This is an instructable for a fire ring with a solar powered "flame stoker" made from an old PC fan and a motorcycle muffler.
Step 1: The Stoker
I made my stoker out of an old Emgo reverse cone muffler. Pretty much any rugged metal cone shaped thing should work, as long as it will funnel air.
For my build, I removed the baffles from the muffler, so I have a "straight through" funnel.
I made sure the PC fan will line up with the wider end of the cone.
Step 2: The Ring
I cheated a little bit here. I already had the overall structure of my ring built, so I tore down just what I needed to add the stoker. The ring that holds the wood is just a big old truck rim. I think it's from a cube van or something. I sat it on some bricks in the bottom so that air can come in from the bottom in the center. I put the small end of the muffler under the center of the rim. Then I busted up a small brick to "level out" the empty space around the muffler. Then I built up the bricks around the rim. I had a couple pieces of steel rod (rebar? Heck if I know!) in my shed, so I laid them across the center hole in the rim to keep logs from dropping in to plug the hole.
Step 3: Powering the Fan
Take an old USB cable (I used one from a broken mouse) cut it off, and strip the wires. You will need the red and black wires inside the USB cable, you can ignore the white and green wires. On the PC fan, identify the positive and negative wires. On my fan, positive is yellow, and negative is black. Wire the positive line on the fan to the red line on the USB plug, and the negative to the black wire. I like to use solder on things like this, but as long as your lines have a good solid connection, you can just use electrical tape. Seal up your lines, and make sure you have no shorts.
At this point, you *could* plug the fan into a USB wall plug (a phone charger) but I picked up a portable solar phone charger from eBay for like 15 bucks, this is what I will use to power my fan. It even has a nifty little on-off switch for added functionality!
Step 4: Finishing Touches
I found this grill insert at Lowes for 20 bucks (I was too excited to use it, so I didn't take a picture while it was brand new.)
I'm a utilitarian, and I like things that do multiple things, this is right up my alley!
Step 5: Fire It Up!!
Using the stoker for the first time, I wasn't disappointed. The stoker won't create a raging inferno, but it keeps a steady stream of air on the fire. It makes that "just right" kind of fire, if you know what I mean. The solar battery runs the fan all night, and never dropped below 75% of its charge! The heat stays away from the fan, too, so there's no danger of anything overheating.
Step 6: Closing Thoughts
I ended up using a different fan than pictured in the first pictures. It just seemed a bit too weak. You may need to experiment with different fans to find the one that works for you. The one I have pictured here works great for me. It doesn't fit as perfectly as the other fan, but it gives better air-flow.
After switching to this fan, the fire got so hot one of my steel rods warped!