Quoted from yaksplat:
I can still leave a nail mark after 7 months. It's harder, but not where it should be.
I was not paying attention to the hardness time check with the clear I put on my play field, but I would say it took at least 12 months to get hard. I am still working on assembling this play field. It is now two years since I did the clear and it is as hard as a rock.
I have been using PPG Deltron clear which is designed for fast cure for auto body shops to get a fender bender job in the shop one day and out the door on Day 2. But body shops are only going to apply a couple of coats of clear.
I applied several coats of clear to my play field. Logic suggests that more coats will take longer to cure. As I said in another post, I placed my first play field in the sun to cure. That play field got almost too hot to touch and it cured out in a short amount of time but I could feel the inserts shift with the heat; That scared me so play field #2 just had to cure the slow way.
SIDEBAR: I know from personal experience that you cannot bake fiberglass in a radiant heat oven ( I turned 3 aircraft wing trim tabs into footballs by doing this). I also know fiberglass does not do well in a forced air oven as an aircraft nose cone I tried to bake started delaminating and showing air bubbles under the skin surface.
Obviously, I cannot make a determination with commercial play fields clearing processes, but I'm thinking a combination of many coats of clear in an effort to make a play field look like it is under a thick shiny piece of glass and (perhaps) no viable means to bake a play field for a fast cure is contributing to these play field problems we are reading about and experiencing.
My conclusion: These play fields need to be baked for a fast cure, but since it is probably not wise to bake wood and plastic then they are just going to need to sit for quite a while to cure.
Mitch, can you take an industrial heat gun to a small corner of your QS apron and heat it up and see what you come up with ? I'm thinking if you use some heat it will cure completely in the area you applied the heat to.