Rigid Foam - Safer Than Wood?

[SteveMaryland]

I currently have a home project which requires fabbing a large number of identical rigid tiles. Any rigid material, including wood, could have been used, but "pink" foamboard was chosen for economy and ease of use. Super easy to get very clean and repeatable cuts of pink foamboard on the table saw - and at the lowest Shopsmith speed. Pink foamboard can be sawn, drilled, planed identically to wood in most cases, but at low speed and without the weight and cutting resistance of wood.

I thought back to my Shopsmith learning curve from 3 decades ago. Early on I had my share of kickbacks and near-misses, but have been very lucky to this day. I think my learning curve on the Shopsmith would have been less difficult had I started cutting on rigid foam before wood.

CUTTING RIGID FOAM 1.JPG (174.67 KiB) Viewed 2349 times

CUTTING RIGID FOAM 2.JPG (163.63 KiB) Viewed 2349 times

Today, if I were introducing a beginning student to power tool use, I might start with foam - just to get the student acquainted with tool setup, tool noise, hand-eye coordination while feeding, and kickback hazard - while cutting a far less resistant, heavy and more hazardous material.

But unlike wood, rigid foam has no grain, and this detracts from realism. Also, the "sawdust" generated by cutting rigid foam is really a nuisance - the dust "static clings" strongly to all surfaces, worse than real sawdust.

We note that in the modern industrial CNC machine shop, rigid foam is first cut to test and debug toolpath and other programming problems before actual metal is cut. By using foam, the CNC machine itself is also spared from much damage as would occur in a metal-to-metal collision during a program run. There are a variety of rigid foam types available to the CNC shop for such use. Maybe a foam specifically made for apprentice woodworker education, which simulates grain and other wood-like properties, could provide a safer (and less intimidating) introduction to power tool woodworking.

[RFGuy]

Steve,

Can you explain what operation you are doing in that first pic you posted? I ask, because in woodworking, you are are NOT supposed to use the miter gauge together with the rip fence in this manner shown here. As you proceed with the crosscut, it is easy for the workpiece to bind between the sawblade and the rip fence. Some use a stop block attached to the rip fence well before the front edge of the sawblade in order to do repetitive crosscuts with the miter gauge. In such a way, the position of the cut piece is set precisely for repetitive cuts, while keep a sufficient gap between the right end of the workpiece and the rip fence once the workpiece contacts the sawblade. In contrast what you are showing in your picture, invites a kickback event.

For rip only cuts, I assume you know that many woodworkers purposely set a few thousandths greater gap at the back of the sawblade to rip fence alignment. In such a way, it greatly minimizes any pinching that can occur between the sawblade and the rip fence as the workpiece is advanced into the sawblade.

[SteveMaryland]

Yes, should have used a fence spacer. Thanks RF.

Note that the workpiece has a 7 degree draft angle. So the workpiece comes in contact with the fence along a line rather than surface-to-surface, as illustrated:

WORKPIECE-FENCE PROXIMITY 1.JPG (99.43 KiB) Viewed 2275 times

Still should have used a spacer if for no other reason than to avoid the 1/16" gap under the fence.

Cut over 100 of these foam tiles and got no kickbacks.

[GetterDone]

I just cut this same board at High Rpm.
Low Rpm may have been a better choice.

I am insulating a Well house.

[edma194]

Large sheets of foam board may need to be broken up on a table saw but for smaller pieces like all those tiles a bandsaw makes a much cleaner cut.