Everything we make is for industrial use. We specialize in industrial marking pens. The inks and paints are all industrial and the containers are all industrial.
All our metal barrels are thick and strong. You can drop it off of a ladder and you can run over it with a small machine. The aluminum is more durable for industrial workplace.
Uni-paint, for instance, has a metal barrel but they have a thin wall. These can be crushed if stepped on or with your fingers if you're strong enough. These are made for artists. All the Japanese paint pens and paint markers made for retail are not going to hold up to the demands of industrial use. This is why we take the care to make these pens for the USA and to the specifications of our industrial clientele in the USA. With a solid construction enabled by a metal barrel, you can keep working without fear of puncture or leakage.
Not all of our markers use a metal barrel, what are the considerations for each? Well, It depends on the kind of marker and the solvent used.
If you are using xylene you cant use plastic unless it’s a specific kind of plastic. In general, you shouldn't use plastics with xylene. It will dissolve. For xylene we need metal barrels. They do have plastics that you can put xylene in but they are cost prohibitive in most cases.
For alcohol, we can use both metal and plastic. We are cognizant of the fact that some dyes will attack the aluminum and create a gas and create pressure. We adjust our formulas accordingly and in some cases, we switch to a plastic barrel on some colors. One that comes to mind is Detergent Removable Blue.
For water-based, we can't use metal barrels. you may notice we use only plastic unless they have a phenolic inside coating. It's rather expensive but we have to use it or else it will corrode from the water. With water-based formulas used in coated metal barrels, we also take precautions such as using small amount of anti-corrosive additive that helps in the long run for the life of the product. The additive helps but it is always better to use plastic for water-based or inside coated-barrels. We have that for everything we make that is water based.