Spoil Board Insanity

[Ken Sully]

So after tamming my unit installed a new spoil board all glued down.
Started thinking it is all great now, but when humidity starts moving my spoil board around things won't be quite as good. I had some oil finish that needed to go to the trash...why not thin it and seal the top of my board it does penetrate the wood.

Guess we will see what happens after all the finish was going to the trash

[harryball]

If pulling a vacuum through it then sealing it would reduce or prevent airflow. If you are not using vacuum you'll be fine so long as the sealer itslef doesn't "move" the mdf. I glue my spoil board down and have 4 vac zones. I find as long as I clean up the chips after cutting so they don't attract and hold moisture I have little trouble with movement of the mdf. If it does swell then surfacing takes care of it.

[scottp55]

Ken,
Desktop experience only, and the jury is still out on personal experience as one doesn't have any big humidity changes and Kirk hasn't used his enough(Both oil finished ALL sides).
I REALLY think sealing ONLY 1 side would make things worse, Just like sealing only 1 side of a workpiece.
That being said I wish I had Drenched both sides of my Desktop spoilboard out of the gate, as the CHEAP big box store MDF I used can move .015"in 18" overnight if humidity changes 30%:)
I'd leave it, But I'm just Desktop.
scott

[David Iannone]

Ken,
I was thinking the same thing when I decided to spray paint my plenum today......LOL

1 spray can of Shelac and 3 spray cans of matte black. This is my first try at a vac hold down table. I first was thinking the plenum had to be sealed everywhere it was cut, then realized I think i only the edges need to be sealed becuase the plenum is glued down to the Base MDO layer. I will use Aluminum Tape all around the sides once done.

Anyhow, I just decided to get silly with it spray it all, and hopefully it will help my plenum not move. My Bot is in the back part of my shop with no Heat or Air Cond. I might be overthinking it? But i'm having fun following the advise on this forum to try to make it all work.

I started cutting my first 2 zones and it took too long in machine time trying to make it "pretty" So by the last 3 zones I just started plowing in .375 deep and seeing how fast I could run the machine with that bit, that deep, in mdf. (The 4g board is still new to me, im used to cutting at 1.5ips max) I got it up to 6ips at 19,000rpm with a PC router. No problem. I want to see it using different plenum cut out sizes make any difference.

Although I'm not gonna seal my bleeder, I have not decided if I am gonna skim bleeder on glue side yet. I am getting ready to start plumbing up the zones right now, so since I will glue my bleeders down in pieces I think I'm gonna grab my shopvac tomorrow and do some crude testing to see if the sheet of MDF I have will bleed, and to just play around with the theory of Vacuum Hold Down. (Its just whatever they have at HD. I dont know what kind)

I dont have my vac box done yet, still working on it. I went fishing over the weekend instead of working on the box.....haha

Dave

[barrowj]

Dave,

Finished cutting my plenum yesterday but haven't decided if I want to seal it or not. The only issue I see with yours is you painted the edge and the areas between the grid. I haven't decided if I will permanetly seal the bleeder board or not, seems to be some do and some don't. I've attached pictures of mine too. I went with a standard cut with 2x2 areas and was happy with 4in/sec cut speed. Mine is a PRT Alpha and I just haven't let her run full speed yet. May never but will depend on what I am cutting.

Joe

[jerry_stanek]

Dave,

Finished cutting my plenum yesterday but haven't decided if I want to seal it or not. The only issue I see with yours is you painted the edge and the areas between the grid. I haven't decided if I will permanetly seal the bleeder board or not, seems to be some do and some don't. I've attached pictures of mine too. I went with a standard cut with 2x2 areas and was happy with 4in/sec cut speed. Mine is a PRT Alpha and I just haven't let her run full speed yet. May never but will depend on what I am cutting.

Joe

Are you thinking of gluing your spoil board down. If you do I find that if you cut your spoil board into 2x2 squares and glue each one separately it would be easier I cut some .25x.1 inch strips of Sintra to put between each piece to keep the vacuum from bleeding from one area to another.

[Ken Sully]

Dave,
Keep me posted on your vacuum system. I am on the edge of adding vac.
Are you going to use light house or something different.

[barrowj]

Ken,

We both bought the Lighthouse 7218 (i believe) motors, made a Black Box (although I made mine for 2 only). We both also made different plemuns (mine is for 8 2x2 squares and dave is for 7 different size areas) and I have patterns from others too. I will be happy to continue my posting on my progress as I'm sure Dave will to. I will start my plumbing this weekend as time permits (i'm oncall for my day job this weekend), that is the last thing I need to do.

Joe

[David Iannone]

Ken,

We both bought the Lighthouse 7218 (i believe) motors, made a Black Box (although I made mine for 2 only). We both also made different plemuns (mine is for 8 2x2 squares and dave is for 7 different size areas) and I have patterns from others too. I will be happy to continue my posting on my progress as I'm sure Dave will to. I will start my plumbing this weekend as time permits (i'm oncall for my day job this weekend), that is the last thing I need to do.

Joe

Yep, that's it. I am building my box with two lighthouse motors, but am just sealing off the other two ports for now in the box in case I add two more motors later on.

I will add, I am rereading up on Brady Watsons "ova da hump" article. This is just the beginning of my education of how vacuum hold down is going to change the type of things I want to cut in the next 20 years, but in the end ya got to hold it down.

I turn 40 in May......

Dave

[David Iannone]

I just finished playing with the shopvac. All I did was throw a piece of 1/2" MDF over the plenum. Neither side has been skimmed. I just clamped it down to the plenum. No sealed edges, no glue on the PVC and a large sized shopvac shoved in the open end. HEHE, it works. Obviously it does not have a ton of holding power but when I threw a piece of 18"x24" .040 aluminum on there I couldn't push it with a good amount of sideways force, then I put a piece of 1/2" MDF on the zone next and it held it very well for such small amount of vacuum. The zone I used was only about 2'x3' but it is still bad ass to see it coming together. Now I need to finish the real vacuum source.

Dave

[barrowj]

Dave,

Now I am really excited, can't wait to get mine plumbed.

Joe

[Tim Lucas]

I just finished playing with the shopvac. All I did was throw a piece of 1/2" MDF over the plenum. Neither side has been skimmed. I just clamped it down to the plenum. No sealed edges, no glue on the PVC and a large sized shopvac shoved in the open end. HEHE, it works. Obviously it does not have a ton of holding power but when I threw a piece of 18"x24" .040 aluminum on there I couldn't push it with a good amount of sideways force, then I put a piece of 1/2" MDF on the zone next and it held it very well for such small amount of vacuum. The zone I used was only about 2'x3' but it is still bad ass to see it coming together. Now I need to finish the real vacuum source.

Dave

Dave, just wait till you get 8lbs of holding power:D

[David Iannone]

Tim,
I can only imagine. I can see once all is complete this may just be one of the most valuable upgrades I have done.....I can't wait. :)

Dave

[barrowj]

Dave,

I totally agree, this will be a great add on.

I have both a 3/4" mdf board and a 1/2" mdf board that I can use as a bleeder board, will it be acceptable to use the 1/2 after I surface it?

Is it necessary to seal the side with the grid? I have sealed the side that is on the plywood board.

When attaching the 2" pvc to the table, I read where some have just used silicone to attach the pipe to the table. I sized the holes to be exact and very tight to hold the pipe, if not then I can run the file again to enlarge the holes to allow for the flanges that I purchased.

This is all I will need to run the pipe this weekend and get started playing with a new vacuum table.....

Thanks for any help :)

Joe

[David Iannone]

Joe,
I just cut some 1/2" thick PVC squares with holes in the center, then sprayed rusoleum flex seal on the fitting, when dried I siliconed around it. The pvc is a good fit also in the table holes. I will screw the fitting into the bottom of table and silicone it also.

I think 1/2" mdf is ok for bleeder. I might use 1/2" also.

I think it's only nessisary to seal the edges not the cut plenum area, but I sealed my cut area anyhow. Once I silicone down the bleeder I will run aluminum tape all around the outside of each zone to get a good seal.

As a side note. Joe Crumley recommened I try using flex seal to spray texture on pvc letters. It works great so I figured once I have all the pvc pipe glued I might just flex seal all the pipe. They make it in white or black.

Dave

[Tim Lucas]

Good morning Dave & Joe,
When I assembled mine I did seal the grid side with a lacquer sealer then to add the spoil board I used silicone but I cut sections to match my grid sections and silicone between them to keep from bleeding vacuum section to section. Also could not figure out how to hold up the full sheet to add the silicone by myself.

Adding the pipe I thought about the force pulling down and opening / closing the valves - figured I had to add something to keep from pulling them through so I glued a piece of coupling to the pipe on the grid side, feels solid now.

I started with a 3/4" MDF spoil board from box store skimmed both sides - my next sheet will be ULMDF 1/2" - just did the 3/4" first as I wont be cutting through all of it before adding the 1/2" (I hope):eek:

Tim

[barrowj]

Tim, the info about the pipe just gave me a bright idea, I will take a 2" coupling and cut it into 3/8" sections to glue to the pipe on the cut side. I can then sand and round the edges of the pipe and the piece of coupling to smooth it up. Ok, that solved, now I feel better about moving forward, gotta visit HD unless I have a coupling in my storage area.

I have a piece of 1/2" that has been up against the wall for years so I will use that to start with. Can't find ulmdf locally and when I go visit my son in ATL sometime this year, I will go get a few pieces to of it. Now I just need to find where it is carried there, saw some posts a while back about that so will just search.

I like the idea of cutting the bleeder to prevent bleeding between sections, didn't really think of that. I had the same thought Tim about how to apply the silicone and place the board by myself, was going to use some 2x4 boards on the side along with some 1" hickory to hold it off the table and then start removing them from one end and work my way to the other but would be very cumbersome even going that route. I used to use a solution of 50% and 50% water to seal the cut ends of mdf prior to painting so that may work along with tape to really make it solid. I will also use silicone to hold down the pieces and turn on the vacuum to pull it tight. Sealing the plenum on cut side will also allow me to remove the silicone easier when it comes time to remove the top and replace (i hope).

[Tim Lucas]

Tim, the info about the pipe just gave me a bright idea, I will take a 2" coupling and cut it into 3/8" sections to glue to the pipe on the cut side. I can then sand and round the edges of the pipe and the piece of coupling to smooth it up. Ok, that solved, now I feel better about moving forward, gotta visit HD unless I have a coupling in my storage area.

I have a piece of 1/2" that has been up against the wall for years so I will use that to start with. Can't find ulmdf locally and when I go visit my son in ATL sometime this year, I will go get a few pieces to of it. Now I just need to find where it is carried there, saw some posts a while back about that so will just search.

I like the idea of cutting the bleeder to prevent bleeding between sections, didn't really think of that. I had the same thought Tim about how to apply the silicone and place the board by myself, was going to use some 2x4 boards on the side along with some 1" hickory to hold it off the table and then start removing them from one end and work my way to the other but would be very cumbersome even going that route. I used to use a solution of 50% and 50% water to seal the cut ends of mdf prior to painting so that may work along with tape to really make it solid. I will also use silicone to hold down the pieces and turn on the vacuum to pull it tight. Sealing the plenum on cut side will also allow me to remove the silicone easier when it comes time to remove the top and replace (i hope).

Joe, try A & M Supply http://marketing.a-msupply.com/web_sales/locations.html
that's who I use and they show a location in Atl and TN!
You don't need to remove the old spoil board to replace it - as you flatten your table after cutting through your products it will get thinner then just silicone the new spoil board around the edges and partitions down on the old leftovers
Tim

[coryatjohn]

Just a side note... I used flex PVC pipe to plumb my vacuum system. Saved a lot of trouble trying to get exact lengths of pipe. Everything fit easily and I used simple pipe hangers under the table to keep everything snug. The stuff is a bit more expensive than rigid pipe but for the ease of use, well worth it. No worries about collapsing under vacuum either. It's strong as rigid pipe. Glues just like it too.

[David Iannone]

John,
Where did you find that 8" PVC to make your filter out of? The biggest I can locate is 4" I still haven't made my in line filter yet.

Thanks,
Dave

[coryatjohn]

I got it from the same place as I got the flexible PVC.

http://flexpvc.com/

The 8" pipe can be purchased cut to length.

The item code is: Sch40-080

I used a shop vac air filter and made the rest of the parts with my machine.

[David Iannone]

Thanks John, that is the last piece of my puzzle.

[David Iannone]

PVC pipe came in today. Gonna make the end caps tomorrow. The blue box will fit just to the left of the pipes. And the mill finish AL box will tuck under to the right. Just a monitor and keyboard arm will remain.....

Dave

[Ken Sully]

Dave,
Looks like a great setup!
I am going to the Mcgrew camp and would love to stop by and see your setup
Would that be ok?

[David Iannone]

Ken,
Sure, stop by any time.
Dave

[Ken Sully]

Dave,
I will give you a heads up as we get close
Thanks

[kenkelsey]

You guys are ahead of me in building your vacuum tables, but hope you will indulge my questions/learning. I have built the black box similar to what I see in one of the photos, but I'm not sure that I have it right. I'm using two LH vacs and I have two, 2-inch PVC pipes going into the plenum area of the black box. Should it only be one?

In my opinion it does not seem to pull a lot of vacuum, but I don't know how to measure.

Will regular 3/4 inch HD MDF work for the bleeder board; can't find Ultra Light in the Pittsburgh Area? I know that I need to skim both sides.

I have not cut the table plenum yet, nor have I stated the piping. Probably start both this weekend. I was going to use 3/4 inch MDF for the plenum (grid area) with six zones. Any tips on how to attach the pipe where it comes through the plywood (bottom layer on the Shopbot) and the MDF Plenum?

Any photos you can share of the black box vac source and/or the under table piping would be appreciated.

[coryatjohn]

PVC pipe came in today. Gonna make the end caps tomorrow. The blue box will fit just to the left of the pipes. And the mill finish AL box will tuck under to the right. Just a monitor and keyboard arm will remain.....

Dave

That filter looks oddly familiar! I used threaded rods to hold the top and bottom of the filter together in the event I had to open it up. I painted everything blue as well. It matches nicely. I used the Krylon Plastic paint (HD sells it) on the PVC. Their blue is a very close match to the ShopBot blue.

http://usnaviguide.com/shopbot/aircleaner.jpg

[David Iannone]

Hi Ken,
Can you post a pic or two of your box? If you built the box Gary Campbell designed there should be one pipe that comes out of the vac box that will go to your PVC and your valves/zones.

However, if you have designed your own box with two motors and simply have PVC pipe from each motor to your zone and only using two zones, I don't know. I'm not sure I understand exactly what your saying.

That being said I am totally new to vaccum hold down. I am following what others have done on this forum. I am almost done mine, but had to put it on hold because work picked back up and it's been a little crazy lately. But my plenum and table top is done, box done, pvc. Only thing sadly enough is about 2-3 hrs work to make inline filter and then I'm good to go.

I used whatever 3/4 MDF they sell at Home Depot. Skimmed both sides. I have hooked my shop vac to my PVC manifold and closed all zones except for one of the smaller ones and it pulls just under 3 on the vac gauge, and the holding pressure from side force I can not push a flat smooth substrate covering the whole zone sideways.

I got just a plain old Vac gauge off of eBay and put it inline the pvc.

Maybe do a little testing? Machine out a small plenum, seal it, drill hole in it to fit shop vac hose, skim two sides of piece of the MDF you have, glue it down and do a little test. You will be hooked for sure. Some say you don't have to skim the bleeder board, some say you do. I think it depends on the type of MDF used. Whatever you do keep at it, it will be worth it in the end.

And if you haven't already, search this forum every which way for subjects of vaccum hold down, black box, etc.

Dave

[kenkelsey]

Hi Dave. Thanks for the reply. I progressed my project quite a lot today based on extensive searching and exchanging messages on the Forum. Today I finished the vac box with one 3 inch vac port. Also finished the 3 inch manifold with six 2 inch PVC valves. I will post the pics tomorrow. Did not have a camera with me today.

Attached is the "as built design for the vac box. I did replace the 2, two inch vac ports with one 3 inch. I do believe this box is a variation of the Gary Campbell design, with changes by others and a few changes by myself. If anyone wants the Sketchup design, I am happy to share. Sketchup files can be imported as vectors into Vcarve Pro or Aspire.

Ken

[David Iannone]

Looks good Ken,

I'm a Sign guy too so my woodworking skills are basic at best.

After I posted my reply to you I was reading other posts and found where some others had helped you out. Glad you got it going in a better direction. That's the great thing about this forum. Tons of knowledge and nice people. I think you will find the two motors working together is gonna be the ticket. Although I don't have my vac box connected to my PVC manifold yet, when I put my hand in front of the hole in the vac box and turn on motor one, then turn on motor two it feels like the vaccum power more than doubles with number two going. Gonna try to wrap mine up tomorrow. Decided to be lazy today cause it's raining....lol

Dave

[kenkelsey]

Dave: I am up and running with my 2 motor vac. Have not cut anything yet, but held down several different materials to see how the system works. Actually pretty good. My six zones are 2 foot by 2 1/2. At one point in m experimentation, I placed a 1 foot by 1 1/2 foot piece of HDU in the middle of one of the zones and it held tight enough to route. I did not cover the rest of the zone (about 50% of the area was not covered), but it still held tight enough to route. I could move it if i pushed really hard, but I believe its going to be fine. I'm sold.

[David Iannone]

OK Gentlemen,
I have my first official Vac results to report. I finished sealing my Vac box and making filter Friday. Came in this morning and hooked the box to the manifold and heal to the yeah!

First pic shows the Vac Box with 2 motors both on pulling 10hg with all Zones closed and bleeder value closed. Great news, this means I got the Box correct.

Pic two shows all zones open with a 4x8 sheet of 3mil Sintra on the table covering all zones. I still have not sealed the edges of all 7 zones of spoilboard. But still couldn't push sheet sideways. Since there is WAY too much leakage I left the bleeder valve closed. I had two large paint stencils to cut so I said.....Yep, let see if it will hold.

Cut some more paint stencils for a local sign company out of 4x8 sheet at 3ips ms. The pic you see is exactly as it finished with that ms. The stencil didn't move at all even know some of the cut out letters didn't hold, I have leaks all over the place in my spoilboard edges. Once I seal my spoilboard edges its gonna be a monster.

Last two pics are the temp of motors which makes sense since there was a lot of air going to them to cool them. And the Decibel meter off my Iphone App. The noise is acceptable to me. That is with PC router running at 10,000rpm with 1/8" bit. DC running and Vac box running with two motors.

While it was cutting (about 10 min) I had my noise canceling Dr. Dre Beats bluetooth headphones on playing one of my old school favorites "U Can't Touch This" by MC Hammer. I even danced a little jig too.......:D

I will seal my spoilboard edges today. Super excited to start learning how to use vac hold down now to make my jobs easier and faster.

Thank you to this forum for the info, inspiration and help through this project. I would have never been able to do this on my own.

Dave