a stupid jointer question

[Ray Schafer]

I just bought a new jointer and have not had a chance to try it out. here is my question: can I use a jointer on plywood? Probably a stupid question, but I have to ask, since I don't know how to use a jointer yet.

Thanks.

[Matt Bickford]

Despite having heard of people running plywood through a planer in a desperation move to fix a mistake, I have not heard of people putting plywood through a jointer for any reason. The jointer will most likely remove any of the desired veneer in a single pass. Once below that top veneer it will shread the plys as opposed to jointing them.

Why do you want to joint plywood? If your plywood isn't flat I would find a new distributor. Flatness is probably listed as one of plywood's main benefits.

[Paul Fitzgerald]

I'm assuming you're talking about edge jointing... and there was a thread about this recently.

Basically what I gleaned from the thread was "yes you can do it, but it will tear up your knives". Same thing goes for MDF.

Paul

[Matt Bickford]

Edge jointing would make more sense. I didn't even think of that.

[Harry Niemann]

The glue resins used in plywood construction play havoc with the knives. Lots of little nicks.

[Ray Schafer]

Yes, I meant edge jointing. I guess the best way to get a straight edge on plywood is to use the TS or router.

[glenn bradley]

Yes, I meant edge jointing. I guess the best way to get a straight edge on plywood is to use the TS or router.

I would agree with the TS or router. Edge jointing plywood . . . ? You ever seen those exploding cigars in the cartoons? Yeah, kinda like that.

[Larry Browning]

It is not so much of a human safety issue as it a jointer safety issue (injury to the machine). It will do a good job on the edge, but it will do a job on the jointer.

[Ed Gerken]

I prefer judicious belt or block sanding after the final table saw pass.
-Ed

[Jules Dominguez]

A tablesaw will cut a straight edge on plywood, 90 degrees to the face. I don't have one of those guided circular saw systems, but I'm sure they'll do the same, so jointing shouldn't be necessary to straighten an edge.
Either of the saw methods might leave some minor sawtooth marks or burns on the edge, but you wouldn't make a nice piece of cabinety with exposed plywood edges anyway.
If for some reason you had the need to clean up a plywood edge, sanding would probably the best way to do it. A router might do the job on an edge in the face grain direction, but the edge on the cross-face-grain direction would be iffy - you could easily get tearout of the face veneer.
I don't know whether a router bit would stand up well to cutting edge-wise into plywood glue layers, as I've never tried it.