There are adhesives designed to be permanent or removable, with low tack or high tack, and you can combine those with air egress features and other features that reduce the initial tack. They put all of these adhesives on either vinyl type.
Removability has just as much to do with the adhesive as the vinyl’s ability to stay pliable and resist cracking over time. I imagine that they also try and save a few pennies on the adhesives when they are putting them on cheaper less durable calendared vinyl.
Good points. There is great variation in the adhesives used for vinyl film. And there are many combinations of vinyl and adhesive being marketed, both in cast and calendered. I know one house brand of cast vinyl that is made by a major manufacturer and is marketed right alongside one of the major manufacturer's premium vinyl offerings as an equivalent, but it is not the same. Why? Because the house brand asked for an altered adhesive mix. They wanted a shorter, more aggressive initial tack, though they wanted the overall life expectancy to be similar.
While it's not always accurate to generalize about vinyls, usually the more expensive vinyls have better ingredients.
"Plasticiser migration" is a term used by manufacturers to describe how vinyls become brittle as they age. The plasticisers, chemicals that keep vinyl pliable, migrate. They leave the vinyl film from both the front side and the adhesive side as the vinyl ages. Plasticisers vary in quality and price. There are chemicals that can be added to resist plasticiser migration and this adds to cost.
There seems to be a use for all grades of vinyl, though sign shops may use certain grades more than others. I know a shop that uses Scothcal 50 almost exclusively. And though they have learned the hard way that cheap calendered vinyls like Scotchcal 50 are not long-lasting on most vehicle lettering jobs, they use the cheap stuff for everything else. They have been in business for many years peddling low price, so using less expensive materials fits their standard operating procedure. They have a steady clientele of customers whose main, if not only, consideration is low price. Yet they exist in a town that also has a shop known for high prices and high quality.
Cheap products exist in every industry. Walmart has built an empire based on "Low Prices Every Day," though they have abandoned that slogan in recent years.
Low price, low quality. These are not really moral issues, though I used to think of them in that way. Each sign maker decides what market segment to pursue. And they buy the materials and use the methods they feel are appropriate to what they are selling.
Certain materials, of course, work far better in certain situations. And unfortunately, much of what we learn is through trial and error. That is why forums like this one can be very helpful, especially when we share experiences about specific materials and substrates. We learn what works well and what doesn't.
Brad in Kansas City
