Lapping film question
- This topic has 4 replies, 4 voices, and was last updated 05/07/2018 at 12:00 pm by
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I don’t use lapping films, but if you’re referring to the diamond lapping films, no, paste is not used.
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The lapping film is a plastic type film with an abrasive of consistent size adhered to it. There are several different abrasive materials used to make lapping films: diamond, aluminum oxide and silicone oxide the three most popular. I find the Diamond Lapping film is the most efficient and most durable. They are just as their “name sake” a finer grit version of diamond stones. Also the most costly of the lapping films. The films are available with pressure sensitive adhesive, (PSA), on the backing. These are used like a band-aid and simple peel and stick to the blank platen you’re using. There are less expensive lapping films made without any pressure sensitive adhesive. These must be tapped to adhere or some adhesive used, (like spray rubber cement) to attach them to the blank platen.
I prefer to use PSA Diamond Lapping films adhered to blank glass platens like Wicked Edge offers. I do sand the edges of the glass smooth before I use the glass platens, the first time, to prevent a possibly sharp glass edge from scratching my knife sides while using the films. Some users prefer to use metal blank platens such as aluminum or brass mounted to WE handles because the metals are easier to sand smooth the surface and edges, compared to hard glass, also to prevent the metal platen from scratching the knife while using the films.
The films are used as they are applied to the platen, clean and dry, usually in a edge trailing fashion, (i.e., up and away, or up and off) the knife edge. The stroke is similar to that used with strops to prevent the films from being cut and gouged by the knife. Some users employ a side to side direction stroke longitudinally along the knife edge feeling it gives them the best, clearest, scratch-free, mirrored bevel appearance. Although this side to side scrub may sacrifice the edge sharpness some. I have experimented with a water spritz to the lapping film with no perceivable gains or enhancement so I now I only use them clean and dry.
Some users report they can use the same film to sharpen/polish 10 knives or more. There is no break-in period on the lapping films. I find, they are they’re best and most abrasive the first time you use a film and they wear from the first use on. The films can be cleaned to remove impregnated metal with rubbing alcohol on a clean paper towel.
The films are manufactured and described by grit particle size in microns and are used in a progression from large µ to small µ. They range from 30µ down to 0.1µ depending on the abrasive material and manufacturer. The normal progression is diamond stones through 1500 grit followed by 6µ DLP then down, 3µ, 1.5µ, 1.0µ, … as low as you chose to go. The very fine films sometimes are difficult to use and see improvement.
I have seen lapping films manufactured and offered in single, pre-cut to size strips, in full uncut sheets, (requiring you to cut-to-size the strips) and in precut cut/perforated sheets allowing you to peel off individual ready to use strips, (this is what WE offers).
Marc
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The diamond pastes are intended to be used with the strops. The lapping films are ready to use right off the sheet.
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You can finish or follow up any abrasive medium progression whether it be diamond stones, whetstones, ceramic stones, and/or any of the lapping films, with strops. There are various strop mediums also. Common ones include: cow and kangaroo leather, balsa wood, card board, and nano cloth. Some people use newspaper on a block as a strop medium.
Abrasives, such as diamond emulsions, diamond pastes or jewelers rouges, are usually applied to the stropping medium and used in a progression of decreasing particle size, analogous to all the other medium progressions, but stropping is generally the very last progression used.
Marc
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