muleshoejoe
off to a rocking start
Member since July 2008
Posts: 16
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Post by muleshoejoe on Apr 9, 2009 22:34:38 GMT -5
Has anyone had any experience with using one of the wet angle grinders that use the velcro diamond pads? I have some bigger faces on pet wood and montana agate that I want to polish and wonder how one of these things would work? Will it remove saw marks with the coarser grit? Montana agate is pretty hard and I wonder if I will go through pads so fast it would be uneconomical? Any thoughts? Thanks. MSJ
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Post by johnjsgems on Apr 9, 2009 22:50:03 GMT -5
You do the rough grinding with the turbo wheel or new convex wheel. The pads are only for removing scratches, sanding and polishing. How big are your Montana agates?
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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 Apr 10, 2009 0:39:54 GMT -5
I've got a wet stone polisher myself.... The one I have is a Makita compared to the Barranca's model. I agree with johnjsgems though.. You want to use a 4" grinder with a dry cutting diamond head... The flat diamond wheels work, however trust me, I'd spend the extra money upfront and buy a cup model. www.fastenal.com/web/products/detail.ex?sku=59450&ucst=t Heck when I found this link I see these are cheap! Might have to get another for myself lol. Anyrate use this wheel to rough out your shape. Be easy with it as it can chip the edges easily. Then prepare to get wet, and start with your 50 grit velcro pad and continue to your highest step my machine goes to 3000grit. The only thing is mine works fantastic, however you still need to polish afterwards... I can't seem to being a high gloss finish with the pads. Good hard materials take time... go slow and make sure to spend a fair amount of time on each step. Soft material this machine rips through! Large Septarian nodules work fantastic! Oh also this machine works well on outside dome shaped pieces, rather than a inside dome. The machine I have came with the complete set of pads and they work well and last for quite awhile. I did hook an edge and tear one pad so I got into my replacements (ebay special from china) which seems to work fantastic. Keep in mind it has a fair price tag for the complete set-up. So make sure to have plenty of rocks to make the machine pay for itself. I find mine sitting under the bench more than I ever use it. Hope that helps Jason
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Post by johnjsgems on Apr 10, 2009 9:24:09 GMT -5
Makita makes a great grinder. The pads made for counters generally stop at 3000. Barranca pads are made for rock and go to 13000 giving a nice finish to most rocks. Pad prices are much higher though. Their latest model of grinder is having dependability issues so "not available" from most dealers.
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muleshoejoe
off to a rocking start
Member since July 2008
Posts: 16
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Post by muleshoejoe on Apr 10, 2009 9:52:50 GMT -5
Thanks guys, great info! I have a Makita 4" angle grinder for metal work that I have used for a long time and it still is going stong, so I like Makita for sure. I am looking at either a vibrating flat lap or the angle grinder. I like the fact that for domed surfaces the angle would be better. My agates aren't that big really, prolly 5" x 7" or so . There are bigger but finding them is another story. LOL. The problem I have is that on stuff that size I invariably get chatter marks or divots when trying to get saw marks out. I am using my 220 galaxy wheel for that. Operator error for sure, so thats why I was looking at the grinder for maybe a easier way for me to face them up. The cup wheels look like the ticket but I have heard since they don't flex that they can chatter easily?
MSJ
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Post by johnjsgems on Apr 10, 2009 10:02:36 GMT -5
If you are grinding flats the flat surface wheels work great. For contours on really hard materials you can experience chattering with the turbo cup wheels. You have to use a light touch and plenty of water. To correct that Barranca went to a variable speed control. On flats the wet polishers will work pretty fast and handle up to 12" slabs. Over that and you will have a problem getting a uniform finish.
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