I made my pvc base board for my Shapeoko 3 from those pvc 4’ x 8’ sheets at hom depoe. It is crazy stuff to cut as it heals itself faster than I could cut it. I cut a disc out on the scroll saw and by the time I completed the circle the pvc had welded itself back together, I couldn’t break it out with a hammer, had to recut faster and it still was hard to hammer the disc free. On the Shapeoko though it was a different story. PVC cut wonderful once I got the speed anf feed right for me. I do not know what is correct or how fast I should or could feed so I refrain from showing my cut data, 20 mm/sec, 6 mm DOC, double flute 1/8" staright router bit, but I had to slow the feed rate (estlcam option) down to 37% and turn the router speed down to number 2. It took some playing with the speed dial as it was cutting while watching the debris chips fly to get some good looking size chip load that didn’t weld itself back together. The router bit after 2 hours of cutting slots for the vacuum table was only 90 degrees, the collet nut was 98 degrees and the plastic as it was being cut was 96 degree, so I think I had a big success finding the right speed and feed. Also the main reason that the plastic stayed cool while cutting was I used Estlcam’s trochoidal cutting command. Taking those little bites instead of constantly stripping off a long thread kept the Shapeoko cool. Here’s some pictures of the chips and the coolest strip of pvc from the slot trochoidal cuts. It took 2 passes side by side to cut the slot and there was a slight slice of pvc cut off and it shows the trochoidal cutting action as a ripples along the slice.
forgot the base board pictue, 4 layers of 1/2" pvc glued and bolted to the frame, there is one more layer that will be the vacuum tale top to be cut, held to the sloted layer by the vacuum, waiting for the rubberized paint to dry to see if it seals the pvc layers.
I remember a Honda commercial from TV loooong ago…it had a guy who bought a Honda engine for his project(a home built aircraft if I remember correctly) and then said that he liked the engine so much he went out and bought the whole car… Jude, your base reminds me of that, and I like it so much I am going to follow your lead!
Off to the Big Box Store to pick up a sheet of PVC-won’t cut it today-don’t like to make too much noise outside on a Sunday-but, it will be ready to go in the spare minutes during the week!
Ok, now the MacGyver theme is playing in my head just thinking about this…and I can’t stop thinking about this…Today will obviously be a day spent on getting My work space and SO3XXL ready to make stuff on a regular basis-instead of the mad rush to do something around the current mess…
Thanks William, I hope you can “see” my path so you can blaze your path like you do so well. Who knows, you could easily beat me to the target, but I know we’ll both get off a good shot, and with that in mind, multiple target aquisition points are always better than both from the same view. I won’t mind being your spotter either. And like my Dad told his Sargent when the Sargent complained that he marched like a squirrel hunter…“Yes Sir, and it was those squirrel hunters who helped win our independance also.” The American Spirit lives only when we adapt, improvise and overcome whatever stands in our way. So glad to see (read) your appreciation of that because that spirit is more important than the accomplishment itself. D I Y should be A I O. I know they teach that somewhere. Jude
ps, you can’t have only the McGyver theme, you have to mix in the A-Team theme also and don’t forget the cigar!
The pvc sheets are incredibly flat and uniform, much more than the HDPE cutting boards, cutting the slots did cause the sides to raise (curl slightly) on one side that wasn’t completely bolted down, bolting it down after pulled it back flat so make sure you have it bolted down all around. Once the “rubber” paint cures and I put the top layer on the vacuum table I will dial indicate it to see how flat it is. Than I’ll surface it as needed. But I think it will be very flat and the layers of "paint " may offset or maybe increase any surface variances found. As usual I will report any McGuiver and A-Team intrinsicalities initiated (as if that phrase really needs explaining). Hom Depoe claimed they don’t cut pvc because it dulls the blade, I complained to management and they walked back there and instructed the employee to cut my pvc as a “favor” to me. The saw cut through it like butter. They just don’t like doing “extra” . Good luck,
Jude
Both, I glued 2 layers together and bolted them to the bottom of the frame (see picture in that post) than added a 3rd layer with the flanged inserts in the bottom side which the vacuum slotted board is bolted to sandwiching the 2 glued layers and the frame in between them. The 5th layer is the vacuum table top which is about 1/8" higher than the top edge of the angle iron front rail, just sitting there I can’t feel a difference in height along the edge of the rail, looks "perfect. Have to build the vacuum connections with the gauge into the vacuum slot board before I can pull the vacuum and D I the surface. Maybe today, maybe tomorrow, need some more dbl sided tape and I know I don’t have any in any “safe” spot so need to go to hom depoe (sp intentional). The 2 layers glued and bolted to the frame add significant rigidity and all 5 layers add weight. See the "cutting pvc " thread, the picture of the strip of pvc cut with toroidal cutting , all the strips are the same thickness from all areas of the panel, meaning I believe this shows the machine is as square as can be otherwise some would be shorter and cut off different, every full length strip was identical so no variance in squareness. That was because of the recessed edge in the 1st layer that I butted the frame up to and bolted tight before squaring the back frame rail. That’s in another post also, maybe I need a secretary to keep track of where in what posts I have stored information (information is good stuff too, my mind is full of it (just like my son says I’m full of it.
Also the whole contraption n ow sits flat on the self leveling cement I poured into the bench so the machine is on a flat level solid base. (from yet another post somewhere).
I saw this last night, either in my dreams or somewhere on the web. Started to read it but …Great minds see great things and knowledge is the language most misunderstood. Also it’s good when a plan comes together.
Found some more good stuff for my SO#XXL-6 pieces of heavy aluminum(that just sounds hypocritical) extrusion made for adding rigidity to panels, Flanged “U” channel:
So I slotted a sheet of that pvc for the vacuum table. Could not get a vacuum with it, it bleeds as bad as mdf, the inside is real soft so maybe it is really a pvc foam sheet, H D is not trust worthy. Anyway I painted one slot with elmers glue and connected the vacuum system to that one slot and pulled a 29 inch vacuum. So I painted the slots with that rubberized paint to see it that will seal the slots. I’ll see tomorow. What a pain… but I have the pump rebuilt, a vacuum gauge, a shut off valve and a filtering jar all in a nice little package. One step at a time, usually backwards or into a hole but maybe we can call it progress. Jude
The sheet (at least at all sources in my area) is cellular (foamed) PVC, not solid, in thicknesses greater than about 3mm. The sheet at HD is listed as 21Kg, and, if solid, should be about 38Kg (Solid PCV has a density of about 1.3, or a bit more, depending on the plasticizer). This also contributed t the tendency to curl once the skin is cut.
To seal, you might try shellac (dewaxed, sanding sealer) over the cut surfaces, then a light spray of clear rattle-can acrylic or enamel. Shellac will adhere to anything, and anything will adhere to it, moderately well.
The last time I was at my local hardwoods shop, there was a piece of plastic wood they sell for decks leaning against the wall. I asked what the smallest piece of the stuff I could buy and they said I could have that one. I took it home, drilled a 3/8 inch hold into the end and put the tube from my vacuum into it. I turned the vacuum on and got nothing. I came to the same conclusion that it must be some kind of porous core. I ordered a piece of 1/2 inch HDPE, and that works great.
I’ve had so much curling of the hdpe after surfacing that I am done with hdpe, potato chips. The pvc sheet which I agree with enl public to be foamed at least stays down after bolting. I’ve had the slots cut into it for a week or more and no curling. I did seal one slot with the elmers glue and than when I painted the slots with the rubberized paint last night, this morning the paint reacted with the elmers glue and neither dried. I wiped out the goop and left a residue layer . This afternoon I’ll check it again. The only problem I had with the rubberized paint earlier was I could not get an even layer on a large surface to seal but I think it will be fine in the slots. We’ll see later on. Thanks for your thoughts.
the top layers of the vacuum table (the templates) will get a coat or two of shellac, thanks for the thinking about this. Your explanation of the pvc sheet is right on. Not the way they discribe it but oh well. There is appearantly a real solid pvc sheet called grey pvc sheet that is solid but over $300 a sheet (on the shopbot forum under pvc vacuum table). So oh well to that also. I enjoy yourinsights, very informative on many subjects, Appreciate it, thanks again, Jude
Here’s an interesting thought about the vacuum table itself, JB vacuum pump 85c (35 yrs old) pulls 4 cfm and the slots with a 1/8" air gap between the surface and the board (thickness of sealing tape) is 30 cubic inches, That should pull down in less than a second. Will that be the case, we’ll see.
I post this not as a recommendation, but merely for informational purposes if anyone passes by in the future. This link provides some good information about a variety of plastics https://www.onlinemetals.com/merchant.cfm?id=209&step=2&top_cat=181 . I’ve gotten some aluminum from them, and I received what I ordered in a short amount of time.
Thanks for the tip buddy, it’s hard to believe that the rubberized paint did not create any surface seal. I hooked up the vacuum and roped a seal around the vacuum table and put a top layer on it. now the top layer has a continuous layer of rubber on the bottom side so the slotted table is completely sealed and it did not catch a vacuum. So I sprayed a heavy coat of shellac on it and I’ll test it again tomorrow. Can’t believe sealing a board has to be this had. next time I’ll go with the shellac only. I’m glad I had a can of it in the shop. Jude
later on…I tersted the shellac but no go, it IS the vacuum pump, I held the shop vac nozzel to the vacuum port and the top plate on the vacuum table sucked down immediately without even a seal at the nozzel. So the old vacuum pump needs a couple o-rings, will get an assortment pack and find the right size. and even change the oil, that’s 30yrs old too, gee maybe that’s the problem but I don’t want to buy a new pump until I prove to me that it’ll work. Thanks
