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Post by Deleted on Jan 4, 2017 14:07:47 GMT -5
jamespI don't worry about toxic. But polyester resin stinks real ugly. You outin a greenhouse won't worry. But us city folks.... Yukky!
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jamesp
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Post by jamesp on Jan 4, 2017 14:30:22 GMT -5
jamespI don't worry about toxic. But polyester resin stinks real ugly. You outin a greenhouse won't worry. But us city folks.... Yukky! So, should I mix up a batch of epoxy and give the the SiC 30 a go ? I would use slow dry. Can epoxy be warmed(110-120F) up so it is more viscous ? Probably before mixing. What mix ratio 10:1, 20:1 ? higher ? HankRocks ?
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Post by HankRocks on Jan 4, 2017 15:48:28 GMT -5
I can't remember the exact ratio from 45 years ago.
I would say that you don't want it too low, 20:1 at the lowest, maybe start higher, can always add a bit more if it does not form up. For wheels it was the addition of very high pressure that helped to bond it initially, then the extended baking to set the resin.
You may need to make a few trials, high ratio. All you are wasting is the epoxy. No matter what kind of results you have, you can always use the Silicon.
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jamesp
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Post by jamesp on Jan 5, 2017 7:41:57 GMT -5
I can't remember the exact ratio from 45 years ago. I would say that you don't want it too low, 20:1 at the lowest, maybe start higher, can always add a bit more if it does not form up. For wheels it was the addition of very high pressure that helped to bond it initially, then the extended baking to set the resin. You may need to make a few trials, high ratio. All you are wasting is the epoxy. No matter what kind of results you have, you can always use the Silicon. Yep. No waste. I have a two 3 ounce bottles each resin and hardener of G/flex epoxy, leftover from an aluminum boat repair. Here is a flickr link to crushing SiC 50 wheels. Note rhyolite after two weeks and left over rounded chunks. They did a number on that rhyolite. I found about 100 pounds of those 5" X 1" grinding wheels in an industrial junkyard for $50. That 3 pound hammer is needed to break them on concrete slab, well bonded. Look at the close up of the partially used chunks, looks like natural sapphire and ruby particles are added. They are at least 20-30 years old, way back. Lead lined holes. There is still several thousand pounds of aluminum oxide wheels stashed there. But they are useless for cutting Mohs 7 rock. Great for tumbling metals and cleaning trash or limestone coatings off of agates and corals. They get used AO wheels by the truck load. Not SiC wheels. flickr link www.flickr.com/photos/67205364@N06/albums/72157649671884531two weeks, rhyolite. Tumbler always had fresh 60 grit shedding off these SiC nuggets. Damn right it cut them fast. Fresh SiC at separation mid-stream of rhyolite tumble
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Post by MrMike on Jan 5, 2017 21:13:23 GMT -5
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Post by MrMike on Jan 5, 2017 21:16:31 GMT -5
Maybe the wife could get them wholesale through the plant biz (used in hydroponics). They are also available made out of AlOx.
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jamesp
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Post by jamesp on Jan 5, 2017 22:31:36 GMT -5
Maybe the wife could get them wholesale through the plant biz (used in hydroponics). They are also available made out of AlOx. Are they SiC ?
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Post by MrMike on Jan 5, 2017 22:45:54 GMT -5
jamesp Yes, don't know how well they are bonded together though.
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jamesp
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Post by jamesp on Jan 5, 2017 23:11:42 GMT -5
jamesp Yes, don't know how well they are bonded together though. Why the heck would the use SiC/AO ? Seem peculiar to you ?
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Post by MrMike on Jan 6, 2017 5:49:05 GMT -5
My guess is because of their properties they can be formed, pressed, etc. into something durable and porous.
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jamesp
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Post by jamesp on Jan 6, 2017 7:02:47 GMT -5
My guess is because of their properties they can be formed, pressed, etc. into something durable and porous. That's a mind blaster. You would think crushed quartz sand or bonded pumice. AO is darn heavy, SiC too. Maybe the fact that it is dense and would sink and pull the air hose down into the water. So a question. If the SiC chunks time releases, what size chunks makes the best size-half or one or two inch chunks ? The length of time to break down depends on how well it is bonded AND the chunk size. If 1/2" chunks of these grinding wheels is used it takes about 4 days to break down. If 1" chunks it takes about 9 days. If 2" inch chunks it takes about 15 days. And you don't get something for nothing. If you are dosing 1 cup per week powder, then you should dose chunks 3-4 cups for two weeks.? To continually release fresh grit. Only the larger fresh grit is going to do the deep fast cutting. ? And the less chunks you have the less the chunks rub against each other. No idea what that effect has. ? Time release fertilizer 100 pounds pre acre per year -or- Not time release fertilizer 25 pounds per acre every 3 months Is a fertilizer analogy off ? Fresh large grit time releasing HAS to cut rocks faster. That's a fact no matter what. In the end, more grit is being used per unit of time but more cutting per unit of time. Like adding smaller doses of powdered grit daily, which is a lot of work. I say at least bond up a couple of golf ball sized coarse grit chunks and add them to the tumbler AND do normal grit additions less times.
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Post by HankRocks on Jan 6, 2017 8:29:39 GMT -5
It seems that using the chunks of silicon would really be a convenience factor, you can eliminate the re-charges. One can duplicate the effect of using the chunks by re-charges, as long as the re-charge frequency corresponds to the silicon depletion rate. In my case I am re-charging my 15 pound tumblers every two days, in 10 days of grinding that's 4 re-charges plus the initial charge. I am using about 3/4 cup for each re-charge. To duplicate that I would have to add at least 3 cups of chunks along with the initial charge. I may get slightly better grinding rate, but I am losing 3 cups of rock space to the chunks.
I haven't tested but my guess is that 2 days is a bit too long as all the initial charge has been reduced after that time. It would probably improve the overall grinding to re-charge after 36 hours or so. Both tumblers are coming off their 10 day cycles of rough grinding today, assuming I brave the cold,wet, windy conditions. May start a bit of testing with the new loads, increasing the re-charge rate. I suppose for an more accurate test one would need to weight out the rock load going into each barrel and use the same type of material. Then weigh out the tumbled rock at the end of the cycles. The trick is finding two loads of the same material. Will wait until warmer weather this spring and assemble two equal loads of Texas Petrified Wood.
Now I have a headache again. That's too much thinking so early!!
H
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jamesp
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Post by jamesp on Jan 6, 2017 9:22:08 GMT -5
It seems that using the chunks of silicon would really be a convenience factor, you can eliminate the re-charges. One can duplicate the effect of using the chunks by re-charges, as long as the re-charge frequency corresponds to the silicon depletion rate. In my case I am re-charging my 15 pound tumblers every two days, in 10 days of grinding that's 4 re-charges plus the initial charge. I am using about 3/4 cup for each re-charge. To duplicate that I would have to add at least 3 cups of chunks along with the initial charge. I may get slightly better grinding rate, but I am losing 3 cups of rock space to the chunks. I haven't tested but my guess is that 2 days is a bit too long as all the initial charge has been reduced after that time. It would probably improve the overall grinding to re-charge after 36 hours or so. Both tumblers are coming off their 10 day cycles of rough grinding today, assuming I brave the cold,wet, windy conditions. May start a bit of testing with the new loads, increasing the re-charge rate. I suppose for an more accurate test one would need to weight out the rock load going into each barrel and use the same type of material. Then weigh out the tumbled rock at the end of the cycles. The trick is finding two loads of the same material. Will wait until warmer weather this spring and assemble two equal loads of Texas Petrified Wood. Now I have a headache again. That's too much thinking so early!! H As far as recharging. I hate to see people running a charge of coarse grit for 1-2 weeks or longer if it is broken all the way down after 2-3 days. That is a lot of wasted time wear and electricity. Recharging more often appears the way to go. The recharges can be a bit relaxed. 2 days here. 4 days there. 1 days here. When time and energy allows. Casual. No sweat. Quite doing controlled tests on that issue. State of mind at ease. The space taken by the chunks is a concern. Point of diminishing returns situation. My attitude is get the dang rocks rounded fast and with least effort. Winter, less trips to the tumbler please. 12 pounds or 10 pounds, no big deal. I only use those chunks in the winter. A few pounds lost rock per batch is of no concern. It would be up to the man at the tumbling helm. Again, state of mind at ease. That sums up my approach Henry. But my mind went through the same considerations before relaxing.
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Post by HankRocks on Jan 6, 2017 10:22:07 GMT -5
Just spent a bit over an hour outside with the hose and the strainer and sludge bucket in 34 degree, windy, misty weather. I think the feeling is coming to my fingers as I type. There was no 80 grit left in either barrel. The slurry was perfect as I poured it off. Took anther 20 minutes sorting between "ready" and "not ready" for the next stage. I have become more careful about grading each tumble and only passing the well rounded ones.
Agree that re-charging is not a precise exercise and one can be casual about it. Since I am in the retired mode I have more time to fill and re-charging is one more fun activity for me. Maybe not so much in these weather conditions. Started one tumbler on 220 with some of the rocks that passed the next stage inspection, started the other on a load of with about 150 Pre-forms. The re-charge schedule I use for both is very different from the coarse stage, For the Preforms I use several handfuls of pea-gravel and small saw trimmings along with 2 cups of dried slurry along with the 80 grit. I will re-charge 1 time at about 3 days and one more at 6 days as it seems the grit breaks down a lot slower with the pea-gravel and small pieces. For the 220 load I will recharge once about the 3rd day and then let it run out for 7 or 8 more days, letting the grit break down to very fine. Then straight to Polish in the Vib Tumbler.
Good news is I get a 3 day break during the cold weather. But there is the Vib Lap......!!
Stay warm and good luck with any frozen accumulation.
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jamesp
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Post by jamesp on Jan 6, 2017 10:45:13 GMT -5
Big rock in the batch breaks grit faster. Lots of smalls breaks grit slower. Fuller barrels breaks grit slower. I recently ran a 2 pound rock in a 8 pound(@80% full) barrel in AO 80 for a finishing run. With 6 pounds of average 1 inch tumbles. I liked that combo. It ran quietly. It broke AO 80 down from 80 to about 3000. Went straight to AO 14,000 in the vibe for 18 hours and got the liquid shine. Probably my favorite finishing job in a rotary(excepting final polish) ever HankRocks. Dodged the cold fingers doing 220-500-1000 clean outs on that run.
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jamesp
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Post by jamesp on Jan 6, 2017 10:56:22 GMT -5
Bundled up and headed out to weld. And burn a giant stack of piled bamboo. alternate between the two, heat up at fire, cool down at welder. Snow to start in a hour.
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jamesp
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Post by jamesp on Jan 6, 2017 18:34:21 GMT -5
I can't remember the exact ratio from 45 years ago. I would say that you don't want it too low, 20:1 at the lowest, maybe start higher, can always add a bit more if it does not form up. For wheels it was the addition of very high pressure that helped to bond it initially, then the extended baking to set the resin. You may need to make a few trials, high ratio. All you are wasting is the epoxy. No matter what kind of results you have, you can always use the Silicon. Broke the 5" X 1" wheels into quarters for longer runs. Each wheel = 1.5 cups Running 1 wheel(4 quarters) with 7 pounds rock. Should run 14 days. They had a few of these ~16 grit wheels, molten lead cast hole. Old stuff. Scary
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Post by HankRocks on Jan 6, 2017 18:42:52 GMT -5
I think Fred and Barney used that 16 grit wheel to repair the wheels on their cars!!
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jamesp
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Post by jamesp on Jan 6, 2017 19:17:09 GMT -5
I think Fred and Barney used that 16 grit wheel to repair the wheels on their cars!! That thing would have to eat tumbler barrels. Yes, looks like it came straight off a Flintstones sedan.
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