How to Make an 'everlasting' File to Deal With Callosities on Your Feet, Hands and Body

This is an instructable that has evolved from a presentation made over fifteen  years ago to help individuals with neglected callosities, corns and warts on their feet, hands and other parts of their  body. This tool was meant to be used after soaking the part in water or if preferred on dry skin, it is supposed to gradually abrade the keratin off a little bit every day till the skin becomes soft and pliable. While the original purpose was as a grooming tool, it was found to be a good general purpose finishing tool in the workshop!

Having made one such device for myself as a grooming tool about twenty years ago (and still using the same tool occasionally  without any refurbishment ) I believe it does qualify for the 'everlasting'  prefix.

ITEMS  REQUIRED :
Silicon Carbide Waterproof / Emery / sand paper (grade or grit 150 to 220)
A piece of wood (14 x 2 x 1/4 inches)
A tube or can of quick drying adhesive
A  scissor, utility or sharp kitchen knife
A wood file, (not essential)

Step 1: Getting Started…

Some details to understand the items listed:
The Silicon Carbide Waterproof abrasive  paper:
This is chosen because it is water proof and virtually lasts forever when used on skin and nails. Should it lose its abrasive ability, all one has to do is wash it with water and its original abrasiveness is restored.
Sand paper and aluminium oxide / emery cloth can also be used but cannot be refreshed. Should either lose their  abrasiveness, they would have to be removed and replaced with new pieces of paper / cloth.

Step 2: Choosing the Abrasive Paper

Choosing the grade …
Waterproof abrasive paper is available from any hardware store.
The grades / grit recommended (220 to 150) are reasonable for use on skin and nails. 
The higher numbers indicate a finer texture the lesser the numbers the coarser texture
These grades are commonly available at most hardware stores and are quite cheap
A sheet is usually 11 x 9 inches in size.

Very fine grit paper  (220) should be used if one intends to use the tool as a nail file  and the coarser grade (180) if one is intending to use it on skin.

Step 3: The Wooden Slat

The wooden slat that was used in the instructable was two inches wide, about  fourteen inches long and a quarter inch thick. The wood slat was picked off a pile of waste wood. It was not especially planed or polished, it was given a once over with coarse sandpaper so that any splinters or loose fragments were removed. 

Step 4: Using the Adhesive

It is preferable to use a  waterproof adhesive ( e.g. rubber adhesive),  this permits the emery paper to be used after a bath while the skin is wet and to wash the tool when it requires to be cleaned.
The rubber  adhesive solution is spread evenly on the smooth side of  the adhesive paper using  a spatula (I used fingers as can be seen in the illustration). The non-abrasive side of the emery paper is coated with a thin layer of adhesive, the adhesive is allowed to dry. The wood slat is coated with adhesive in a similar manner using a spatula (so as not to get splinters into the skin of the fingers).  After application of the adhesive it too must be allowed to dry.

Step 5: Applying Adhesive to the Wooden Slat

Spread the  adhesive on all four sides of  the wooden slat in preparation to attaching the emery paper to it. It is important to have sanded the wood down to remove any splinters before using your fingers (as I did) to apply the adhesive. Once the adhesive has been applied set the slat aside to permit it to dry.

Step 6: Positioning the Wooden Slat on the Abrasive Paper Prior to Adhesion

The adhesive having dried on both, the paper and wood slat , the slat is being positioned preparatory to compression on the emery paper. This step has to be carefully performed, for once the abrasive paper adheres to the slat it cannot be readjusted.

Step 7: Attaching the Abrasive Paper to the Four Sides of the Slat

The abrasive paper is carefully rolled onto the wooden slat before pressing so that there  are no air bubbles / pockets left between them.

Step 8: Trimming the Excess Abrasive Paper

The excess abrasive paper is being removed by the use of a scissor (in the picture).  A sharp utility or kitchen knife can be used instead. Caution is recommended when using the utility or kitchen knife so that personal injury  or damage to the surface on which it is being used is avoided.

Step 9: Marking the Proposed Shape of the Handle

The bare portion of the slat that will go to make the handle is marked. Though making a handle is not an essential step, it is one that makes the file very comfortable to use, and therefore recommended. The handle is easily fashioned using a coarse wood-file or rasp.

Step 10: Shaping the Handle With a Wood File...

A coarse wood-file can be used to shape the handle, the portions that are to be removed having been previously marked.

Step 11: The Handle Beginning to Take Shape

This picture shows the handle beginning to take shape. Once the required shape has been achieved the uneven areas may be smoothed down using any remnants of the abrasive paper, making the handle splinter free and smooth.

Step 12: The Final Shape of the Handle on the File...

The waist of the handle having been formed the end has also been rounded off to make the handle comfortable to hold while in use. The file is now complete and ready to use.The exposed wood (handle) may be waxed or polished to make it water-proof and comfortable. A hole could be drilled into it for hanging or the handle made bulky by gluing two pieces of wood on either side of the bare area of the slat to give the handle some substance...