jamesp
Cave Dweller
Member since October 2012
Posts: 36,561
|
Post by jamesp on Mar 29, 2017 5:40:48 GMT -5
This is about using fused SiC 50 grinding wheels for time release SiC 50 grit.
Dose is one 5" X 1" thick grinding wheel broken into 4 quarters on 5.5 pounds of rock in a 7 pound rotary. Calculating, a 5" X 1" thick grinding wheel = 20 cubic inches = 1.3 cups less center hole. (.07 cups = 1 cubic inch) The quarters broke down to about a 1 inch ball after 18 days.
The normal dose is 1/3 cup SiC 30 at least 2-3 times per week for 7 pounds rock, so 18 days could be 9/3m= 3 cups/7 pounds rock. So likely less grit usage. Perhaps the sharp edges of the SiC are preserved and particles not shattered being bound in fused state.
The rotary is rated at 7 pounds, but the grinding wheel took up space so the rocks were cut back from 7 pounds to 5.5 pounds. So capacity was lost.
No slurry thickener was added as the smaller 50 grit circulates well with CLEAN water and slurry builds fast with quadruple (over)dose of time release grit. The time release of full size SiC 50 seems to have a big effect on creating a constant grind.
At the end of 18 days the slurry was very thick but protective as barrel had gone from 75% fit to 60% fill... The rocks were substantially shaped. Again, the quarters were reduced to 1 inch balls. Timing of wear was darn good, protective slurry was created with reduced barrel rock fill.
Am rolling the second 5" X 1" quartered grinding wheel for another 12-18 days for a total of about 30 days coarse grind time. Will take photos of this 30 day grind when done.
RPM 30, 6" PVC barrels
If a way to fuse or epoxy coarse SiC powder into time release say egg sized tablets coarse grind may be a much more user friendly process. Fusion is probably a super high temp process, not practicable. However, epoxy is fairly resistant to tumbling(relate to tumbling epoxy based Fordite paint). May be the way to go for a binder.
Perhaps an old frying pan at 200F on the oven to make the epoxy flow better when mixing the grit. Pour contents into a card board egg crate to make egg sized 'tablets'. Tear into a dozen tablets. A bit of paper will not hurt tumbling process. Old timers use newspaper for slurry thickener. Have purchased cheap epoxy on Ebay. Will try bonding SiC 30 with epoxy on the stove top.
I have used these grinding wheels many times. Every time a clean out is done be it day 3-6-9-12-15 there is always a couple of tablespoons of fresh SiC in the bottom of the settlement pan. Perfect time releasing.
|
|
|
Post by HankRocks on Mar 29, 2017 7:51:34 GMT -5
Recently picked up a small box of 25 used AO grinding wheels from a friend. The grit size runs between 60 and 46. It would not seem that having pieces of time release AO wheels in a tumble mix would serve much purpose. SiC is fine as it replenishes the coarse grinding. I suppose pieces of AO wheel would not hurt anything. Suppose I will hang onto to the lot until JP labs come up with a use for them. What's one more box of stuff in the garage!!
H
|
|
|
Post by HankRocks on Mar 29, 2017 8:03:04 GMT -5
sorry too early, should have said "not serve much purpose"
|
|
Deleted
Deleted Member
Member since January 1970
Posts: 0
|
Post by Deleted on Mar 29, 2017 15:02:04 GMT -5
It looks like the least expensive option for epoxy paint is ~$6/#.
At a 30/1 mix that adds 30¢/# to grit cost. Not bad for not having to touch a barrel for 3+ weeks.
My plan was to mix it in a concrete mixing tub to achieve a flat cake and break that into tumble sized hunks.
I really like your egg carton concept. Solid noggin usin' ya did there.
I checked epoxy paint because it's already pourable. May have too long of a pot life, 6 hours.
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,561
|
Post by jamesp on Mar 30, 2017 1:50:44 GMT -5
Recently picked up a small box of 25 used AO grinding wheels from a friend. The grit size runs between 60 and 46. It would not seem that having pieces of time release AO wheels in a tumble mix would serve much purpose. SiC is fine as it replenishes the coarse grinding. I suppose pieces of AO wheel would not hurt anything. Suppose I will hang onto to the lot until JP labs come up with a use for them. What's one more box of stuff in the garage!! H AO cuts steel well. Tried AO wheels. Gets rid of limestone coating on coral, that's about as far as it goes. The AO chunks don't break down near as fast as SiC chunks. They just get smooth in the tumbler for the most part. Any chunks of abrasive in a tumbler rub against each other to some degree. In the case of SiC perhaps the rubbing sheds more loose SiC particles.
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,561
|
Post by jamesp on Mar 30, 2017 1:59:53 GMT -5
It looks like the least expensive option for epoxy paint is ~$6/#. At a 30/1 mix that adds 30¢/# to grit cost. Not bad for not having to touch a barrel for 3+ weeks. My plan was to mix it in a concrete mixing tub to achieve a flat cake and break that into tumble sized hunks. I really like your egg carton concept. Solid noggin usin' ya did there. I checked epoxy paint because it's already pourable. May have too long of a pot life, 6 hours. Either casting it to size or breaking a cast slab into chunks is about the best way. Never thought about casting and breaking, makes perfect sense. Never thought about thinner epoxy paint. Been super busy and out of town. Never touched the 3 barrels for 18 days. Did clean out and replenished chunks, now at 8 days without touching. Some easy coarse tumbling. Since increasing the size of the chunks to last ~3 weeks and reducing the rock volume a bit the chunk method is working those rocks over. Adding loose SiC is described like a reverse saw tooth wave, add fresh coarse SiC every 2-3 days and have to loose grit size between peaks. Grit size(1 = 100% or 50 grit in this case and 0 = ~220 grit) is vertical axis and time is horizontal(1 = 3 days, 2 = 6 days, 3 = 9 days, etc): The chunks come closer to constant 100% since full size 50 grit is constantly shedding. Theoretically providing 100% grind rate in perfect conditions. Most of the grind takes place in the upper 75% grit size, so the grind rate is way exaggerated.
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,561
|
Post by jamesp on Mar 30, 2017 2:37:40 GMT -5
Grit size curve may even look more like this when adding grit every 3 days. With good kick start slurry SiC 30 is often gone after 24 hours. Bulk of grinding done in first day. Not so good: it could be that the rocks are not being reduced in the orange zone. Feeding 50 grit on time release along dashed line could mean 100% grind rate: Analogy-Time release fertilizer on plants.
|
|
|
Post by MrMike on Mar 30, 2017 3:41:06 GMT -5
jamesp, Search Silicon Carbide Briquettes, not many US suppliers. This company use Portland cement as a binder. May break apart too quick in tumbler. www.lampus.com/alloy
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,561
|
Post by jamesp on Mar 30, 2017 4:16:35 GMT -5
jamesp, Search Silicon Carbide Briquettes, not many US suppliers. This company use Portland cement as a binder. May break apart too quick in tumbler. www.lampus.com/alloy For melting steel Mike. May have hit a home run. Have tumbled Portland, can and has produced gas but who knows, may be a small percentage Portland. Definitely worth looking into. Low grade SiC is plenty good for tumblinng. Tumbling coarse does not need high grade. Got to do some research.
|
|
Deleted
Deleted Member
Member since January 1970
Posts: 0
|
Post by Deleted on Mar 30, 2017 8:29:51 GMT -5
65% SiC and the rest foundry needed stuff like graphite and ferromanganese...
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,561
|
Post by jamesp on Mar 30, 2017 10:17:56 GMT -5
65% SiC and the rest foundry needed stuff like graphite and ferromanganese... Curious how much a 50 pound bag costs. Another RTH member mixing SiC for steel operations. His company ordered in SiC 30 in bulk. SiC 30 would work for tumbling. Noticed the 65% content. Seems like they are even making landscape pavers with high SiC content ?? Why ?
|
|
Deleted
Deleted Member
Member since January 1970
Posts: 0
|
Post by Deleted on Mar 30, 2017 10:30:47 GMT -5
65% SiC and the rest foundry needed stuff like graphite and ferromanganese... Curious how much a 50 pound bag costs. Another RTH member mixing SiC for steel operations. His company ordered in SiC 30 in bulk. SiC 30 would work for tumbling. Noticed the 65% content. Seems like they are even making landscape pavers with high SiC content ?? Why ? No, i think those go into the smelter to add minor components to the steel. The silicon becomes glass slag and protects the melt from oxidation. Doubtful it comes in 50# bag. Bet it comes in 2000# bags or even loose bulk truck loads
|
|
|
Post by MrMike on Mar 30, 2017 18:13:43 GMT -5
|
|
notjustone
spending too much on rocks
Member since January 2017
Posts: 426
|
Post by notjustone on Mar 30, 2017 21:51:46 GMT -5
I learned the other day our sic is not always consistant. I had gotten some that was like 30 grit size consitant screened I looked at a diferent pallet they were working out of tonight and the sic in that 3000lbs bag looked unscreened with some chunks as big as a pencil eraser. I asked the melt deck supervisor about it and he said its like that, some bags look screened and others don't. doesn't matter for our application.
I would imagine in the briquettes size probably isn't as critical either.
|
|
notjustone
spending too much on rocks
Member since January 2017
Posts: 426
|
Post by notjustone on Mar 30, 2017 22:01:41 GMT -5
I might grab a couple pounds of the real coarse stuff and give it a try looks to me like the big chunks are made of small grains that will just crumble and break down anyway leaving smaller grained sharp chunks. either way ill grab some even if its just a few pounds and get some pics. tomorrow night.
|
|
|
Post by captbob on Mar 31, 2017 15:19:02 GMT -5
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,561
|
Post by jamesp on Mar 31, 2017 18:47:33 GMT -5
Yea captbob, had a delivery to biggest aquatic plant customer. Not 3 miles from the bridge. Had to cancel. Watching to see what happens.
|
|
notjustone
spending too much on rocks
Member since January 2017
Posts: 426
|
Post by notjustone on Apr 1, 2017 23:37:51 GMT -5
I might grab a couple pounds of the real coarse stuff and give it a try looks to me like the big chunks are made of small grains that will just crumble and break down anyway leaving smaller grained sharp chunks. either way ill grab some even if its just a few pounds and get some pics. tomorrow night. unscreened sic
|
|
notjustone
spending too much on rocks
Member since January 2017
Posts: 426
|
Post by notjustone on Apr 1, 2017 23:55:38 GMT -5
65% SiC and the rest foundry needed stuff like graphite and ferromanganese... Curious how much a 50 pound bag costs. Another RTH member mixing SiC for steel operations. His company ordered in SiC 30 in bulk. SiC 30 would work for tumbling. Noticed the 65% content. Seems like they are even making landscape pavers with high SiC content ?? Why ? antislip?
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,561
|
Post by jamesp on Apr 2, 2017 0:49:39 GMT -5
I might grab a couple pounds of the real coarse stuff and give it a try looks to me like the big chunks are made of small grains that will just crumble and break down anyway leaving smaller grained sharp chunks. either way ill grab some even if its just a few pounds and get some pics. tomorrow night. unscreened sic Is this the bulk SiC your company receives notjustone ? Do you think it is 30 grit in size ? The chunks should be no problem and actually a bonus, and yes should break down. Trial by fire ? Try grinding with it ? The pavers must be antislip, only thing that makes sense.
|
|