I plan to spray some kitchen cabinets. They have solid wood frame and MDF center panel. The result I want is low-luster solid-color cabinets.

I want everybody here to rank or at least point out the worst and the best schedules. It would be helpful to know the reason behind your worst and best pick.

Below are 6 finishing schedules I have observed from multiple professionals.

Schedule 1
2 coats of Vinyl Sealer 1K
2 coats of Topcoat 2K (tinted to exact color by paint supplier)

Schedule 2
Same as Option 1, but with the Vinyl Sealer also 2K

Schedule 3
2 coats of 2K Poly Primer
2 coats of 2K Poly Topcoat
- both primer and topcoat tinted to the same color

Schedule 4
1 coat of transparent Poly Primer
2 coats of white or grey Poly Primer (White for light cabinet colors, grey for darker cabinet colors)
1 coat of 2K Poly Topcoat (tinted to the exact final color)

Schedule 5
Same as Schedule 4, but with every layer 2K

Schedule 6
2 coats of 1K Poly Primer
1 final coat of 2K Poly colored topcoat

When defining what’s best, I generally think about which one will look the best and which one will be the most durable.

View higher quality, full size image (1125 X 1519)

View higher quality, full size image (1030 X 1011)

View higher quality, full size image (1000 X 1295)

I actually asked the professional who did Schedule #4 why he used the clear Poly primer as first coat. He told me that he was trying to “seal the fuzz.” After talking to him, I am wondering why he didn’t just skip the clear primer and head straight to the pigmented primer from his second step. Do pigments in primer decrease the primer’s performance as a sealer?

What do you guys think?

For interior kitchen cabinets, should we use 1K or 2K Poly primer?

I am wondering why we need to harden the primer layer when we usually catalyze the topcoat.

Can we get away with using just a 1K Poly primer? Why or why not?

Does the color of the primer matter that much?

Should primer be white or grey or clear? Or should it be tinted exactly to the color the client picked from the fan deck?

Some professionals only spray 1 layer of 2K poly topcoat. Some spray 2 layers of 2K poly topcoat.

Are the 1-layer sprayers under-cautious or are the 2-layer sprayers over-cautious?

1st thing I noticed is you had a schedule with 2 coats of vinyl sealer. As far as I know you aren't suppose to do that. Might just be an MLC thing though.

You are suppose to use a special sealer/primer underneath 2K products. I don't think a vinyl sealer is appropriate. Again, MLC products.

The sealer/primer is a 2 part for MLC, it is catalyzed.

I would do 1 coat of the appropriate poly primer, tinted if you'd like. Then 2 coats of 2K poly. You can do three for durability as most 2Ks don't have a 5 mil limit. MLC Polarion has an 8 mil limit I believe.

I usually spray Schedule 3, I find I get the best finish with 2 topcoats vs 1. I echo the warning of spraying 2k poly over vinyl sealer, pretty good chance it will wrinkle. Anything that's not white/ off white I spray over tinted primer. If you're spraying 2k poly be sure to use an air fed mask and tyvek suit.

Answering your questions :
1 - a pigmented primer has the same performance as a transparent sealer. You can use transparent sealer in MDF edges to help avoid absorcion of the finishing with years gone by. 2 coates of primer it ok.
2 - Use 2 K only. Never use 1K under a 2K topcoat, it will wrinkle as time goes by.
3 - Use white primer for white or off-white colors. All the other colors is better to use primer with the same color. It is interisting because if you have a damage in the furniture one will see the same color under. And some colors as orange is very difficult to hide and then using the same color as primer will help.
4 - if the furniture is low gloss one coat of final top coat is ok. if it is high gloss you will need to coats to polish.
Always buy good stuff, in the end it will pay, good material has more quality, hiding power etc.
Good luck!