My Foreman should be arriving in a couple of weeks. My previous Journeyman used a QCW frame and hence MDF.
This time I hope to branch out into some metal work… which will likely mean at least a mist of lubricant/coolant.
I know TMToronto went full on metal, but the cost of a cast aluminum 4x4 (approx) at 3/4 thick is only about $1800 dollars.
I will likely continue to use the idea of T-Slots so that give some dimensional flexibility.
So I am open to ideas.
Thanks
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Hey Carl and Lynn,
I plan to make the wasteboard slats of HDPE (see HDPE wasteboard example). You know the stuff of which milk bottles are made. It is resistant to all liquids including acids and lubricants. It is not directly cheap, but has many advantages, and it can be recycled by 100% by simply melting it, it cannot be glued but it can be welded. I have a source here for 169,25 € / m² incl. VAT in black 15 mm thickness, so much less expensive than aluminium.
If you use HDPE, I highly recommend a stress relived variant. Otherwise, the stock can warp (think potato chip) after facing the first side. Another way around this is to face both sides equally to even out strain on both sides, but that can be problematic without some very reliable workholding methods.
I have domestic quotes for full size sheets (4’x8’) that are stress relieved:
0.75” thick for $333 (USD)
0.5” thick for $221 ($USD)
Just FYI
I had thought of HDPE but I had heard bad things , ie the potato chipping. The more stable plastic I have been think about is Delrin ( Polyoxymethylene aka POM), But a 2’x4’ by .75" is only $675 …ouch.
Though I think I will get some of this stuff to play with. (Machining Delrin: A Complete Guide to Delrin CNC Machining)
Jace is there a chance you could private message me your source?
If cost is a concern then just use 3/4" pvc sheeting. You can get a 4x8 sheet for a little over $100 from the big box lumber stores. You might need to add extra support under it but it would handle any cutting fluid you might use.
Phenolic sheets are another option, but also relatively expensive. Several manufacturers, like Camaster, offer phenolic tables.
Hey Jace,
Thanks for the advice. I have asked the supplier about stress relief. They answered that their sheets are generally stress-free and have no tendency to deform. If I mill away 1 mm, it should not warp. They added, it is however important to note that as with all plastics, certain factors should be taken into account, such as cutting speed, tool quality and condition, and the specific conditions of the machining operation. Professional machining and the use of appropriate tooling can help minimize unwanted deformation.
Also @jarrfarr, who is the one with the HDPE wasteboard linked above, wrote that even after hammering in a T-nut every two inches (50 mm), a 3/4" sheet (19 mm) did not warp:
I would however rather use HDPE slats with extruded aluminium T-slots between them, and fix the steel vises used to hold metal workpieces with these T-slots.
I have experience with this material as well and use it often for custom workholding. Expanded PVC is amazing if you get the right grade. Actually running some now! More on that in another thread later.
Good suggestion, but might be difficult to clean given the slight cellular structure. Could be worth a shot given the cost difference.
$100/sheet sounds really cheap. Can you send a link for that @Dr-Al ? I’m at around $270/sheet right now given the “quality” of the material I’m using. Very consistent throughout. Probably just paying for a name brand TBH. I’ll test another brand that’s much cheaper soon.
Hmm, I work with PVC sheets at work, I personally would stay away from using it as a spoil board, especially if @CandL wants to machine metals in the future (would be sooo messy).
If its a choice between MDF and PVC, just stick it with MDF.
That being said, we only use one type of PVC, you may be referring to a different type of PVC.
Could you link to an example?
“Phenolic sheets” as in solid phenolic sheets? I have only seen/used phenolic plywood. 
I have not researched the material to a great degree, but remember there being various types - some paper/cloth resin, others resin with various fibre types.
Here is one example from ShopSabre - 240% Upgrade to ShopSabre CNC Router ATC - YouTube - where they are adding modified tool holders and need to machine into their phenolic top.
Agree it’s not good for cleaning up cutting fluid. Too “cellular” as I mentioned.
I’m using a Vycom PVC. What do you use at work?
I’m using a product called TRESPA (Google is your friend here). it’s a chemical resistant material used for laboratory worktops. It’s really dense and flat. Might be possible to pickup a used lab bench top?
Stuff looks amazing. And like most amazing things 
These are all great ideas… but I will likely, and for the short term use JimHatch solution …
“If you use oil or cutting fluid (vs a mister with IPA), you might want to use a piece of 1/8” tempered hardboard on top of your spoilboard. You can pin it into place with a pin nailer, brads or staples. That way any overspray or excess oil will be captured by the hardboard and not soak into the MDF spoilboard. You can hold your material down using blue tape/superglue or double-sided tape.
*When you’re done, just pop a flat paint scraper or other wide blade and lever off the hardboard. It’ll come off easily leaving your spoilboard unspoiled 
"
Yes I know an off topic solution… but there was a lot of good information here. This may get me to make a plastic fixture plate or pod out of plastic if the disposable hardboard is to annoying.
Thanks again
Not to mention extremely cost effective, and a very quick and easy way to temporarily transform the main spoilboard.
Just remember that a spoilboard’s job is to be replaceable if the bit cuts into it. If you use pins to hold it down and your bit hits it you’ll most likely dull or damage your bit. If using hardboard I would try double sided tape first.
I understand your comment … I have grown to believe far to much time is wasted on spoilboards.
On the other hand, I am hoping my skills are now to the point where I measure off of the spoilboard, and not off of the project. My goal is to “split the tape” and not touch the board… kinda like splitting arrows in archery.
Maybe if you’re using HSS end mills but not a problem if you’re using carbide mills. 23ga pins are soft and thin steel so if your end mill hits one it just sails right on through - no nicks, crack, fractures or other damage.
If you’re really worried you can get a version of the pin nailer that uses plastic or nylon pins. But the nailer will run you about $200, not to mention the pins are radically more expensive too.
Check out the thickness tolerance chart in table 2 of this standard. Hard to know if this tolerance is across a single sheet or (more likely) if it’s variation from sheet to sheet, but if you’re machining soft metals, it would be nice to dial in your Z reference by facing the top surface of whatever you’re placing your stock on. Depending on your application, +/- .040” could be something to watch out for!
The approach is definitely worth a shot for such little up front cost. ACM could be another material option with the same method and relative cost, but potentially harder to source depending on where you are. Typical thickness tolerance is +/- 0.20mm [.008”] for 3mm ACM panels.
Curious how it goes with the hardboard if you go that route. Sure would be easy!