FB, Did you repair from the inside of the barrel previously? Rough of the surface at the crack. Use some sort of plastic or fiberglass webbing and cover with epoxy resin or glue. Should work. Has to be done from inside the barrel. Don't breathe the are inside the barrel for too long or use a small fan while doing the job. JMHO Aloha

Thanks all for commenting. Of course we know it's not about "fixing the crack", but more about garden whimsy and perhaps a little encouragement to look differently on whatever seeming defects come up like that wonderful admonition of making lemonade when life gives you lemons. Making the sign on the back of a large iron skillet that my friend passed along is taking more time than making the 'river'. IF it turns out okay I'll post a picture. Happy whimsical gardening!

Shellac sticks come in all colors - you heat the shellac stick until consistency of putty then fill crack - use hot knife to smooth surface before it dries (dries pretty quickly) - once dry can be polished to match luster of chair. Can purchase at woodworking supply, art supply and online - run @ $4 per stick - it's what restorers use to fill and color match cracks in furniture.

Best way to do this is to chase the crack with a chisel and clean up the edges. Buy 1/4-1/2" closed cell backer rod, you can get it on amazon for $6. Put that inside the crack along entire length about 1/2" deep and in the same place you can order and get Quikcrete Cement Crack Filler (home depot might be cheaper for this item) You can also use Sika or Quikrete self leveling concrete filler it sold in most Home depot stores HD also sells the backer rod, but I'm not sure if they have 1/4" or 1/2" I think they only have 3/4"... just make sure to get the one intended for concrete not windows (frost king brand), it would be Sika brand usually, they would know "hopefully". Good luck