DIY Chimney Flue Cap for Shed, Pizza Oven or Outdoor Wood Burner

A quick and (relatively) easy chimney flue cap for a workshop wood burner/heater, or outdoor pizza oven made from an offcut of flue.

Step 1: Getting Started:

Recently I decided to install a wood burner in my workshop after struggling through a few weeks of winter.
Once the heater was installed and the flue run up through the roof and everything cut to the correct height, I had a 42cm offcut of 6" flue leftover.
After having a look to buy a prefabricated flue cap and seeing that the prices started at $50aud, I decided to just make my own.

Step 2: You Will Need:

Materials:

Your flue pipe offcut
stainless steel pop rivets (dont use aluminium, they will melt eventually)

Tools:

Drill & bits (I used 3mm)
Pop rivet gun
Small clamp
Grinder (or dremel with cut off discs)
Tin snips
Gloves (I didnt use gloves, and well, most of the red in the pics isnt permanent marker...)
Permanent marker
Cardboard or thick paper

A hole punch or big nail could be handy too

Step 3: Cut the Flue Piece:

Using the grinder or dremel, cut along the edge of seam.
Once it pops open, carefully turn it over and flatten it out as best you can.
I used a couple of pieces of wood and stood on it. Actually worked out pretty well.

Step 4: Trace Your Circle:

Trace a circle onto your cardboard or paper and cut it out.
This will be your template for cutting the circle from your stainless steel so have a play around until you find the size that works best for you.

Draw a line down the center of the paper and cut it half way through so it can be folded into a slight cone shape, this is how big the finished cap will be.

When you have the size you need sorted out, trace it onto your flat piece of steel and cut it out with the tin snips.

Step 5: Folding the Circle:

Cut half way though the steel circle and carefully fold it into a cone shape like you did with the paper, use a small clamp to hold it in place, then drill and use 3 - 4 of the stainless steel pop rivets to secure everything.

Step 6: Supports:

From the offcut, I used some tinsnips to cut the seam from the edge, mine was 42cm long, so I cut it into 3 14cm pieces, drilled two holes at one end of each, and one hole at the other end, then bent the end with the single hole over with some pliers.

Pop rivet the end with two holes to the top of the chimney flue.

I installed mine on a 20cm piece of male edge flue which just needed to be slotted in to the top of the chimney on the roof.

Step 7: Putting It Together:

Drill 3 holes in the cone, line it up to the three holes drilled in the supports and secure with rivets

Step 8: Done!

Install it all on the top of your chimney/pizza oven etc and enjoy.
After installing this my wood burns longer, theres no down drafts, no more rain coming down to damp the coals and most importantly, no more sparks shooting out into the air.

Step 9: Enjoy:

Note: Before installing a wood heater on your property be sure to check your local laws, Im in a rural area so things are pretty relaxed, but I still had to make sure it was 3m from the property boundary line and reaching 60cm above the roof line.
Always better to check these things first.