Alternative to MDF for table tops

[PaulRowntree]

I am planning a larger steel framed machine to improve on my wood framed system. I am now working on the table top material. MDF is easy (I top my table with it now), but if I want to spray coolant on Al or acrylic, we know that bad things would happen.

I don't think buying an Al table top is an option right now : $$$.

Home Depot sells wood/plastic composite 'planks' for decks called Trex that can be cut, machined, etc pretty easily, and it is waterproof; the piece I saw was ~1" thick. There are probably several different manufactures of similar products, such as recycled PVC. Has anybody tried using this sort of material for a table bed? I would put my T-rails between planks, fasten the Trex to the steel subframe using nylon bolts, then surface it like an MDF top.

[JohnZ]

I tried something similar to this, but had problems with the plastic moving over time. My table was more of a hdpe material and not the trex trade name planks. The trex planks do have a mixed content and fibers that may work better than what I used, but my problem came when I surfaced the table releasing stress in the plastic. Your results may be better with trex than I had with hdpe, and I had considered replacing my table with trex planks until I found an optical breadboard the perfect size to replace my table.

[willstony]

Try solid grade laminate. Very solid and water and bullet proof. Used to face buildings across Europe and for internal panelling too.

Tony

[RossMosh]

People use PVC all the time for vacuum tables. If you have plans of using coolant, use PVC as your base material and then MDF as your spoil board.

[PaulRowntree]

Thanks everybody for the tips. Sounds like it is doable.
@RoshMosh : I hadn't thought of the vac pods but you are right, and so I will look into PVC and solid laminate, although the laminate seems to be built of a paper core. PVC is probably less expensive than Trex to boot

[willstony]

You are right, solid grade laminate is paper laminated up but this makes it incredibly tough. It comes in 6mm and 12mm as standard (or 1/4" and 1/2" to pre metric civilisations). You must use carbide cutters on it as steel will be blunt in seconds. We specify loads of it for skinning wash rooms.

[PaulRowntree]

@Tony : Does this mean that surfacing the solid laminate is difficult-to-impossible?

[willstony]

If you mean thinning down the surface then very definitely the answer is yes it is impossible but edging, drilling, sawing and local machining preferably by CNC is fine. The desk I sit at is 12mm white faced SG and there is not a mark on it.

[ger21]

You can surface solid laminate (phenolic). From my experience, you don't want to use a large diameter tool. A 1/2" 2 flute upcut spiral works well, but you need to take very light passes. If you're surfacing the table, .01" should be fine.

I'm building a 4x6 machine made mostly of wood, and using HiWin linear rails. The rails are mounted to phenolic plates which are epoxied to plywood and surfaced flat. I did the Z axis on my homebuilt machine, but I'll do the longer X and Y axis on our Morbidelli router at work.

Be aware that phenolic can be expensive, depending on thickness, up to $10-$15 per sq. ft or more.

[louieatienza]

Originally Posted by ger21 You can surface solid laminate (phenolic). From my experience, you don't want to use a large diameter tool. A 1/2" 2 flute upcut spiral works well, but you need to take very light passes. If you're surfacing the table, .01" should be fine. I'm building a 4x6 machine made mostly of wood, and using HiWin linear rails. The rails are mounted to phenolic plates which are epoxied to plywood and surfaced flat. I did the Z axis on my homebuilt machine, but I'll do the longer X and Y axis on our Morbidelli router at work. Be aware that phenolic can be expensive, depending on thickness, up to $10-$15 per sq. ft or more.

I bought a piece of 1" thick phenolic, 4 x 8, for a project, and used the leftovers for my second machine. That sheet cost me $570, but since I have an account with the supplier, I paid only $25 for shipping - not bad considering the gross weight was over 350 pounds!

As for machining, I used my old Solsylva to cut the parts and it went well. I also use phenolic for some of the fretboards I do for guitar necks and it works great (though fretting is a bit tougher.) I also plan to use phenolic on my next build, since I have a couple nice chunks of it.

I don't think moisture is a huge concern with phenolics; I've installed quite a few panels for bathroom stalls and partitions and they hold up well.

[acondit]

Louie,

I bought some small pieces phenolic resin board years ago from a plastics warehouse. What type of dealer did you get yours from? I thought phenolic resin board was really great to work with but someone told me that it is really hard on tool bits.

Alan

[louieatienza]

Originally Posted by acondit Louie, I bought some small pieces phenolic resin board years ago from a plastics warehouse. What type of dealer did you get yours from? I thought phenolic resin board was really great to work with but someone told me that it is really hard on tool bits. Alan

Alan,

I get my 1" phenolic sheet from Atlantic Plywood in New Jersey. The brand name is Arborite. The thickest sheet they normally produce is 3/4" but they made a 1" sheet custom for me.

As far as bits, it is not exactly kind to them. You need good dust extraction, as any extra chips in a slot or pocket can really muck up an endmill. The fiberglass based stuff is even tougher on bits and blades. It does finish nicely, and some knifemakers use it for handles.

I do have a phenolic/compsite bit from Onsrud that looks like a rougher/finisher bit, which is supposed to ease cutting forces, but havven't tested it yet. I've actually used straight flute bits with success...