Quoted from Marvin:
This is from 6 months ago-12 freaking coats! But this has been discussed literally for at least 5 years probably 8.
I spray in one session, 12 coats become 1 thick coat annealed together that will generally cure and pass the fingernail test in about 2-3 days. It will completely harden within 2 weeks once the remainder of the thinners that keep the clear coat wet finally evaporate. In my experience when you block sand between coats with any clear coat if you examine it in the brightest of led lights you'll see each block sanding session's scratches in layers, so you want to keep that at a minimum because that dampers the clarity for me at least. I will do two block sanding sessions with this stuff, prep sanding and a final block sanding. If I'm spraying on a bare pf sometimes I'll shoot a diamond plate like clear coat on it first (2-3 coats) and let that sit overnight then prep sand it before I really start adding multiple coats, mainly just for the inserts to bond well to the clear. If you don't block sand between dried coats that just seems like a poor way to add multiple coats of clear just to achieve depth without giving any integrity (tooth) to make all those coats become one strong layer. Which is the point of spraying a clear coat in the first place to protect the artwork from wear and encapsulate the playfield. Everybody is working with different materials that have very different cure times and very different procedures they have perfected so there's really no comparing any of us.
I bought a clear coated play field. It arrived looking very nice and I put back in the ship box for storage.
3 months later when I removed it from the box I discovered that the the clear had settled at a different rate over the inserts and I could close my eyes and run my hands across the play field and feel the depression over every insert. But I wanted baby butt smooth so I did a light block sand and polish to get smooth but i did not like the look.
I swung a paint gun for several years painting small aircraft parts. But my work was mainly for parts protection and not beauty type work.
The only way to get the finish I wanted was to go buy a paint gun and equipment and go back into the painting biz.
I put all my coats of clear on in one session starting with a dry starter coat that I let flash for about 15 minutes. And then I went wet.
Dry to the touch did not take much time. I let the play field cure for about 2 weeks, block sanded and buffed. That play field sparkled in the sun. The play field was cured and dry and I started installing parts. But a few weeks after I had the play field built up I noticed that my clear was settling at the inserts just like it had been the first time.
I had to strip all of the parts. At this time I noticed when I removed the rails that the clear had become distorted under the rails; in essence, while my clear felt dry to touch and had several weeks to cure it was not really cured at all.
I did another block sand and buff and put it all back together. Several weeks later my problem with “sunken” inserts bit me again. So, one more time, I had to strip, block and polish.
So, my experience with my automotive clear that body shops use for fast work for next day delivery needed a lot of time—8 months maybe—to cure.
For my 2nd play field, I only put on 4 coats in one sitting. That was last summer. And this play field is still in storage before I go further with block and polish.
I am in the camp that unless you can oven bake a clear coat then it is going to take a long time to fully cure because trying to oven bake a play field would be equal to committing suicide.
And my 3rd play field will be something like 3 coats of clear maximum. Because I have discovered that a play field does not need to be baby butt smooth to provide a great playing surface; And that once the play field is under glass and the lights are flashing it is going to be a very nice looking play field with great play action.