Time between sanding and painting?

[MAKZ06]

After spraying 3 coats of Motorcryl single-stage a month ago, I’m prepping to spray another 2-3 coats. I’m now sanding with 600 to remove the dust nibs and flatten the orange peel and a couple runs. I’m doing in sections and had planned to sand one day and spray the following day in 5 phases. However, it’s easier for me to complete all the sanding and then paint, as opposed to switching back and forth due to cleanup, etc.
I’ve read about the sanding scratches “healing” or closing up… and needing to spray soon after the sanding. How many days can I safely wait between sanding and the wipe-down and paint?? Do I need to spray the following day or two, or can I wait up to a week or more if the panels are inside and out of the sun, etc.?? It’s been curing for a little over 30 days.
thanks

 

[Chris_Hamilton]

The self healing is hard to quantify. Some products do more than others, same product might not behave the same if you used different amounts of reducer or even different speed reducer at different times. Easiest thing to do is to do all your sanding. When you are ready to spray get a grey 3M scotchbrite pad and a quart of sanding paste. Presta Scuff Stuff is a popular one. Use it wet, apply some to the scotchbrite pad, wet the panel with water, and scuff the panel shortly before you paint. Rinse occasionally and completely when finished. It also has a soaping agent in it so it cleans as well (don't skip wiping the panel down though). After scuffing, let the panel dry and you are ready to wipe down and paint.

 

[Chris_Hamilton]

Just to be clear, you want to scuff the panels that you have sanded. This ensures you have a good tooth or scratch on the panel for more clear or single stage.

 

[MAKZ06]

Just to be clear, you want to scuff the panels that you have sanded. This ensures you have a good tooth or scratch on the panel for more clear or single stage.

Thanks again for the great information. Are you saying that I still need to use a scuff pad and the compound even if I have sanded with 600 the day before? Or just if it’s several days later after I swamped everything?

 

[Chris_Hamilton]

Thanks again for the great information. Are you saying that I still need to use a scuff pad and the compound even if I have sanded with 600 the day before? Or just if it’s several days later after I swamped everything?

It's a good idea to always do it before painting anything as it will get any spots or edges that may have been missed. It's not neccesary though if you have recently (few days) sanded. If you are worried about something you sanded self healing you should scuff. I do it on everything as a final step. It doesn't take very long to do and it ensures everything is clean and scuffed.

 

[MAKZ06]

It's a good idea to always do it before painting anything as it will get any spots or edges that may have been missed. It's not neccesary though if you have recently (few days) sanded. If you are worried about something you sanded self healing you should scuff. I do it on everything as a final step. It doesn't take very long to do and it ensures everything is clean and scuffed.

Thanks again.

 

[jcclark]

You will have plenty of "scratch" a week later to paint over if you have sanded the panel with 600 grit.
As long as it's clean it won't be a problem, it's done at body shops all the time.

 

[MAKZ06]

You will have plenty of "scratch" a week later to paint over if you have sanded the panel with 600 grit.
As long as it's clean it won't be a problem, it's done at body shops all the time.

Thank you.

 

[Lizer]

I still do as Chris mentioned and I go over tricky areas like recesses, corners, and contours with a scuff pad prior to painting. These are all areas that you can’t get into well with sand paper. It’s something I do regardless of when I sanded 600.