I have made several. I like a metal piston but wood works well too. Get a copper plumbing fixture called? I dont recall. It is a copper tube and has about a 1/2 in ID and is closed on one end. Costs about $6.00 at ACE HDW.This is obviously the cylinder. The piston is made from a hardwood dowel. At the end of the rod ie. end grain, cut out a dished shape divot so you can put the charcloth in this divot. The divot should be about 1/8 deep or a little deeper. Whatever is need to hold the cloth. Dont make this recess too deep because it will lessen the pressure when compressed.Make a shallow groove around the rod about 1/4 in from the end, this is where the o ring is seated. Get a few 1/2" od and 3/8 "id o rings from ace.You will have to play with the size of the groove to get the ring seated so it makes a reasonably tight fit in the piston. Make charcloth and go at it. It will take some fiddling to get the hang of it.
You can cut the O ring groove with a pen knife or chuck it in a drill and put a small round file in postion and turn the on the juice.I just put my hand drill in a vise and set the trigger and file with the corner of a triangle shaped file.
You need to compreess hard and fast to get an ember. On a set up this size, I hold the cylinder and slam the piston.If the o ring is sealing properly, you wont bottom out the piston. You can start with a larger dowel and turn it down for the length of the piston . That way, you have a shoulder that will prevent the piston from bottoming out.
You could bang this thing a thousnad times and it probably wouldnt work because I left out a subtle detail.Most hardwood dowels are very porous. Coat the entire piston with some spray acrylic or whatever the stuff is called and let it dry before using. I assume any paint will also seal. Test by putting the end in your mouth (when paint or clear is dry and blow. If air still passes thru the wood pores, add another coat.
There is a lot on this on you tube and the internet. Seems impossible at first and then voila. Have fun.
After you make this clumsy sized piston, you will discover ways to make smaller piston from other material. If you want to be old school, you can put thread in the groove instead off an O ring. You will have to play around to get the right fit. Dont give up, they are easy once you get the hang of it.
