Help! Cutting Hardie backer - is it safe?

[curlywurly]

Please help!
I have bought some hardie backer 500 to make a built in bath.
I need to cut an elipse out of it and my partner has looked at the label and says he's not keen to cut it as its toxic. Also, not sure what will actually cut through it.
I'm wonding if it is a health risk and whether I should change it for No More Ply but can't find any info about its composition. Is is the same or safer and easier to cut?
Many thanks!

 

[cornish_crofter]

Cutting hardibacker is fine provided you do it in a well ventalated area and wear a mask/follow their COSHH advice, which you can find on line.

Don't go for those decorating masks at 99p for 10. they are not good enough. You need P2 minimum. These should cost you around £2 each at Brandons or similar.

Ideally, cut it outside and you have the option of damping the area to be cut with a damp sponge to keep the dust down.

These are really not that hazardours if you compare them with asbestos.

To cut on a curve, you need to mark it out and use a jigsaw with a medium or course blade.

There are many old wive's tales about how dangerous certain materials are. For this reason I always go back to the manufacturer if I am concerned.

 

[pete f]

hardibacker do there own cutting tool its good for straight cuts or angled straight cuts you just scribe it on the board and snap it like plasterboard no dust

 

[oogabooga]

If you only cut hardi every now and then, and with a decent dust mask, you'll have no health issues. Constant exposure to the silica dust over the years would be another story - you'd run the risk of developing silicosis. Same could be said of sawdust though (or virtually any other dust particle) breathe in enough of that long term and you'll damage the tissue in your lungs.

Use a carbide scoring blade and the dust will be minimal, just score and snap.
You can tidy up the edge with a razor knife if it is needed.

 

[sranners]

i wear a mask and i cut with a angle grinder, it is very dusty though! never tryed the jig saw will give it a go in the morning.

 

[cornish_crofter]

The reason I mentioned a jig saw is because the OP wants to cut an elipse, I assume for an inset bath.

The hardibacker tool is great for straight cuts, I use one myself.

 

[curlywurly]

Hi
Thanks for your replies. have decided to stick with the Hardie backer. It sounds as if its no problem to cut straight edges, but yes I do want to cut out an ellipse for an oval bath. I have bought some P3 masks and some medium grit jigsaw blades. Hope they will do the job?!

 

[kaharrison9]

I've recently used medium grit Plasplug jigsaw blades which were reduced to 99p for 2 on Hardie backer board.
Couldn't have been any easier taking off slithers or curves and didn't even blunt the blades.
Kev

 

[cornish_crofter]

Are you using the term elipse in its true sense, or as another term for a radius?

If it's a radius, as mine was, a string line from the centre of the curve and a pencil on the end is a great way of marking out.

 

[curlywurly]

Are you using the term elipse in its true sense, or as another term for a radius?

If it's a radius, as mine was, a string line from the centre of the curve and a pencil on the end is a great way of marking out.

Its an ellipse. I'm going to put the bath upside down on the board and mark round it. Then cut about an inch inside the line.