Glass Grinding Guidelines

This is part of a series of posts about tips I've learned while working on my projects; hopefully they will be helpful to those just starting out.  These lists aren't meant to cover everything, and if you have additional tips, please share in the comments!

Last time, I talked about glass cutting; the next step after all your pieces are cut it the grinding.  This topic should be relevant whether your interest is in stained glass, fused glass, or just in using stained glass sheets in your mosaic projects.  

My Essential Glass Grinding Tools

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Of course, the number 1 essential tool here is a grinder.  I'm sure many grinders out there work great, so I'm not suggesting one over another, but the only grinder I've owned is my Gryphon Gryphette grinder, and it is great!  It's small, but I haven't found that it's too small for any of my projects, and it's perfect for my small workspace.

You can buy an optional face shield that will mount over the work area; I don't have it, but I always wear safety glasses.  In fact, I store them as shown in the picture; on top of the grinder - that way I never forget to put them on.  It's super important to wear them, as little shards can fly around, especially for certain textured glass, and especially when you have a new bit.  I like my eyes so I never grind without my safety glasses!

I clean out the water reservoir of my grinder every 4 or 5 projects.  It always amazes me the amount of glass dust that collects in there.

 

The grinder is the main tool you need, but it needs new bits sometimes.  I use these bits for my grinder, and they last a good long time.  You also need good old H2O to fill the water reservoir (you can see my old Nalgene bottle in the background here.  Our slop sink is in an inconveient spot, so I use it for my water needs while working.  And last, you need little bits of sponge to insert behind the grinder bit to keep everything wet while you're working.

So that's it for the tools; on to the grinding tips:

1.  Order Matters!

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My first tip is in the order of the pieces you choose to grind. You're always going to have to do some touching-up to make all of the individual pieces fit together well, but the main pieces of your design will need to have specific shapes in order for the panel to come out the way you want.  So, I always start with the "essential" pieces to grind first, and get those to look exactly how I want.  Then, I grind the ones that are part of the background - and if they don't fit perfectly in their spots, I can always remove a little here or there and it doesn't matter since it was just a background piece anyway.

For example, check out the piece to the right, which had just gone through the grinding stage when this photo was taken.  I ground the sun, boat, and frog first, then made the background yellow/orange, blue, and green fit around those main areas of the design.

 
 Would it be faster to cut away or grind out that inner curve?

Would it be faster to cut away or grind out that inner curve?

2.  Minimize Grinding

This is probably more of a cutting tip, but one thing I find to really speed up how quickly I can make a project, as well as minimizing cost (grinder bits are pricey!), is to really make sure I've cut away as much glass as I can before I grind.  I want to make sure I only have to do a quick pass with the grinder to remove those sharp edges, and MAYBE do a little extra work on a tricky inner curve.  

But poking around on YouTube, I found videos that tell you not to even try cutting away the glass on an inner curve, and instead to grind out the whole area!  You'll go crazy, it will take forever, and your husband might threaten your life if you don't make that grinder noise stop!  (The last happens often enough to me even with my strategy to maximize cutting and minimize grinding...)  Take the time to get comfortable with glass scoring and breaking, trust me, it will be worth it!

 

 

3.  Change/Move Grinding Bit

Grinding bits wear out, but they do so slowly, so sometimes I don't notice that the area of the bit I'm working with is getting dull until it's doing nothing at all.  I usually put on a new bit so that the bottom part is the grinding surface, then slowly move it down the shaft as it gets dull.

4.  Work With Direction of Rotation

Grinding bits rotate counter-clockwise on the grinder (at least on mine, and google says this is how most of them work).  So, if I am pushing my piece to the left under the spinning bit (against the direction of spin), it will grind away more of the glass than if I push it to the right, with the direction of spin.  This is useful to know, because if you have a big chunk of glass to grind out, then going against the spin will have more of an effect than going with the spin.  And then do the opposite when you're mostly done but just want to take that final smoothing pass.

5. Perfection is the Last Step!

Last tip - as you are grinding each piece and fitting them together, don't worry if it's not perfect.  I'll do my first pass at grinding, and often still have a bunch of pieces that aren't fitting nicely.  Once I've given each piece one go at the grinder, I'll look over the whole thing and figure out where I still need to trim away some glass.  By waiting until the end, I find that I can make sure I'm trimming those background pieces and not the ones where the shapes are more critical.

Those are my top 5 grinding tips!  The final step after I finish grinding a piece is to see if it fits in the bigger glass puzzle; before I do that, I always dry it off so it doesn't get my pattern paper all wet and blotchy.  And I keep a Sharpie close by; if I end up needing to trim a piece down in multiple spots or don't want to lose my place, I'll mark the problem area with the Sharpie, do another grinding pass, and usually the water in the grinder is enough to clean up that Sharpie line.