Those references were very helpful and line up with my own research into the topic. The key point in the last reference is the protection used should reduce exposure from being above a safe level to something below the safe level. The OSHA practice of only recommending the equipment that reduces it the most is not entirely valid. In this case a full face pressure fed respirator is obviously better than a cartridge mask. It does not mean that the cartridge mask is inadequate, its just not as good.

All modern 2PACs are Urethane based. The Poly urethanes that are much safer to use are the ones that tend to yellow. That being said, the new ones that specifically say they are UV resistant really do not yellow much that I can see. The oil based traditional ones even say on the label now that they 'amber' over time. Overall clarity of 2PAC is still better and it is tougher.

I saw HEPs comments on dry sanding too, but I have no idea what he is talking about saying dry sanding has improved so much there is no need for wet sanding. Anyone know what he is talking about?

Try rubbing it between your fingers, is the cutting grit obvious? It may be using a progressive grit that crumbles up and becomes finer emulating multiple sanding steps.

I think that is normal die-back that happens during the longer term cure. I think all polyurethane clears will do it. I am not fully aware of what is actually the cause.

I think 30 days is most of the movement. Would like to know what the cause really is. How does clear know it is on an insert. But definitely, thinner coats suffer from it less.

My experience is with an unpopulated playfield standing up against a wall, and it did it.

I had obtained the KBS product SDS a few years ago and concluded nearly the same as you guys here. It left me wondering that if KBS wants full protection for spraying it but not rolling it. Why not roll on regular 2PAC, probably the same risks. Makes me wonder if KBS is actually different in any way.

It will sand out fine, you can definitely polish it up without needing any more on top. However a light additional coat after sanding might be faster than running up through all the grits and then polishing a wheel.

Per Wikipedia, typical breath volume is only 0.5 litres (smaller than I was expecting). If you are breathing through a 1 in (25 mm) tube, your breath only make it about 1 meter (3 feet). So if your tube is longer you are only rebreathing the same air over and over. If you have a one way valve so you are only pulling in air from the tube and exhaling locally this would work.

Google translate app on your phone can translate using the camera.

Looks great, for the sandpaper was that hand sanded, wet or dry, or using a machine?

While I am sure this product will work as advertised, be careful with the choice of air compressor. A shop compressor is definitely not rated for human breathing in terms of cleanliness. The biggest issue would be an oil lubricated compressor, you are dependent on the filter removing nasty oil vapours. An oil-less compressor will eject particulate matter for the most part that should be easier for a filter to remove.

Just look up the manual online for any compressor, even old ones, you will definitely find a warning about using it as an air supply. There is this style of respirator. It uses a more simple turbine style compressor, more like a big shop vac motor to feed the mask. No particulate or oil issues.

https://axispro.com/index.php?l=product_detail&p=4

Honestly I would be okay with the aliexpress unit. Why? Because it is deterministic whether or not it is working, you get positive airflow or not. There is no dependence on filtering which you have to trust to work. Keep the pump upwind of your work area. If the unit failed while using it you will know and you can just stop and exit the paint area.

I don't subscribe to the 'its quick and easy so can't really harm you' theory. Its also super quick to drink gasoline, but I know not to.

I restored an EightBall about 4 years ago where the graphics were process ink printed onto the playfield. I was worried about 2PAC reacting with it so I protected it with Varathane, then used 2PAC (not Sparaymax). No issues at all, just a light sanding then sprayed it on.

Probably 2 years now. The Clyde Ave. store is more of a commercial outlet.

Any chance the turbine intake was picking up the over spray from the Spraymax 2K? That is my worry with those systems is the inlet is grabbing whatever is around it.

It is hard to tell from the photos but that sure looks like too light a coat. It did not flow out since there was not enough clear. I assume the drops look more normal?

I would suggest doing a little more of a coat to let it flow out for the next coat. The lower right corner looks like it could use some more of a coating. The interior parts look more like the wood grain. I did something similar, sanded an Eight Ball playfield down to bare wood, replaced the inserts and wet sanded all of them before bonding them in place. I had a different process, I started on the bare wood with clear UV proof Varathane, then process printed my own art work onto the playfield. So by the time I had to do the clear the grain structure was already smoothed out. You will want to dig into those crevices to roughen them. It will probably take two more coats minimum but it will look great.

I second the use of InkScape. I did my Eight Ball as a complete redraw using scans and photos. In InkScape you can import photos into one layer, and then draw in another layer on top. Just keep building up small pieces at time layer by layer. You can use various InkScape tools to punch through the graphics and when printed the wood is there instead. I probably had 50 layers. My artwork is the finished product, not templates for stencils. Zoom in on the 5 ball, I even mimicked the half-tone of the original. I actually sanded this to bare wood, replaced all inserts, used water based Varathane spray to seal the wood then took the playfield to a flat bed printer place to print directly onto the wood. Then I went to a local body shop and had them clear coat it.

Before the printing stage I sent smaller scale test print files to the print place with colour tiles all over the playfield art. I selected the best fit colour matches then updated my master. InkScape lets you select master colours that when you change them the artwork all updates at one time for that colour.

Very geometric playfield art can be helped with CAD tools as well. Check out FreeCAD and use the sketching tools normally used for making a machined part to draw your geometry. Why do this? Because you can use constraints on your lines and assign lengths, angles, radii, etc and adjust as needed until it is correct. InkScape has nothing like that. It is more freeform drawing, manually moving vertices. The measuring tool is a bit clumsy. I found a utility that lets me set a Windows PC window to 50% visibility. I drew my CAD lines right over a photo in a window behind, export as DXF, InkScape can read in DXF. The scale would be wrong but InkScape can accurately scale the line drawing. Sped up a lot of features in the artwork.
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A question about your side rails. Does the ball ever thump into them anywhere on the playfield? On my Eight Ball I did something similar to you for the side rails using regular spray paint. It does not hold up to ball contact at all well. I found using a topcoat of spray Varathane made all the difference in durability. In your case you can just use more SprayMax which be even better.

I was surprised how quickly damage showed up in my case, the outlanes are the same as yours. You could put mylar on the vertical surface in that area as an alternative.

Early on in my pinball hobby I bought an old Bally with very hazy original mylar. I did not really find much info on people polishing mylar, all topics were about polishing clear. I have an old air powered 6" DA and tried a bunch of things including Novus. Polishing soft mylar may be quite different than an actual clear coat. In the end I found Novus 3 is barely any coarser than Novus2. My favourite compound is a 3M marine boat polish. It is actually a cutting compound but seems to be a progressive grit. In one go it progressed through multiple grades and did a great job. Pin_Fandango is more to be listened to for polishing actual clear but wanted to bring up mylar in case others want to try it, you don't have to remove it.