cutting 1/4 inch plywood

[joesxm3]

I am doing a repair project at my father's house and delivered some 1/4 inch sanded plywood to use to cover some holes in the walls. The plywood is there and I am here, so I can't do a test cut.

I have a Makita circular saw with a Diablo blade in it. The writing on the blade is mostly worn off but I can make out "60" which I assume is the tip count and "Ultra". Looking on Amazon there is a Diablo Ultra fine cut blade.

I hardly use the saw and have had it forever. I would guess that I replaced the blade with the Diablo at some point. Probably bought the blade at Home Depot since it does not show up on my Amazon order history.

About 10 years ago I did a lot of cutting on some very nice 3/4 inch plywood and the saw had no problems doing a nice clean cut. That makes me think I may have bought a special blade to cut plywood with.

My basic question is whether there are complications between cutting 3/4 inch plywood and cutting the thinner 1/4 inch plywood. That is would the thinner plywood be more prone to chipping or cracking on the edge when cutting? If this blade was successful on 3/4 inch is it likely to be ok on 1/4 inch?

Of course I will do a practice cut to be sure, but if that goes badly I will have driven an hour only to postpone to get a better blade.

Thanks.

[wolf]

If my memory is correct. I remember using a circular saw blade, especially made for
plywood. It had many, many, many, little cutting teeth.

Look it up.

[skyking1]

Set the depth so you don't go too far through the wood. IF you want really precise clean cuts, you may want to score the top ply right on the edge of the cut with a razor knife and straight edge.
I use a clamped straight edge for a guide when cutting finish plywood.

[BrianB]

I always put a strip of 1.5" painter's tape across where the cut will be, on both sides. The tape reduces the tearout & splintering, reduces marring from the saw's shoe, and gives you a place to draw your cut line without marking on the wood.

BrianB

[mountainsoft]

Whenever possible, I cut plywood (1/4", 1/2", or 3/4") on my table saw (good face up), or with my tracksaw (good face down). The tracksaw actually leaves a better edge as it has a rubber splinter guard on the guide, but setup takes more time and my guide is limited to about a four foot cut.

Otherwise, a circular saw with a straight edge and a fine tooth blade should work fine. Put the good side down so any splintering occurs on the back side. As others mentioned, you can put painters tape on the cut line before cutting to minimize splintering somewhat.

Depending on the situation, you could also get good results with a router using a flush trim bit and a straight edge.

[joesxm3]

Thanks.

I had not thought about having rough side up.

I have a nice clamping straight edge that I have used to guide the saw, but it is only 6 feet and my pieces have to be 7 feet. Just occurred to me that I can possibly use one piece of plywood to guide the other or maybe bring a 2x4 and some clamps.

[sengsational]

One trick you can try if you are getting too much break out is flipping the blade over so that it's teeth are backwards. It's slower, but with some materials, still plenty of progress, and a much smoother cut.

I also like the pre scoring with utility knife idea, by I'm usually too impatient to get the score and the cut aligned, so end up with a bit of a mess.

[target2019]

You need a fine tooth blade to improve the plywood cut. Even a cheap, new plywood blade will suffice.

Use 2x4's under the sheet to support the sheet and reduce flexing. THe thinner sheet will flex more than 3/4".

Cover the saw shoe with tape to prevent marring.

Cover the underside with tape to reduce breakout of fibers and you rip.

The depth of the cut should be slightly more than the thickness of the sheet.

If a neighbor has a table or radial saw, that is a real time saver.

[Surewhitey]

Good side down for sure. The splintering will mainly be across the grain. 60 teeth blades should do a good job minimizing tear out. Tape on the top of the sheet, cross grain if you are anal...

Some cut on top of foam insulation sheets for support...

[Music Lover]

I've cut through 1/4" plywood with a utility knife. Although, it depends on how many cuts you need. But it works without splintering.

[retire48in2018]

If you are cutting with grain - more teeth is better, and set depth to just barely more than you need. Tape may or may not help. There are ultra fine finish blades that work excellent.

If you are cutting across grain - there will be chips and splintering no matter what - especially with a harder wood vs softer wood. Going too slow or with too many teeth can sometimes over heat or cause burn marks. Maybe not in 1/4”, but be aware. Certainly need blade in proper direction. Going steady pace, maybe with tape, maybe precut with box cutter - but still a risk. (We’re taking small imperfections/dents along cut - not large splinters). Using exhaust system to suction dust/debris definitely helps as well.

I try my best to always cut with grain. If you have to cut across grain (cross cut) - and it’s a hard wood or thicker - you should use a different blade. If you want a perfect finish, I cut a little wide (1/64th or 1/32) than sand it to size.

[Out-to-Lunch]

Quote:

Originally Posted by joesxm3 Thanks. I had not thought about having rough side up. I have a nice clamping straight edge that I have used to guide the saw, but it is only 6 feet and my pieces have to be 7 feet. Just occurred to me that I can possibly use one piece of plywood to guide the other or maybe bring a 2x4 and some clamps.

You can make a 8' straightedge cutting guide from a spare piece of plywood:

https://www.youtube.com/watch?v=-6tUyID8Sws

[pb4uski]

Quote:

Originally Posted by BrianB I always put a strip of 1.5" painter's tape across where the cut will be, on both sides. The tape reduces the tearout & splintering, reduces marring from the saw's shoe, and gives you a place to draw your cut line without marking on the wood. BrianB

+1

[l8_apex]

Seconding the suggestion to put a piece of masking tape on the good side of the plywood where you'll make the cut. 60 tpi should be fine. IIRC, I've got a 80 tpi blade which would of course be a bit better.