Wednesday, November 30, 2005

What Type of Polish Do I Use in My Rock Tumbler & Other Lapidary Equipment? Click for more rock tumbler tips

There are many types of polishes on the market that work in rock tumblers and other lapidary equipment. Deciding what one to use can be confusing. Here are some basic tips on picking the right polish for the your rocks.

Aluminum Oxide Polish. This is a common rock polish that works well on hard "silica" type rocks like agate, petrified wood, and jasper. It is generally the cheapest polish, which is why it is the polish of choice for most beginning rock tumbler kits. Sometimes you'll find Tripoli or red rouge in rock tumbler kits. Tripoli and red rouge are not rock polish. Read about them below. Aluminum is fine for the beginner, unless there is a special need.

Cerium Oxide Polish. This is a medium grade polish that works well on all types of agate, quartz crystals, petrified wood, jasper, feldspar, and obsidian.

Tin Oxide Polish is the best. This high grade polish works well on everything. It will put a great polish on all the hard materials such as agate and even the harder stones like corundum (rubies and sapphires) as well as softer stone like glass and obsidian. This is my pick! If you want the glass-like shine use Tin Oxide.

Linde A ( or "B" or "C") Polish. This is facet grade polish and even though it works on agates, it is cost prohibitive. It is generally used only to facet gemstones.

Polishes to avoid…

Some companies package Tripoli & Red Rouge as rock polish. These materials are designed for polishing metals (which are much softer than stones) and will not do anything to polish the rocks. They are abrasives contained in a wax. When you use them as polish you are only putting a wax on your stones that will wear off rapidly leaving you with a non-polished stone.

Fabuluster, Lusterite, Luster-Rite, and many of the other trade name polishes are usually just other names for aluminum oxide. Buying it generically will save you money.

Thursday, November 24, 2005

Hobbyist Rock Tumblers vs. Toy Rock Tumblers…


There are lots of cheap rock tumblers on the market. None of them will compare with the two major brands, Thumler's and Lortone. When you buy a Thumler's Rock Tumbler or a Lortone Rock Tumbler you are buying a tumbler that is made to last for many years. It is not uncommon to see one of these tumblers that is 20 years old and still working.

Thumler's and Lortone rock tumblers are made of high quality parts and thick rubber barrels. This makes for QUIET rock polishing.

I looked at the rock tumbler a major discount retailer sells. It comes with a 2 WEEK warranty. The rock polishing process takes 4 weeks to complete, so this tumbler is not meant to do anything except frustrate the owner (or purchaser). If you are getting one of these rock tumblers for a child (of any age), you are setting them up for failure! They will never know if they like rock tumbling when they have a tumbler that is not meant to finish the job.

Any tumbler with a plastic barrel is noisy. We are talking the type of noise that makes you cover your ears.

Plastic barrels will NOT tumble rough stones. You must use pre-tumbled stones so you won't wear a hole in the plastic barrel.

Another common "toy" rock tumbler looks very similar to a Lortone rock tumbler. It appears that the company that makes them sent one of Lortone's tumblers to China and said make this as cheap as possible.

I have never heard of one of these rock tumblers lasting for more that a couple of weeks. Most don't last more that a few hours! The belts break within hours, and if you keep replacing them or if you replace them with a quality belt, then the pulleys break. Once again, you are setting yourself up for a huge disappointment with one of these "toys."

Thumler's and Lortone rock tumblers cost more up front, but in the long run you get a lifetime hobby. Being able to polish almost any rock in a quiet, long lasting rock tumbler is a satisfying experience.

Wednesday, November 16, 2005

Rotary Rock Tumblers vs. Vibrating Rock Tumblers…

I am often asked the question of which type of tumbler is better--rotary or vibratory.

The real question people should ask is "what type of rocks do I want when I am finished?"

A good rotary tumbler (Thumler's or Lortone) will take your rough stones and make them beautiful rounded, polished gems. A vibratory type tumbler (Thumler's) will take your rough stones and polish them only. Vibratory type tumblers do NOT round or shape the rock. Whatever shape you put in is the polished shape you will get out.

"So why get a vibratory tumbler?" you ask. They have a very useful purpose. They don't change the shape of your stones. If you have stones that you have cut and ground to a specific shape and you want to polish a lot of them at once, then you can use a vibratory tumbler. This is great if you have made a lot of pre-formed cabs and want to polish them without changing the shape. I know a lady who cuts out little dinosaur shapes from slabs on a diamond band saw, and then fills her vibratory tumbler to polish all the dinosaurs at once. This process will save her a lot of time and money in the long run.

Another advantage with a vibratory tumbler is that they only take 7-10 days vs. 30-45 days with a rotary tumbler. The trade off is that vibratory tumblers are usually a lot more expensive.

There is another type of tumbler on the market that I am often asked about. That is the -sonic type tumblers. These type use ultrasonic vibrations to create the action that polishes the rock. Once again, they are like a vibratory tumbler except they tend to not last long, as the transducers are easily broken with prolonged use.

If you have other questions, e-mail me at rockshop@rocks4u.com, or call 1-888-Rock-Shop (1-888-762-5746).

Thursday, November 10, 2005

Getting White Lines Out of Your Tumbled Stones

Often after tumbling rocks, you will notice white lines on your newly polished treasures. These lines are caused by polish getting in small cracks in the rocks.

Sometimes there is nothing you can do to fix this problem. However, you can try a few little tricks to get them out.

First, try putting the rocks back in a very clean barrel after you clean the rocks of ALL polish and any dirt that may have gotten on them. Put water in them as you have for all the tumbling stages.

Instead of putting in polish, put in any soap that doesn't produce suds. Ivory soap flakes work well but have become difficult to find in the stores.

After you have the soap and water in the barrel with your stones, you will want to add CLEAN plastic pellets. Do not reuse the pellets from the polish because they are contaminated with the polish.

Seal up the barrel and let it run for a few hours and check. If the white lines are gone, you are done. If they are not let it go a few more hours. This process can take up to 24 hours. If the polish has not come out by then, it isn't going to come out at all.

I have heard of some people grating up Ivory soap bars with a cheese grater. That seems to be working well. My wife got a little agitated when she saw me headed to the food processor with a bar of soap. You might want to get permission or purchase a cheap cheese grater just for this purpose.

Do not use dish soap, laundry detergent, or even dishwasher soap. They will not work.

As always, feel free to call or email with questions.

Rick

Tuesday, November 01, 2005

Make Your Own Beach Glass in Your Rotary Rock Tumbler

Beach Glass 101

Beach glass is the frosted glass you find along a beach or sea shore. It is caused by glass, usually from broken bottles, that rolls around in the sand as waves move it back and forth. The frosted effect is caused by the sand acting as a sandblaster on it. If left long enough in the sand, the glass would completely disappear.

This glass is often used to make jewelry, stained glass, and a number of other projects because it is very attractive. Because of recycling and responsible beach goers, these days you find very little beach glass. However, it is still in high demand.

Here is how to make your own beach glass:

Some people like their beach glass heavily frosted, some like it very lightly frosted, and more even like it somewhere in between. So here are the steps to produce beach glass, but you will have to determine how long to let it go to get the effect you want.

1. Choose a tumbler (see bottom) and fill the barrel 3/4ths full with your broken glass. The size of glass and the amount of finished product will be determined by the size of tumbler.

2. Add enough water to see it just under the top layer of the glass.

3. Start with a coarse grit like 60/90 silicon carbide. The amount you will use is determined by your tumbler size. This step is not so much to frost the glass but to shape it. This step will do all the rounding for you.

4. Close up the barrel and start the tumbling. Rock takes 7-10 days per step. Glass is not nearly as hard so it will take a lot less time. For your first few experiments I would recommend checking the glass every day to see if it is round enough for you. Once it is round enough for you, then move to the next stage.

5. You must wash the glass, barrel, lid, and your hands before the glass is ready for the next stage. Do NOT put the sludge in your drain as it WILL clog your pipes!

6. Start the whole process over again with step 2 or 120/220 grit silicon carbide. Let it go until it is frosted enough for you or very close to frosted enough for you. It should take about as long as step 1 did.

7. If you want a more refined frosting then do a step 3 or 500 or finer grit silicon carbide for 1 to 5 days. The longer you go the finer the frosting will be.

8. If you want to polish the glass then you can do a step 4 or cerium oxide polish (chrome oxide also works well) for 3-7 days with plastic pellets added to the barrel to bring it up to 3/4ths full again.

This last step will create a gloss shine on your glass which is not beach glass but still looks great!

How to choose the right tumbler....

The size of tumbler you will want will depend on the size and the amount of glass you want at the end.

The smallest tumblers will do glass up to 1 inch in diameter and you will get about 2 cups of finished glass.

The 6 pound tumblers will do golf ball size chunks of glass and you will finish with about 4-5 cups. This size machine will do smaller ones as well but no larger than a golf ball.

The 12 pound tumblers will do up to 2 inch glass chunks and you will finish with about 10 cups of glass.

The 40 pound tumblers will do up to 3 inch pieces (you might be able to do slightly larger but not a lot of them at once) and you will finish with about 20+ pounds of glass.

The amounts you finish with are all approximate. You can do smaller pieces of glass in the larger tumblers but you can't do larger ones in the smaller tumblers. If you are doing a lot of glass on a continuous basis then you may want to get a larger tumbler.

Good luck!

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