What is this imperfection?

[Joe028]

I resprayed these doors because there were dust nibs of white primer color showing through. That problem is now fixed, thanks for the help on that previously. I've done 1000, 1200, 1500, 2000, then 3m compound on a rotary with white 3m pad. Sanding was done mostly on a block in front to back motion as opposed to cross-hatch pattern.

I notice that the light reflections are not crisp but have an orange peelish look. I really don't think its orange peel as I blocked that out completely before buffing.

I sprayed 4 coats of universal clear. Is this urethane wave or something else? Trying to identify it so I can do better next time.

Thanks!

 

[Chris_Hamilton]

It's orange peel or what's left of it after sanding. This usually happens when using a relatively soft block and too fine (not coarse enough) paper. What grit paper did you do the initial sanding with? What type of block?

 

[Joe028]

Durablock and 1000 for first grit.

So even though I knock down the visible orange peel and it looks completely matte finish, once polished it comes back.

 

[Chris_Hamilton]

I'm assuming you had a fair bit of orange peel to start. So starting with too fine a paper is the cause. The paper when wet after a bit starts following the peel rather than flattening it. It's still sanding but it's not sanding it flat.The paper is following the surface. You won't see any shiny surface. Hard to tell the difference when you are doing it.

 

[Chris_Hamilton]

Just to add to what I said above. I'm sure when you were sanding it, there were times it felt like the block was "stuck" to the surface as you pushed it along? Feels like there is a vacuum? That is an example of what I'm talking about the paper following the surface.

If you have enough clear on the panel, you could sand it again with 600 to 800 grit on the durablock. Keep the paper fresh and pad pressure light. Keep the surface very wet. Then finish off with the normal grits and buff.

 

[Joe028]

That is great Chris. Makes sense and thanks for the tips. I do believe there is plenty of clear on there so I will take it back a step and see how it looks. I also noticed I probably didnt use the block as much on the doors as I should have. Because of the contours of the door I think I did more hand sanding. For example on the deck lid where I exclusively used the block, it looks better.

Thanks again for the quick response and helping me to identify the problem!

 

[texasking]

Oh, the dreaded wave. Longer, stiffer blocks work better for me on initial cut when there is wave present. You can cut initially with 600-800 just enough to remove the wave, then go to finer grits with a softer block after that.