It will work, but will eventually wary on you. 1/4" is just a little thin, I would use 3/8" or greater. Mine is 3/8" and hasn't warped yet in several years.
I used a 1/4" plate for the baffle in my Baby Bear but I really didn't leave it in long due the reduction in firebox size. For the 10 fires I did have it in there, it did not warp but I am not discrediting the aforementioned advice. With that said, I don't think it would cause any safety issues. For my new Momma Bear project I'm working on getting set up, I got a 3/8" plate from a local steel shop for $25. No way this one will ever warp!
The smaller the plate, (W x L) the longer it will last in 1/4"...baby bear plate a lot smaller than the larger models? If you don't run the stove too hard that helps the thinner steel last longer too...I made some secondary air tubes out of BIP at one point...worked fine until cold weather hit and I had to start running things a little harder...things drooped quite a bit after that.
Thanks to all. I’ll use what I have until it warps. In the mean time I’m on the lookout for a piece of 3/8” thick stock. Sent from my iPhone using Tapatalk