Fellow woodworkers, PLEASE HELP ME! I’ve been woodworking for approximately 8 years and have never had this issue before now. During my finishing process, whether I’m using water/oil based poly, lacquer etc., I have always sanded between coats of finish with 400 grit sandpaper, brushed or vacuumed it off and usually wiped it down with a damp rag with no problem. The next coat has always covered up the sanding marks. But now, for whatever reason, I’m seeing my sanding marks through my next layer of finish clear as day! I’ve tried to double check that I’m not pressing to hard…sanding enough but not too much, cleaning my paper so there are no nibs in it…But nothing about me,my process, the paper, the product or the wood has changed. WHY IS THIS HAPPENING?!?!?
Could this somehow be related to a extremely low humidity issue? I wonder because I’m also having another problem where my water based finishes are drying with an orange peel texture (again, a first time problem for me). I usually spray outside with a Fuji Q5 and get great results. But, ever since colder weather has set in, it’s like my finishing skill has reset to zero.
SOMEONE PLEASE HELP ME! THIS IS HOW I MAKE MY LIVING AND I DON’T KNOW WHAT TO DO!!! I NEED SOLUTIONS A WEEK AGO!
Replies
obvious question but did you change sandpaper brands? because if you switched from 'p400' to regular 400 or vice versa that might account for bigger scratches
I’m not sure about the p vs regular part but I’ve always bought my paper from Home depot or lowes. The 3m brand.
Something in your process has changed, maybe you just skipped a grit?
If you're making your living at what you are doing you need to remove all variables that you can. Having to think about the weather is bad for any business with deadlines and controlling your process is the only route to consistant results. Right now you're looking for an answer without really knowing which question to ask.
Have you changed manufactures with some or all of these finishes products?
I usually get my finish products from either Home Depot, Lowe’s, Menards or Sherwin Williams depending on what I need. So no I’m still getting my stuff from the same places.
Have you tried buying some sandpaper from a different store. While very unlikely, it's possible that bad batch/mislabeled batch made it onto the shelf. I know ir's a long shot, but it's fairly easy to try and there doesn't seem to be any obvious cause.
Sounds to me like you have scratches that aren't sanding out with that 400 grit paper. I'm sure you know by the feel that its 400 grit by using it in the past. If it persists, I would try the next coarser grit to make sure the scratches are removed, finish with the 400 grit and reapply finish.
I found this blurb by searching "orange peel with water-based finish" on the internet. Might be helpful. I don't personally have any experience with the orange peel problem.
https://generalfinishes.com/faq/what-causes-orange-peel-when-spraying-water-based-topcoat#:~:text=What%20Causes%20Orange%20Peel%20When%20Spraying%20A%20Water-Based,smaller%20fluid%20tips%20or%20a%20larger%20spray%20unit.
In my experience, 400 grit isn't coarse enough to sand out anything deeper than previous 400 grit scratches without lots and lots of work. If you think you have coarser scratches in the previous coat, I think you will have to start with 320 or coarser. If the scratches are as prominent as you describe, I'm wondering if the scratches are much deeper in your finishing layers; maybe even in the wood itself. I usually sand between coats with 220 or 320 and most finishes will fill those scratches. Something is going on that is not related to the 400 grit you are using.
Maybe time for a good, thorough sprayer & hose cleaning. Just my 2 pennies' worth. It's the little things...
Mikaol
Sounds like your finish isn’t completely hardened before you sand. The softer coat will build hard nibs on the paper. This will leave unwanted grooves and valleys which will reflect light differently through the next coat. With the weather changing on you be aware that temperature and humidity effect everything when finishing. Regarding orange peel finish check out Flexner on finishing. He has some great fixes for orange peel finish. Good luck.
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