Refinishing a Metal File Cabinet
How to sand and clean a metal file cabinet, then shoot it with automobile finish. February 8, 2008
Question
I know this is not wood finishing, but it is finishing related. I also know from reading past posts that some of you have auto finishing experience. I need to re-shoot a file cabinet (metal), and I picked up a single stage auto finish (Nason). What kind of prep work do I need to do? There are a couple of small scratches that go to metal; otherwise, the original finish is intact. Do I need to shoot a primer first?
Forum Responses
(Finishing Forum)
From contributor G:
If you don't want the scratches to show through, you have to fill them somehow.
From contributor A:
Sand it all down p600. Use glazing and spot putty to fill scratches and chips. Sand and prime putty with metal primer. Spray whole unit with primer surfacer. Sand p600. Spray finish coat. That's how I'd do it.
From the original questioner:
Thanks. I'd have known exactly how to handle this job if it was wood, but I haven't done metal for at least twenty-five years. What I didn't forget was how helpful people are here.
From contributor E:
Contributor A's advice is pretty good, except for a couple of points. First clean the surface with mild solvent, Naphtha or Xylene. Sand the old finish down to 180 or 220. Spray on an automotive primer/surfacer. Sand the primer to 320-400. Then apply the spot-glazing putty to fill the scratches; they are designed to be used over a primer, not on bare metal. Re-prime and sand to 600. A primer/sealer may then be used for better color hold out, but that's optional and probably not necessary on a file cabinet. Spray the topcoat, single stage or base clear system.
From contributor A:
Yeah, didn't wan to get to carried away. It's a file cabinet, not a car. ;)
From contributor E:
Hey, I've seen some pretty nice file cabinets... :)
From contributor O:
I would scuff up the cabinet with 150 sandpaper, wash it down with naphtha or mineral spirits, spray a couple coats (3-4) of feather fill, dynagrout or the like. This is a high solids content spray on filler that will fill most small dents and scratches. Ask the guys at the auto paint store - they will know what you are talking about. Sand this down with 150 to sand smooth where the scratches and dents are, apply the primer, scuff, then topcoat. This cabinet will look as good as a brand new car.
From contributor J:
The only thing you should use to clean it with is wax and grease remover. Everything else mentioned is a huge no-no for car paint prep. They all leave residues and are not recommended. You can get wax and grease remover in a spray can from auto stores like Autozone for just a few dollars.
Also, the only auto primer made for bare metal is epoxy. If it's not bare metal, you can use urethane (2K), but epoxy gives better adhesion. Much better for resisting scratches and nicks. Urethane primer is for leveling and smoothing, mostly for bodywork. For light smoothing you can sand the epoxy the same way. Epoxy is also an excellent sealer - it's all you need. It's all I'll use on car bumpers now.
From the original questioner:
Any brand of wax and grease remover that you're fond of?
From contributor G:
Are these standard battleship gray file cabinets? You can hide a multitude of scratches by putting texture in your lacquer.
From the original questioner:
Yes, it is a standard metal, lateral file cabinet, but it is not battle ship grey. While texture can hide a multitude of surface issues, I'm inclined to keep a smooth finish. (I know, I could've taken the easy way out.)
From contributor J:
I have no preference on brands of wax and grease remover. It's usually sold in gallons, that's why I suggested the aerosol cans. Which single stage are you using? There is acrylic enamel and urethane. The urethane is at the top for durability and the enamel is actually at the bottom. Most cars aren't done in enamel anymore. If your paint is enamel, be sure to use a hardener - that makes it so much better. I have had good luck brushing/rolling enamel because it stays wet longer than other car finishes. It flows out real nice. The urethane is the toughest paint I've ever put on a car. Really hard to chip off. And then there's polyurethane, even better - that's what's used on aircraft.
PS. Dawn or Joy dish detergent works real good for cleaning before painting. I wash every car I work on with Dawn first, as it removes all the wax and silicones.
From contributor E:
I'll admit it's been a while since I painted a car, but from what I remember most products packaged and sold as "wax and grease removers" are nothing but Xylene. Has this changed in the past 10 years?
From contributor J:
I don't know, it very well may be. A lot of people use different things and get away with it. I got away using lacquer thinner for years, then one day it gave me problems, so never again. Some car finishes are a lot more sensitive than others, so just switching types or brands starts showing problems there never were before. Auto wax and grease remover is cheap and really good - so I recommend it. I use it for a lot of things in cleaning. And for small quantities, the aerosol can I found at Autozone works really well and is easier to apply. It is important to allow extra time for it to dry. It can cause problems if you don't. (Don't ask me how I learned that one!)
From the original questioner:
The paint is Dupont Nason Acrylic Enamel, and it does require a hardener. The paint store guy said that for a file cabinet, he didn't see a need to go with the more expensive finishes.
Do you remember the name of the spray can you bought at Autozone? So are you saying that you'd feel comfortable using Dawn instead of the wax and grease remover? Or use the Dawn as a first step?
From contributor J:
I use the Dawn all the time for cleaning cars. I wash it first before any sanding, then again after sanding the primer. I don't use the wax and grease remover after that. The Dawn is enough, as long as you clean it really good after sanding. But if you have any bare metal, you don't want to get it wet, so wax and grease remover is better for that.
