CUTTING MIRROR BLANKS AND TOOLS




Cutting your own mirror blanks is not a difficult task to accomplish, all you need is a piece of scrap metal or pipe , some wood, and a drill press. The only limiting factor regarding the size of mirror you can cut is the throat of the drill press. Small mirrors in the order of 6" - 8" are easy to cut, larger ones may pose the odd pitfall.

Start by cutting a piece of metal for your pipe remember to keep it square, your stretch out, or length will be your desired mirror diameter x 3.1416. remember to allow 1" extra for your lap to join them together. Galvanized steel is cheap and easy to come by , if you can locate a piece of perforated metal your way ahead of the game already. Lets say your making a 6" mirror , your piece will be 19 7/8" x 6" to 8" the length isn't critical just so long as there is enough clearance . Scribe a 1" mark for your lap form up your metal cylindrically clamp or screw it on either end and solder it , use a 50/50 leaded solder and muriatic acid (HCL) as a flux. remove the clamps or screws and peen the seam down flat . Cut 2 discs out of a good quality 3/4 plywood the inside diameter of your pipe, so for us this will be 6" , and cut 1 at 1" larger than your pipe , so in our case it will be 7" ,the larger disc only has to be 1/4" ply but 3/4 " will work just as well. Stack all your discs on centre and drill a 1/4" diameter hole through them. Screw one 6" disc into the centre of the pipe ,slide a piece of redi rod through the hole and double nut it on both sides. Screw the 7" disc to the 6" disc ,make sure the holes are aligned , then double nut it in place and screw it to the pipe. If your not using perforated metal and want to put relief cuts in your pipe to aid in water/abrasive abrasive flow feel free to do so . If your pipe isn't perfectly true don't worry about it , this will actually work in your favour as the slot cut by your tool will actually be wider than the thickness of the pipe wall and will aid in water and abrasive flow.



I generally place a piece of rubber underneath the glass prior to cutting and fabricate a crude dam 1" wider that the cutting tool , you can stick in place with some butyl tape ,window putty, or whatever you have at hand.


You may clamp it to the base plate of your drill press but be careful to pad your vice- grips or clamps and be sure to clap it with very very minimal force. Remember glass loves to break.



The key to doing this successfully is to keep the glass cool, heat is our enemy . Use 80 grit carbo and lots of water, if the glass starts to get warm take the apparatus apart and cool it down with water. Don't take any chances it's not worth it!!!



I generally cut 90% of the way through , seal up the groove with putty to stop the abrasive from running out then flip the glass over and cut from the other side. This really helps to minimize chipping. I never cut with constant pressure, I prefer to cut with short rapid strokes which helps the abrasive and water to flow between the cutting tool and the glass, I also run the corner of my sharpening stone around the groove of the glass and give it a slight bevel , this also lessens the chance of chipping by the tool.





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