Advice on plywood tearout...

Can you guys give me some advice on how to best avoid tearout on edges of hardwood ply. Blade recommendations (circular saw), technique, tricks, etc. Thanks! Sorry for all the noob questions lately! Anyone herte live in the Asheville, NC area? Peter
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snipped-for-privacy@gmail.com wrote:

Use a new plywood blade (lots of small teeth) and run some masking tape (blue) over the bit you are about to cut. The side the teeth enter will get less tearout than the side the teeth exit. Hope this helps :) You could also pre-score the cut and/or put on a backer board.
Damian
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Are you going to cut a lot? Festool has a circle saw and blade that does not tear out on top of bottom when using its guide bar. I would not have believed that had I not seen it.
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snipped-for-privacy@gmail.com wrote:

If you are using a circular saw, get a finishing blade. High tooth count, from a quality manufactuer. They aren't that expensive for a circular saw. Also, adjust the base so that the blade is only slightly higher than the thickness of the plywood. If the blade is fully extended, you have a greater risk for tearout. But the "good side" (the side that will be most visible) in contact with the saw. Tearout is more likely to happen on the bottom side of the cut.
The other thing I've noticed is that sometimes the plywood you are cutting is more prone to splintering when cut. I bought some 1/2" stuff for drawers at Lowes that was horrible.
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On 8 Dec 2006 12:17:33 -0800, " snipped-for-privacy@gmail.com"

* Use a hollow ground veneer/plywood blade * Cut from the backside of the sheet (I find this to be the best method/tip and it leaves a near perfect edge) * Cover the entire cut line with a piece of scrap ply or other thin material *Cover the cut line with tape * Do not feed to fast
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As Joe indicated, one general rule of thumb is to try cutting plywood with the good side down when using a circular saw, and the good side up with a table saw.
May not totally solve the problem, but doing so, along with other suggestions like an appropriate/sharp blade, will definitely give you a better chance of success
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snipped-for-privacy@gmail.com wrote:

so I did use a utility knife blade and make a very shallow cut first and then actuely did use Router to make a rabit, it turn out it did had zero tear out after cut, if you can make exact cut aling the knife cut, surely you will get no cut, as long as you use a decent blade. Again, if you are going to make a litle cut one or two ply cut, this is the best method worked for me, other wise the other methods worth a try suggested by others. However I did not have good results with masking tape. Max
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snipped-for-privacy@gmail.com wrote:

I had to make a cross cut on Birch Ply and could not have any tear out, so I did use a utility knife blade and make a very shallow cut first and then actuely did use Router to make a rabit, it turn out it did had zero tear out after cut, if you can make exact cut aling the knife cut, surely you will get no cut, as long as you use a decent blade. Again, if you are going to make a litle cut one or two ply cut, this is the best method worked for me, other wise the other methods worth a try suggested by others. However I did not have good results with masking tape. Max
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snipped-for-privacy@gmail.com wrote:

I had to make a cross cut on Birch Ply and could not have any tear out, so I did use a utility knife blade and make a very shallow cut first and then actuely did use Router to make a rabit, it turn out it did had zero tear out after cut, if you can make exact cut aling the knife cut, surely you will get no cut, as long as you use a decent blade. Again, if you are going to make a litle cut one or two ply cut, this is the best method worked for me, other wise the other methods worth a try suggested by others. However I did not have good results with masking tape. Max
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Thought I'd never say it, but a few years back I bought a Bosch jigsaw to replace my 30 yr C'man, and now it's my choice. With the "progressor" blades and one of those clamp-on fences, it's incredible. You can even cut lauan with minimum splinter.
Just bought the eldest one for Christmas. SiL gets a PC speedbloc. I still get to buy tools with a full shop this way.
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To get minimum tearout with my circular saw I put a piece of 3/8 plywood on the base of the saw with a hole large enough for the guard to operate through it but with an area just ahead of the guard that I plunge cut a slot only the width of the saw blade after mounting the wood to the base of the saw. It becomes sort of a zero clearence insert that holds the plywood cut edges down as the saw teeth cut up through the board. I also use a thin kerf high tooth count plywood blade like the other posters are suggesting. It works great for minimizing (nearly eliminating) tearout, but it restricts the view of the cut line at the point of cut. I've considered making a new one out of clear lexan so I could see the cut line better, but the the wood version has done the job for long straight cuts using a guide and that's all that I've been doing so it hasn't mattered much. My shop is small, so I precut sheets to workable sizes on sawhorses in the driveway.
I'm a few hours drive from you, just North of Charlotte.
--
Charley


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Thanks for all the help guys! Charley wrote:

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snipped-for-privacy@gmail.com wrote:

very fine triple chip blade will reduce splinter out to almost zero
mark your line with a craft knife
cut your ply from the back
When using power saws go slowly
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