One of the things that are most used for the finishing of a knife is the abrasive metal paper that will “go away” in large quantities.
Abrasivepaper, sometimes also called sandpaper, is used to rough, smooth and clean wooden or metalsurfaces.
The abrasive paper you will use on the steels of the knives before and after the temper and for the finishing of the handles in the various materials, from the most “common” wood, to the G10, Micarta, Bones, Synthetics, etc.
The weights of the abrasive cards range from the largest to the finer according to the type of finish you want to get.
The grain and abrasive capacity
The abrasion capacity of an abrasive paper is indicated by a number called
grain that is
printed on the back of the sheet as happens with abrasive tapes.
The higher the number the finest the abrasive and as a result the smoother thefinish.
Clearly, to get a good job you need to perform gradual steps from one grain to another until you reach the desired end result.
Some makers always go from the same direction, others weave the passes from one grain to another to highlight “the scratches”.
Personally I always run the passes in the same direction and the ideal is also to get used to following the same linearity.
This method is especially good if you make finishes from 600 and 800 to have the signs all in the same direction without creating waves or curves.
To achieve this it is better to make a precise and steady hand even if you go in the same direction.
Ps. Then do with the best method for you to get the result you are looking for, there is not only one way.
The number used roughly corresponds to the number of meshes that a sieve, used to separate the abrasive dust, has per linear inch.
The acronyms of the grains
The grain numbers, according to the classification of the European Federation of Card Abrasive Manufacturers (FEPA P), can be:
12, 16, 20, 24, 30, 36, 40, 50, 60, 80, 100, 120, 150, 180, 220, 240, 280, 320, 360, 400, 500, 600, 800, 1000, 1200, 1300, 1500, 2000, 2500, 3000, 4000, 5000, 6000, 7000.
The number is preceded by the letter P but the letter P is not always indicated.
The grain of sandpaper is printed on the back for easy identification.
There are other classification standards, such as ANSI (American standard) or JIS (Japanese standard).
The coarse grain corresponds to low numbers, to the fine grain high numbers.
Another more coarse way of pointing to the grain is:
- large, suitable for roughing operations;
- average, suitable for intermediate processing;
- ,suitable for finishing operations;
- veryfine, suitable for smoothing and smoothing.
- ultra-fine,suitable for polishing and shine.
Anyway I’ll tell you the most common are from 40/60/80/100/120/150/1500/2500/3000/5000/6000
Which one to use depends on the degree of finish you want to achieve, it could be enough up to 800 if you want to get a satin effect at 800 or 600.
At the beginning you just need the 120/180/220/400/600/800 but clearly the more intermediate steps you have, the simpler and cleaner the job.
You can buy them in various shapes and formats:
In pre-cut sheets usually in A4 format and in ribbons to be cut as needed in roll or sheets.
Prices vary according to brand, grain and ability to work as well as dry even with wetcanvas, by the type of flexibility.
In fact the abrasive paper consists of a flexible support, which can be paper, canvas or other, covered for bonding with crystalline granules of abrasive material, which can be glass, emerald, aluminum oxide, silicon carb, zircone.
Depending on the composition, you will
thus have more suitable sandpapers
frosted canvases that are suitable for
It is also marketed in other forms for electro tools, round, rectangles and triangles, with and without holes for orbital sanders, discs for the platorello or joined ring for tape sanders, etc. but are not suitable for the construction of the knife where that kind of finish is done by hand.
The assortment of abrasive paper can be used in dry and wet conditions, but do not add soap to the water because the soap damages the sand and the neckline from the paper.
I personally use abrasive paper that can work in wet conditions.
How to use abrasive paper
The abrasive paper can be used for various operations such as:
- Putting the knife flat after the discounting or possibly after cutting the bar, if you do not have a tombhead to do the grinding (rectifying) is something you need to do by hand with a feedback plan and abrasive paper.
- For the surface finish of the knife (saturation, polishing, etc.), after you have hardened the knife and finished with the tape sander.
- For forming the handle in different materials.
- et cetera.
The abrasive paper is used by hand generally folded on itself or fixed to a more or less rigid and sometimes even shaped support, but apart from on the tape sander and on the platorello plane the operations with the abrasive paper is manual.
Ps. Sandpaper is mainly used for woodworking, while the emerald canvas is mainly used for the processing of the metal, but I personally always use the same type of paper.
Supports for abrasive paper
For convenience my advice is to cut yourself while you work the sheet of abrasive paper or striped tape in the various grains that you will use of the size of the support that you will use to help you.
The supports are usually wooden bars or in my case alumi with under a rubber on which you rest the canvas, much more comfortable than by hand and more precise having a wider surface.
Then you can make small shaped supports to get to the smaller and more complicated areas.
Everyone has their own method and watching videos on YouTube you will find different ways to support yourself, from those who use compact solutions to solutions with wider sockets.
Find the method that allows you to get the result you want.
Clearly the more the finish of the knife is of quality and the more abrasive material you will use and will take time to complete your knife.
This is one of the things that makes the cost of the knife grow a lot in terms of indirect materials used (tapes and paper) that in order of time for the maker.
These are operations that require patience and a lot of practice, especially if you want to do quality sadithes.
Even more complex for mirror polishings that are really complex to achieve an excellent result and requires many hours of work in addition to the use of special abrasive pastes to use with fabric wheels, etc.
My advice is to buy quality abrasive cards because even during work their durability on hard materials such as steel improves by saving you sheets or meters of abrasive paper.
There are several brands on the market, some of which are different with the same grain, to feel the difference and find the one offering higher quality.
My advice is also to prepare yourself before working the strips already prepared of paper in the various grits to give a good continuity of work and not having to stop constantly to cut other pieces of abrasive paper.
Consider that you will not be working with full sheets or large tiles so having the abrasive strips of the size you need ready can be useful and allows you not to waste paper.
Good luck with your work
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