turn the vacuum on when you surface the table, right? Nope. Now the table has high spots if you want to use it without the vacuum for smaller parts. So now you have to have the very loud and annoying vacuum on for every cut.

If you don't cut full sheets all the time, you may be better off making a set of wedges to secure the work to the table

joejinky
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Re: Vac Table Top Surface

Post by joejinky »

Mikehell wrote:
Tue Mar 10, 2020 2:49 am
A vacuum table can be great, or it can be a useless pain in the butt. Depends on what you are cutting, and the quality of your vacuum table. I find it really only works for full sheets. If you cut smaller pieces, it's typically useless, and you end up screwing the material down to the spoilboard anyway.

One problem I've had is with a vacuum table that didn't suck the MDF down evenly, causing low spots. So, just turn the vacuum on when you surface the table, right? Nope. Now the table has high spots if you want to use it without the vacuum for smaller parts. So now you have to have the very loud and annoying vacuum on for every cut.

If you don't cut full sheets all the time, you may be better off making a set of wedges to secure the work to the table
Thanks! I will add WEDGE capability to the table surface. I had not thought of that. By drilling holes into the top material but not penetrating completely through, I should be able to put pegs into the holes, and then use wedges to secure the smaller pieces. THANKS!

Joe
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