Reply with QuoteYou can get away with drilling aluminum dry. Just keep your speeds a bit lower if your spindle will allow it. May need peck operations to break the chips, but drilling is pretty easy.
Can babysit it with a can of WD40 if you're really worried.
Table Material
I have a router with an MDF table, 700x1100x21mm. I mostly dry cut brass, and also some wood and machinable aluminum. I would like to have a table which would allow me to cut wet. I could get a slotted aluminum table easily enough, but I kind of enjoy just drilling mounting holes where I need them. The first option would be a solid piece of aluminum, but then I would need coolant to drill the mounting holes. I'm wondering if there might be some composite material out there which would be easier to drill, and also be waterproof, and perhaps a bit more durable than the MDF. Any ideas?
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Re: Table Material
You can get away with drilling aluminum dry. Just keep your speeds a bit lower if your spindle will allow it. May need peck operations to break the chips, but drilling is pretty easy.
Can babysit it with a can of WD40 if you're really worried.
Re: Table Material
Yes, I suppose I could do it, but it would be slow, and I'd have to tap the holes. I like the quick and dirty method of sinking deck screws in the MDF. Someone suggested Corian?
Re: Table Material
Corian expands and contracts a lot with temperature changes, and can be brittle. And you can't screw into it.
Aluminum is probably your best bet.
Gerry
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Re: Table Material
OK. I just ordered a small piece of it for testing, but I guess I have to keep looking.
Re: Table Material
You forgot really expensive! LolOriginally Posted by ger21
I had Corian left overs so I tested it as a waste board since I sometimes cut wet but next one will probably be slotted alu for. Corian is good countertop material not waste board material.
Edit: I forgot to add that if your machine isn't grounded properly, you might encounter static electricity problem leading to false alarm trigger.
Re: Table Material
I use a lot of SRBP (aka phenolic board/phenolic paper laminates/tufnol kite etc etc... don't confuse the solid sheets with phenolic coated plywood).
Very dimensionally stable and it's not really affected by water, will happily take threads for fixtures... haven't tried a self tapping screw but I'm sure it would be fine... perhaps pre-drilling might be best.
Not super cheap though.
Re: Table Material
Hello Robobass,
At this very moment I am replacing my table base and spoil-board with HDPE, it is easy to machine and water and coolant fluid resistant.
I have also integrated a 100 X 100mm M6 nut grid and you can drive a wood screw in it easy without predrilling.
I can post some pictures if you are interested.
Kind regards,
Rob.
Re: Table Material
Another option is water resistent MDF. But it may be hard to find.
Gerry
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(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
Re: Table Material
That sounds good. So far I only find copper clad PC board though. I naturally pre-drill before inserting screws. I'm not that much of a cave man!
On the HDPE, I have used that for certain jigs on the past and iIt seems like a candidate. I remember it producing some particularly nasty dust when cutting, but I suppose drilling it wouldn't cause such an issue.
One last note on the Corian, It seems to come no thicker than 12mm, so I think I would need to reinforce it somehow. Aluminum bars, or perhaps a double layer. Can it be solvent bonded?
Thanks everyone!
Re: Table Material
I found something called Tricoya, which is water resistant MDF designed for outdoor use. It is fairly cheap, and comes with a 50 year guarantee! Only up to 18mm thick, but I could work with that. It claims amazing properties for both moisture resistance and dimensional stability (Performance | Tricoya). I think the problem is solved.
Re: Table Material
Only problem is I have to buy 3x the board size I need, and the stuff isn't that cheap!
Re: Table Material
I glued my 12mm on an 1/2in mdf board using epoxy then sealed te mdf with epoxy.
It's holding well
Re: Table Material
Composites like carbon fiber and fiberglass do not hold screws / screw threads particularly well. Where I need to add screws to a carbon fiber part, I use threaded inserts, aluminum bedding blocks or some other type of metal insert.
It isn't particularly difficult to add threads and screw holes but there is definitely a learning curve to making anything out of carbon fiber or fiberglass. For most people it is going to be more difficult than buying some aluminum extrusions or a ready made T-slot table.
As with all these things, it comes down to budget and time. I am currently researching what to make my table from too. I am kinda worried about it becoming the point of weakness in terms of how if effects accuracy. I have gone to great trouble and cost in using steel, carbon fiber, epoxy granite and aluminum for the rest of it. I am wondering if I should just invest in a steel t-slot table.
Re: Table Material
All points taken. I think I'm going to go with the Tricoya. I'm guessing it will perform similarly to my current MDF board, but maybe even better, not to mention that I can work wet. MDF has served me well. In four years I still haven't changed it. I can drill a pattern of mounting holes in minutes, and as long as the pilot size is correct it holds wood screws well, although not indefinitely. Since the Tricoya is only 18mm thick (my existing board is 21mm) I think I'll just mount an aluminum rail or two underneath. Tricoya is available locally and a full board is about $300, but will be enough for three tables. I'll post results in a few months!
Re: Table Material
Paper-based phenolic, like Garolite, Arborite, PaperStone, BakeLite, RichLite...
Re: Table Material
With something like tricoya, you could laminate it with woven composites like carbon fiber or fiberglass fairly easily. It would give you the benefits of both if done right. If the wood is strong enough to hold your screw threads then the cf can be used to add stiffness.
I don't know how much experience you have with composites but if I were asked to recommend a process that was easy for someone with no prior experience with cf, it would look something like this:
First I would put down a black surface coat such as the epoxy black surface coat offered by ACP composites. I would apply it with a disposable roller to ensure it has no lumps or uneven areas. This step is optional but it makes it easier for the cf to adhere to the surface. If you skip this step, I would rough sand the wood to make the surface flat but not smooth. It will stick better to a rough surface.
Next you would lay your carbon fiber material on the surface. If you used the black epoxy gel coat layer, lay the cf on it when it has partially cured and is still tacky. You can use a 3k 2x2 twill weave carbon fiber fabric. A 5.7oz or 6oz is fine.
If you want to guarantee a perfect finish, I highly recommend using the weblock 2x2 twill sold by Composite Envisions. This is a stabilized fabric which means you can't accidentally pull threads, poke holes or distort the weave when handling it. It's almost idiot-proof for a job like this. It's $10 more per yard so I only use it for the surface layer where the appearance is important.
When fhe cf is in place, apply your epoxy resin. I prefer to use a squeegee as it's easier to remove excess resin without pulling threads. Some people use a brush.
If you goal is strength and stiffness, the more layers the better. I typically use 7 layers, each one laid with the weave in a different direction to give it multi-directional strength. The fabric I buy usually comes in 50" wide rolls and is sold by the yard so it's easy to see how much you need for something flat like a table.
Even though it is not optimal, I recommend doing this in two or three steps if it's your first time. It is far more difficult to luck and cure 7 layers at once than it I should to do two or three at a time. Your call.
Once all your cf is laid in place and wet out properly, avoid the temptation to prod and poke it to flatten it if it raises up in places. It will be like a game of wack-a-mole and you will only disturb the weave and make it look bad. We'll make it flat later. It won't stick properly until the resin start to cure and get tacky anyway.
Cover the surface with a layer of smooth release film. You can buy this and all your other supplies from Composite Envisions if you are in America. This is key because the finish on the cf will mirror the release film as if it was a mold. The release film will also let you see any trapped air. Gently push out all the air bubbles with a squeegee. It will be easy while the resin is still wet. Do this right and you will end up with a perfect finish with no resin pools or unsightly trapped air pockets.
Next, place another equally sized board on top of the release film to create a tricoya or MDF sandwich with the cf as a filling. Then add weighs on top to press it down. You can't really add too much weight (as long as it doesn't break the wood) but you want to make sure it is spread out evenly. If you have a lot of large books then these will works nicely. You can use anything heavy though.
Make sure it is all resting on a fairly flat surface or the weight will bend the board and it will cure with a bow.
leave it overnight. The next day, remove the top board. The smooth release film should then peel off easily and reveal a perfect-looking glossy cf surface for your table.
You can trip the edges with a simple dremel. I use the diamond cutting wheel. Trip almost to the edge and then use a flat sanding block to straighten out the edges.
If your your budget Is really tight, the basic thin laminating resin with medium hardener from CE is fine and easy enough to use. If you can spare an extra $40-$50, I highly recommend Adtech 820 resin and medium hardener from Soller Composites. It offers higher temp resistance without an oven post cure. It looks nicer when cured too and it has UV resistance built in.
If you go with the cheaper resin, you should add a clear coat when it has cured. If you aren't set up with a compressor and spray gun, you can get away with a cheaper acrylic clear coat spray. Apply it in thin layers and let each layer dry before spraying the next.
If you screw up a little and there is one or two uneven or unsightly bumps or craters in the surface, you can use a quality epoxy Bartop to level it out and hide any sins.
If the table will have holes drill in it, do it after the cf has cured. Any uneven areas in the wood will show through in the cf and, unlike wood, cf does not sand flat particularly well. You can sand it a little to improve the gloss but you won't change its shape with sanding.
For cutting cf, you want a good dust mask. Not one of those cheap disposable ounces. If you have to use a cheap disposable one, I suggest wet-sanding to avoid the cf dust becoming airborne. You don't wan't to be inhaling it because what goes in will not come out.
Re: Table Material
Thanks for the idea, but it sounds like more effort than I need. I am currently just using a plain piece of MDF, and it has worked fine for four years. I just got a sample of a Corian type board today. It seems really good. It takes wood screws well with the proper pilot hole, and I can solvent bond it. I think that's where I'm going now. It is pretty stiff, but at 12mm I think I will use a double thickness.
Re: Table Material
Sounds sensible to me. It's easy to get carried away and lose sight of what is actually fit for purpose. If you get the required and desired accuracy from a $50 investment then there is no need to spend $200.
I was assuming that the need for a new table was because the old one was not sufficient.
Still, if you ever do decide to strengthen it, you can always add cf or fiber's later.
Btw, the method below is also suitable for making carbon fiber plates if you ever have the need. You just add an extra sheet of smooth release liner on the bottom to prevent the cf sticking to the wood.
Re: Table Material
Finally did it. I decided to go with Corian. I found a slightly scratched piece for about $100, so it was cheap compared to the alternatives I was looking at. It's only 12mm thick, but with the addition of a center brace along the Y-axis it is plenty stiff. It is easy to cut, drill, and tap (nasty dust though). I think it won't hold threads as well as some other materials, but an M6 or M8 thread through the full thickness seems durable enough. The other cool thing is that it solvent bonds really well and has excellent stability, so the cut-off pieces are useful for making parallel bars and fixtures. Why the bars? I have certain jobs where I like to cut slightly past the bottom of the stock.
