Repairs after spraying 2K

[TX79Z28]

I shot two coats of 2K over the epoxy. The 2K came out somewhat bumpy, afterwards I found a couple of areas that may need some more filler work, that I obviously missed before the 2K. From the searches I have done, it appears it's not a great idea to apply filler to 2K. My questions:

1. Do I need to sand off the 2K in those areas down to the filler and/or epoxy, make the repairs and then shoot 2 more coats of 2K only on those spots to bring it up to the same level as the rest of the 2K? (I have not blocked the 2K yet)

2. I made an expensive mistake of mixing too much of the 2K and ended up losing 2 full quarts that cured FAST on me. If I reduce it with 885 (4:1:1), would that help with it spraying smoother AND not curing as fast?

 

[crashtech]

1. It's best practice to remove urethane primers before filling, but I've filled on urethane primer lots of times. I think it depends on the extent of the work. I believe a skim of fine poly putty is almost never a problem on CURED primer. It's important that the solvent be out and the cure complete.

2. What you propose is fine in warmer temperatures, just make sure you get all that solvent out before moving to another material. A day in the sun is great for this.

 

[TX79Z28]

1. It's best practice to remove urethane primers before filling, but I've filled on urethane primer lots of times. I think it depends on the extent of the work. I believe a skim of fine poly putty is almost never a problem on CURED primer. It's important that the solvent be out and the cure complete.

2. What you propose is fine in warmer temperatures, just make sure you get all that solvent out before moving to another material. A day in the sun is great for this.

1. I was able to sand one of the repairs on the 2K and I may not have to do anything else, it filled enough that it gave me something to work with. But if I have to actually build it more, I will wait several weeks to make sure the 2K is cured before trying putty. The spot that is on the lower quarter may be deeper than putty can address, so I may have to sand all the 2K off down to the epoxy and do the filler work.

2. Our temperatures have been hovering between 95 to the low 100s, and the fact I am using a 4-stage turbine sprayer makes a slow reducer almost mandatory. I ordered some today, and I will try it on the third coat of 2K and/or the repairs I may have to make.