John Maher:  Hi, I’m John Maher, and I’m here with Melissa Mitchell, product manager for potting compounds and encapsulents at Key Polymer. Today, we’re talking about Tough‑Seal potting compounds packaging, cartridge systems, and bulk‑dispensing.

Welcome, Melissa.

Melissa Mitchell:  Hi, John. How’re you doing?

Purchasing Tough Seal Potting Compound

John:  Good. Melissa, after I’ve tested the Tough‑Seal potting compound, and a product is approved, how can Tough‑Seal be purchased?

Melissa:  Tough‑Seal is available in 50 milliliter, 200 milliliter, and 400 milliliter cartridges. Those are pre‑packaged cartridges, and also available in bulk containers: 1‑gallon containers, 5‑gallon containers, and then 55‑gallon drums.

Cartridges vs Bulk Containers

John:  OK, and what’s the basic difference between cartridges and bulk containers?

Melissa:  Cartridges are pre‑filled, side‑by‑side, two‑component barrels that similarly look like a caulking tube that you buy at your local hardware store, but they’re side‑by‑side. Your A‑component of the mix of Tough‑Seal and the B‑component of the mix of Tough‑Seal is pre‑packaged in the cartridge itself, and…

John:  That’s to keep them from mixing together, because once they mix together, then a chemical thing happens, and they turn into this potting compound that hardens.

Melissa:  Correct. The cartridges are a good delivery system for customers, especially if you’re a little bit on the lower‑volume side and not ready for bulk, which is larger volume. Like I said, 1‑gallon, 5‑gallon, and 55‑gallon containers of material, where you would need bulk‑dispensing equipment to actually dispense it into your application.

Potting Compound Dispenser

John:  OK. What is the dispenser like, and how does that work?

Melissa:  The dispenser would either be a manual dispenser or a pneumatic dispenser. The pneumatic dispensers run off of either a compressor or shop air, typically around 70 psi, and the cartridge itself gets put into the dispenser. Like I said, a typical caulking dispenser, you pull the trigger on the dispenser, and material is dispensed out. But one important part is that you need a static mixer to go with the cartridge and the dispenser.

John:  OK. What is a static mixer?

Melissa:  The static mixer is a long tube or straw ‑‑ a lot of people refer to it as a straw ‑‑ that has helical elements inside; little criss‑crossing elements that the material flows out of the cartridge, passes over the elements in the mixer, and it mixes your material completely by the time it exits the static mixer.

What’s really great about cartridges is that you don’t hand‑mix anything. It’s pre‑packaged volumetrically, so you have the right ratio every time. You don’t have to worry about improperly mixing, which can result into problems such as curing issues or gelling issues/ hardness issues.

Your material is pre‑packaged volumetrically. You dispense it through the cartridge, through the static mixer, and it comes out with minimal waste. No air bubbles, because the cartridges are pre‑packaged without air in them.

Then you can actually point the dispenser and mixer and cartridge right where you want the material to flow into your part. If you’re hand‑mixing something, and you’re hand‑mixing it in a cup, it makes it a little difficult sometimes to get it into your housing or into your printed circuit board area, especially if you have a small opening that you’re trying to dispense through a port.

You can put the static mixer nozzle right into the opening and dispense right into your boards. It’s a very minimal waste process and very, very easy to use. Simple, actually.

John:  And like you said, with the cartridges, you’re ensuring that you have the right mix. Like you said, there’s an A‑component and a B‑component, and the cartridge ensures that you have the right amount of A and B so that there’s no guesswork involved.

Melissa:  Exactly.

Bulk-Dispensing Systems

John:  Explain then what a bulk‑dispensing system is and how that differs.

Melissa:  It’s a large‑scale dispensing system that would feed from 5‑gallon pails or 55‑gallon drums. It would actually be pumping your material from these large containers, or you’d pour your material into a large vessel that’s built into the unit. It’s a dispensing system that volumetrically dispenses your material.

Typically, these systems are more on the costly side. It’s more of a capital expenditure for your company. If it’s a newer product project, you might want to start out with cartridges. If you need mobility, you might want to start off with cartridges. But as you grow, typically people will move into a bulk system, and they have to do a little more planning.

Bulk systems can be very, very basic, with minimal automation, start in the $5,000 range and move up to $20,000 plus for a more fully automated system. It can be very simple or complex, but allows you to feed from bulk containers.

John:  OK. With the static mixer that I need for the cartridge system, can I use any type of static mixer with your potting compound?

Melissa:  Static mixers are a little bit specific. We would do testing internally at Key Polymer to determine the best static mixer. Static mixers come in different diameters and different lengths. There’s different numbers of elements in each static mixer. Every time the material passes over an element, it mixes exponentially actually. The right diameter and the right length is key to making sure the material that comes out is mixed properly.

Some customers want to use a smaller static mixer because they’re hoping to eliminate waste, and that the number of mixers they use and the amount of material in the static mixer, they feel is a large amount of waste.

That’s in fact not really true. There’s very little waste in the mixer if you really calculate the volume. But more importantly, it’s very, very important to not pick a static mixer because you want something smaller. You always want to make sure it’s what is recommended by the manufacturer. Key Polymer does have all the specific static mixers that go with our products.

John:  What about bulk dispensing equipment? Does Key Polymer sell that as well?

Melissa:  We do not sell bulk dispensing equipment, but we work with a lot of dispensing equipment manufacturers that are very familiar with Tough‑Seal, and we can work with customers to help guide them with a local supplier. We work specifically with a lot of local people, and are very happy to help pick a system that would work for our customer.

John:  Great. Well, thanks again for speaking with me today, Melissa.

Melissa:  Thanks for having me here.

John:  For more information, you can visit the Key Polymer website at, or call 978‑683‑9411. That’s 978‑683‑9411.