Playing with fire: setting up a clay chimenea

Clay Chimenea from Home DepotI bought a clay chimenea at Home Depot during one of the end-of-summer sales.

In reading the comments before making the purchase, I learned a lot about curing the chimenea; fortunately, I remembered this because the included instructions say nada.

What is a chimenea, you ask? It is a freestanding outdoor fireplace shaped like an upside-down lightbulb; typically they are made of clay.

However, you can also buy one made of cast iron or cast aluminum. Metal ones are more weather-resistent than clay.

Before you light a match

Before you start your first fire, here’s how to extend the life of your clay chimenea. Clay is very absorbant and brittle, so a little planning will go a long way towards extending its life.

  1. Figure out where you are going to put the chimenea; this is where you should assemble it. Be sure it is clear of any overhanging trees or brushes that could catch on fire from the chimney exhaust. Keep it on its stand for use. If it is going to live on a wooden deck, consider how you will protect the deck from embers or sparks (e.g., UL Listed stove mat or hearth board).
  2. Insulate the bottom of the chimenea; the fire should not rest directly on the clay. How? Line the bottom of the chimenea with lava rocks (the kind you would use in a gas grill, for example) or pea stone or even sand (although some people recommend against sand). The depth needed depends upon your chimenea; fill to within about 1/4 of the bottom of the mouth. So if there is a 4″ drop, you’d fill the bottom with about 3″ of insulating material.
  3. A clay chimenea will need weatherproofing even if it had a finish when new. Two products have been recommended by several sources (off-label use!): Future floor wax (now Pledge) and Butchers wax. Another source recommends Thompson’s Water Sealer. Apply to the outside of the chiminea; spray or rub on using a clean rag, towel or cloth. Your goal is to seal any pores or hairline cracks not visible to the naked eye. Only seal the outside, not the inside, of the chimenea.

Next, season the chimenea

You will burn small, controlled fires to season the inside of the chimenea.

  1. Start your fire on top of your insulation layer of sand or rock. Consider using a small log rack or a couple of bricks to provide additional circulation beneath your wood.
  2. Build a small fire with a few pieces of kindling and (news)paper; no lighter fluid, gasoline or other liquid fire starter (clay is very absorbent). Then let the fire go out naturally. Never put out a fire using water; the shock will probably crack your chimenea.
  3. Let the chimenea cool completely before starting another fire. You should season the chimenea with 5-10 small fires, each slightly larger than the one before.
  4. In curing, your chimenea will accumulate spent ash in its bottom and soot on its interior walls.

Everyday use

  1. The chimenea will pull a strong draft, so place a few sheets of balled up newspaper near the front of the chiminea. Then rest kindling against the paper. Light the newspaper and then it will light the kindling as the draft intensifies. Then you can add more kindling or a few small logs.
  2. Start a small fire and then slowly add larger pieces of wood to prevent shocking the clay with abrupt temperature changes. The clay expands as it is heated; heat too fast and it will crack.
  3. Keep the fire in the center of the bowl.
  4. The chimenea will get very hot. Be sure to keep pets and children at a safe distance and don’t let them touch the chimenea.
  5. If you have flames coming out the top of the chimney, you’ve gotten too carried away as a fire-maker!
  6. Should you need to quickly stop a fire, use sand or a dry chemical fire extinguisher. Remember, no water.
  7. Do not use in the rain or when wet, because clay is very porous and the odds of developing a crack are great.
  8. If your wood is green, you’ll have sparks. Fashion a spark arrester using piece of chicken wire or small-holed fencing.
  9. Charcoal will burn too hot; stick to wood.
  10. Tools to consider: long-stemmed matches or butane lighter, a poker, fire gloves and a dry chemical fire extinguisher.

Storage and weather protection

Normal Pacific Northwest winters are mild enough that keeping the unit covered is probably sufficient protection. Where temperatures get significantly below freezing and stay there, the chimenea should be garaged. Most sources recommend storing a chimenea on something other than its wrought iron stand, like a pallet, and removing the insulating stone/sand.

Protect against precipitation by using a cover. There are several available on Amazon.

Periodically, reseal the exterior. I’ve read once a month and I’ve read a couple of times a year. I think it depends on the weather where you live and how often you use the chimenea.

 

Resources

 

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