A few years back I went to the national trappers convention in escanaba mi. I camped out on public land to say money rather than renting a room. Rooms were all booked up anyway. Down in the woods were I set up camp there was a pile of debris. Looked like someone burned down a outbuilding, shoveled it in a truck and dumped it in the woods. Being the scrounger that I am, I scrounged up a big splitting maul head, no handle. Yesterday I picked up a fiberglass handle for it. I'm not much for fiberglass handles but they are tough. The handle is set into the head and a epoxy is applied to the eye and let set up. I think the head may have got hot but don't think heat treat is that critical for a splitting maul. I like the toughness of these handles and will leave them back in the woods were I cut firewood.
here's a link to the handle I used. They seem to hold up pretty good for me. https://www.homedepot.com/p/True-Temper-36-in-Replacement-Fiberglass-Handle-2036100/202057450
I like fiberglass handles on my shovels, hoes and rakes. I tend to be hard on tools. Especially handles. Fiberglass will take a lot more pressure than wood. I do prefer wood handles on my axes. I usually carve the handle down from factory size to suit my hands and to reduce weight. Hadn't thought about fiberglass on a maul, but it makes sense. Dale
I have a few rakes and hoes that I welded on a handle made from 1/2 inch galvanized pipe. I leave my hoe in the garden year round.
My luck I would constantly get my hoe against the electric fence and "light up my life". LOL! That is a great thing about fiberglass. No worries with electricity. Dale