Both balsa strops and abrasive pastes have been used for a long time in an effort to improve an edge, maintain an edge, or just simplify or economize the process of making a razor sharp. Generally the results leave something to be desired. You can take a perfect lapping film edge or Jnat edge and actually make it duller with poorly conceived pasted stropping methodology. But if you do it right, it works crazy good. IF YOU DO IT RIGHT. Do it my way and you can improve a good edge whether it is from Jnat, Thuringian, Welsh Slate, Cnat, Arkie, synthetic stone, or lapping film. Lapping film is the ideal precursor to the pasted balsa strop, but it works on any edge if that edge is fine enough to treetop arm hair. You can improve virtually any good edge, and then maintain it perfectly.
Like most of my tutorials, this does not involve learning. Learning takes time. Learning requires intelligence. Learning is subjective. Learning is abstracted away from the actual task. Learning is good but not necessary and will slow down your pursuit of excellence. This tutorial is not about learning. It is about doing. It is about following instructions. It is paint by the numbers. Get that straight right now before reading further. Learn on your own time. Right now you will just DO, not learn. DO. According to the instructions. Newbies are particularly welcome because they have not already spent years learning razor sharpology. Newbies are a blank slate hopefully open to suggestion. Newbies that have tried and failed to create great edges are particularly well prepared for this tutorial.
First, the absolute most important thing you must know about this method is it does NOT WORK if you don't do it right. If you "freestyle" it, cut corners, make substitutions, or think that this or that detail just isn't important, you will find out why abrasive pastes are not much used for edge maintenance or finishing. It is because they have a demonstrated history of giving meh results, even backing up an edge in some circumstances. It ONLY WORKS IF YOU DO IT RIGHT. But then, it does work sooooo nicely! If you can't follow directions, or WON'T follow directions, please hit your "BACK" button now.
Okay, did we get past that little bump in the road? Good. Now first let me tell you what this method will and will not do. It WILL keep your sharp edge, sharp. It WILL take a very sharp edge, and improve it. It will NOT make a dull edge sharp. It will NOT make even a so-so edge sharp. When used properly to maintain a sharp razor, you should never have to hone that razor again, ever. EVER.
Start with a piece of balsa. Please, don't cut corners. Get a piece 3" wide, 12" long, and 1/4" thick. This is the substrate. This is what will carry the abrasive. You can get 36" long pieces at Hobby Lobby or other hobby shops, or online. Cut a 36" piece up into 3 pieces. Did I say one piece? I meant you need three pieces.
Next, you need a base. A dimensionally stable base. NOT WOOD!!!!!!! Wood warps. It matters. Not soft bendy plastic. It bends and twists. Not even thin glass. Thick glass, such as from a glass coffee table top, would work except it is too thin. A polished marble 4x12 edge tile or "Bullnose" tile would work, but it is a bit clumsy and heavy, and still too thin. A 3" wide by 12" long piece of polished marble tile would work except still too heavy and too thin. A similar piece cut from the sink cutout from a polished granite countertop would work except it is too heavy. Lately I have been using 3/4" or 1" thick acrylic. Thinner is no good. You absolutely do not want thinner than 3/4" thick. It must be dimensionally stable. It must be reasonably light. It must be thick enough to not put your fingertips where the razor can slice them off. Serious. Play right, or don't bother. Oh, and you need three of these. My source is TAP Plastics but there are others. TAP has good prices.
If you think these details are not important then you will fail. If you think you can freestyle it and do it your own way you will fail. If you think I am full of crap you will fail. If you are not intelligent and meticulous enough to follow simple instructions you will fail. You may even think you succeeded and proved that I am wrong but you will have failed and not realized it, not knowing that you made a good edge but not a Method edge, and nowhere near the potential sharpness of the steel. Or maybe you will realize that your edge is not what it could be, and wonder what went wrong, and the answer I am giving you right now. You did not follow directions. If you can't or won't, then don't waste your time reading this. Just don't. Because you will fail.
Follow the directions exactly and you will succeed. And to recap, you need an edge that is already very sharp, treetopping sharp. You need balsa, and 3/4" acrylic, and you need three pieces of each, 3" wide and 12" long. What did I say? You must follow directions exactly. If you are saying "that's bigger than it needs to be" then you will fail. I promise. Okay and you need glue, either spray adhesive or rubber cement. I will give you the choice. I prefer 3M spray adhesive.
Glue the balsa securely to the base. I use 3M Spray Adhesive and that is what I recommend. Turn it base upward on a smooth table and weigh it down in lieu of clamping.
Here is part of the secret. You must LAP the balsa. To do this, carefully glue a whole sheet of 200 grit sandpaper to a very flat and smooth surface. The same spray adhesive works good. A light spray is all that is needed. Keep the sandpaper stretched tightly as you press it down, starting at one corner. It is extremely important to not allow any lint or air bubbles or wrinkles under the sandpaper. Now take the balsa strop and lay it balsa down on the sandpaper, and rub corner to corner. Don't overrun the edges more than you have to. overrunning causes a slight dish in the surface of the balsa, which you most certainly do not want. Keep rubbing until you have a whole new surface. Then you know that the balsa is as flat as the sandpaper. Smooth is not the goal. FLAT is the goal. Flatter than you can eyeball or estimate with a straight edge. If you want, you can repeat with finer sandpaper up to 400 grit or so. It really doesn't help to go any finer than 400 grit.
Next, you need some diamond paste. Ted Pella is where I used to get mine but now I mostly just get it off ebay. NOOOOOOOOOOOOOO!!!!!! Do NOT try to substitute other stuff! When it doesn't work you will think I WAS THE STUPID ONE, not you!!! Use diamond. Not diamond spray. Not slurry. Not powder. Paste. Not Chromium Oxide, not Iron Oxide, not any proprietary paste no matter how many glowing reviews you read about it. Diamond paste. This is a Diamond Paste method. Yes, .1u CBN has been used successfully. I don't care. Get diamond paste. You want the following grits: .5u, .25u, and .1u. DO NOT allow any cross contamination. Even a minute amount of coarser grit on a finer grit board will totally defeat your best efforts. LISTEN TO ME. The details are important. You have been warned several times now.
Start with the finest grit, the .1u diamond. Apply an amount about equal to two or three BBs to the balsa. It will seem like it is not enough. Trust me, any more is TOO MUCH, and believe it or not, your results will suffer. Divide and spread this tiny amount over the balsa and rub it into the balsa. This is the secret. When it is rubbed in to the balsa, only part of each crystal is above the surface of the balsa. You do not want a coating. When you have too much or it isn't rubbed into the balsa, you have a billion microscopic diamonds rolling around like little nano-boulders, and the edge is colliding and smashing into them. This is called the slurry effect. It cuts steel quickly but the edge will be vastly inferior to what you could be getting. Wash your hands well. Apply the .25u to the next board. Wash your hands. Apply .5u to the final board. Rub rub rub. Two or three BBs worth only. Now wipe the excess off with an old tshirt. Yes, there is excess. Wipe it off. Don't argue, just do it.
Now you have your pasted balsa strops, properly prepared, ready for use. Take your sharp razor that you just shaved with or just honed to a VERY GOOD 12k edge or better, carefully wipe it by pulling it through folded toilet paper, and begin stropping on the .5u balsa. Contact the balsa with the spine first, then let the edge come down with the spine remaining on the balsa. Technique is critical. Now with both spine and edge on the balsa, stroke the razor with the spine leading, to the end of the balsa. To turn, flip the EDGE over, keeping the spine on the balsa at all times, and once again stroke the razor spine leading. That is one lap. I recommend about 50 laps, more if experience tells you that you need more. It doesn't hurt a thing to go a couple hundred, if there is any doubt. Light, very light pressure, of course. There isn't much feedback, so go until you are getting an improvement in sharpness as indicated by treetopping or HHT. Light pressure is the key. Once you have the stropping motion down, and the feel of the razor on the balsa, begin holding the balsa vertically, one end up and one end down. Now you can strop using less than the weight of the razor. This is very important!
DO NOT rest the balsa strop on a flat surface or fixed object. Hold it in hand. (Watch out, don''t slice off your left hand fingertips!) This is important. Ignore me if you like, but don't tell me the method doesn't work if you stubbornly refuse to do it right. Hold the balsa in hand, loosely, arm and hand and balsa sort of floating in space in front of you. The razor and balsa can then find their own alignment. And yes the balsa is wide. Still, I recommend using a slight "x" stroke. In other words, pull the razor slightly across the balsa as you stroke it down the length of the strop. Also, halfway through your laps for the stage, turn the balsa around. Let the end that did point toward you, point away from you. This equalizes the wear and tear on both sides.
The next stage is finer, and you must be absolutely certain to not get even a crystal or two of the coarser grit onto the finer grit balsa. So between grits, always wipe the razor carefully. Wash your hands with soap. Strop on the .25u about the same number of laps. Repeat the process, guarding against contamination, on the .1u board but I recommend going about 100 laps the first time. Light pressure. LIGHT pressure. I mean it. LIGHT LIGHT LIGHT pressure.
Not done yet. Next, a few "pull" strokes. This is when the razor is laying on the balsa, and you pull it straight toward the right hand edge about 1/2" or 3/4". This helps strip any fin edge away that may have formed. Flip the razor and do the other side. Flip flip flip. About a half dozen pull strokes on each side. Then about ten more regular laps, the lightest pressure you can manage. See the page on pull strokes if you don't understand.
If you did this correctly, you have a very very very sharp razor. To test, sweep the razor 1/4" above the skin of your forearm. ABOVE, not touching. It should neatly sever the tips off at least a couple of hairs. More = sharper. Quieter = sharper. Less snap back = sharper. If it doesn't even drag on the hair at all, it just plain doesn't move, and it gets a bunch of hair tips treetopped in one stroke, it is science fiction sharp. Witchcraft, sorcery sharp. Mystical legendary sharp. But just a hair or two is good. If not, then try again at 1/8" above the skin. If it won't treetop hair at all, even at 1/8", it is not fit for shaving. But if you followed instructions and started with a good edge, the improvement from the balsa routine will give gratifying results indeed. Now, strop on your regular hanging leather strop, and the razor is good to go.
I strop on the balsa after every shave, and strop on the clean hanging leather strop before shaving. My daily post-shave routine is 50 laps on the .1u unless the razor seems to be losing its blistering frightening sharpness, then I double the lap count. If that doesn't seem to work then back up to the .25u or even the .5u but normally the fine grit is all I need. I refresh the balsa with more diamond about once a month. Don't do it too often or use too much. You will defeat your efforts and get inferior results. If you do this correctly, you will never need to re-hone your razor.
For post finish after honing on a 12k grit stone or 1u lapping film, do the same way. If you only have say an 8k stone or 3u film for a finisher, you can use 1.0u diamond paste and then the other three. Get another piece of balsa and acrylic, and set it up. 1u is approximately equal to a 12k Naniwa stone.
Be careful. Your razor is now sharper than you are used to. I recommend reducing your shave angle so that there is a gap between your razor's spine and your face of about 1/2 the spine thickness. Stretch the skin nice and tight. Watch the pressure. Sharp sharp. You will pay in blood for any carelessness. But it will shave like never before.
FOLLOW THE DIRECTIONS. If your results aren't so hot, you did not follow directions. Don't bother asking for help because you won't listen, anyway. Do it again, and follow the directions. The Method won't let you down as long as you don't let The Method down. If you get the amazing results I am promising you, then do some more razors. Reinforce the instructions in your noggin. After you have put insane edges on a half dozen razors, do feel free to experiment. If anything gives you better results than The Method, you are doing The Method wrong.