Hi I have a soil warming cable and thermostat that I used to have in a sand
box on a bench in my greenhouse. However it was very heavy and my bench
collapsed. So I thought I would update my bench and propagator and use the
soil warming cable to make a pad similar to this.

http://www.keengardener.co.uk/produc...cm-(42w).rails

So what type of material should I use to make the pad from? And how would I
fix the cable to the material? I suppose I could put it in the middle of
two layers and sew it in place with nylon fishing line but would that melt
with the heat?

I did try using a sheet of expanded polystyrene but the cable is melting
into it plus I used cable clips and they keep coming out of the polystyrene
and I am worried it might catch fire.

So any suggestions?
Thanks, Jenny

On 22 Mar, 18:10, "Jenny" wrote:
So I thought I would update my bench and propagator and use the
soil warming cable to make a pad similar to this.

I don't think you can. The lightweight pads have a distributed heating
element, you have a cable. Your conversion is going to need something
that spreads the heat from the cable sideways a few inches, and holds
the cable in an evenly spaced zig-zag.

Simplest option sounds like reinforcing the bench and a thin-layer
sand box, with the cable in it. Maybe use a lighter compost than sand,
or damp wood ash.

Alternatively, a sheet of thin metal with insulation beneath it.
Polystyrene might do, if the heat is more distributed than bare cable.
Otherwise a layer of wood ash, which is light and a good insulator (so
long as it's dry).