Composite Decking

[Birdhunter]

i am repairing some outdoor fixtures for my club. The original structure was made of pressure treated 2X6 boards. Boards that lay essentially flat have rotted. i am using composite boards 1X6 to replace the rotted boards.

Home Depot refused to cut the boards saying their saw blades would be ruined. i had a Festool jigsaw with me so was able to cut the boards down to where they would fit in my SUV.

I called Forrest (I use their blades). They recommended using a cheap throwaway blade.

It surprised me that the composite decking would ruin a high quality carbide blade.

 

[CeeJay]

I cut a bunch of composite decking recently. I didn’t notice any issue with my blades. Used a Dewalt 6 1/2” blade on my cordless circular and a Diablo 10” blade on the chopsaw.

Sent from my iPhone using Tapatalk

 

[Michael Kellough]

Cutting composite decking does dull a carbide blade much faster than cutting natural wood but it doesn’t ruin the blade.

 

[waho6o9]

Interesting thread......

 

[peter halle]

It has been a couple of years since I did a composite deck, but in the course of that deck I had to rip a bunch of boards using my TS-55.

Yes, the material did dull the blade faster than wood have, but I managed to power thru at a much slower rate towards the end of the project.

The blade didn't appear to be damaged but is in the pile to send out for sharpening.

Peter

 

[CeeJay]

Likewise my Diablo blade was on the ‘needs a sharpen’ pile after the composite until I dropped it and broke 2 teeth off….

Sent from my iPhone using Tapatalk

 

[jamesckelley]

i am repairing some outdoor fixtures for my club. The original structure was made of pressure treated 2X6 boards. Boards that lay essentially flat have rotted. i am using composite boards 1X6 to replace the rotted boards.

Home Depot refused to cut the boards, saying their saw blades would be ruined. Since I was working on composite decks, I brought a Festool jigsaw and was able to cut the boards down so they would fit in my SUV

I called Forrest (I use their blades). They recommended using a cheap throwaway blade.

It surprised me that the composite decking would ruin a high quality carbide blade.

Hello. Yeah, I’ve run into the same thing before. Even with high-end carbide blades, cutting composite decking eats them up way faster than normal wood. My advice is to use a cheap, throwaway blade for the rough cuts like you did. Once it’s roughly cut to size, you can switch back to your quality blade for any precision trimming or finishing. Also, go slow and let the saw do the work. Composite generates heat fast, and forcing it will just wear your blade quicker. Masking tape along the cut line can help reduce splintering too. It feels overkill, but it really saves your good tools.

 

[Packard]

I asked Google why? And they were polite enough to reply:

Composite decking dulls saw blades quickly because it is a highly abrasive, dense material composed of plastics and wood fibers that generate intense heat, causing "gumming" or premature wear. Unlike wood, the mixture of plastic resins and filler materials acts like sandpaper on blade teeth, requiring carbide-tipped blades to prevent melting, fraying, or rapid degradation.


I would guess that a blade with a large tooth offset would mitigate the heat build up. If you are using a battery-powered saw, I guess you could use a a ketchup squeeze bottle to lay down a bead of water to reduce heat too.

Ha hand saw would not generate much heat—and would give you a good arm workout.



I would note that about 20 - 25 years ago, they passed new regulations on what chemicals could be used to create pressure treated lumber, and the early versions were not very good. I understand that the PT has improved over the years.

The same thing happened when they outlawed asbestos for brake linings. I used to get 30,000 miles out of a set of brake pads, then the price doubled and I would get 8 to 10 thousand miles. My last brake job lasted 103,000 miles (mostly highway, and I am easy on brakes—I rely on my horn mostly.)

 

[demographic]

Ive used the polycrystalline diamond tipped blades on my HKC for the highly abrasive decking boards that have the epoxy and what seemed to me to be sand mix on a trench in the board.
Normal TCT blades didn't last a full morning on those boards but the PCD blades (they only had four teeth, with tungsten carbide teeth and a PCD layer of about a millimetre* thick on the leading edge of the tooth) lasted for weeks of hard use.

They sounded a bit odd while cutting as with only four teeth the noise was much deeper than usual but they cut just fine. It was a Dewalt PCD blade.
Normal composite boards Ive used have been nothing like as abrasive as the ones with the sand in them and have cut well enough with a normal TCT blade.
Possibly slightly more abrasive than a plain wood board but thats what cheap blades are for.




*A millimetre is about a 560th of a Cubit for those of you still using the Liberian measurement system.