rhncue said:
Companies advertize that the light only has to be directed at the finish for 2 to 4 seconds but I leave it there for about 15 seconds.
I'm confused. Maybe this is a good opportunity for some cross-education. When I say I'm confused, I mean I'm confused because I probably have purchased two dozen or more UV systems in the past few years. In my industry, I have to know as much about these systems as reasonable. On retrospect, it's easily more than two dozen.
That being said, every ink, every adhesive, every whatever that I have to UV cure is chemically formulated specifically to be UV cured with UV polymers. I can't just get anything off the shelf and expect it to UV cure. If it's ink, it has to be UV-curable ink. If it's glue, it has to be UV-curable glue. I can blast it for several seconds with a UV light, and it may cure, but if it takes more than a couple of seconds to cure the surface, it usually means it's the heat, not the UV that is doing the curing. Also, in my industry, too much UV can destroy the product, so the formulation and the process has to be correct.
That being said, there is certainly the probability that only the surface is being cured, and that the liquid continues to set under the surface. So, I guess that's the biggest issue if you're going to sand and repeat.
So, there's my input. FWIW.
Fred