So gonna be making a little folding three sided deal out of ply wood to sked the flame of my fish cooker from the wind . What can a guy put on the ply wood as a heat shield? So it doesn't burn if I have to put it kind a close ?

Have any fire blanket around from a welder shop?

Asbestos

Screw hardybacker or concrete board to it

Get a piece of light sheet metal, bend it in 1/2 round shape to wrap around the cooker and forget the plywood.

Yep just use tin. Often the simple solution is right in front of us. If you need the wood to keep tin in place wrap the wood with tin and leaves an air space between them.

a metal garbage can bottom cut out , cut down one side , open up a bit is what we used on the fish cooker

a cut down part of a 55 gallon barrel would work well also

on boiler room doors they shielded the door with tin, usually galvanized tin , but if you need to have tin to shield the wood then even easier to not use the wood for structure and just use metal for the structure , your the welder man.

these are my Uncles fish boil pots they are SS speed queen washing machine tubs with a SS patch welded in the hole where the agitator would have gone through.
the stands are just angle iron and flat
the heat shields are old garbage cans
the bottoms had a way of rusting out around here so cut them of and a cut down the side and perfect heat shield noting to burn

my uncle made the gas burners before he retired from the ship yard we used to always build would fires but LP makes it all much cleaner to pack back up in the truck and regulate heat and you can boil fish nearly any where now

used to be at the end you tossed a half pint of Kerosene or #2 on the fire and you got a big fireball for a over boil and it carried the grease off the top onto the fire
he mounted a sieve on a broom handle and you scoop the foam as it comes to the surface and swish the baskets up and down once and it does the same thing without the show and again opens up where you can boil fish at

Cardboard backing,..take rhe time to ser it up

Get some of those old knob electric wire insulators that they used years ago in knob and tube wiring insulation, and run a screw through a piece of cement board, then through one of those knobs, then into the plywood, leaving a 2 inch air space all along the bottom of the thing.
Of course place the cement board towards the heat source. You will get a good updraft between the two boards and create a good heat shield.

Cement board. It’s cheap.

Yes, plywood will burn.

I use scrap tin but love the metal trash can ideas above. I even have a metal can with the bottom already rusted out.

THIS!

Fiberglass sheet

fiber glass is polyester resin on glass fibers it burns the resin

ever seen a fiberglass boat that caught fire

Tin

The barrel idea or the trash can look like the simplest and the better ideas.