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Common Questions and Answers About The Small-Media Mill
time2012/05/02
WE GET VARIABLE RESULTS ON EXACTLY THE SAME FORMULA AND MILL, ESPECIALLY IF WE AREN'T RUNNING THEM FREQUENTLY. SAME PIGMENT, SAME RESIN, EVEN THE SAME MANUFACTURER AND LOT NUMBER. ANY SENSIBLE REASON?
This can be a tough one, but you can localize your search to the materials themselves. USUALLY it is a pigment matter, and even more specifically, a pigment like a blue which is used in small quantities, and which by nature is made of almost colloidal-size particles and is highly hygroscopic. If you open a bag in March, and finish it off on a batch in May, you have gone through some violent changes in humidity, certainly enough to cause havoc in the condition of the pigment. Other pigments, as the pigment people will tell you, are extremely hard to hold to exact similarity unless they are kept under good moisture conditions. Look under the last bag or skid of pigment the next time you use up a pile, and you will probably see a moist spot in the concrete! If you have such a pigment, buy as sparingly as possible, and store carefully, favoring these materials in location in storage.
horizontal bead mill
WHY DOES MY SCREEN PLUG SO RAPIDLY? MY OPERATOR HAS TO STAND WITH A BRUSH OR SPATULA AND SCRAPE IT OFF TO KEEP FROM FLOODING.
horizontal bead mill
You could have a worn batch of media, or an excess of fines, but probably not. Medias just do not break up in a mill, except possibly some sands, unless there is something like a loose disc or a broken piece in the mill. There is just not enough force to break up a quality media, even sands, certainly not the glasses or shots, all of which are much stronger. One popular type of zirconium silicate bead that is made in Europe does commonly fracture in a mill. The solution is to consider a stronger zirconium silicate media such as Quackenbush's QBZ-58. Worn media usually comes right through the screen and is picked up in a filter or in the filling area in a strainer. More often screens skin over because of too high pigment loading, producing high pigment concentration as the volatiles hit the screen and flash off, right where they are hottest and most agitated in the presence of air. Sealed screens help, but the mill will still be operating at low rates. Check your PVC and raise your resin solids a little.
horizontal bead mill
I HAVE TO RUN AT BOTH HIGH PIGMENT AND HIGH RESIN LOADINGS, ESPECIALLY IN SMALL PARTICLE PIGMENTS. I GET MORE THAN PUFFINESS - IT IS ACTUALLY LIKE A MARSHMALLOW TEXTURE. IS THERE ANY MOVE INDICATED HERE?
Marshmallow is a good word. Marshmallow is nothing more than corn syrup and air. Corn syrup flows. Marshmallows do not. The air is the only difference. Your high resin solids are just like corn syrup. At the top of the mill, if there is air available, it will be whipped into the mix and produce a tough, stable, air emulsion, for the exposed discs are excellent air pumps and whippers. You can eliminate these discs (at some small loss in output) or you can seal the mill against air. This is one of the real advantages of a sealed mill.
horizontal bead mill
WHY CAN'T I PUMP SOLVENT UNLESS THE PUMP IS NEW?
Because the pump is worn already, and the clearances are opened up. Any rotary pump depends on close metal fits, and when they open up, the material pumped is merely bypassed inside the pump. This is no problem with paste or viscous material, but thin materials bypass readily. Some adjustment may be possible within the pump, and your pump peddler can show you how to do it. At best, it is a short-lived patch. Improve your pre-mixing, and keep the beads out of the pump. Quackenbush stocks all of the Viking pumps and parts common to many mills and can also offer technical assistance for your Viking Pump questions.
horizontal bead mill
This can be a tough one, but you can localize your search to the materials themselves. USUALLY it is a pigment matter, and even more specifically, a pigment like a blue which is used in small quantities, and which by nature is made of almost colloidal-size particles and is highly hygroscopic. If you open a bag in March, and finish it off on a batch in May, you have gone through some violent changes in humidity, certainly enough to cause havoc in the condition of the pigment. Other pigments, as the pigment people will tell you, are extremely hard to hold to exact similarity unless they are kept under good moisture conditions. Look under the last bag or skid of pigment the next time you use up a pile, and you will probably see a moist spot in the concrete! If you have such a pigment, buy as sparingly as possible, and store carefully, favoring these materials in location in storage.
horizontal bead mill
WHY DOES MY SCREEN PLUG SO RAPIDLY? MY OPERATOR HAS TO STAND WITH A BRUSH OR SPATULA AND SCRAPE IT OFF TO KEEP FROM FLOODING.
horizontal bead mill
You could have a worn batch of media, or an excess of fines, but probably not. Medias just do not break up in a mill, except possibly some sands, unless there is something like a loose disc or a broken piece in the mill. There is just not enough force to break up a quality media, even sands, certainly not the glasses or shots, all of which are much stronger. One popular type of zirconium silicate bead that is made in Europe does commonly fracture in a mill. The solution is to consider a stronger zirconium silicate media such as Quackenbush's QBZ-58. Worn media usually comes right through the screen and is picked up in a filter or in the filling area in a strainer. More often screens skin over because of too high pigment loading, producing high pigment concentration as the volatiles hit the screen and flash off, right where they are hottest and most agitated in the presence of air. Sealed screens help, but the mill will still be operating at low rates. Check your PVC and raise your resin solids a little.
horizontal bead mill
I HAVE TO RUN AT BOTH HIGH PIGMENT AND HIGH RESIN LOADINGS, ESPECIALLY IN SMALL PARTICLE PIGMENTS. I GET MORE THAN PUFFINESS - IT IS ACTUALLY LIKE A MARSHMALLOW TEXTURE. IS THERE ANY MOVE INDICATED HERE?
Marshmallow is a good word. Marshmallow is nothing more than corn syrup and air. Corn syrup flows. Marshmallows do not. The air is the only difference. Your high resin solids are just like corn syrup. At the top of the mill, if there is air available, it will be whipped into the mix and produce a tough, stable, air emulsion, for the exposed discs are excellent air pumps and whippers. You can eliminate these discs (at some small loss in output) or you can seal the mill against air. This is one of the real advantages of a sealed mill.
horizontal bead mill
WHY CAN'T I PUMP SOLVENT UNLESS THE PUMP IS NEW?
Because the pump is worn already, and the clearances are opened up. Any rotary pump depends on close metal fits, and when they open up, the material pumped is merely bypassed inside the pump. This is no problem with paste or viscous material, but thin materials bypass readily. Some adjustment may be possible within the pump, and your pump peddler can show you how to do it. At best, it is a short-lived patch. Improve your pre-mixing, and keep the beads out of the pump. Quackenbush stocks all of the Viking pumps and parts common to many mills and can also offer technical assistance for your Viking Pump questions.
horizontal bead mill