# Cutting pressure treated lumber



## klr650

I'm beginning the process of building my new shop addition and will need to lay the flooring soon. That means lots and lots of pressure treated 2x8s. What kind of blade should I use to cut pressure treated, presuming I DON'T expect the blade to last the cuttings. It's my understanding that pressure treated lumber is heck on saw blades because of the metallic compounds in it.


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## mdntrdr

24 tooth carbide 7-1/4" blade. :smile:


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## klr650

This is the one time I wish I bought the sliding compound miter saw instead of the vanilla compound miter saw. Every 2x8 will have to be flipped to cut all the way. Although i guess I can use a circular saw - I just hate using one for some reason, probably because I couldn't cut a straight line freehand to save my life.


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## mdntrdr

I wouldnt put my miter saw through the abuse of cutting PT framing lumber. :no:


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## Willie T

Don't freehand. Use a framing square to guide the circular saw.

And why lift all your lumber to a miter saw? Simply carry the light little circular saw to the pieces of lumber wherever they lay.


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## firemedic

Willie T said:


> Don't freehand. Use a framing square to guide the circular saw.
> 
> And why lift all your lumber to a miter saw? Simply carry the light little circular saw to the pieces of lumber wherever they lay.


That's right... This came up a couple months ago... A speed sqaure will make for easy accurite 90's and 45's...

~tom


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## klr650

It may be a moot point - at 12x6 the building is perfect for a 2x8x12' with a few odd sized to tie it together. But I'll take a look at a speed square - no reason not to learn a new technique.


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## ihackwood

do it this way and it will be super fast, measure your lumber, and set your speed square. then when ya mark all the rest of the lumber mark where your speed square goes, lay the square make the cut,

layout all your lumber at once and then cut it all, its alot quicker than having to go back and forth,


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## Daddy's Cool

klr650 said:


> This is the one time I wish I bought the sliding compound miter saw instead of the vanilla compound miter saw. Every 2x8 will have to be flipped to cut all the way. Although i guess I can use a circular saw - I just hate using one for some reason, probably because I couldn't cut a straight line freehand to save my life.





mdntrdr said:


> I wouldnt put my miter saw through the abuse of cutting PT framing lumber. :no:


 
I think you may be missing a golden opportunity here. Put your current miter saw through the abuse, which will then justify the need for a new, sliding compound miter saw. :yes:


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## NorCal Scot

Not trying to push a product here. However, since you say you will be cutting with a circ saw, I'd recommend the Diablo Demo Demon 7 1/4". It'll stand up to the abuse you'll be throwing at it.


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## Ycreek

What's the deal with treated being so abusive on blades? I've never noticed anything like that. Am I missing something?


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## mdntrdr

Ycreek said:


> What's the deal with treated being so abusive on blades? I've never noticed anything like that. Am I missing something?


 
I've ripped miles and miles of PT, and never noticed it being any harder on blades either. :smile:


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## jschaben

mdntrdr said:


> I've ripped miles and miles of PT, and never noticed it being any harder on blades either. :smile:


Same here, PT is generally wet and soft but I haven't found it particular abrasive. MDF, particle board and plywood, yes:thumbdown:


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## klr650

Depending upon which type you get PT is loaded with metallic compounds, as well as the chemical soup that it is injected with - which of course is why it's heavy and soggy when cut. It may not be as bad as hardiplank or the like - but it definitely will eat a blade.

But that brings up a point, mdntrdr, why did you post this comment: "I wouldnt put my miter saw through the abuse of cutting PT framing lumber."
if you don't believe it to be worse than normal lumber?


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## firemedic

klr650 said:


> Depending upon which type you get PT is loaded with metallic compounds, as well as the chemical soup that it is injected with - which of course is why it's heavy and soggy when cut. It may not be as bad as hardiplank or the like - but it definitely will eat a blade.
> 
> But that brings up a point, mdntrdr, why did you post this comment: "I wouldnt put my miter saw through the abuse of cutting PT framing lumber."
> if you don't believe it to be worse than normal lumber?


If he's like me, it's because he has too much invested in his saw and blades and built in table and fine tuning to drag it out to a construction site and throw 6x8 LOGS on it... I no longer do rough construction for a living and don't have a saw dedicated to it now... 7 1/4", 9" circ & 15amp recip saws works just fine for me 

~tom


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## dat

only thing I've really noticed that you have to watch for with pressure treated is the fact that it is usually wet, it can bind or kick back more than dry wood if you aren't carefull


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## Fishbucket

Watch for splinters getting infections.


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## mdntrdr

klr650 said:


> But that brings up a point, mdntrdr, why did you post this comment: "I wouldnt put my miter saw through the abuse of cutting PT framing lumber."
> if you don't believe it to be worse than normal lumber?


 
Cutting any 2 X framing lumber with a miter saw puts undo stress on a saw that should be reserved for precision cuts IMO. :smile:


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## dat

it is much easier on a saw to cut purpleheart or birdseye maple than pine :yes: :laughing: :thumbsup:


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## ed_h

I haven't found PT lumber to be particularly hard to cut or hard on equipment. It's much easier in both areas than, say, Ipe.

The worst thing abourt PT is that it is often wet and heavy.

Also, the presence of a metallic compound doesn't imply in any way that you are cutting metal or anything necessarily abrasive.


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## jschaben

I suspect that the problem is a buildup of gunk on the blade that makes it want to pull down. A good cleaning should take care of the problem. 
I also don't see where cutting 2x pine construction lumber puts any more stress on a saw than 1x oak or maple. Assuming both are properly supported. 
On the other hand, I also don't throw it in the back of the truck and trundle it all over to jobsites either. Most I will do is move it to the backyard/patio for picnic table/deck work or some other domestic project.


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## klr650

firemedic said:


> If he's like me, it's because he has too much invested in his saw and blades and built in table and fine tuning to drag it out to a construction site and throw 6x8 LOGS on it... I no longer do rough construction for a living and don't have a saw dedicated to it now... 7 1/4", 9" circ & 15amp recip saws works just fine for me
> 
> ~tom


 Well okay I guess I can see that side of the coin. I only use mine for construction - for woodworking I use a sweat powered miter saw. I tend to think of a powered miter saw as a construction tool only.


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## NorCal Scot

As people have previously mentioned, the wetness of the PT lumber can cause uncoated blades to bind. Don't mistake paint for coating...

A dust mask is nice too...that PT stuff is yucky. No more arsenic though...


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## MJames53

klr650 said:


> I'm beginning the process of building my new shop addition and will need to lay the flooring soon. That means lots and lots of pressure treated 2x8s. What kind of blade should I use to cut pressure treated, presuming I DON'T expect the blade to last the cuttings. It's my understanding that pressure treated lumber is heck on saw blades because of the metallic compounds in it.


 MJames53, post: 203150, member 510
Do you want makes a blade for treated wood, But they are pricey. I was building stairs for my deck and wanted to use treated wood and so they’re form all I did was go buy a brand new blade for my skills saw That was made for wood It was called a demo blade. It cut through that treated wood like butter perfect!


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## Brian T.

Cutting freshly treated lumber will throw a lot of spray of preservative. Wear a serious chemical mask with the correct filters. You never need lungs full of that juice.


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## DrRobert

klr650 said:


> It may be a moot point - at 12x6 the building is perfect for a 2x8x12' with a few odd sized to tie it together. But I'll take a look at a speed square - no reason not to learn a new technique.


+1 on the speed square. I had to cut a notch out of the lip on for my saw.

Running the joists in the short dimension is more efficient b/c you can run the flooring lengthwise with less cuts - 1 1/2 4x8 sheets plus a half sheet coming back with the overlap = 3 sheets. Plus you only need 2x6's.

Joists lengthwise, you'll have to cut a sheet 6', leaving a 2' piece of ply which coming back the next row can only span one 16" joist space so you lose 8" of plywood.....

What am I missing?


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## Rebelwork

I just used the Dewalt slider to do my deck. What's a $30 blade. Saved me time...

I've got a worm drive and a speed square. I use neither...


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## _Ogre

ten year old thread here


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## Brian T.

PT lumber lasts along time in pictures.


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## allpurpose

Letting the sopping wet treated stuff dry might help.. I absolutely HATE wet treated wood, but that's me..


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## allpurpose

Brian T. said:


> PT lumber lasts along time in pictures.


Even longer in the movies! Not that I've watched too many movies about pressure treated lumber. Maybe it's a new genre.. Pressure Treated Nior..


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## GCTony

I enjoy seeing some of these older threads pop up from time to time. When I started house framing around 40 years ago, the cut man cut off the lumber stack with a worm drive and rarely used a square, yep he was good.

I made a nice outdoor shooting bench/table for a friend about a year ago. Made it like I would make a indoor piece of furniture. That crap from the PT gunked up the inside of my planer, the jointer, table saw and that was after I let it dry a couple of weeks. PT sucks.


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