wplmartin
off to a rocking start
Member since August 2008
Posts: 2
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Post by wplmartin on Aug 1, 2008 21:26:06 GMT -5
Hey, I just started this with my daughter and son, beach combing and bringing back rocks to tumble. any advice on tumbling the "chert" that is found on all the rocky hilltops of San fran?
I also read a thread about using beach sand in the initial stage. I specifically went to and area of beach where the heardest sand collects... I'm just goofing around to see what happens.
BTW Anyone know where I can get grit in SF?
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Post by Bikerrandy on Aug 1, 2008 23:50:52 GMT -5
Welcome! Alot of us get our grit from www.therockshed.com , Shawn is a great guy to deal with (and he always sends a little bag of candy with each order) ;D Also, the aluminum oxide polish that he sells seems to be the best. There's alot of great info on here. The main thing about tumbling is that you gotta be very patient. I'm not sure about doing the initial stage with beach sand. The media must be harder than the rock itself in order to cut. In a rotary tumbler, you'd do the initial stage with 60/90 grit, how much depends on the size of the tumbler. There's also detailed instructions on Shawn's website about the different stages. Good luck and keep asking questions, there's a ton of knowledge on here Oh- here ya go, click on this and then click on where it says "Instructions on how to use a rotary rock tumbler", it's toward the top of the page.... www.therockshed.com/tumbler4.html
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wplmartin
off to a rocking start
Member since August 2008
Posts: 2
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Post by wplmartin on Aug 3, 2008 23:17:50 GMT -5
I have my tumbler, and sample grit. I've already used my 60 grit. So what I have been doing, until I order some 60 grit, is to recharge daily with coarse beach sand. I'm just experimenting to see what happens. It seems to be working, although I did not take any before pictures. I've only been using the sand for 2 days. I open the tumbler everyday to check it. Previous to that I used my orginal baggie of 60 grit to do the 1st stage of my first tumble. I still need to buy 2-3 more barrels for the other stages. I am now doing the 1st stage of my second tumble. Hopefully at some point I will have something to post.
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Post by rocklicker on Aug 6, 2008 11:01:34 GMT -5
Welcome to the board wplmartin! The nearest shop I know of is in San Jose called Wenrics. They have grit but if you are serious about tumbling then buying larger quantities on line is better. I don't think they sell grit kits there. A lot of people here get grit from the rock shed. Another good place is Kingsley North.
As far as using beach sand, it will eventually work but will take a very long time. Basically by using sand you're doing the same thing waves are doing as they round pebbles found on the beach. In a pinch it will get the job done but it's not as hard as grit. Just be ready to let them go a looooooonnngg time.
Glad to hear you are from SF! I am from Santa Rosa and am a big fan of the chert beds in SF. I know that stuff well. Actually, it's a little softer than most jaspers so sand might not be all that bad. That stuff fractures easily so using pellets in the later stages are a must. Chert should polish up real nice. I know some of it around SF and up here near Sonoma County can be pitted so watch out for that. You may have to spend some extra time in course to get them out.
Welcome again to the board. It great to see another Bay Area rocker! Have fun with the tumbling. I hope the beach sand works out until you get regular grit. Steve
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