Welding: Protect benchtop/floor from heat with HardiBacker?

[Bolster]

Guys help me out here...I need to do some welding of 1 or 2" square tubing with my little oxy acet rig, but I don't have a good surface to lay out my project on. I need a couple square feet of good working space to do it. I don't want to burn my formica laminated fiberboard benchtop (obviously), and I don't want to set the project directly on my shop's concrete floor.

I have a large piece of 1/2" HardiBacker Cement Board left over from a job, I would like to use that if possible, no additional investment needed. What do you think of using that as a backstop for my welding project? Will getting HardiBacker hot, cause any unforeseen consequences?

 

[snorky18]

You thinking of putting the Hardi on the cement floor or on the laminate bench top?

I would think it would be fine, especially if you're just talking about incidental flames from the torch hitting the Hardi ocassionally. Main thing is not to burn yourself on it; it will probably stay hot for a while.

If it were my house, I would experiment with it (with garden hose / fire extinguisher ready just in case) and see if there are any adverse affects.

 

[blazemaster83]

I work as a glass artist, and I use hardibacker for my benchtop. It can take some serious heat. I lay molten glass on it all the time. If i can lay a 1 inch molten chunk on it, and everything is ok, i think youre fine.

The only thing i dont like about it is it can start to break down after a long time, and gets everywhere.

 

[Bolster]

Cool!

I was going to place the HardiBacker on my cement floor and just work there...or possibly suspend a piece of 3/4 ply over saw horses and then place the hardibacker on top of that, if the work pieces are short enough that level doesn't become an issue.

I do know that you don't want to be breathing free-floating HardiBacker dust. I recall it is a silica product. I always wear a 95 NIOSH-style dust mask when cutting or drilling it. So I assume long-term flame may disintegrate it, and it's probably a good idea to wear a mask if the HardiBacker is disintegrating. Cheap enough you can just get another piece of it if it starts to deteriorate.

 

[blazemaster83]

I have a 2200 cfm ventilation system above my bench. I didnt really think about fumes or dust, good thinkin!

 

[Bolster]

Goodness! That must **** all the oxygen out of the room!

 

[Iron-Iceberg]

I have a 2'x2' piece with a length of alum. angle screwed to one side. I clamp it to the edge of my bench when Im grinding to keep the sparks from shooting all over the shop.