How to Grind and Polish Glass with a Rociprolap

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@garymcmullin2292 2 жыл бұрын

the "rust" is more the micro particles scoured off the pan as the carbide does it cutting action. I have found the splash shield to be a worthless item. I tried it for quite a time and they eventually would break along the rim edge of the pan due to fatigue from the orbital motion. I finish slabs of stone, if you limit the amount of water into the pan and have plenty of weight on the rocks there is very, very little splash to worry over. Some slabs want to be rowdy and fly around so you have to experiment to find a weight placement and total amount that will settle that one down. Been doing this with a 24 inch model for 10 years now. I only remove the heavy pan to clean, reoil and or replace the nylon bearings in the cups. Clean up of spent grit and mud from lapping is accomplished with a good shop vac with a 4 inch wide tool on the hose. After the first vac job, scour the sides with stainless pot scrubbers. Use a steel end brush on a hand held drill to clean all the circular divots in the pan bottom. Do this cleaning with a fresh charge of water. Vac again. Wipe pan with a wad of paper towels and you are ready for the next grit level. I never use a grit larger than 220. Found it wastes too much rock, induces a lot of undercutting that takes forever to remove with 220. Some slabs not well sawn may take 8 or 12 hours to get nice and flat, removing all saw marks but in my estimation it is worth it in that that avoiding use of coarser grits extends pan life considerably.

@nunyabidness1888 2 жыл бұрын

Gary, I just picked up an old 20-in.rociprolap that will need some machining to fix damage to the raceway caused by the use of steel ball bearings instead of nylon ones by a prior owner. I really appreciate your comments on cleaning, but still have a number or questions, perhaps you or hisglassworksinc or anyone else would like to answer. Since I'll only have one pan, I'll need to clean between grits. I'll also be doing rock slabs, and wondered how many per load you can usually run through before changing grits. Can you just add a bit more grit and water to freshen it up? Next question, you say you don't use grit larger than 220. What other grits do you use prior to polish? Next, how are you attaching the weights to your slabs? Just laying it on top or some sort of epoxy? Regarding my rociprolap, it is an old one made by Rose Enterprises that has three bearing keepers mounted to the base of the machine, each holding two bearings. This will give me a total of 6 bearings under the pan instead of the 12 bearings beneath the pan on the newest model shown at the first of the video. Does anyone have experience with both models, the old with 6 bearings and the new with 12? Would it be worth the effort to get the new bearing keepers to mount on the base so that it can hold 12 bearings? Last question, have you figured out about how much $$ the grit powder and polish cost you from start to finish per load in the pan, assuming you clean each time? Just trying to factor that in to see what my costs will be. Thanks a lot.

@garymcmullin2292 2 жыл бұрын

@@nunyabidness1888 I just spent over an hour doing a thorough reply to your question and something hit a wrong turn....lost it all. Sorry, maybe I'll try again but really have no interest to invest that kind of time again. Would love to help you but ability to communicate is a pain. Maybe I can try doing a paste in reply so I won't lose my work here.

@garymcmullin2292 2 жыл бұрын

@@nunyabidness1888 Upgrade to the 12 nylon bearings is a good idea. That is one reason that the previous owner went to using steel bearings, just too much pressure on the 6 nylons and they were failing all the time. I get about 60-80 hours on a set of bearings. When I rotate the pan by hand and can feel and hear the “rough” grumble I know it is time. I will depend on how much weight load is in the pan as to how your bearing experience goes. I buy bearing in bulk on line, 1-200 at a time. Their uniformity is not so critical, as the come the are just fine because they compress down under a load anyway. The idea I have heard that they need to be individually miced for uniform size is baloney. Just use lot run and you will be ok. I use 2 heaping tablespoons of 220 grit to start in my 24 inch. I load about 60% + or - of the pan with slabs. Barely cover the pan with water….BARELY. Then add the grit and load the slabs. This will bring the total liquid volume up to more than enough. Keep and eye on it if you are operating outside or in conditions where evaporation is high, may need to add just a bit of water time to time. After about 2 hours I usually add another 1-2 tablespoons of 220 grit, then after that maybe a tablespoon every hour or so, depending on how long the grind has to go for that batch of slabs. Grit use is really pretty modest for me. I do agate and jasper slabs, no glass. I do the entire lot of slabs I have set up which may be up to 30 in number…2,3 4….6 at a time depending on their size, so that I load the pan for optimum function. I believe a lot of operators get the idea to load the pan to the hilt so that they “economize” . Loading the pan too much leads to slabs fighting each other, banging around like a pin ball machine and slashing grit slurry all over hell. It is an experience thing. Slab shapes play into it, the more circular the shape the better behaved the pan contents and the more you can load. Using more weight is essential to keep the slabs “quiet” it increases the cut rate and dampens the tendency of the slab to be slung around the pan. I have seen all kinds of weight recommendations. I just found what works for me and really have no comments of help for you to find what will be best for what you do. But just ballpark….I would estimate I use about 16 pounds for a slab 4x4 up to 8x8 inches. Larger will require more. That is quite a range of weight per sq inch but my lead ingots are around 8 pounds so it is a one size fits all. Smaller slabs will grind quicker and tend to be much quieter in the pan with the higher weight to surface area relationship. As each pan loading of slabs is finished with a grit I wash them with a high pressure hose immediately. For me it takes some time, the way I mount the slab to backing plate/board there is a small gap of up to ⅛ inch where grit slurry gets collected and it takes considerable time to flush it all out with a garden hose nozzle. Then I blow out the crack and the face of the slab with compressed air. This is important, especially so if you have a slab with lots of surface pits, vugs and such, like plume agates and things that have a natural porous like surface. After each pan load is finished I wet vac out the pan. Leaving the old slurry does not work for me, it gets real viscous and interferes with good pan to slab contact. So…new water and grit for every pan loading. After the entire lot of slabs has been ground I add ¼ inch or so of clean water to the pan and scrub it with those coarse stainless pot scrubber pads. Then I chuck up a steel end brush in a drill and push it down into every dimple in the bottom of the pan. Wet vac out. Add more clean water, run the lap a few seconds to slosh it around and then wet vac out. Do this twice. Use a wad of fresh paper towels to thoroughly dry the pan. It should look real clean to you. The next and last grind is with 800 grit. This is a strict 4 hours for agate and jaspers. By the clock because the variable time in the coarse grit is past due to uncertainty about how long to grind because of saw marks or such on the slab. I use two tablespoons at start and that is all, add no more. End of 4 hours you will have some starting to shine slabs. I use ⅜ inch thick white polypropylene cutting board stock for backing/mounting plates. Get the real big ones cheap from Walmart, cut out the shape and size you need. In time you will have an inventory of back plates to suit all your slab mounting needs. These backings are very durable, stable and will facilitate the attachment of weight to the rock while at the same time adding protection and rigidity to the slab. When mounted, the slab perimeters are inside the edged of the backing plate so any contact in the pan is back plat to back plate with the other mounted slabs. Works sweet. No need for bumper rings and other crap to put around the rock slab….which leads to a lot of slash activity and noise. My rociprolap runs nice and quiet and grit splash is negligible. I took a year or two for me to develop these techniques. I started like most do, using the guidelines published. Just really not workable for me as they are written so I started devising my own approach….and learning as I went…what worked….what didn’t. Even today I still have to be on my toes for some unusual situations but that is the fun of doing this work. Back to the mounting boards, I used a good grade of heavy duct tape…a few strips to one side of the board, the lay down hot glue and set the slab. Get a HEAVY duty glue gun and buy some 12 inch glue sticks. You will go through a lot of glue and some tape. Then I turn over the mounted slab, attach a couple of strips of duct tape to the back side (opposite the rock side) and there I attach my lead ingot with hot glue. The mounted slab is ready to run. Later, when the slabs have been polished and ready to demount I use a hair dryer in high to heat the rock side, in time the glue will lose its grip. It is an art. There is a sweet spot for the heat. I use a stiff blade putty knife in that crack between the back plate and the rock slab, light pressure at about the right time and you can feel/see the release of the hot glue. The weight can be pried off the back with a screwdriver or other leverage device. If it pulls the tape and all no problem, just peel it off your weight ingot. The rock side tape sometimes lets go from the poly board instead of the gluem usually when too much heat is applied. No worries, just use a single edge razor blade scraper to remove it and the hot glue from the rock slab. You might have some slabs loosen from the hot glue, some surfaces are that way, just clean, dry and reglue the slab to the backing. I have had to do that on some slabs for every grind but it is not common. I have a lot of lead ingots, besides the glued one on the slab mounting I add another to the the top..piggyback..once the pan is loaded. I have some ingots that are velcroed so it is a quick attachment and detach later. Adequate weight is very important to efficient and successful lapping. Some slabs, due to large size require two ingots glued down, then two piggy backs. Slabs up to8x8 inch are ok with one ingot placed in the “point of balance” of the rock slab. Another words get the weight in the center of the rock piece or you will get off side grinding and result in a wedge shape slab. Large or longer slabs need a weight at each end of the mounting board. This too is an art form, figuring out what will be about the right position and amount of weight for each slab. School of experience involved here. When you mount a rock slab that is mixed hardness be careful of soft areas concentrated on a particular side. Such a slab will cut faster to that side when the weight appears to be mounted properly centered. You may have to shift the weight position or you can glue a piece of harder waste stone along that soft edge. The waste will act like an outrigger to buoy the soft area. You need to get the waste piece to be as close as possible to the same level as the surface of the slab or you will be grinding a while to get it cut down so the the slab is in full contact with the pan and if the height difference is too great you can actually introduce a wedge in the slab the other way. Got to be on your game here. Polishing is a whole subject in itself for me. I abandoned the “recommended” methods and developed my own. I use NONE of the materials suggested for polish pads. But I will say that you can go to polish using what ever pad materials/devices you like, just do the full pan clean up after grit grinding and you are good to go. Polishing for me is also quick….a couple of hours. I have long favored tin oxide, nothing beats the finish it will produce. But I have used Meyers rapid polish with ok results too. Polishing is a controversial subject, ask any number of people for their recommendations and you will likely get the same number of opinions. What works for you works for you. I can say this, if you have too run the lap for hours and hours to get to a shine something is not right. Truthfully the polish step I believe has more potential for things to fowl up and be a source of hair pulling frustration than any other aspect of lapping rocks.

@nunyabidness1888 2 жыл бұрын

@@garymcmullin2292 I can't thank you enough for your time in spelling out all the things that experience using this device has taught you over time, and for your careful explanation of it all. Perhaps at some point you may consider making your own KZbin video(s) showing the process that you have developed over time. It is such a help to learn some methods that are proven to be successful, such as using the cutting board as backing material, how to tape/glue the weights down, the proper amount of water/grit to get a slurry that won't usually splash, etc. You have likely save me many hours of avoidable frustration, though putting it all into practice brings its own challenges. I really, really appreciate your time and advice!

@fredfalting 2 жыл бұрын

If you don’t mind, where did you get the plastic for the splash guard, and how tall is it ? Thanks

@hisglassworksinc 2 жыл бұрын

The Rociprolap comes with the splash guard. They are made from Formica.

@fredfalting 2 жыл бұрын

Sorry for another question, does water get between the metal and the splash guard and splash out water ? I have a HP Lap, removed the inner ring to fit more stones, though I’m now getting more splashing and want to add a splash guard. 😉

@hisglassworksinc 2 жыл бұрын

@@fredfalting The splash guards fit pretty tight and also bolt onto the rim with a bolt and wingnut to hold them tight. You will get some splash, but it's minimal.

@detectvt9849 5 жыл бұрын

Did you do a clean out between the 220 grit and the garnet?

@hisglassworksinc 5 жыл бұрын

Yes! You will need to thoroughly clean out the pan between each different grit style to prevent contamination.

@detectvt9849 5 жыл бұрын

@@hisglassworksinc k, TY. I was just curious. Because it wasn't shown or mentioned in the video.

@robertgoidel 7 жыл бұрын

Do they make these rociprolap machines in a smaller diameter?

@hisglassworksinc 7 жыл бұрын

The smallest is a 20 inch diameter: www.hisglassworks.com/shop/machinery/flat-grinders/rociprolaps.html There are smaller machines called vibralaps that only vibrate for smaller pieces and lapidary work

@makkyd123 4 жыл бұрын

If you dont want your cast iron plate to rust, a good rust inhibitor is crystalcut: add a little to the water, no rust. Rust can stain some rocks, so its a good idea for lapidary work.