Blue Bowl Concentrator 

Blue Bowl Gold Concentrator - The D.A.M. Gravity Concentrator 
Blue Bowl
Panning fine gold concentrates by hand is difficult and tedious, however, when set up and operated properly, the Blue Bowl can recover Gold as fine as talcum powder! Used by thousands of gold miners, the Blue Bowl Concentrator makes easy work of what would take hours, and does a more thorough job of removing the black sand from the gold dust. This unit can be used at home or in the field. Completely portable, the The D.A.M. Gravity Concentrator, otherwise known as the Blue Bowl, weighs just 3 pounds, and has few parts to wear out or replace. Its rugged construction is made for a lifetime of use!

Purchase the Blue Bowl by itself, or purchase the Blue Bowl Kit that includes a pump and other items. A set of 3 Blue Bowl Leg Levelers are sold separately for use with a 5-gallon bucket. 

Every new piece of recovery equipment has a learning curve, but the Blue Bowl system is so simple that anyone can learn to use it effectively! Scroll down to read how-to instructions below and watch the video to see the Blue Bowl Gold Concentrator in action! 
    Blue Bowl Concentrator
    D.A.M. Blue Bowl Concentrator #6823
    Blue Bowl Concentrator Kit
    Blue Bowl Concentrator Kit #5020
    Blue Bowl Leg Levelers

    Blue Bowl Concentrator Leg Levelers #6825

    Johnson 12 volt submersible pump
    Item: 5153
    Blue Bowl Instructions 
    How to Use the Blue Bowl Concentrator

    Before getting started, wash the interior surfaces with a mild dishwashing detergent such as Ivory, Joy, or Dawn to remove any oily residue. This should be repeated periodically to ensure the Bowl surfaces are clean and oil free. Never ever scrub the Blue Bowl with an abrasive!

    Pre-screen your concentrates to at least 30-mesh using a classifier before adding to your Blue Bowl. Classifying concentrates using nested classifiers or sieves (30, 50, 100 mesh) will speed up the process considerably. For example, 100-mesh concentrates require more time to process than 50-mesh, etc. Keep the concentrates wet with water treated with an emergent such as "Jet Dry" to break the surface tension, and prevent fine gold from floating over the top. Jet Dry and similar products are available at most grocery and discount stores.

    To recover micro-fines, prescreen the concentrates using a 50 or 100 mesh classifier. After adding the concentrates to Bowl, adjust (increase) the water flow slowly until waste discharges over the center cone. Set the control valve to maintain a constant water level. Note: Maintain the water level 1/4" from the top of the outer rim of the Bowl when using 50 mesh pre-screened material; 1/2" from the outer rim if prescreening using 100 mesh pre-screened material. A good rule of thumb is, the higher the screen mesh number, run lower and slower.

    Level your Blue Bowl so that the water is even with the top (outer rim) of the Bowl. The Bowl is equipped with adjustable wire folding legs so you can level the Bowl on the bucket it rests on during operation. A set of 3 Blue Bowl Leg Levelers with hold down clips are sold separately for use on a 5 gallon bucket.

    Fill the Bowl with treated water; shut off the water supply, then add one cup of concentrates along the outer edge the Bowl (inside). Always close the water supply valve before adding more concentrates. Add no more than 1.5 cups at a time. After placing the concentrates in the Bowl, open the water control valve until the water level reaches the top of the outer rim without spilling over the rim. When the water reaches the top outer rim of the Bowl, adjust the flow to prevent it from over flowing.

    If material flows over the edge of the Bowl, or the water flow is too great causing gold to be swept over the inner cone into your retention bucket, don't panic, the gold will remain in the bucket or tub or whatever you are using. If the water flow rate is too great, cut it back; too low, increase the flow. Watch the discharge over the rim of the inner cone; if you see micro gold being swept over the rim, slow it down a little.

    Blue Bowl Setup Instructions to create an optimal re-circulating recovery system:

    Place the Blue Bowl over a five-gallon plastic pail inside a 18-gallon tub; attach the hose from the pump (water supply) to the Blue Bowl, then level the Bowl. Position the pump inside the tub, beside the pail, about 2" +/- from the bottom (placing the pump in the tub helps avoid getting trash in the pump.) Placing the pump on a brick works well. Fill the pail with water first; then fill the tub to within two inches of the rim of the bucket; add Jet Dry to the water then start the pump.

    Once the Blue Bowl is level (leg levelers sold separately if you need them), adjust the water flow so that the water is running at the top of the outer rim of the Bowl, but not over flowing. An even swirl pattern around center cone is desired. Keep the water inside the Bowl; this will allow the vortex to maintain its strength and remove the black sands from your Bowl.

    If you notice a small amount of minus 30 garnets, black sand, or other foreign matter that will not wash out of the Bowl, shut the unit down. When the water flow has stopped and the level has dropped, use a bulb snuffer to blow the material to the outer side of the Bowl then restart the unit. Material trapped by Gold can be able to be swept away by the vortex. Before cleaning out the Bowl, shut off the water supply and allow the water to settle down. The Gold can then be removed with a snuffer bottle.

    Panning fine gold concentrates by hand is difficult and tedious. The Blue Bowl can recover Gold as fine as talcum powder, so give it a try -- the Blue Bowl Gold Concentrator system is pretty simple to use and delivers outstanding results!

    NOTE:  To save on batteries, the easiest way to run a 12 volt pump from 110 volt AC is to buy an inexpensive battery charger like you would use to charge a car battery. Be sure it is rated for at least 3 amps. Most Wal-Mart type chargers are at least 6 to 10 amps. You can buy basic chargers at Sears, K-Mart, Harbor Freight or just about any auto parts place for around $20. Be sure to set it up so as not to short out the leads from the charger.
    See the Blue Bowl in action -- watch the video below!
    Blue Bowl Instructions
    Click to download Blue Bowl instructions