Tom
fully equipped rock polisher
My dad Tom suddenly passed away yesterday, Just wanted his "rock" family to know.
Member since January 2013
Posts: 1,557
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Post by Tom on Apr 10, 2014 15:21:45 GMT -5
Hi all,
First I would like to say that we need a forum room for equipment questions, I was tempted to put this in the saw and slab board:)
Ok do flat laps suck? I have bought the complete set of end laps for my Cab King, 80. 100, 180, 240, 360, 600, 1200 and 3000 grit. I can't get the scratches out of my flats. Fact is the finer I go the more scratches I get.
these wheels are more or less brand new, I have used them very little. I have searched the net for info on breaking them in and found that they should be broke in. But no love on "how to break them in"
There is really no issue with the courser wheels as they do what they are supposed to do, they remove material. But the finer flats seem to pull at the stone at times. This seems more prevalent closer to the outside edge.
So should I be running a Brazilian agate over these disks for a bit or are they just not designed to get out scratches, which they must be or faceters would be tee'ed off.
Any help welcome and thanks.
Tom
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Post by Pat on Apr 10, 2014 17:09:16 GMT -5
I don't know. Sounds like something coarse has been embedded in the finer flat lap discs. I have an Ameritool flat lap. Haven't had the problem.
Can you isolate the offending discs? Then you could examine them with a magnifying glass.
What a bummer! Good luck with it.
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Post by FrogAndBearCreations on Apr 10, 2014 20:21:39 GMT -5
working agate up through the grit sizes will be a good break in for them - also if you think they are cross contaminated you can use the rubber block that one uses to clean sandpaper belts with water spray or use a soft tooth brush under running water to clean them
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gemfeller
Cave Dweller
Member since June 2011
Posts: 3,801
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Post by gemfeller on Apr 10, 2014 21:09:00 GMT -5
Hi all, Fact is the finer I go the more scratches I get. these wheels are more or less brand new, I have used them very little. Tom, your statement that the finer you go the more scratches you get makes me strongly suspect what you're seeing are deep scratches left by your coarse wheel. I have a hunch you didn't sand long enough in the next grit sizes to eliminate them. This is a common problem in faceting. Coarse grits remove stock fast but they also leave lots of sub-surface damage. Those scratches often are not noticeable until later when the surface begins to take a semi-polish. The fact your wheels are new adds to my suspicion -- the diamonds are sharp and leave deeper scratches. I recommend checking for scratches after your second or third grind with a 10-power loupe or equal magnification. You might be surprised how many from the first grind remain. I use flat laps a lot. They vary tremendously in quality and price isn't always the best indicator. I've used cheap toppers that are much better than more expensive ones...but I've also had the opposite experience. Mileage will vary from user to user but when I'm breaking in a new lap I grind a piece of inexpensive synthetic sapphire (hardness 9 Mohs) across the whole lap's surface for 4-5 minutes, using lots of water to wash away any debris. That should knock off any diamonds that are sticking up above the others and begin the break-in process. Good luck!
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Post by jakesrocks on Apr 10, 2014 21:21:56 GMT -5
Wash and dry your work piiece between grits. Inspect the dry piece under a loupe for deep scratches. Inspecting a wet piece won't work. Water helps to hide the scratches.
Wash and dry each lap after use. Store each in their own zip lock bag. Label the bags by grit size. This will help to eliminate cross contamination.
What Rick said about breaking in each disk.
Inland machines are junk, but Their steel backed discs are good and inexpensive.
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gemfeller
Cave Dweller
Member since June 2011
Posts: 3,801
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Post by gemfeller on Apr 10, 2014 21:43:59 GMT -5
Don's points are very important. I forgot to mention that drying is crucial before inspecting a piece for scratches. Try keeping a dry towel and loupe right by your machine.
Separate lap storage is very important too. I often use a Sharpie to write the grit size on the bottom of the lap for quick reference as well as the storage container.
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aimeesrockworks
spending too much on rocks
I really do look like my avatar... it kinda freaks me out.
Member since December 2010
Posts: 458
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Post by aimeesrockworks on Apr 10, 2014 21:59:21 GMT -5
I'll bet $$ that you're not getting the heavier scratches out... and I say this only from experience my recent forays into the Flat Lap World. It's been taking me a really long long long time at the 325 to get them smooth (and the harder the rock, obviously the harder it is to get those deep scratches out). Patience is what everyone keeps telling me. PATIENCE AND LOTS OF KICKING INANIMATE OBJECTS!!!!! (and taking deep breaths) AND KICKING!!!!
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gemfeller
Cave Dweller
Member since June 2011
Posts: 3,801
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Post by gemfeller on Apr 10, 2014 22:35:28 GMT -5
Patience is what everyone keeps telling me. PATIENCE AND LOTS OF KICKING INANIMATE OBJECTS!!!!! (and taking deep breaths) AND KICKING!!!! I often think about what Mark Twain considered "the innate cussedness of inanimate objects." Don't kick too hard!
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rykk
spending too much on rocks
Member since September 2011
Posts: 428
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Post by rykk on Apr 11, 2014 3:46:11 GMT -5
The scratches are probably leftovers from the coarser grits. They can be very hard to spot until the finer grits make them obvious. I've had this happen a lot with my vibrating lap where scratches become obvious only after the 600 grit grind or, most often, during the polish phase. I've learned to clean the slabs really well and inspect them under a good, bright light after the 220 grit phase.
I had the same problem as you're having when I was using my 8" Inland flat lap and was pretty frustrated. I didn't know what I know now, back then. I quit using it when I got the "jiggle pan". Does just a good a job, maybe better anyhow. No danger of heat caused crazing and faded colors. Takes longer, but you can do 15-30 at a time and have you hands free for cabbing, slabbing, or... honey do's. :-) C-ya, Rick C-ya, Rick
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Tom
fully equipped rock polisher
My dad Tom suddenly passed away yesterday, Just wanted his "rock" family to know.
Member since January 2013
Posts: 1,557
|
Post by Tom on Apr 11, 2014 12:08:34 GMT -5
Thanks for all the responses, much appreciated! OK:
These are pretty much brand new chinese made sintered laps, seem to be pretty decent quality Always kept separate (not in bags but on a rack to air dry) Always air dryed Each grit is well labeled on each disk I do dry the stones well before looking at them
I offer no argument that I may be impatient and not getting all the scratches out. But I will say that when I get to the 600 mesh lap it seems to be going good then near the edge I feel a grab and there seems to be a new scratch that was not there before. This happens with all the fine laps. Its like the edges are not finished well, or need to be broke in.
So what I will try to do over the weekend is to start on the 80 with a hunk of agate and work it all over the disk, then work up through the next seven laps. I will wash and dry the rock well and check for scratches and see how it goes. if there are any high spots on the laps the agate may fix that.
Its frustrating to say the least, and I will admit I have not used them much so don't have much experience. I have a jiggle pan as well and use it for slabs and geodes etc. But I was grinding a 2 inch long triangle piece of obsidian and needed the lap to get my angles right. I ended up finishing it on the wheels. Still a couple scratches, damb flats LOL.
Thanks again for all the help
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Post by 150FromFundy on Apr 11, 2014 20:45:33 GMT -5
gemfeller and a few others nailed it when they indicated that the scratches you are seeing in later stages are deeply embedded scratches from your early stages. I struggled with this for a long time when I started finishing flats.
In addition to all the great advice add this ... Flip your finished piece 180 degrees between each disk change. The spinning disk leaves a pattern of concentric circles on your piece. For you first disk (80, or 180) get all the scratches aligned in the same concentric patter. When you examine your piece (dry under bright light with a 10X loupe) if there are any scratches not aligned, you are not done yet. When you move to your next disk (325) flip the piece 180 degrees and establish a new pattern of concentric rings. Once again, if all the scratches are not aligned, you are not done yet.
There is no magic here. This technique simply makes any previous disk scratches stand out from your current disk scratches.
Good luck.
Darryl.
PS - How many minutes are you spending on the early disks (80 and 180)? It takes a L O N G time.
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gemfeller
Cave Dweller
Member since June 2011
Posts: 3,801
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Post by gemfeller on Apr 11, 2014 21:36:44 GMT -5
I offer no argument that I may be impatient and not getting all the scratches out. But I will say that when I get to the 600 mesh lap it seems to be going good then near the edge I feel a grab and there seems to be a new scratch that was not there before. This happens with all the fine laps. Its like the edges are not finished well, or need to be broke in. So what I will try to do over the weekend is to start on the 80 with a hunk of agate and work it all over the disk, then work up through the next seven laps. I will wash and dry the rock well and check for scratches and see how it goes. if there are any high spots on the laps the agate may fix that. Scratches from near the edge of a lap are usually caused by insufficient break-in. Cutters tend to avoid the edges, keeping their work more toward the middle. That means the middle gets broken-in but the diamonds on the edge remain sharp and can scratch. When you grind your agate this weekend be sure to give the lap edges a good workout. That may help. Let us know how you do.
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Tom
fully equipped rock polisher
My dad Tom suddenly passed away yesterday, Just wanted his "rock" family to know.
Member since January 2013
Posts: 1,557
|
Post by Tom on Apr 17, 2014 7:48:01 GMT -5
Thanks for all the suggestions guys and gals. Darryl, I like your idea and will try it out next time I am doing a flat. My problem was likely a combination a everything suggested. The predominate issue was break in, I am not sure of the manufacture of these but the very outer part of the disk (in every grit) was causing most of the problems. I was making a bunch of mandants and decided to use the laps to rough them out and break them in. I still have some break in work to do on a couple of them but all in all I think they will be great and my frustration will end, at least for the laps LOL
Again I appreciate the help, sorry it took so long to get back to you all.
Tom
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