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Dissolving Grinder Swarf? Or other Removal Methods?

dalmatiangirl61

Diamond
Joined
Jan 31, 2011
Location
BFE Nevada/San Marcos Tx
The fiberglass shield for my flywheel grinder has excessive dried up grinder swarf, easily up to 1" thick, solid as a rock (previous owner did not believe in cleaning). If it was metal I'd knock the bulk off with needle scaler then wire brush to bare metal. The inside of shroud was not "finished", you can see it is rough fiberglass and see the fabric weave, not sure how well needle scaler would work, and hitting it with wire brush seems wrong.

Any suggestions on how to dissolve this stuff? Muriatic acid?(no idea what that would do to fiberglass). Ultimately I would like to clean, maybe smooth interior surface so it does not hold swarf, and paint it white because it gets awfully dark in that hole. Any suggestions?
 
I'd try sandblasting, using lower air pressure and finer grit to start. Use a fan to blow debris away, and good lights to allow you to track removal and not cut into the fiberglass too much.

If that doesn't work, a 4.5" disk grinder and a lot of patience!
 
Ferric Chloride won't usually touch fibreglass/epoxy, but not sure about what would happen if the shroud was laid up using a different type of resin... Likely all the grinder dust is held in place by dried up coolant gunk, maybe try soaking it for a few days in some degreaser to loosen it up?
 
I'd assume the blob of aggregated swarf is pretty monolithic. And the bond between the blob and the shield is pretty weak.

I'd try and get in between the fiberglass and the grinding swarf with some sort of thin blade or chisel. Try and work that joint to pop the 1" think gunk free as a great big blob. Work your way around the shield popping bits loose.
 
CLR? I think once it's really dry, it's rust that's bonding it all together. All my grinders have had aluminum or iron covers on them, so I'd just use a hammer and chisel.
 
Just to add another $0.02.

Many grinding wheels are resin bonded. Fiberglass is inherently a resin bonded matrix. Anything chemical that's going to eat away at whatever is holding the swarf together is likely going to eat away at what holds the fiberglass shield together.

Also, grinding swarf is going to be pretty brittle. Fiberglass is pretty flexible. I think you can capitalize on those different characteristics.

I think you're best looking for a manual not chemical way of removing the collected swarf.
 
Vitrified wheels also build up like that. They are made of rocks (Bits of abrasive)stuck together with the likes of molten glass. The building is much like making a grinding wheel with the molten glass and likely some rust of metal grindings. Knocking off the likes of iron or steel is common...Soaking it off the likes of fiberglass is not likely to happen. Knocking it off may damage the fiberglass IMHO.
 
I'd remove the shield and soak it overnight in a strong solution of Zep Purple. Probably be loose enough by morning to scrape the stuff off. After cleaning a coat of epoxy resin should make future cleanup easier.
 
Do it the same way as you clean dried concrete out of a cement mixer. Hit the back side of the shield with a hammer or lump of wood. The fibreglass will flex, the swarf will pop off.
 
I had the same issue with a Berco head and block grinder. Previous owner never controlled coolant concentration and all the swarf turned into a solid mass of material. Problem is that stuff is essentially iron/steel particles that have rusted together. I ended up using a pneumatic needle scaler to get things cleaned up. Problem with that is in your case, the needle scaler would probably beat up the fiberglass. I would try a rubber mallet on the outside and see if it will knock the thick stuff off. Hose it down with straight Industrial Purple in a spray bottle. Good luck with it.
 
I've managed to get main part of shroud semi-clean, next step will be soaking in purple stuff. I hammered as hard as I felt comfortable doing, little came off but the bulk held on. I went back to needle scaler, just 50psi on air, backed side I was working on against concrete and worked it away in layers till I got to fiberglass. Too cold to do purple stuff outside, part is too big for sink, so into the shower it goes:), the excess purple stuff should clear out any conditioner sludge in those pipes, so its 2 jobs in 1!
 
I've managed to get main part of shroud semi-clean, next step will be soaking in purple stuff. I hammered as hard as I felt comfortable doing, little came off but the bulk held on. I went back to needle scaler, just 50psi on air, backed side I was working on against concrete and worked it away in layers till I got to fiberglass. Too cold to do purple stuff outside, part is too big for sink, so into the shower it goes:), the excess purple stuff should clear out any conditioner sludge in those pipes, so its 2 jobs in 1!

That's what I do with used solution of purple. Of course I'm so che.., ah frugal that I also use the hot vinegar when I clean the coffee maker as a drain cleaner. I pour it in and then follow with a slurry of baking soda and water.
 
Had the same problem with my Van Norman flywheel grinder ,mechanically removed all I could and then soaked in phosphoric acid to get rid of the rest . Bill
 
This solution to your problem might sound a bit odd, but it worked for me. A few years ago I purchased a horizontal bandsaw in similar condition your grinder. The machine had run for years using water soluble coolant and had rarely if ever been cleaned. It had a coating of dried on swarf an inch thick in most places that seemed permanently attached to the saw. The sump had a nearly a 2 inch thick layer in the bottom that seemed almost impervious to any chemicals or cleaning solvents I tried.

I also tried various methods mechanically to remove the stuck on crud, but was minimally successful. Finally on my wife's advice I disassembled the machine and took it to a local do it yourself car wash. The combination high pressure, detergent, and hot water melted through the crud like warm butter. It took less than half an hour to completely remove any evidence of dried coolant or swarf.
 
A few years ago I purchased a horizontal bandsaw in similar condition your grinder. The machine had run for years using water soluble coolant and had rarely if ever been cleaned. It had a coating of dried on swarf an inch thick in most places that seemed permanently attached to the saw.

Fine chips + coolant + time = giant metal rock. :willy_nilly:
 








 
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