Plywood Splintering - Advice Needed

[hobbm013]

Hi Everyone,

I'm an A Level Product Design student currently designing and making a chair. The aim is to make this chair out of thick plywood, one of the reasons being for the unique edge. The design of the chair features two repeated curved pieces. However after some prototyping work today, it became apparent that the plywood splinters along the edge as the curves were being cut out. Does anyone have any solutions to this problem? Our workshops has a bandsaw, table saw, and we have access to routers and jigsaws. I have attached some CAD drawings of the components which will need to be cut.

So if anyone has any advice on how to stop thick plywood from splintering while being cut into curves I will be most appreciative.

Thanks

 

[marcros]

what plywood is it? you will need high quality birch ply to get a decent void free edge.

 

[hobbm013]

what plywood is it? you will need high quality birch ply to get a decent void free edge.

I'm not sure exactly what it is, but I do believe it is a fairly high quality variant. That said I can order pretty much any material I want for the final outcome

 

[nev]

Put a sacrificial piece under the workpiece, that way as the teeth of the blade cut (push) through the wood and out of the underside its only the sacrificial piece that splinters.

 

[rbland]

Personally I would cut the first curved component oversized (2-3mm away from the final line) then sand to the line using a disc sander for the external curve and a spindle sander for the internal. Then I would cut the rest of the components oversized and fix the first finished component to these (using screws if the face doesn’t show or carpet tape if it does) and use a router with a bearing guided bit to trim the rough-cut components to final size (the bearing rides against the finished component and the cutter trims the rough component to the same size as the finished component). The router should leave a nice clean edge. This approach would be particularly useful as (if I understand correctly) your design is made up of a large number of identical parts.

As already mentioned I would agree that using a Birch throughout ply (not just birch faced) is a must. Also use a sharp Bandsaw blade with high tooth count (something like 6tpi for 18mm ply). When I was at school the Bandsaw blade was so blunt it made smoke instead of cutting.