[amricca]

Anyone else have a hard time score and snapping hardibacker? I scored it deep and the break was real ugly. Maybe there is a trick?

[massplumber2008]

Amricca... dewalt sells a tool for this... an electrical shear like tool (others sell similar as well) that is great as it cuts smoothly with almost no dust whatsoever. BUT it is around $300.00 or so... *frown*

Now, I am not going to admit that I suggested this... because I'm not suggesting anything... :cool: BUT a lot of the guys in the trades use old circular saw blades/circular saw to cut hardibacker (VERY VERY DUSTY.. so cuts must be made outside and you MUST wear a good quality respirator... ok?)

I have seen some use diamond saw blades in rotary tools like the rotozip or angle grinder... This is what I do as well. It is also very dusty so need to be outside with a mask on as well.. OK? I think this is your best bet.. almost everyone has an angle grinder.. or can purchase for 50-60 dollars or so PLUS cost of diamond blade (30-40 dollars).

Otherwise... just got to score that hardibacker on both sides of cut and then snap... that gives pretty good cut... but hard on hands.

Hope that helped. I am sure a few others will be along soon with other ideas.

[hkstroud]

Well, I just score once (on the smooth side) and snap. After snapping, I cut the glass fibers on the other side. I didn't know anybody cared that much. I get a straight but not a smooth (like a sawn) edge. Now, I'm talking about the Durarock brand of cement board. Don't know if there is a difference.

[massplumber2008]

Hi Harold... yup durock cuts different than hardibacker... hardibacker requires more passes with a knife than durock. Durock is more brittle so follows the score better (like sheetrock really... huh?). Hardibacker is less brittle so seems to break unsmoothly if not scored deep enough. I got tired of pressing knife so hard... finally went over to scoring with diamond saw... very quick... messy but nice clean, smooth edges. Hey! Talk soon.. Ok?

And HArold there is a guy at plumbing post (bakerb is name) post reads something about initial rust in water (posted last couple days)... has PUMP system. I know you know way more than me here... you mind popping over and seeing if you can shed some light? Complains about excessive rust in water... I told him it is sediment buildup that gets disturbed every time he changes filter (changes every 3 weeks!? ).. Anyway, pop in and see what you think. Thank you... MARK

[hkstroud]

Just as an aside here. On drywall, if I want a to smooth the edge of a cut I use a little Surform block plane. A couple of strokes will really clean up a edge. Don't know if it would have any effect on hardibacker or not.

[glavine]

You can buy a tool for hardy backer that is basically a single carbide tooth on a handle for scoring backer, this also works on durock as well. Lowe's also sales a mini saw for 85 or 90 dollars that is basically a small skill saw with a grinding blade on it. This is what I use myself
You can also use a grinder as well. Keep in mind to wear safety glasses and there is a lot of dust so do it outside

[ballengerb1]

Glavines got this one. The tool is just a square cut tempered piece of steel that cuts a trench into the Hardoebacker. I usually give it two or three hard passes and it will snap but not quite as clean oir easy as drywall. It is much better and quicker that cutting with a circular saw, you mus have a mask if cutting with a saw.

[the1unv]

Hello,
I cut all my hardi-plank with 7 1/4" saw. I use a blade made by HITACHI. The blade is acctually called the " HITACHI HARDI-BLADE". It only has 4 carbide teeth on the entire blade. It is dusty but a lot less dust then all other blades I have tried... and I think I have tried most of them. I always cut with the finished side down for a smoother cut on the finished side. I hope this helps.
Mike

[ballengerb1]

Thanks for that tip, I'll be looking for that blade since I will be doing lots of inside corner cuts this weekend. Got to spread the ratings around before I can give you another greenie but thanks.