jccaclimber
Supporting Member
Up front reminder. Wear PPE. At a minimum this includes safety glasses, although glass dust isn't something you want in your lungs either.
Unfortunately my 18" AIO cube tank was not well packed in the move here earlier this year. Two corners are chipped at the top, and there is a chunk missing from the (thin) overflow. I didn't get a picture of the back corner, but here is a picture of the front corner. The back corner was much worse, but neither is exactly display quality at this point.
Leaving the sharp and broken glass in place didn't seem acceptable, and while I'll tolerate a scratch here and there for the right price, I don't want something to get cut on and I don't want glass bits falling off. I figured I had nothing to lose, and decided to try grinding a relief in the corner. I took a diamond burr leftover from an old project and put it in a Dremel*. Into the shower to contain the water and an RO system feed line connected to the shower for a fast drip rate water source that doesn't spray everywhere. That left a bit of a wavy finish, so I flattened it off with a diamond hand file. That got me to here:
It could use a bit of cleanup if I was going to keep it on display somewhere, but the flatness is reasonable, the chamfer isn't too bad, etc. I was happy with the shape, and this was as little material as possible to remove while still getting the entire chip out. I was still unhappy with the surface appearance, so pulled out the 40 micron diamond paste. I tried that on a couple different felt tips, a wooden lap, and 1/8" dowels of a few different materials. As expected, the roughness of the glass was very hard on the felt. The wood fared better. This was done dry to avoid washing away the diamond. Unfortunately the diamond paste I have really works much better when the material is just above the melting point of the grease in the diamond paste, and that would be a liability with glass. It was very slow going. The felt got me to here:
The wooden tool worked a bit better and got me here:
This was still taking too long, so I made a drum out of some nice stiff plastic backed 15 micron film I have. That had all of the benefits and downsides of something that goes faster. It rounded the chamfers just a bit more than I like, but the overall surface clarity is much better. Being more like sandpaper, but waterproof I was able to run cooling water again, which is always nice when making glass dust because it rinses the dust down the drain instead of putting it in the air.
I opted not to take the full chip out to the corner because that's past the seal and is rounded enough to not cut me. The silicone still needs to be trimmed back and the polishing revealed some waviness in the surface I ground down. I also bumped the back of the overflow during the polishing step, so it has some cosmetic defects now. One other minus, the polished surface now looks better than the factory surface (see the right panel that is unmodified), so the rough factory finish stands out. I'm loosely considering relieving all four corners, then making a custom lid that sets in to those, but I'm not yet sure I'm willing to put that much work into this tank, it's just an 18" cube.
I do want to polish the ground overflows in my large tank whenever it goes back up, so this provided some nice practice for that. Now that I've done it once this wasn't all that hard, so it shows that there are options other than looking at a sharp chip. Clearly care should be taken to avoid weakening a tank depending on where the chip is.
*Dremel, plugged into a GFCI, was used with the flex extension this time. I've done it without in the past. Obviously I do not condone mixing electric power tools and water without substantial care. Don't wrap the tool in plastic to keep it dry, you'll stop all motor cooling. An air powered die grinder would be a better option, but you use what you have.
Unfortunately my 18" AIO cube tank was not well packed in the move here earlier this year. Two corners are chipped at the top, and there is a chunk missing from the (thin) overflow. I didn't get a picture of the back corner, but here is a picture of the front corner. The back corner was much worse, but neither is exactly display quality at this point.
Leaving the sharp and broken glass in place didn't seem acceptable, and while I'll tolerate a scratch here and there for the right price, I don't want something to get cut on and I don't want glass bits falling off. I figured I had nothing to lose, and decided to try grinding a relief in the corner. I took a diamond burr leftover from an old project and put it in a Dremel*. Into the shower to contain the water and an RO system feed line connected to the shower for a fast drip rate water source that doesn't spray everywhere. That left a bit of a wavy finish, so I flattened it off with a diamond hand file. That got me to here:
It could use a bit of cleanup if I was going to keep it on display somewhere, but the flatness is reasonable, the chamfer isn't too bad, etc. I was happy with the shape, and this was as little material as possible to remove while still getting the entire chip out. I was still unhappy with the surface appearance, so pulled out the 40 micron diamond paste. I tried that on a couple different felt tips, a wooden lap, and 1/8" dowels of a few different materials. As expected, the roughness of the glass was very hard on the felt. The wood fared better. This was done dry to avoid washing away the diamond. Unfortunately the diamond paste I have really works much better when the material is just above the melting point of the grease in the diamond paste, and that would be a liability with glass. It was very slow going. The felt got me to here:
The wooden tool worked a bit better and got me here:
This was still taking too long, so I made a drum out of some nice stiff plastic backed 15 micron film I have. That had all of the benefits and downsides of something that goes faster. It rounded the chamfers just a bit more than I like, but the overall surface clarity is much better. Being more like sandpaper, but waterproof I was able to run cooling water again, which is always nice when making glass dust because it rinses the dust down the drain instead of putting it in the air.
I opted not to take the full chip out to the corner because that's past the seal and is rounded enough to not cut me. The silicone still needs to be trimmed back and the polishing revealed some waviness in the surface I ground down. I also bumped the back of the overflow during the polishing step, so it has some cosmetic defects now. One other minus, the polished surface now looks better than the factory surface (see the right panel that is unmodified), so the rough factory finish stands out. I'm loosely considering relieving all four corners, then making a custom lid that sets in to those, but I'm not yet sure I'm willing to put that much work into this tank, it's just an 18" cube.
I do want to polish the ground overflows in my large tank whenever it goes back up, so this provided some nice practice for that. Now that I've done it once this wasn't all that hard, so it shows that there are options other than looking at a sharp chip. Clearly care should be taken to avoid weakening a tank depending on where the chip is.
*Dremel, plugged into a GFCI, was used with the flex extension this time. I've done it without in the past. Obviously I do not condone mixing electric power tools and water without substantial care. Don't wrap the tool in plastic to keep it dry, you'll stop all motor cooling. An air powered die grinder would be a better option, but you use what you have.
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