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Hey all
I currently use MDF as a spoilboard on my 1200x1200. Problem i am having is i have to skim almost every time i use it due to the weather etc - i assume. Anyway - this is getting a bit perplexing as i can't do a "quick" job because i never know how even the bed is.
Has anyone used polyurethane sheet as a spoil board - NOTE: i don't use a vacuum system.
Any feedback would be great - other ideas etc. Also if you have used sometghing other than wood what have you used for hold down?
I use 1.5 inch thick hdpe for my table top. I have threaded inserts imbedded to use machine screws for clamping. It has been very stable. Another good option is phenolic used in the same manner.
Ben
AH thanks bhurts! I can actually get Urethane sheets cheaper than MDF so it will also work out better for me. What is your spacing for the embedded inserts? This will also work better for me as when i need to use the rotary 4th axis then i can just lay it direct on the sheet and bold it down rather than remove the MDF and bolt down via the T rails.
Quote:
Originally Posted by bhurts
Hdpe is actually polyethylene no urethane. If the urethane is hard not soft it should still be fine though. By hard I just mean not rubber urethane. As for inserts I use these.
100 Pieces Threaded Insert Nut 1 4 20 Int Thread Made in Germany | eBay
Hopefully you can find something similar. I drill or mill a hole then use a single point threading tool to thread the hole to match the insert. If you get inserts that the od thread is a standard size you can use a tap. I put a few dots of superglue on the outside before screwing them in. Make sure you make the top of the insert at least 1/16-1/8 below the surface of the board or you run the risk of hitting them if you need to surface the top. If you can find brass inserts you can usually surface the board and if you hit them it will just skim them down a little to and not hurt anything.
As for spacing I just add them as needed to match fixtures or other setups. If I were to just make a grid I would go at least 2x2 inch or even 4x4 inch then add new ones in between as the need arises. Good luck.
Ben
I have used 3/4 plywood as it was free and it was good to hold the screws no vacuum system too everything get held down some how
Hey guys thanks for ALL The info. I have the lady from the supplier coming to see me tomorrow with a few samples of the sheets they sell in different densities. I will then see, i assume, what will be fit for purpose and how strong it will be in terms of being a bed for the hold down methods i use - GREAT idea from bhurts - probably go with this!
Best stuff is phenolic sheet. Paperwood is one brand used for residential and industrial countertops. They sell drop-offs and blems at a deep discount. You won't regret using it; a lot of commercial machines use it.
Agree with phenolic sheet ( also called thick stock by some....IE ;FORMICA)....but personally, I use a cheaper and as stable....and in my opinion & usage, much simpler ( it's easy to glue up).....EXTIRA or MEDEX ext grade.
These two are essentially exterior grade, moister & humidity resistance MDF !
Easy....er to machine, glue"able".....and...cheaper the any poly or composite ( Phenolic or...)
My 2cts...enjoy, R.