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What To Do If Your Rock Tumbler Barrel is Leaking

Leaking tumbler barrel
Gray muddy liquid on the base of your tumbler indicates a leaking barrel.

How to Fix a Leaking Rock Tumbler

Most rock tumbler leaks are easy to fix. The leak almost always occurs where the lid and the barrel are in contact with one another. The most common causes of a leak there are listed below in the approximate order of frequency.

  • Debris on sealing surfaces of the barrel or lid
  • Lid is not properly seated
  • Lid with rough edges or cracks
  • Lid is not tightly secured
  • Damaged lid gasket
  • Lid is worn out
  • Damaged barrel

  • If your rock tumbler is leaking, one of the suggestions below will probably solve the problem. You can also use an easy 30-second procedure to prevent most future leaks.

    The Most Common Causes of Leaks

    Clean the lid seat
    The most important place to clean a rotary tumbler barrel is the rim where the lid seats
    1) Grit or Rock Particles on the Sealing Surface of the Barrel or Lid: Small particles of grit or debris often cling to the rim of the lid or on the recessed part of the barrel where the lid seats. Water can escape in the tiny space produced by these particles. This is the most common cause of a rock tumbler leaking - just one drop of water at a time. Here's how to fix it.

    Simply open the barrel and pour the contents into a container. Then, thoroughly rinse and scrub the barrel until every speck of grit and rock has been removed. Now, get a used toothbrush and thoroughly scrub the edges of the barrel lid and the part of the barrel where the lid seats (the accompanying photos show where this scrubbing needs to be done). Make sure to thoroughly scrub the entire edge of the lid and the entire recessed part of the barrel where the lid seats. Just one speck of grit on either of those sealing surfaces can cause a leak.

    Then, carefully pour the grit and rock back into the tumbler barrel, being very careful not to spill anything on the newly-cleaned rim. Tiny pieces of grit that are too small to see can cause a leak. Then, replace the lid and place the barrel back onto the tumbler.

    Thirty Seconds of Prevention: To prevent this problem in the future, we spend 30 seconds thoroughly scrubbing the rim of the barrel and the edge of the lid every time we change our tumbler. Since we started doing this we have had very few leaks. Before we started doing this we had a lot more leaks.
    Lid not seated properly
    This image shows a lid that is not completely seated in the barrel.
    2) Lid Is Not Properly Seated: Sometimes the problem is this simple. When the lid was positioned, or secured by a retainer ring or threaded nut, it was either not straight or it was not firmly against the sealing surface of the barrel. This fix requires emptying the barrel as described above, cleaning the sealing surfaces, returning the rocks and grit back to the barrel and replacing the lid - and making sure it is straight before placing it on the tumbler.
    Damaged lid
    This image shows a lid with what appears to be minor damage but when looked at close up shows that it could easily cause a leak.
    3) Lid With Rough Edges or Cracks: Some rock tumblers have a plastic or fiberboard lid. A rough edge on the lid can be a manufacturing artifact or it can be caused if a lid is accidentally dropped or scraped against a hard object. This problem can be solved by very lightly sanding the lid edges with extra fine sandpaper. Don't sand so much that you round the edges of the lid. Just give it a very light rub on the upper and lower edges of the rim. Lid roughness can often be detected by rubbing a finger or a piece of fine cloth along the edges of the lid - the cloth will snag on the rough spot, a finger might feel it. Wash the lid and the barrel before you put the tumbler barrel back together. If a light sanding does not solve the problem, try it again. If that doesn't work, or if the lid is cracked or badly damaged, a new lid is probably needed.
    loose lid
    It is easy to tell when the outer lid on a lortone barrel is not tightened down all of the way.
    4) Lid Is Not Tightly Secured: Many tumbler lids are secured by rubber retainer rings, wing nuts or threaded nuts. Sometimes these are not tight enough to prevent leaks. Rubber retainer rings can stretch and become ineffective. Nuts not tight enough can make an incomplete seal. Care must also be taken not to overtighten, which can lead to a deformed lid, deformed barrel, which is another cause of a leak. Sometimes a new retainer ring is needed when the original ring has lost its ability to hold the lid secure.
    5) Damaged Lid Gasket: Many tumblers have a rubber lid gasket that serves as the sealing surface between the lid and the barrel. They can have cracks along their edges that can leak. Or, a small hole in the center of the gasket can allow water to escape from the barrel and cause a leak. These gaskets are inexpensive and easy to replace.

    6) Lid is Worn Out: This problem mainly happens with barrels that have a plastic lid. As the tumbler runs, grit and rough scrape against the plastic lid. Over time this will wear the center of the lid thinner and thinner. If not checked and replaced this lid will eventually develop a hole and cause a mess.
    Worn out UV-10 barrel
    This UV-10 barrel is worn so thin that light can pass through the bottom of it.
    6) Damaged Barrel: This is a common problem in barrels that are several years old or barrels that have been stored in a hot or cold location or in direct sunlight. Age or exposure to heat, cold or sunlight can cause the rubber of the barrel to develop tiny cracks or deform. Cracks can often be detected by tracing your finger around the sealing surface of the barrel or doing the same with a soft cloth. You might feel damage with your finger or the soft cloth might snag. The damage might also be visible if you flex the barrel rim slightly This problem can only be solved with a new barrel.

    Rarely, a well used barrel will develop a hole in the bottom. The hole will usually develop in the center of the base of the barrel. That is the concentrated point of friction that occurs when a barrel full of rocks is turning. The solution for this, unfortunately, is a new barrel.

    We Hope You Solved Your Leak!

    We hope that one of the solutions above has fixed your leaking barrel. Most of the time the leak can be fixed without spending any money. When that isn't possible, a new lid, lid gasket, retaining ring, or barrel nut can usually be obtained for a small cost. When that isn't possible a new barrel is the only solution.

    Happy Tumbling!

    Article Authored by

    Brad Cole Bradley Cole: Bradley is the manager of and has authored much of the content on this website. He also does customer support, photography, maintains the website, and consults with customers about rock tumbler repair and maintenance.
    Hobart King Hobart M. King: Hobart is the owner of and has authored much of the content on this website. He has a PhD in geology and is a GIA graduate gemologist. He also writes most of the content for