Author Topic: Spoiler board options  (Read 18000 times)

Offline Displayvets

Spoiler board options
« on: February 17, 2023, 01:09:30 PM »
I'm setting up my SCV44 and wondering how others setup and attached their spoiler board.  First question is on the gasket tubing for the vac table, do I silicone seal in the channel before installing?  Once I spoke with Nick last year about the board setup.  That I needed to surface both sides and than silicone sealant about the edge and seal the edge of the board with lacquer.  Is there anything else I need to hold done the MDF board?  Sorry, last question.  Do I drill small holes in rows to improve the SUCKING power. 

Brian

Offline drew

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Re: Spoiler board options
« Reply #1 on: February 17, 2023, 03:10:02 PM »
I'm setting up my SCV44 and wondering how others setup and attached their spoiler board.  First question is on the gasket tubing for the vac table, do I silicone seal in the channel before installing?  Once I spoke with Nick last year about the board setup.  That I needed to surface both sides and than silicone sealant about the edge and seal the edge of the board with lacquer.  Is there anything else I need to hold done the MDF board?  Sorry, last question.  Do I drill small holes in rows to improve the SUCKING power. 

Brian

there is a lot here to unpack, brother. 

You can use the gasket material to further isolate your zones- and it works like a charm.  a dab of silicone in the corners is all that's needed. 

the MDF or LDF (which is even better) is factory sealed on the faces- you have to cut through that when you surface- so the air can be pulled through it... that's both sides... plus, as flat as we think MDF is, it isn't.. you'll have to go as deep as required to make sure it's flat in relation to your gantry.  as an example, I shave a 32nd off for the first pass and "see what that leaves"... usually I end up shaving at least another pass to a 16th".  for the first side only shave off enough to get through the factory seal... it'll be obvious to you once you get through... no more- then flip it, and this time do as many passes and as shallow of a pass as you can to make sure it's flat- really flat- and there you have it. 

the sides of the MDF/LDF are not sealed.. you MUST seal them or all your vacuum will escape through the sides... contact cement works... silicone works... a few coats of latex paint works... i've even used hvac tape and that works... don't be shy with it- make sure it's sealed.

for affixing the MDF to the bed, the most secure way is with screws into the bakelite material- which is some kind of tough and will need to be pre-drilled with a smaller diameter bit... and then countersink a screw that has a dab of silicone on its threads.  that is the easiest way. another way is to use the rails and clamps, but i find they can get in the way sometimes...

here is the tricky business:

you're not actually 'sucking' material down.. you're lowering the air pressure below the bed as compared to the air above it.  yeah, i know, same thing- but this trick relies on volume of air not pressure- the more volume of air you can remove from underneath that MDF the bigger a hole the material you're cutting tries to fall into and the greater holding power you get- you're actually making the material 'heavier' as it falls into that void... that's what this vacuum hold down thing is all about- it's about volume removed, not a silly high negative pressure that can only be achieved when the volume being removed is slight... .. the zones are nice to have, but you may find leaving all zones open allows for greater removal of air (especially if the gasket material between zones wasn't used)... it's counter intuitive sometimes... better yet, and as a for instance- leaving the zone you're cutting in and an adjacent zone(s) open often times provides more hold down than just the one zone isolated.  i had a helluva time wrapping my brain around that for the longest time..

Offline Displayvets

Re: Spoiler board options
« Reply #2 on: February 17, 2023, 03:39:31 PM »
Thank you Drew.  Next question.  I see the piece of hose that was provided.  Can someone post the proper setup of the hoses?  I can handle the wiring part.  Is there anyway to get the size and specs for the hose?  I have separate room built for the vac and the pump.  I'm going to need a long piece.   EDIT:  Just popped into my head.  I guess I could use black cast iron pipe than use the plastic provided.  I'll have to think about that.
« Last Edit: February 17, 2023, 03:45:18 PM by Displayvets »

Offline drew

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Re: Spoiler board options
« Reply #3 on: February 17, 2023, 04:05:00 PM »
rigid is absolutely the best way to go, especially over a longer run... it's amazing the flow lost in flexible tubing... the hose provided, the clear wire bound stuff, is semi-rigid... i don't think a lot is lost through it.

some run the pumps in parallel while others run them in series.. i've done both.. in series they use less power and 'can' be ran off of one 30a breaker, but the hold is likely 2/3 of what it is in parallel.  in parallel they need separate breakers at least 25a, but they run cooler and the hold down is better. 

mine come off the table into the particle separator, and then splits in a Y using schedule 80 pvc (the heat hasn't been generated yet)... then into the intakes.. the exhaust flares immediately from the 3" diameter to 6" and a 6" elbow from one and a 6" Y on the other, and then 6" pipe through the wall.  I vent it outside... the exhaust is where all the noise comes from.  venting into the shop, the noise is more than the machine cutting hickory- venting outside makes the whole prospect about as loud as someone mowing across the street, if that makes sense.

Offline Displayvets

Re: Spoiler board options
« Reply #4 on: February 18, 2023, 07:32:21 AM »
Great video on the setup.  I was really confused until I saw him unscrew the little pipe on the pump.   


Offline Displayvets

Re: Spoiler board options
« Reply #5 on: February 19, 2023, 03:39:02 PM »
No video but I got it all setup.  Pictures/video coming soon.  Thanks for the help Drew.

Offline Aardvark

Re: Spoiler board options
« Reply #6 on: March 07, 2023, 07:18:02 PM »
novice question:
do I really need to attach my spoilboard to the vacuum table via screws? Watched some videos and some machines (shop sabre) don't seem to need it, so I am a bit confused as to how important that is if the vacuum pump is working properly. I have a SCV44.
Thanks!

Offline Aardvark

Re: Spoiler board options
« Reply #7 on: March 09, 2023, 10:53:14 AM »
It seems like one of those things you'll find out by trying. But the cost of the spoilboard not holding down without additional screws and just by vacuum would be...a broken bit and workpiece? A broken gantry? Kinda nerve-racking for a newbie.



I'm thinking to epoxy some 10-32 insert nuts into the vacuum table and then use recessed nylon flat-head screws to attach the spoilboard. So in case the bit hits the screw it's not screwed.

Offline Displayvets

Re: Spoiler board options
« Reply #8 on: March 11, 2023, 03:20:19 PM »
My CNC is up and running.  I have done the MDF surface thing and sealed the edges of the board.  Yes, the vac system pulls the MDF down but nothing on top of that will "SUCK" down.   Any advice?

Offline drew

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Re: Spoiler board options
« Reply #9 on: March 11, 2023, 04:30:45 PM »
Did you surface both sides? If not, it's not pulling through the mdf- but I bet it's dang sure holding it down!

After I mount a new spoilboard I'll walk around table with my hand on the edges... you'd be amazed what one little leak can do... ive gotten into habit of just running a bead of silicone around it.  Doesn't take much- amd you'll see a leak as it gets pulled under. 

Offline Displayvets

Re: Spoiler board options
« Reply #10 on: March 12, 2023, 05:26:08 AM »
Yes, I surfaced both side.  Still won't hold down I 10" x 10" piece of cherry.  doing more testing today to see if I can solve my issues.  Yes, the boards hold good to the bakelite top.