Having your Electroless nickel tank properly designed and built is critical to having a sustainable EN operation. Poly/Co poly or Stainless Steel will work best.

Polypropylene Natural, stress-relieved polypropylene is well regarded for tank construction, as it is inert to plating solutions. Tanks are easily fabricated, and when using proper nitrogen welding techniques, are fairly reliable. The relative low cost and versatility of design considerations make polypropylene the most widely used material of construction for electroless nickel tanks.

Stainless steel tanks have infinite life spans. Electroless nickel, however, will plate onto the stainless steel tank walls, and these tanks may prove expensive to operate because of periodic plate out, which necessitates downtime for tank stripping and clean-up. Satisfactory operation has been sustained using well-stabilized electroless nickel solutions with one or more of the following techniques: Chemical Passivation, Applied Anodic current to take during operation, & Bag liners

Traditionally, most “polypro” tanks are made with what is called “propylene homopolymer,” or “natural polypropylene.” This type of polypropylene has a high strength-to-weight ratio and is known for its stiffness and rigidity. In the plating industry, this natural polypropylene is the go-to material for most plastic-type tanks.

There is, however, another material, called “polypropylene copolymer” which is a less common material but is nonetheless superior in many ways. This copolymer polypropylene is a type of polypropylene that has a modified polymer chain which includes a different, “random” monomer molecule (for instance, ethylene). This molecular change results in some serious changes in physical property.

Compared to homopolymer PP, copolymer PP has a much higher impact resistance, increased flexibility and durability, and a lower melting point (which results in a lower heat-sealing temperature). Copolymer PP also tends to have a better stress crack resistance and lower temperature toughness than homopolymer. At the same time they exhibit essentially the same chemical resistance, water vapor permeability, and organoleptic properties (low tatste and odour contribution).

Given the comparative advantage of copolymer PP, it seems like a no-brainer to have a copolymer PP tank over a natural polypro tank. Because the copolymer is much more flexible and less stiff than the homopolymer, it will have a longer life than a natural polypro tank, and will be more resistant to stress and impact (for example, if a heavy anode or cathode falls of the bussing to the bottom of the tank). This means they are also less likely to get damaged during delivery. Copolymer PP also has a moderately better impact strength at temperatures down to 0°C, and have limited utility down to -25°C.

Plating International offers rigid plating tanks in both propylene homopolymer and copolymer polypropylene materials. Contact us for a quote today.

One of the major decisions that plating shops have to deal with is “what kind of plating tank should I get for my plating line?” Of course, we wish the answer was as simple as the question, but the truth of the matter is it depends on a lot of different things. What are you plating? Plating chromic acid is a completely different process than zinc or cadmium plating. How much are you plating? 300 gallons or 3000 gallons? What method are you using to plate? There are so many questions to ask and factors to consider, we thought it would be nice to see it in the form of a pros/cons table:

As you will see in the diagram above there are many different things to consider when choosing a plating tank. Polypropylene tanks are great for smaller bath sizes and they are well-suited for the harsh conditions provided by plating shops. Polypropylene tanks are also very durable and they are great for use with acids and alkalies, which is why you can sometimes avoid buying a liner for your tank (unless you’re plating chromic acid, which you’ll definitely still need a liner for!) Polypropylene tanks are also much more flammable than steel tanks, which can be an issue if you are using electrical heaters to heat up your bath. While steel can hold up to well over +2000°F, polypropylene melts at around 320°F. Another factor is their size limit - because of polypropylene’s lower tensile strength and modulus, you will likely need supports to prevent bulging and breaks at the seams; but steel tanks have a lot more natural support because of their higher tensile strength. However, steel tanks are vulnerable to other conditions that the polypropylene tanks will almost never encounter: they can rust and they are susceptible to pinholes, which can be very dangerous if not immediately fixed.

At the end of the day, you’re really going to have to take the time and think about what solution works best for your business needs. That’s why you should ask the experts here at Plating International. With over 40+ of working experience, we can help you well above-and-beyond all your plating needs. Contact us today for a quote on plating tanks!