Poured epoxy as is used for counters / bar surfaces is one material I’d seriously consider if my machine didn’t have to be portable.
My poured self leveling concrete top for my stand is as level as can be made. I’ve looked at resin for surface plates that are extremely level for industrial uses such as machine shops and auto makers for calibrating from an absolute level base, but they are extremely expensive and probably shouldn’t be breathed in. They are threadable and durable which is why I thought of just using fibreglass resin which also may be mire accessible for our members in Australia. Epoxy has to be poured an 1/8" thick each pour and lightly torched to draw out the air bubbles I believe. My Self leveling concrete can not be threaded so I used it only as a topping layer on the bench. One idea for the SLC is to coat bolts with wax and screw them into threaded inserts that are not coated w/wax and hot glue them to the top of the plywood and than pour the SLC to lock in the threaded inserts and unscrew the waxed bolts. There are always ways around problems, it’s just that the harder the problem the more complex the run around maguivering “solution” will be. Epoxy and resin can be “thinned” to make it runnable for self leveling but that also greatly extends the drying time. Google epoxy surface plates for more info.
2 Likes
Wow. Sounds like you’ve given this a lot of thought and maybe have some practical experience with these solutions as well. In the book in my imagination on CNCing, maybe I’d have a short chapter on self-leveling (pourable) surface options…
1 Like
a subject worth musing…or even it’s own topic
Many thanks to Jude et al.
From my reading it looks like I have a fairly expensive but useless for its intended purpose, piece of HDPE. Perhaps I can cut it up and make a number of small (but expensive) breadboards. 
While Poured Epoxy might be an elegant idea I don’t think it would be terribly successful for me. What I am looking for is a stable base on which to mount a waste board.
Getting back to my original idea of using the HDPE as a firm base. I wonder if I were to strengthen the front and rear steel sections of the XL would allow the HDPE to pull down without deforming the X axis rails? I am thinking of something like 50 x 50 x 3mm steel tube bolted to the underside of the XL’s front and rear steel sections. I do not intend to surface the HDPE but cover it with a waste board (MDF).
Any thoughts?
I dunno — I feel badly about folks not being successful w/ HDPE as a spoilboard, since I was quite successful w/ it on my machine: http://www.shapeoko.com/forum/viewtopic.php?f=35&t=6045
I’ve never had much success with tubing as far as rigidity goes, maybe I overstress things too much. I get 2 1/2" wide 1/4" angle iron at the scrap yard, Thinking of my pvc base board, maybe multuple layers of the hdpe will allow you to still use it as a base board, contact cement or other plastic’s type glue. Also by cutting it to the size for the base board first, it may be easier to flatten …
Lot’s of thoughts…your thoughts are the most important…please remember that I have the SO3 not the xl so my ideas need your consideration to apply them to your larger machine. Also you could easily redeem the cost of the hdpe by cutting clamps from it and selling them for cheap rather than loosing that investment…also children’s bad behavior motivational enhancement activators…(paddles), spatulas, kitchen knife holders, easy to clean boot jacks, many many alternatives, don’t give up Pat, you can do it. Jude
1 Like
On my original shapeoko 3 I replaced the mdf with 12mm thick aluminium, with great success. It significantly increased the rigidity.
Just priced some 6061-T651 – M61 tooling plate for my xxl in Sydney http://www.calm-aluminium.com.au/
15.88mm 1000mm x 1000mm cut plate at $485.50 each plus GST
19.05mm 1000mm x 1000mm cut plate at $565.50 each plus GST
It’s not as scary as I thought… I want to cut aluminium on the shapeoko, and having a rigid, waterproof base is a definite plus for that.
4 Likes
Don’t worry about it Will, we are all responsible for our own actions. In my case I will just write it off to experience.
stutaylo Stuart
Just priced some 6061-T651 – M61 tooling plate for my xxl in Sydney
Looks good Stuart and seems ideal but a bit more than pocket money can afford at present. I can’t find any suppliers here in Brisbane so it would probably cost me an arm and a leg to get it here as well.
3 Likes
My search for a good but not too expensive wasteboard continues. While stutaylo’s solution is ideal it’s far too expensive for me - particularly since I have an XL.
Was at the hardware store (Bunnies for people in Oz) this morning and spotted panels (2200x600x25 mm) of Laminated Bamboo. Three layers as shown in the Pix below. This is solid and fairly heavy stuff. I wonder if anyone has had experience of using such a product as their wasteboard?
2 Likes
I’ve not used it for a wasteboard, but used it elsewhere - bamboo ply is serious stuff. It seems to be quite stable and reasonably uniform (on the order of MDF) in thickness. It’s VERY durable as it’s bits of bamboo and a high-strength resin cast under extreme pressure and heat.
1 Like
How flat is the bamboo ply you found?
Even high-quality Baltic Birch plywood in the US is a little wavy.
Hard to know Phil until I buy a sheet and fit it to the XL. To the eye it looks pretty good but that is not really much of a guide. My Pix above shows the pieces of laminate 3mm thick but it is closer to 4 maybe even 5mm so there is enough ‘meat’ for skimming the board.
2 Likes
I like the look of that, I would imagine it is pretty rigid, and the price is right.
In my opinion, the wasteboard doesn’t have to be perfectly flat, obviously if it is thats ideal, but my experience has been that having a sacrificial wasteboard the size of my cutting area (so I can machine it flat) on top of the base board works well enough, as long as you square the machine up as per the info on this forum, the results are pretty accurate.
Mine is currently 1” ply and my machine is very accurate, far more than it was originally with the mdf board
1 Like
Thanks Stuart, what troubles me with the MDF wasteboard is the give toward the middle of the machine, just a little pressure will move it many thou. in the z direction. Following a thread some time back in this forum I have removed the feet from the XL and fitted a rubber mat underneath. http://community.carbide3d.com/t/sounds-suppression-xxl-bed-flatness-and-other-musings/4875 This has improved the situation but still leaves a lot to be desired.
I agree that a sacrificial wasteboard the size of ones cutting area mounted on top of the ‘baseboard’ is a good idea and this is the way I intend moving. Flattening the ‘baseboard’ has problems by leaving a ridge that could get in the way with some jobs.
I think the bamboo will be fairly rigid and I probably will spend the money on the 25mm bamboo sheet, fortunately I have a friend who will take the other half sheet off my hands.
1 Like
I couldn’t believe the amount of flex in the mdf. If took me a while to work it out, I was getting several millimetres just pushing the baseboard with my finger…
I changed to plywood, and with a dial indicator I can see no flex at all, and have none of the issues I used to, with pockets not cut to depth, and rough stepped finishes on 3d toolpaths.
I imagine the bamboo is just as rigid, if not more so. It is probably more resistant to moisture too, which was a big weakness of the MDF. It may even be worth putting some type of finish on it, maybe a lacquer or even acrylic paint, do you have any thoughts on this?
Nice find, I am interstate for work but may also give this a shot, I like the look of it!
Agreed Stuart, a lacquer on both sides would probably be a good idea. I don’t know how susceptible the endgrain of bamboo is to moisture absorption. In any event it may also be a good idea to coat the edges also.
1 Like
The iron plate is an excellent idea, has weight and does not buckle like MDF or engineering plastics, being a stable investment. For me, I would buy a 12 mm sheet. or 1/2 inch and I would make a rectification on both sides, to finally have a flat surface technically elaborated, then I would place my plastic sheet as protection to the tools and to fix the stock of the materials to work.
OK, I purchased the 25mm Bamboo panel and cut it down to the 3XL size (purchased size 2200x600x25mm). I quickly gave it two coats of Shellac all round to seal against moisture ingress and will probably give it more before installation. It’s really porous stuff.
Cut down to XL size it weighs in at 20 kg and is truly a solid lump of wood. I put a straight edge on both the x and y axis, on one side I cannot see light between the straight’s edge and the panel in either axis. On the reverse there is about a 0.3mm (0.012") ‘valley’ about 1/3 along the x axis. This side will face terra firma.
Haven’t started to drill the mounting holes yet but plan only to use this panel as a baseboard and mount a sacrificial levelled board above it as noted by stutaylo above. I am looking forward to seeing the results.
3 Likes
20kg for XL size?? That sounds perfect! It’s a pretty well known rule that more weight = less vibration & more rigidity.
I think shellac is a good call, personally I think I’d go with threaded inserts in the base then screw the mdf to the base so it can be removed if cutting thicker jobs, that has worked well for me in the past
1 Like