DIY Vacuum Box

[kenkelsey]

Hello Forum. Just finished building a modified version of the Gary Campbell vacuum box using two Lighthouse 7123 230v Vac motors and have these comments for others to benefit from my learning curve. First lesson, the horn of the vac motor is the exhaust, not the vac connection. Dumb me, I assumed this was the intake. As a result, I built the box incorrectly. Not a big change, but I learned that the idea is that the bottom of the box is considered to be the plenum and the vacuum lines tap into the bottom side of the box. Corrected that problem, but have to say that the vacuum pull at the entry to the box is not that impressive. I would say that with both LH7123's running, I have a vacuum pull a little less than my Craftsman shop vac. I am going to disassemble the box and seal all of the edges, but I wonder if I'm going to have enough vacuum to do the job. Have not built the table plenum or the piping yet. Appreciate anyone else's experience in building your own vacuum box. Here is a photo of the box, before I corrected the direction of flow (the vac should pull from the bottom and exhaust from the top (out of the left side in my photo). I thought just the opposite. I have sense sealed up the holes that appear on the bottom left of the box and cut in two holes on the bottom left side of the photo for the piping connection. Note photo appears on its side.

[jTr]

Two years ago, I built the 4 motor version, but 98% of the time, all I run are the two primaries. I'm quite a bit above sea level, so I only get about 6 -7" of pull, but it is enough. Kicked on the secondaries a day ago because I had an unruly sheet of 3/4" that was curled on the edges. The primaries added just enough pull to keep the edges down after manually pushing down to the table to aid the seal.

You could easily build an identical box of two and gang up by connecting with a check valve if you feel the need down the road, but you can proceed with a reasonable amount of confidence with the two you're starting with.

Congrats on delving into the vac project. Once you've got a system in place, you'll be very happy - it is key to productivity with these machines.

jeff

[barrowj]

I built the 2 motor version with the Lighthouse motors and only after throughly sealing the vacuum area of the box did I get 7-8" of pull. I still have not sealed the bleeder board down (too cold for me to want to be in the shop, it is a semi-hobby for me anyway right now) so i'm not positive of the success. It did hold down a completely unsealed 2x2 area of my table. Here are some pics to see where i'm at on this project.

[kenkelsey]

Really appreciate the pictures, but I don't see where the vacuum lines hook up. My original mistake was not understanding that the bottom of the LH motor is the suction end and the area below the motors in the box is the plenum. My current assumption is that the vac lines must connect into the plenum area, but I don't see that from your photos. By the way, the plenum (grid) on your CNC table looks great.

[barrowj]

Ken,

Here are pics of how I piped my system. I routed the holes in the plenum to match the outside diameter of the 2" pvc, then cut a shoulder the diameter of a coupler. I glued a 3/8" piece of coupling onto a piece of pipe, applied silicone to the shoulder and pushed the pipe all the way down. Let me know if you have any further questions, you can email directly at joe@joebarrow.com if you wish.



Joe

[barrowj]

Sorry Ken,

I guess my pics got deleted during the upgrade.

[Tim Lucas]

Hello Forum. Just finished building a modified version of the Gary Campbell vacuum box using two Lighthouse 7123 230v Vac motors and have these comments for others to benefit from my learning curve. First lesson, the horn of the vac motor is the exhaust, not the vac connection. Dumb me, I assumed this was the intake. As a result, I built the box incorrectly. Not a big change, but I learned that the idea is that the bottom of the box is considered to be the plenum and the vacuum lines tap into the bottom side of the box. Corrected that problem, but have to say that the vacuum pull at the entry to the box is not that impressive. I would say that with both LH7123's running, I have a vacuum pull a little less than my Craftsman shop vac. I am going to disassemble the box and seal all of the edges, but I wonder if I'm going to have enough vacuum to do the job. Have not built the table plenum or the piping yet. Appreciate anyone else's experience in building your own vacuum box. Here is a photo of the box, before I corrected the direction of flow (the vac should pull from the bottom and exhaust from the top (out of the left side in my photo). I thought just the opposite. I have sense sealed up the holes that appear on the bottom left of the box and cut in two holes on the bottom left side of the photo for the piping connection. Note photo appears on its side.

Hi Ken,

I wanted to take a moment to address your question - I set up my vacuum like you are doing using 2 lighthouse motors with a 5 section plenum - below are a couple pictures of some corbels I cut today - Using one section 24"x33" of my plenum with a piece of 1/4" plywood to cover the top but not covering the ends as the board was 7"x26" I could not move the board and it held fast with no problem. I think you will have plenty of vacuum and really enjoy it once you finish.

Tim

[kenkelsey]

Thanks Joe, Tim.
Joe I believe your first pic is showing the vac line into the vac box. It looks like you went into the vac box with a 3 or 4 inch pipe connected via a toilet flange.

I currently have two, 2 inch lines entering into the vac box. Should I change to one larger opening? My thought was I sometimes I would only use one vac motor and one line going into the vac box?

What kind of connection is made to the table where the pipes pass through the table. Are there flanges like you used on the vac box or did you just push the piping through the table and glue them in?

Tim, nice looking work. Were you able to hold the wood down even as you were cutting all the way through all of the openings?

[barrowj]

Ken,

I used a 3" pipe going into a flange, i have done a good bit of research on this forum and found the majority use 3" but don't hesitate to experiment and let us know how it works out.

I pushed the pipe through the hole and cut a shoulder in the hole 3/8" deep so I could glue a 3/8" piece of coupling to it then used silicone to hold it in the hole.

To summarize my setup, base is 3/4" plywood then the plenum is cut from 3/4" mdf, sealed by painting (some use different ways to seal), then cut the grid which included a hole large enough for the 2" pipe and a shoulder 3/8" below the grid but not into the plywood and cut a piece of 2" coupling to glue onto the 2" pipe to hold the pipe from dropping out of the hole.

Joe

[Tim Lucas]

Thanks Joe, Tim.
Joe I believe your first pic is showing the vac line into the vac box. It looks like you went into the vac box with a 3 or 4 inch pipe connected via a toilet flange.

I currently have two, 2 inch lines entering into the vac box. Should I change to one larger opening? My thought was I sometimes I would only use one vac motor and one line going into the vac box?

What kind of connection is made to the table where the pipes pass through the table. Are there flanges like you used on the vac box or did you just push the piping through the table and glue them in?

Tim, nice looking work. Were you able to hold the wood down even as you were cutting all the way through all of the openings?

Ken,
yes it holds fast! I am using a 1/4" down cut so it fills the cut with chips and helps to hold the seal.

I have a 3" pipe going into my box also and the 2" going into the plenum like Joe I cut a shoulder and glued part of a coupling on the pipe so it wont pull through the bottom from the pipe weight.