Understanding the Difference Between Brush and Tank Plating
Brush plating is a very
useful and portable method of contact plating. Many different types of metals or
alloys can be applied over another metal. Our company makes far more solutions
available in brush plating chemicals then tank plating due to the large demand
of our customers. In a brush plating set-up we can work with lower powered
rectifiers and much less chemicals then in a tank plating set-up. Larger pieces
can be plated at a lower investment money wise and a smaller work area is
needed. Basically it doesn’t matter how large the piece is, since it will plate
wherever we touch the wand to the work surface. Tough jobs can be done easily
since we do not have to disassemble most items. Car parts can be plated right on
the auto without dismantling the car. This is how the gold emblems on cars are
done. The emblems are never removed from the car to be plated. It doesn’t matter
if we touch the paint on the car as the paint does not conduct electricity so
the paint will not plate. Guns are much easier to plate this way as there is no
worry of the insides getting rusty from submerging them in solutions. If you
have two conductive surfaces close to each other and you only want to plate one
of them, the plating will only occur on the surface that you contact with the
wand. If it is impossible to plate one area without touching the surrounding
areas then you can mask off the area with tape or nail polish or the such. In
brush plating the solution is all used up and therefore you do not have a
disposal problem like in tank plating. It is considered environmentally
friendly.
The theory of Brush plating is simple.
The rectifier supplies
a negative charge to the work piece and a positive charge to a hand held wand
which has the anode attached to the end of it. The anode is covered with an
absorbent material which holds the plating solution. The anode can either be
dipped in the solution or in some large jobs the solution is constantly pumped
up to the area being plated. The anode is then applied to the work piece by the
operator, or the work piece can be moved under the anode, such as a moving
shaft. The movement will apply even plating on the entire area being plated.
Plating occurs only where the anode contacts the work piece.
Advantages
of Brush plating:
Lower initial cost to start. Portability, the equipment can be moved to the
worksite. Ease of operation. Permits the plating of parts too large for a tank.
Reduces the amount of masking. Reduces waste disposal. And don’t let the word
brush fool you, you can’t leave any brush marks since the metal is electrically
deposited on the work piece.
In a tank plating set-up
we must have a tank of sufficient size to hold the work piece with room for the
anodes and at least 3 to 4 inches of space on each side. Jewelry and small car
parts are a good example of items that take well to tank plating, and the tanks
can be as small as one quart size in some cases. In electroforming which is
the plating of non-conductive items, a tank system must be used first to apply
the copper over the conductive paint. A tank has the advantage of being able
to build-up thicker plating without you being there or doing any labor during
this step. With most solutions the anodes must be equal to or greater than the
work piece. If we use anodes of the same metal as the solution then basically
the solution goes on but the anodes dissolve and must be replaced. When using
stainless steel anodes the metal is used out of the solution but the anodes
don’t wear out. The solution is then replaced.
Advantages of tank plating:
Easier plating of complex
shapes. In most cases multiple parts can be plated at one time. In
electroforming the copper must be tank plated over the conductive coating. In
some of the tank solutions the brighteners, which are chemical additives can
save you some of the time and labor of polishing. The pieces plate out bright.
Similarities in the two types of plating:
The finished product
is the same if the plating is done properly. In our showroom you can not tell
the difference between the two. They are both deposited on the work piece and
electrically bonded just the method of applying it is different. In tank plating
the thickness is determined by how long you leave the item in the tank to plate.
In Brush plating the thickness is determined by how many times you go over the
surface of the work piece.
Differences in the two types of plating: The plating chemicals used in brush plating are much more concentrated than the solutions for tank plating, therefore they are not interchangeable. In most cases there are approximately 15 times more metal in them. It does make them more expensive per ounce but they also cover much more area than tank solutions. The nice part is that you don’t have to buy such large quantities of solution to do the job. Also because of their concentration the brush solutions can build-up thickness faster than tank solutions.
Brush plating kits can be found here.
Brush Plating Chemicals can be found here.
Combination Brush and Tank plating kits can be found here.
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