Trupan and Vacuum Hold Down

[jbuell]

In the process of putting together a vac hold down system. I understand you need the plywood support board, then the MDF routed with the plenum grid but how is the Trupan used?
Does it make the entire table one large hold down surface?

[thewoodcrafter]

The whole table, yes.

[Gary Campbell]

J...
Once you surface(skin) a few thousanths off both sides of the Trupan sheet, the vacuum that is distributed by the plenum passes thru the Trupan(spoilboard) to hold your parts down. There are many posts with many versions of both plenum and spoilboard options on this forum that should give you all the info you need.
Gary

[cnc_works]

To hijack this thread just a little...

If you go to vacuum hold down with a spoil board, does that mean you have to have the vacuum on whenever cutting so the table will be flat? Or does the spoil board lay flat enough that you could cut something held down with screws or double sticky and not worry about Z inconsistency?

Donn

[Gary Campbell]

Donn...
There are 2 different methods to consider. In the first, if you have a glued down bleeder/spoilboard that is surfaced, then your table should be dead flat with both the vacuum on or off. If your bleeder/spoilboard is not glued, or you use a separate vacuum bleeder and spoilboard then you will have to test to see if the surface is flat under all conditions. Brady gives more insight here: http://www.talkshopbot.com/forum/messages/312/28619.html?1204976503
Gary

[ccw]

I wonder if anyone could tell me more about the Trupan as a sacrifice board.

The reason for my question is that over the past few days I have been fighting with alignment of the Z I am a level as I can be at the spindle but for some reason when surfacing the Trupan with,

2.750 magnate cuter and a 40% overlay
I still get (Lapping) for lack of a better word.

I also have been reading that a reload in firm ware may be in order.
any thoughts?

Mark

[Gary Campbell]

Mark..
Can you explain more on what you mean by "lapping"?
Gary

[thewoodcrafter]

Gary, I think that is the stepping on the spoilboard from the Z being off trammel.

[ccw]

Off Trammel?
Could you please elaborate?
And yes it is like the bit it-self is out of plum
I have purchased an dial indicator and will set the rail with that I don't know what else to do.

[thewoodcrafter]

Trammel is when the Z is perpendicular to the X and Y.
You are off. Where are the steps? Along Y or X or both?

[Gary Campbell]

Mark...
CHeck out this post:http://www.talkshopbot.com/forum/messages/26/28518.html?1204933196
Gary

[ccw]

Roger im out on the x the Y is just fine

[ccw]

Gary ,
thankx yea I caught that the other day.
I will ask a question .....Is the rail it-self on the Z adjustable with the cam v rollers? or is that rail locked into position by the rack and pinion

[thewoodcrafter]

Then your Z is off left to right looking at the end of the table. I use a bar about 2ft long with a 1/2" bolt at one end and a 1/4 x 20 machine screw on the other end. Chuck the 1/2" bolt in your router and adjust the Z height so the small bolt is close to the table top. Swing the arm to the left and the right. See which side has a larger gap under the bolt. Adjust the Z mounting till you get the same height on both sides. You can get it perfect if you spend the time. Don't forget to check it all the way around. You may knock it out in the other direction.

[ccw]

Thank you Roger i will try it today.
Great idea.
Mark

[maginter]

Hi Guys -

Does anyone know of a Trupan supplier in the northern Indiana area? So far the closest I have found is the Indiana/Kentucky line or in Missouri.

TIA,

Mark

[paco]

What should a guy that cannot get Trupan do about "bleedering" his spoilboard. I have been calling all around this side of the border to find it or something similar without any success what so ever so far. What would you guys, Trupan bleeder board setup, do if there was no more Trupan available?

I'm on the third case where I'm installing/setup/training a new Botter here in Canada. All those three wish to use big pump but when they realize they reach 10 Hg just with the standard MDF (skinned) and there's only about 5 Hg left to hold down their parts they kinda give up. Holding down parts with a grid only has it's problem; where does one accumulate the chips and dust that are aspirated by the vacuum system (big pump)? I know one could bleed through a inch of MDF (Big iron machine - Komo, Thermwood and such) but it require a hell of a pump!

I personally run with the open source vacuum rig but I would too love to have a good bleeder board system instead of only working on the vacuum grid. I already tried to skin MDF down to 1/4" and particulate board also but it just don't work; I only hold down the bleeder board... which does allow the vacuum to pass through.

[erik_f]

If you are using MDF already...why not just create a grid on the bleeder board...it will take a little more time...but this way you can just through it way instead of having to unbolt the main grid. I would guess with the secondary grid between the main grid and the work piece it would get pulled flat.

[paco]

My vacuum system (up to 8Hg) won't pull "any" vacuum through even 1/4" MDF (standard type) so I have to have the grid on top.

Most people with whom I've talk with agree that ultra light stuff is not much more permeable to vacuum.

The main problems I(we) have with the grid only vacuum bed is that it allow chips and dust to be sucked into the vacuum hold down system (big pump don't have chip/dust canister - I have to empty the hold down vacuum "canister" more often than I like) and it loose vacuum rather quickly once I'm cutting through.

[erik_f]

what kind of pump are you using?

[paco]

http://www.talkshopbot.com/forum/show.cgi?tpc=28&post=62618#POST62618

[erik_f]

it would seem you shouldn't be losing 10" with pulling mdf unless maybe you're edges aren't sealed or there is a leak somewhere else?

[paco]

Erik,

without anything on the vacuum grid, I have zero vacuum. With, say, a sheet of acrylic, I reach 7-8 inches Hg. With most attempt with "bleeder board" material, I reach full vacuum (7-8 inches Hg). No vacuum force is left for what I can lay on the "bleeder board". Imagine trying to use a non porous material as a bleeder board...

All material I have tried to create a bleeder board wouldn't allow vacuum through. With very larger vacuum pump at other user's shop, we would reach 10-12"Hg trying to pull vacuum through the standard MDF (3/4" skinned) without anything on the bleeder board. This leave only about 5-7"Hg left to hold down parts with vacuum. In other words, even with good pump, we would end up with minimal vacuum hold down.

What would you do if you wouldn't have Trupan available?

[Gary Campbell]

Paco...
This is WAAAAYYYY of the wall, but if I was unable to get a porous fiber board, I would probably glue up a spoilboard out of 1" thick end grain red oak to try. You can usually blow right thru a short piece. like I said, way off the wall.
Gary

[thewoodcrafter]

I have not found a local supplier for Trupan so I buy ultra light MDF.
Seems to work fine.
Zero vacuum with just the spoil board. You can feel it sucking through the board.

[maginter]

Thanks Roger...

However I am not familar with the Ultra Light MDF. Who makes it an where have you been buying it?

[thewoodcrafter]

I just get it from my local hardwood supplier.
I don't know who makes it.
The stuff is very light and not very strong. Air seems to pull through it just fine.
Trupan is a brand. Try asking for ultra light MDF from your suppliers.
Trupan is suppose to be different but I have never seen any to know the difference.

[cabnet636]

i got a sheet of ldf from the wurth hardwood group in charlotte nc today

[joe]

I've made a handsome living, over the years, using my CNC. I spent a week perfecting the ultimate vac hold down. PVC, Valves, gates, plenum, and all the hopes and expecations. That was eight years ago. It went in the trash, six months after it was made.

The way I see it, there's way too much times spent talking, wondering, fabricating, and screwing around on vacuums.

While there's good reason when holding some flimsey stock to use a vacuum, the subject is way over played.

My CNC runs every day for hour after hour doing all sorts of projects. Never needed any noisey, fancy vac. This is production plant talk. None of my friends who make their living with CNC's find it necessary. For sure it's a convenience from time to time. Now, a dependable tool changer would be nice. But not necessary or worth the money for a two man operation

Here are a couple of my custom designed hold-downs. I have a couple of dozen of these in several sizes. The larger ones are about 12" long and have a height of 2". I made them from some scrap. A solid oak table thrown away. I'd be glad to send a DXF file to anyone who is interested.


8417

There are dozens perfectly good ways of routing w/o a vacuum. Seasoned woodworkers,if they ever ventured here, would laugh.

Lets go make something beautiful!

Joe
www.normansignco.com (http://www.normansignco.com)

[gabepari]

Joe, you're sounding more and more like a crotchety old man each day
"Damn whipper snappers and their new fangled whattaya call 'ems..."

I like my vacuum. 15hp, pulls 14" (4" with unskinned 1" trupan) and will suck the curl out of all but nastiest piece of chinese birch.

I think what people don't realize is that vacuum is just ONE way of holding your work to the table. I too have a hefty collection of cams, clamps, wedges, blocks, all sorts of ways to hold the work to, and sometimes off of the table. Vacuum is a nice tool to have, but I will agree it is not the only tool you need.

Gabe

[thewoodcrafter]

Gabe,
Where did you get your Trupan?

[gabepari]

Weber Plywood in Tustin.

Couple of months ago, 25mm 5x12 Trupan UL 1" was about $105 a sheet.

I like the 1" better than 3/4"

Gabe

[bleeth]

Joe; I certainly understand why someone who does the type of work you do (and it is beautiful) does not need a vacuum. After all, when you are carving one of your creations the cutting time is fairly long for each piece. If that was what I was doing I wouldn't want some noisy power sucking vacuum running all the time either.
But I'm cutting out cabinet parts from full sheets of plywood or melamine. We nest to use maximum amount of the product and at times there is fractions of material left between parts. No way can we screw them or clamp them down and get the same efficiency. When done it takes seconds to pick up the cut parts and remaining scrap, a minute or so to blow off the table, 30 seconds to load the next sheet, and away we go.
With all of our work being done in the commercial market which is highly competitive and needs to be priced extremely close to the bone and being in an area with some pretty high fixed overhead costs (eg: Insurance based on Hurricanes and more lawyers per capita than anyplace besides DC) the amount of extra time and material it would take to use mechanical clamping would blow my production costs right out of the ball park. With cabinet companies closing their doors like crazy right now and material suppliers sending letters announcing price raises left and right any method that shaves a bit off production costs is golden. But don't think I'm complaining-We are blessed with a good back-log, repeat customers, and helpful friends. It would be nice to have some money left over after the bills are paid but you can't have everything. Besides, I'd probably spend it on a new Alpha for me or an Alfa for the other half!!

FYI: My vacuum is a 7.5 regen with a 1" PVC 8 zone system. I need to change out the pipe for two inch for better results but I have a certain obligation to finish taking care of before I spend more bucks on the bot and it does work darn well for our cabinet parts.

Your friend and compatriot in old crotchetyness;

Dave

[joe]

I agree that production work is what a vac is made for.

Lord deliver me from repeat work. Sucess in that realm is speed and attention to profit margins.

There's plenty of high production equipment on the market and cheap labor to run it.
Our next door neighbors have a KOMO. It runs 24 hours a day. That kind of work is WORK. Although their products are beautiful they often come by for coffee and complain about the rat race.

At the end of each day, just before the lights are turned off, a quick review of accomplishments should be a thrill. For me, that doesn't happen with grind out work.

Joe

[beacon14]

I've already stated recently how I feel about my vacuum table so I'll refrain from stoking this fire - all I can say is different strokes for different folks.

[matic_media]

I would like to build my own vacuum hold down system. What power of pump would I require?

Thanks, Richard.

[benchmench]

I've run the 2 Fein shopvacs and 1/2" Ultralight MDF (surfaced to 3/8") for the spoilboard for the last year and couldn't be more pleased. This thread http://www.talkshopbot.com/forum/messages/7/28298.html?1234681860 is a good model for the vacuum plenum and plumbing. Holding power is very good and even better when you learn how to direct airflow with gasketing.

[benchmench]

I've run the 2 Fein shopvacs and 1/2" Ultralight MDF (surfaced to 3/8") for the spoilboard for the last year and couldn't be more pleased. This thread http://www.talkshopbot.com/forum/messages/7/28298.html?1234681860 is a good model for the vacuum plenum and plumbing. Holding power is very good and even better when you direct airflow with gasketing. Having small zones available (2'x 2') and being able to direct both vacs to them makes holding small parts much easier.

[jerry_stanek]

I use the 2 Fein vacs and 3/4 inch LDF just .010 off each side and glued down