Flat Lap Troubleshooting

Heather Behrendt · #1 2010-10-20, 6:00pm

So, I have a flat lap, and it's awesome, but I sometimes run into a bit of a problem and I'm not quite sure what I'm doing wrong.

Sometimes at the edge of the surface I'm grinding, I get a rough course surface. This is only on one side which would make me think maybe I should be rotating the bead as I'm grinding, but I tried that with the same result.

I move on to the different discs, hoping it'll smooth it out, but I still end up with the same crappy looking edge.

Any thoughts or suggestions?

I also just noticed as I'm examining the bead, that it cracked. I don't know why. I'm kinda bummed

houptdavid · #2 2010-10-20, 6:34pm

1. Don't push down, just hold the item and let the disc do the work.
2. Work across the disc, it's all paid for! Don't just use one spot.

myrdlebp · #3 2010-10-20, 7:23pm

Quote:

Originally Posted by houptdavid

2. Work across the disc, it's all paid for! Don't just use one spot.

That's funny! I sorta needed that.

SadiesJewels · #4 2010-10-20, 10:24pm

Large grit sizes will tend to give you chips ... but it's part of the grinding process. The leading edge tends to take the brunt so try to vary the movement so that different sides and edges lead. Make sure as you work down the grit sizes you have removed previous chips on the sides.

Would love to see your results when you're done!

Frit Diva · #5 2010-10-20, 10:44pm

Make sure you aren't putting more pressure on the leading edge. It has a tendency to dig in anyway.

Jo

Jeri · #6 2010-10-21, 6:45am

Sometimes cracking is from the bead overheating. ARe you using enough water and stopping frequently to rinse and check the bead? Also, make sure the bead is clean between steps so the coarser grit isn't contaminating the smoother steps. Jeri

Mitosis Glass · #7 2010-10-21, 7:52am

I'll need to mark this thread for later reference. This is something I'm thinking of buying myself and am interested to know any tips for usage.

And yes, post pics! I love beads that have been worked this way.

FiredDesires · #8 2010-10-21, 10:45am

As I'm grinding, I move in a small circular motion from the inside out towards the edge of the disc and back up again, with an even pressure (just enough so the bead doesn't flip off the disk) with this method I cover all areas of the disc ...all the tips offered above are excellent too...plenty of water, and clean between grit changes are great ones!

Jeri · #9 2010-10-23, 8:23am

I call this bead a "portal". It is the only example I have in a photo (and I can't figure out how to shrink it, duh). I can shamelessly plug my new book, the tutorial for this bead is in it!! Basically it is a hollow bead with indentations made with a tungsten pick, that has been ground and polished to a slice on my flat lap. Jeri

Heather Behrendt · #10 2010-11-14, 8:27pm

So, I did a few more beads and everything seemed to be all good with my flat lap, but I'm still having some troubles with it and I"m not sure why.

I've tried using the lightest pressure I can, different speeds, rotating the bead as I'm grinding it, and I'm still getting some nasty looking edges and I'm not sure why. I've been cleaning the bead and the wheel between uses. I can't think of what else. Am I just not grinding it enough with each wheel?

When I grind a bead that has a smaller flat surface I do alright like a bicone shape, but anything with a larger area to grind away, I have some troubles.

Here's a picture of a bead with a yucky edge. Anybody have any other suggestions for me to try? I'm at a loss. Thanks

squid · #11 2010-11-14, 9:03pm

That looks like you tilted the bead when it was on a coarse grit and then, when you went to finer grits, you didn't hit that same spot again.

Heather Behrendt · #12 2010-11-15, 5:23pm

It's hard to see in this picture, but the nasty edge isn't just on the bottom of the heart, it's also on the top right lobe and the edge closest to the camera. I would think it would only be on one side of the bead if I was tilting it.

I don't know though. I'll try to hold it steady on the course grit and then keep going.

This picture is only on the second wheel. I've been trying to get a consistent surface before I finish up.

Thanks for looking.

squid · #13 2010-11-15, 5:25pm

You may have tilted it more than once. I had the same problem with a bead I was lapping. I ended up with 3 different "surfaces". Good luck!!

Heather Behrendt · #14 2010-11-15, 5:31pm

That wouldn't surprise me actually. If I screw something up it would be very me if I did it three times instead of just once.

Jeri · #15 2010-11-15, 5:45pm

It might be tilting. But it also looks to me that you are being too aggressive on the coarsest wheel, an so the edges of the bead are chipping. Then when you move to the next disk, of course, those jagged edges don't get reached. Try doing the first grind with less pressure and more water to see if the same thing happens. It is all trial and error, for sure. Jeri

squid · #16 2010-11-15, 5:45pm

PittsGlass · #17 2010-11-15, 6:26pm

It could also be too aggressive a first grit. What grit of pads are you using?

Heather Behrendt · #18 2010-11-15, 6:58pm

the first one should be 100 grit. It came in a kit

I wouldn't be surprised if I'm being too aggressive on the first grind. It would make sense since I'm only having trouble with the beads where I have a lot more to grind away. I haven't been having much trouble with smaller beads. I probably get impatient and start pushing down a little more without paying attention.

If I do get too aggressive, is that bead no good? Or do I just need to carefully grind past that ugly part?

Jeri · #19 2010-11-15, 8:29pm

You can probably grind past the ugly part, it's worth a shot!! Jeri

elle · #20 2010-11-15, 10:44pm

Might I add one thing that helps me immensely: fully covering each facet with a black permanent marker between grits. For example, after the first grit (170) I mark each ground off surface with the marker before moving to the 325, so on and so forth. You can be reasonably sure that once the black stuff is gone from every surface, plus a few extra swipes on the lap for good measure, that it's safe to move onto the next, finer grit.

This also helps me avoid indavertently creating multiple facets when there was only supposed to be one facet. This is more likely to sneak up on you with the finer grits, so the black coating is particularly helpful when you're on the 600 and finer grits.

This saves a good bit of time, too, because without the black mark, you may miss the 325 grit scratch with the 600, and the 1200 isn't going to do much for such a deep scratch, if anything at all. And the final glossy polish is going to reveal everything you missed, and you will likely have to go back through all of your grits to correct these mistakes. And then you'll start all over again with the polishing. Sigh. Been there, done that - but with the black marker trick, I rarely have to do this at all any more. And the black marker isn't necessary for the polishing - you can tell if it's being polished or not by how glossy it is.

Hope this helps -
Sarah

Heather Behrendt · #21 2010-11-16, 5:51am

Ooooh, I like that idea. Thank you so much. I think that'll be super helpful.

Jeri · #22 2010-11-16, 5:58am

Sarah - is there a brand of marker you like? I have tried this method, but everything I have used (even Sharpie) washes off prematurely. It is a great idea. Jeri

elle · #23 2010-11-16, 6:40pm

Quote:

Originally Posted by Jeri

Sarah - is there a brand of marker you like? I have tried this method, but everything I have used (even Sharpie) washes off prematurely. It is a great idea. Jeri

I've mostly used Office Depot brand permanent markers just because that was what I had laying around when I had this sudden stroke of genius. I recently started using very wide angle tip Sharpies - those are surprisingly inky. Don't go on a wild goose chase for the OD markers because I'm pretty sure they don't sell them any more. I bought them at least 6 years ago and I'm not seeing them on their website right now.

I haven't had any problems with the ink washing off too soon, no matter the marker. Are you letting the ink dry a bit before putting them on the lap? Are the glass surfaces totally dry before marking them? I keep a buttload of clean, dry rags around for this purpose... and I blow on them a lot.

Sarah

Jeri · #24 2010-11-17, 5:59am

Thanks Sarah - they are now on my shopping list!! I particularly like the thought of help with eliminating those fine scratches that can escape my notice until the polish phase.

One more questions, do your disks turn black from the ink, and have you ever had that black come off on a subsequent piece? Jeri

VivianLampwork · #25 2010-11-17, 7:33am

Can you get a nice polished look with a grinder or do you have to have a flat lap? I have a grinder & always wondered if it would work.

elle · #26 2010-11-17, 1:56pm

Quote:

Originally Posted by Jeri

Thanks Sarah - they are now on my shopping list!! I particularly like the thought of help with eliminating those fine scratches that can escape my notice until the polish phase.

One more questions, do your disks turn black from the ink, and have you ever had that black come off on a subsequent piece? Jeri

Never. The black ink should be ground off along with the glass, and the water drip washes everything into the reservoir. The only disk the ink might hang around on is the felt polishing disk (due to its absorbency) and I have had that happen, but it never came off onto the glass.

Heather Behrendt · #27 2010-11-17, 7:33pm

I just wanted to say a quick thank you for everyone who helped me figure this out.

I'm having much better luck now. I was too aggressive on the first wheel.

The black marker tip is very helpful. I did a few with that and very light pressure and they turned out perfectly.

Jeri · #28 2010-11-18, 6:15am

I can't wait to see what you are working on. Jeri

elle · #29 2010-11-18, 8:34pm

Quote:

Originally Posted by booga119

I just wanted to say a quick thank you for everyone who helped me figure this out.

I'm having much better luck now. I was too aggressive on the first wheel.

The black marker tip is very helpful. I did a few with that and very light pressure and they turned out perfectly.

Great! Just like anything else, you'll get better with practice.

Sarah