Finishing for Lacquer

[Alan Carter]

Who thought that talking about sandpaper would generate so much friction? I guess the bottom line is what abrasives do the best job, regardless of their composition, backing, etc. My skills have improved somewhat since I first aked about sandpaper back in March and have found that the right amount of pressure is as important as the paper itself. Also power sanding and sanding off the lathe have solved a lot of problems. Experience wins out in the long run, right?

It's also a question of what abrasives work best on different finishes. I use mainly spray lacquer as a finish and have had some success with sanding pads up to 320, finishing off with auto polishing compound. Any comments on that without getting overly excited?

Thanks.

 

[Steve Worcester]

Depending on the build characteristics of the finish (how well it will fill in without showing scratches) determines what grit to sand too on wood, in addition to how much bite the finish needs to adhere to the wood. I would make a bold statement that you want to sand the wood to a 320 or 400 before shooting the finish. More than that and you may have adhesion issues, less and you risk scratches so large they get magnified by the finish and not filled in.
If you spray out of a can, it will take a lot more coats than if you spray out of a gun to achieve the same depth. It just won't build as fast.

Now if you buff your finish, as I do, after fully cured, I will wet sand (always wet) starting at 600 or 800 lightly to get the nibs and any slight orange peel out, and generally flatten the finish, then use 1000 and 2000 before polishing with the 3M perfect-it compounds.
But it depends on the look you want. I am looking for the same finish as on a custom car, dead flat, as optically clear as possible and thin but deep in appearance.

 

[Richard Baker]

Steve, Do you do the wet sanding on the lathe? Power?

 

[Steve Worcester]

Steve, Do you do the wet sanding on the lathe? Power?

Mostly in my lap actually with gloves on and a towel. I use an interface pad and abralon on the higher grits, otherwise (shhh! 3M film backs) 600 & 800 then Abralon 1000, 2000 and maybe 4000. Mirka Royal isn't great for wet sanding.

Sanding on the lathe occasionally, problem is holding the work. Vacuum chuck tends to really screw up the clear coats by pulling it off or through the pores, even at real low vac pressure.

Always wet sand the clears though so the finish doesn't ball up on the paper and make horrible swirls marks.

 

[Richard Baker]

Thanks Steve. Yeah, dry sanding lacquer pretty much no workie. Been doing some hf vase shapes (working on "form") and can sorta hold them with jam chuck and flat "point" on tail center. Will use the Abralon samples that you sent me a while back and follow with Novus (3 step) plastic polish. The latter worked well on a face shield and must do headlight covers on the truck. More than anyone wanted to know.

 

[Alan Carter]

As long as we're talking about lacquer, does anyone have recommendations for a particular brand? Stephen Hatcher uses Hood brand, but that's a mail order here in Chicago. I've been using plain old Deft from HD, thinning it so it'll flow a little better (my stuff has a lot of nooks and crannies), giving it 4-5 coats. I've been doing final sanding with 3M pads and topping off with Maguire's auto polish. Seeks to work pretty well, but not compared to Stephen's. "Course he gives it 20 or so coats so maybe that's what I need to do. That and work on sentence structure.

 

[Calamity Jane]

As long as we're talking about lacquer, does anyone have recommendations for a particular brand?

ML Campbell Magna-Lac is great stuff. It is a catalyzed lacquer. Probably the same stuff that your kitchen cabinets are finished with. Most of the time a product can be sprayed and ready to ship in about 20 minutes.

BTW....cost.....@$50/gal

 

[Steve Worcester]

The problem with lacquer research is having to buy a gallon and then not liking some property of it and trying to get rid of it.

You may want to see what your club members are using, or go to the local Sherwin Williams and see what they have in pre-cat lacquers. I am not a fan of nitrocellulose lacquers or water borne, but it has been a while since I have used either.

I shoot polyurethanes now, which I would not encourage others to get into, just too nasty. But if you know a good custom (car) paint shop in the area, ask them if they can shoot the clears for you. The auto custom (not collision repair) products are gorgeous.