user801028

Thanks both. Your information made me see it is probably better to just go for the glass made for the job. I also learned a new thing in thermal expansion. When I was looking at the ads for the stove glass again I suddenly did notice thermal expansion mentioned for one and lauded at "nearly 0%".

Maybe a rudimentary question for yall but was not getting much useful information from diyers. I have a cooktop in a van with the normal heat resistant glass but due to the bumping around when driving as well probably to poor design quality of the glass it cracked. Rather than replace with another glass one which is liable to crack I thought why not replace with metal instead. The size I want is relatively small at 29x29cm. Thickness 1-3mm will do. In my naivety I did not consider the issue of warping at all and just bought standard 3mm mild steel since it was cheaper. Placing the metal in the recess and firing up the cooker the appliance didn't even have a chance to get through its run up cycle to reach full heat and the metal was already bending. At first I wondered what on earth was happening when I saw it raising off the ground then I twigged it was warping from the heat. This also caused diesel fumes, as that is what it runs on, to bellow out so I had to shut it down quick. Now I still have the option to use glass which is made for the job of withstanding cooking heat but if there is some metal that will resist the bending under cooking temperatures, I suppose a few hundred Celsius, then metal would still be preferable due to lack of breakage factor. As I thought and read a little more I realized stainless steel is used for much cookware and that doesn't warp. Also bbq and fast food cooktops I noticed use some kind of sheet metal where they fry stuff right off the cooktop so there must be some metals which will withstand it. Is that likely stainless steel too? Price wise it also seems not too much more than normal mild steel. So will that suffice? It really does have to be well resistant to bending because once placed on the cook surface, after testing it works, it will have to be sealed with heat resistant sealant to keep the fumes contained in the burn chamber and vented out. So it must maintain its form under constant heat and over time. Will stainless steel still be suitable given those requirements or is something else better, again, considering price? It should be at most as much as a ceramic/glass cooktop which comes to about 40-80 gbp for the size I want.