rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Sept 28, 2011 9:14:57 GMT -5
Hi! Ok, I've got a 20" Lortone vibratory lap that I bought used and spent almost a month to get working. The old - I think - type. I've been grinding away on a bunch of faced agates and geodes with a few fair-sized, weighted slabs.
I've done 120/220, 220, and 600 grit steps and am looking at taking them to the polish phase with tin oxide. I have a separate pan and a new pad for this.
I'm asking for any tips - other than the usual, "avoid contamination" ones I've already read - as to the best way to do the polish on a "jiggle pan" and what to expect.
The pad they sent is some sort of porous/fibrous looking material and is maybe over 1/4" thick. I looks like this could require a BUNCH of tin oxide powder - does it?
Also, will the rocks rotate around and around the pan like they do in the grit/water phases? Doesn't seem like they'd be able to move as they might stick to or sink into the pad no matter how wet it is.
I've got more questions but will ask them in separate threads - Thanks! Rick
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Post by jakesrocks on Sept 28, 2011 9:27:04 GMT -5
Don't use too much water. Just damp enough to form a thin paste. And don't let it dry out. A very slow water drip, or a squirt from a spray bottle whenever it looks like it's getting too dry. Don't expect the kind of polish that you'd get on a polish wheel. They'll polish on the lap, but won't have the high gloss, glassy look that you get with a polish wheel.
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Post by tandl on Sept 28, 2011 10:34:58 GMT -5
instructions for my 15" say wet pad and let drip till it stops dripping , put pad in pan , spread 4 tablespoons of polish over the pad and smear it in, i use the measuring spoon . for a 20" i would put 5 tbs , 6 would`nt hurt . Yes they move around , you need bump rings, so they dont chip each other , or do one at a time , if you dont have rings at the moment.
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Sept 30, 2011 16:14:51 GMT -5
Thanks, y'all - I'll be giving it a shot this weekend.
Hey, jakesrocks - "...They'll polish on the lap, but won't have the high gloss, glassy look that you get with a polish wheel... '
I'm really bummed to hear this bit. I'd thought that a "jiggle pan" was what was used on the polished agates,t-eggs, and slabs I've bought that are so shiny. I'd been trying to shine stuff up with an Inland 8" spinning lap but there always seemed to be low spots - especially in the center - that I could never seem to even out. And if I did happen to get a slab fairly flat, I almost always seemed to end up with tiny, internal "micro-fractures" I guess from heat? So, I picked this used Lortone and spent a month making it work without breaking or keeping the neighbors up all night in hopes that it would solve ALL of my problems...
You mentioned a wheel - what, like a 6" x 2.5" expanding drum type? I have one that a good friend is letting me use but I don't figure you could polish a really large nodule or an 8-10 inch slab with it. Any suggestions? What's the best grit - 14,000? (yeah - a noooooob! A million questions)
Thanks, Rick
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rockhound97058
freely admits to licking rocks
Thundereggs - Oregons Official State Rock!
Member since January 2006
Posts: 760
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Post by rockhound97058 on Oct 1, 2011 23:34:59 GMT -5
I use a Lortone 20" Lap strictly for Polishing and I always produce mirror finishes. It's true however if you run the grit stages the polish will be a bit different, however, what I do is - cut my stones - use a Richardsons hi-speed sander, then finish 600 grit sanding on a expando drum then polish with the vibra lap. I always used tin oxide, but lately I can buy French Cerium cheaper so that's what a switched to. - If your saw cuts are a bit rough feel free to lap with a 220 grit to flatten out the face before sanding - One thing I've experience with the Lortone laps is the vibration is very fine and it seems to undercut certain stones. I strictly do thundereggs and course grained eggs such as Lucky Strikes will really undercut with grit. I do all my grit lapping on a Highland Park lap which has a more aggresive shake to it.
The next trick I've done is that "stock" pad they give you with the lap - toss that into the trash. Get yourself a piece of regular knap house carpet (no 60's shag, or berber type) cut it to fit the pan, glue it down with some adhesive (I use silicone). Then I add water (no polish) and some flat faced heavy rocks and run them for a day - this will break a wear pattern into the carpet adn de-fuzz it as well. After that, charge it with polish and go for it. I never pay attention to amounts of water and polish, I sprinkle some polish with every load and keep water on it. You'll be amazed on how well the stones do slide across the pad during polish - they make a nice rotation.
Good Luck!
Jason
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Oct 8, 2011 21:50:06 GMT -5
Thanks, Jason. Good tips!
Well, I've done 3 loads now and man did they turn out nice! Wasn't expecting much after one of the replies here.I used the pad that I got from US&J and it seemed to work ok. The carpet sounds like a great idea, too, for when this pad wears out. Though I don't know how to tell unless maybe a hole wears in it after a while? Or do they just get really thin?
On my Lortone, since it came with 3 balls that didn't match each other, I've found that the yellow hard foam practice golf balls that Walmart sells seem to work pretty good. They do flatten out a little after a couple weeks but they're cheap so whattheheck. I also found some racquet ball sized ones at Toys R Us that were good, too, and don't flatten out. I went to the smaller balls because the big ones made the pan to restricted and I wanted a little more "wiggle to the jiggle". I have cut notches where the 3 motor mount spacers are because, when I first got the rig, they were whacking against the rim of the base and loud as heck. I, also, have TWO springs on each of the 3 metal loops. Originally to try to stop the racket but also because the rig only came with two - again mismatched - springs. I had no idea how big/small the springs should be (they both just looked too wimpy) so I matched the heftier one and doubled them up.
It occurs to me that using bigger or smaller balls or single/multiple springs might be a way to adjust the aggressiveness of the wiggle on these "jiggle pans", ya reckon? c-ya! Rick
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Post by jakesrocks on Oct 8, 2011 22:29:22 GMT -5
Rick, I'm not familiar with the Lortone vibe laps, but my old 20" Highland Park has an adjustable counterweight attached to the shaft. You can change the amount of vibration by moving the counterweight nearer or further from the motor.
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Oct 8, 2011 23:01:34 GMT -5
Ah - ok, I see. That's a great feature! The rig I have only has a rectangular block of steel maybe 2" wide by 5-6in long that mounts to the shaft like a flag using a set screw. Dunno if that's the "original" setup or not since I got it used and pretty cheap.
Kinda funny story - When I first got it, the motor seized up after less than 2 days. It had an internal fan in it and that had completely melted. Bearings, I reckoned. I got a new 1/15hp from Grainger but that one would only go for about half an hour before the thermal protection shut it down. They didn't have anything with an internal fan - that wasn't super expensive and too big. Anyhow, I finally looked at the spec sheet for the new motor and it's only rated for 40deg C ambient temp. 104deg Fahrenheit. Well heck, I'm in Florida! It was freaken 98F in the shade already so the poor motor had no margin. I ended up taking some steel roofing truss straps and strapping an 8" high velocity 12v computer rack fan to the motor plate blowing up through the bottom of the motor and it works fine for a long time! I had a 12V "wall wart" laying around that supplied enough current for the fan.
Here's what I figure: Since Lortones are made in Wash. state, they didn't expect such high ambient and folks up there might never see this problem! lol And, also, motors rated for 50C cost $400! C-ya, Rick
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Post by jakesrocks on Oct 9, 2011 8:58:42 GMT -5
Had basically the same problem with the power feed on a new 16" Covington saw. Only the saw wasn't built for freezing weather use. Sheet metal will shrink a little bit in sub freezing weather. The sheet metal cover on the power feed motor was shrinking enough to bind the motor. Took the cover off the motor and made a shield to fit above it. It's been working fine since. Even in sub zreo weather.
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Oct 9, 2011 15:40:28 GMT -5
Ha! Sorta my problem in reverse. I've wondered about how saws work in winter up north. Like, what happens to the viscosity of the blade's lube oil? Do y'all come out in the AM to find that the sump is sludge with a viscosity of like 2W and the oil slings off the blade in clumps? lol
Since this thread is getting some replies, I have another question: Is the polish pad suposed to move/rotate with the rocks? Last night I started another polish batch and was trying to figure out which 2 rocks were clattering together every now and then. I noticed something that I don't *think* I saw with the first three batches, though I maybe just didn't notice. - I noticed that, not only were the rocks all merrily circling CCW around the pan and doing their usual dances with each other but the polish pad itself was also spinning at the same rate as the rocks were. Seemed to me that this would somewhat hinder the polish process/time since the only friction would be the jiggle of the pan without the added friction of the rocks moving round and round across the surface of the pad. It seems like the pad has sorta shrunk as it has a maybe 3/8" gap all the way around between its edge and the inside of the pan rim. Are you maybe supposed to glue the polish pad down in the pan? I'd thought all you needed to do was toss it in and insert the plastic bumper ring that came with the pan. Thanks, Rick
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Post by jakesrocks on Oct 9, 2011 15:54:23 GMT -5
My Highland park uses a 3/8" round piece of plastic tubing for a bumper ring. The pad fits under the bumper ring. Also, the HP pad is glued to a circle of galvanized sheet metal and just lays in the pan with the bumper pressing down on it.
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rockhound97058
freely admits to licking rocks
Thundereggs - Oregons Official State Rock!
Member since January 2006
Posts: 760
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Post by rockhound97058 on Oct 9, 2011 20:03:05 GMT -5
Rick that's the same problem I have with my 20" Lortone. The motor did the same as you mentioned so I bought a new one from a company which cost over $100 bucks. I told them I needed a Internal Fan (No prob they told me) - Any hoot - I get the motor and of course it's an open air / non fan motor. I call them back and the guy tells me just use it, has a warranty it it fails... So 2 days later I melted the guts out of it and to me amazement they replaced it with another motor. It still gets warm - so I have a 24" box fan which pushes air through it. Middle of summer when it's 100+ it still works with no kicking off. If I didn't run a fan the thermal kicks it within 15 minutes.
If you look at a brand new lap from Lortone - you'll notice a design update - this is to house a actual over the counter motor, rather than the small things we're running.
In regards to your other questions - The machine works much better if the polish pad is stuck down. I use silicone with a few dobs here and there and let it dry good before use. Works like a charm and it's pretty eash to clean when you have to rip it out and replace the pads.
Happy Lapping!
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Oct 9, 2011 20:20:06 GMT -5
Sheet metal? What keeps it from making a racket when it vibrates? Does the bumper ring hold it down? Or does your metal circle and pad rotate in the pan along with the rocks?
My rig came with a ring, as well, but it *looks* like the pad has actually shrunk in diameter since I started using it (on the 4th batch now) and the ring just mostly sits on the metal of the pan itself rather than the entire pad. The pad was only like $13. Is it possible that it has shrunk from being wet sorta like some clothes shrink when you wash them?
I have the thing running now without a lid on the pan. Doesn't seem like a really good idea but I took a plastic toothbrush (only thing handy of the right shape/material) and clamped it to the rim of the pan with the stub end pressing hard down onto the pad to keep it from moving so my lid wouldn't fit. (see my later post for a cool lid idea) I'm running low on tin oxide so I couldn't stop and swap the pad for a piece of carpet. It has a bunch already in it that would be wasted. I did have the thought that I might try to wring it out onto whatever piece of carpet I could come up with but I figured a lot of the TiO2 would still be in the pad... Rocks! - it's always something. :-) Rick
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