Trex Groove Cutter

[Modern Garage]

I posted this question in General Garage Discussion , but thought this might be a good spot to ask also.
I'm building a deck expansion and the decision has been made to use Trex decking on new and old and I have some joints that will require me to route fastener grooves in the ends of some of the decking. The decking grooves are a molded-in rounded profile and the Trex cutter makes a similar rounded profile. I worry that a square cut groove will be weaker and am wondering if anyone here has any experience with this issue.
I'm probably overthinking this and a $50+ router bit is small potatoes compared to the ching I'm dropping on this project...

Joe

 

[tarbellb]

No specific experience with your issue, but I have worked with Trex plenty. You can run a router bit, blade, etc.. just keep rpms in mind, it can and will melt sometimes with higher rpms.

Grab whatever profile bit you want and go to town, most modern routers have variable speed and you can find the sweet spot.

 

[tyyost]

I used my PC 557 biscuit jointer to slot my trex, worked fantastic, no issues 6 years later with the square corners. I found the jointer worked well, and was easy to use in place, where routing may have been an issue

 

[Modern Garage]

Thank you for the replies. It seems the Trex is on back order so I'll have plenty of time to play with various tools and maybe even find someone who did a deck and wants to sell me their cutter.
Well, hope springs eternal, right?
Joe

 

[MN_Pete]

I saw The Deck Store recommending the TigerClaw slot cutting bit as a substitute for the Trex bit. https://www.thedeckstoreonline.com/trex-decking-hideaway-hidden-fastener-system-router-bit-groove-cutter.html

It cuts a straight groove (with a very small radius at the corners) instead of rounded like the Trex. I bought and used one last year and didn't have any issues with it.

https://www.amazon.com/gp/product/B0026SRHKA/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

[rlitman]

I used my PC 557 biscuit jointer to slot my trex, worked fantastic, no issues 6 years later with the square corners. I found the jointer worked well, and was easy to use in place, where routing may have been an issue

That's what I'd use. just cut the biscuit slot where the fastener goes and don't extend it into a full groove. It'll be WAY stronger like that than it would be as a full length groove, even with radiused corners.

Keep in mind that not all composite decking is created equal. Timbertek for example has a weak foam core underneath a hard solid vinyl shell. Slots cut through the shell will be weak, no matter what the profile. Trex is the same consistency through and through, so slotting it is fine.