Table adhesive and Z zero

[zfisher]

Finally got the 1st sheet of MDF mounted and ready to glue on the top sheet. What is every ones thoughts on possibly using contact cement. Or should I stick with some classic Elmers wood glue?

Also been having trouble with the z zero. Upon zeroing, on the second touch it says z zero fail and ends program. Any ideas on either of these 2 topics.

I also wanna thank everyone who contributed to other posts, it has most certainly been a huge help! The forum alone is worth its weight in gold!

Thanks

Fish

[dana_swift]

I just use elmers/titebond to hold my various layers together. If its a bleeder board I dont coat the whole sheet.. as that would block the air flow.

The ZZero is a mystery to me, if you are using the standard code it should work like a champ, so something unexpected is happening. Are you letting it touch the zzero plate on both attempts? Is the driver faulting, or just the zzero routine giving an error?

D

[ken_rychlik]

I had the same zero issue with version 3.6.20

I went back and grabbed an older copy of the zzero file and all went back to normal.

It would not do it every time for me, but it did it to much for me to trust it.

[beacon14]

I'd stay away from contact cement if at all possible. If you are making a vacuum table you can use the vacuum to hold the top sheet down while the glue dries. If not you might still be able to rig up a shop-vac as a temporary vacuum source - much better than clamps or weights on a large surface.

[cedars]

I recently put a new 1" thick pc of mdf ultra lite on for a spoil board. I put silicone between the plemnum and the mdf. I turned on my 7.5 hp vacuum and piled about 8 sheets of plywood on it overnight. By the way I sanded the underside of the mdf and sealed all the edges. In the morning, I surfaced the table. I have the best hold down I have ever had. Now a new problem. I fear that the silicon has created a space between the plemnum and the mdf. When I turn on the vacuum, it sucks down the middle of each zone. When I turn off the vacuum it returns.

My dilemma is this. Take it all off and start over, or always use the vacuum and re surface the table while the vacuum is on. This option would force me to use the vacuum even when I don't need it.

Any input would be greatly appreciated.

[ken_rychlik]

Take if off and redo it.

Yellow glue works great. Use spots on the pads across the whole plenum.

Having it pull up in the middle will give you much grief.

[beacon14]

The problem with leaving it as is is that the centers will not pull down as much during surfacing as they will with a workpiece covering them. You might have a hard time getting consistent results the way it is now.

[cedars]

Thanks guys, I was afraid you were going to say that. When I bought the machine used, it was done using silicon so I used silicon. Oh well, back to the beginning again!

[knight_toolworks]

I have been using instant grab construction adhesive. I don't have to leave it clamped as long and it does not run.

[loriny]

Silicone has been working for me but I do put under all areas of the spoil board, not just the perimeter.
Lorin

[zfisher]

Glued and clamped the mdf today with wood glue. Clamped the heck out of the outer perimeter then I drilled and countersunk holes in the middle and ran screws to pull the top sheet down. I'll remove them tomorrow and fill them in. My plan is to surface the table tomorrow and cut channels for my t tracks. I do have a fein 3 vac that will someday act as my vac hold down. My main concern is getting this thing up and running this school year. My students are on my sh*t to get it going. I am going to use the 50/50 wood glue water mix with multiple thin coats to seal the MDF after surfacing. Is this going to mess with the thickness of the surface that much that I should opt to so something else? I figured that the MDF would soak it up a great deal and I am not too worried.......Or should I be?

[zfisher]

important info i forgot...ran the screws from the bottom up...