When I first tried to make my own bone folder, I couldn’t find any good instructions online so I cobbled this process together from various sources, and from my own experience making other things.
So this is how I make a bone folder.
Buy some bones.
I’ve found beef bones the best from what I have available. I tried lamb bones, but they are too small and the bone wall is too thin. So see if you can get a cow leg bone. At Queen Victoria Market here in Melbourne, they sell them as “marrow bone”. I get the butcher to cut the ends off the bone. Just try to get them to make sure they cut as close to the knuckle as they can so you get the longest bit of straight bone you can.
(Most of the instructions here for preparing the bone comes from this page on Cleaning bone for musical instruments.)
Boil the bones for about two hours.
[I don’t have a photo of the boiling process, but I think people know what a pot of boiling water looks like.]
This is to get all the meat off the bones. I find that 2 -3 hours is enough. After that, I take the bones out of the water and scrape them clean with a knife. This gets almost all of the meaty stuff off the bone. Remember, you only want the straight part of the bone, but I boil the knuckles as well and save the water for soup as it’s now a very nice beef broth.
Let the bones dry a little for 24 hours.
Don’t leave them for too long as the bone marrow is still inside and it will do two things if left too long:
- First, it will go off and start stinking. Not nice.
- Second, the fats in the marrow will start to stain the bones.
Once the bone has dried a little you can cut out some blanks. Look at the bone and try to identify the flattest side. The bone tends to have facets and one of them will be flatter and straighter than the others. This facet will make the best bone folder. Mark out the shape of the facet. I use a coping saw (fret saw) to cut out the rough shape. Keep in mind that you can probably get 1 or 2 more bone folders out of the bone. They won’t be quite as good/long/straight as the main one, but if you cut carefully, you should have enough material for 2-3 folders in total.
Clean and degrease
Once you have cut the bones you will find lots of bone marrow inside the bones. This stuff is full of oils and will stain the bone if not cleaned out. Scrape the inside of the bones to clean as much of the material as you can.
Once you’ve got it as clean as you can, it’s time to degrease the bone. Use purified petrol/gas. It’s sold in hardware stores in Australia as Shellite. I’m not sure what it’s called in other countries. You need to find a container big enough to hold your bone blanks and have them covered in the shellite.
Leave them to soak for two weeks.
After soaking, take them out and let them dry for 24 hours.
The bone is pretty hard, so I use a belt sander with a rough grit to shape the bone folders. I turn the sander upside down. Mine seems to sit well upside down without any help, but you may need to put yours in a vice. Just make sure you don’t cover up the air vents. This may take a while and don’t want to overheat (and kill) your sander.
Shape your bone folder on the sander. Try to get the shape as finished as you can but don’t take off too much material. You won’t get a second chance.
I start with 80 grit sand paper by hand to refine the shape and get out the sanding marks. I progress through 120, 180, 240, 280, then finally 320 grit paper for the final polish.
Pay attention as you go. My first attempt left me with very sharp edges. Sharp enough to cut stuff. So take your time and make sure you have a generous round over on the edges. You are going to be working with paper so you want the tool to score the paper, not cut it.