Thread: How do I 'work' ply?

Aha!

You've been reading too many US instruction sheets!

I'll bet you are using nice cheap luan or whatever construction ply that we get here, not the fabulously expensive birch ply that you see in the photographs with all those wonderfully built jigs and things.

Do yourself a favour, use MDF!

If for some reason you want to persist with using cheap ply, use VERY sharp tools and always place sticky tape over all the cuts holes etc before you make them, I have been known to use a hacksaw blade in the jigsaw when cutting really splintery ply.

The best method of all is to epoxy coat the ply along both faces of the cut BEFORE you make it, which of course is very labour intensive and costs more than buying good quality stuff in the first place.

Did I suggest MDF? Once you've built your jig, give it a coat of sealer (Shellac, lacquer or anything else you've got nearby.)

Cheers, and all the best,

P

You could also use hardboard (Masonite I think the term used in OZ dark brown sheet) it is stable and takes a good edge and takes more missuse than MDF in my view.

Cheers Peter

Best way to work it is with a match...

Go with MDF or masonite. (Peter, you are right. In the US they call it tempered hardboard I think).

Whichever way you go, the cheapo ply just will not be as nice to work with as something that costs a little extra.


(Although, I do have a spiral carbide bit in the router that tends to do ok, but still not perfect.)

Originally Posted by Schtoo

(Although, I do have a spiral carbide bit in the router that tends to do ok, but still not perfect.)

My upcut spiral bit chews out the top veneer something fierce!!! Don't try it!!

Cheers,

P

I work in ply a lot and yes you can get a reasonably clean edge on some ply.

The brand and type of ply realy makes a big difference.

The birch ply is very nice to work with and hes very good edge density and cuts remarkably cleanly.

some of the other plys are a mongrel.
do a cross grain cut or rout in slash pine ply & you'll have lumps the size of your fingernail chipping out

A jigsaw will make a mess of ply at the best of times.
If you want a clean cut from a jigsaw the correct blade and sharp is a must it you want to be in the race.

your best bet is to use a router with a straight bit with as big a cutting radius as practical 1/2" or bigger is good.

for templates you are better with one of the finer grained manufactured boards. MDF is fine for light use templates 10mm sign board is the best I have found It is a version of masonite.

cheers

Midge, it's a brand spanking new 2 flute end mill, not quite a router bit per se. Prolly not quite as aggresive in it's cut, but as I don't have an equivalent router bit, I can't say for sure.

I suspect things might get ugly after it gets a little more blunt though. Only used it on reasonable stuff though, not low grade garbage.

I don't care really, I rarely work with ply anyway, and when I have to, I use a proper blade in the saw to do it, and try eliminating the need to use anything else.

Tape/staple/screw/glue'n'paper/otherwise attach another sheet of ply on top as a sacrificial offering to the fuzzy gods before cutting. Cut out template, remove remnants of sacrifice, replace blade and send off buggered one for resharpening. Realise MDF, masonite or damned near anything else would've been a better choice in the first place and offer contrite apologies to forum members for advice ignored.

I reckon about $10- each would be sufficient apology.

The making of a template implies replicated use. Not only should the template be durable, but also as perfect as possible. I don't know how good or crappy your ply is - but here's some general jigsaw info that might help:

Getting a clean cut in any material with a jigsaw depends mainly on the type of blade used.

• If you have one, try using a small blade for curve cutting that has 0° pitch on the teeth. This means they are like little triangles instead of waves. It is these waves that are creating most of the breakout.

• Also make sure the orbiting blade action (if your jigsaw has this feature) is turned off. A cam-driven hammer inside the gearbox tilts the blade bottom forward on the upward stroke which also increases breakout.

Damien

I agree, MDF is the way to go for templates and jigs. As to cutting ply, sharp blades and take it slow (not so slow to burn though). Sacrificial techniques work OK in some instances.

I like to use clear Plexiglass for templates because it's easy to work with a good fine tooth jigsaw blade and even better with a router, provided you don't let your bit temperature get too high. If you have a scroll saw big enough to accomodate your template, try one of the round "all-direction" blades. Plexi is tougher than any plywood, can endure the pressure of a "follower" without wearing away, and best of all allows me to see the actual material if I'm using the template to overlay the material and mark out the pattern. Costwise it's not bad, especially since I don't have to remake patterns.

Thanks guys.

Yeah it is construction ply I bought.

I'm happy to use MDF...It seems like all the DIY articles mentioned ply.

One thing...does MDF compress under repeated pressure from the ball bearings on flush cut router bits with repeated use?

I have shellac on hand. How does it help with the templates or jigs?

Thanks for all the advice.

RobSm

Yep, the MDF does compress a little. Depending on how precise your templates are would dictate how big a problem it might be.

If you drown all the edges in shellac (or anything else that will glue them up again, like glue size), there's a good chance the edges will hold up a heck of a lot better than raw edges will.

For some stuff, I rough cut, soak in shellac then finish cut when it's all dry. Very smooth, if a little sticky on the router bits.

As I said befor if you can use a whole sheet and you are considering durability you cant go past sign board.
cheers

Don't know if this will be any help.

6mm mdf between 3mm luan. Using 6mm mdf pattern and flushcut bit without a problem.

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