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View Full Version : Reclaiming sheet steel- paint removal



darryl
11-12-2016, 05:07 PM
I picked up some street signs some days back, bus route signs. Steel, and the right gauge for a lot of what I would be using it for. They are not so large that I'd have a problem handling them in my shop for cutting, etc, yet large enough to supply several typically sized pieces for various projects. And they were cheap. It was a good score.

Most of them have a stick-on reflective strip stuck to each side. Question is how best to remove those. I'm sure the adhesive is similar to what licence plate stickers have on them- in other words a waterproof and very tenacious glue. This can be dissolved with an appropriate solvent, but usually the strip itself is durable enough that the solvent takes too long to get through, or never does.

I'm thinking about putting them in the oven, then mechanically peeling the strips off, followed by using a solvent to remove the glue. Whether I then remove the paint or just scuff it up for repainting- depends on the application. I could simply belt sand to get down to bare steel, and I'd be fine with that, but I know how glue tends to stick in a belt and render it useless. I don't mind wasting a belt or two, but I think I'd rather remove the stickers and the glue before deciding what to do with the paint that's left- either nothing, or belt sand it off.

I don't have a blast cabinet, but size-wise my oven can handle most of these.

What would you do?

digr
11-12-2016, 05:18 PM
I would try a heat gun first

Alistair Hosie
11-12-2016, 05:45 PM
The guys in UK, Europe , etc would pay through ebay UK etc for these , I believe I hear collectable novelty items in my little head-voice as I type. L O l Alistair

brian Rupnow
11-12-2016, 06:35 PM
The street signs I know of are all galvanized material---not much good for building with even if you do get the paint off.

kendall
11-12-2016, 06:52 PM
I normally use a hair dryer or heat gun works well enough.
Here the ones I get are heavy gauge aluminum.

dave_r
11-12-2016, 11:34 PM
Great. Which part of Chilliwack is missing all it's signage? :eek:

darryl
11-12-2016, 11:46 PM
Have you tried to take a bus lately? Everyone is confused, nobody knows where to go. Best prank I've pulled in a long time :)

Update- after considering the potential collector value, I decided to give the oven a try. At first I used about 270 F and was getting much of the paint off with a scraper along with the adhesive strips. Then I took the temperature down to about 240 or so. Every sign behaves differently- on some everything comes off, on others only the strips come off, and on one I was able to pull the strips off with the paint but leaving the primer behind. The process is quick but not ideal.

Next I think I'll run some fans to ventilate the kitchen well, then crank it up to about 300 or so, maybe a little hotter. Hoping then to affect the paint enough that I can scrape most of it off too.

I now believe this metal IS galvanized- I earlier said it was not because what I exposed by peeling the paint looked like only primer. I ran some at a higher temperature which allowed me to remove everything easily, and what's left is a well etched surface but not bare steel- doesn't have the look of bare steel anyway. It still looks like primer- Anyway I'll live with it

SGW
11-13-2016, 08:39 AM
For the paint, you could try a lye solution. 1 can of drain-cleaning lye to a quart of warm water. Use a plastic bucket, avoid aluminum, and beware of splashes because it will eat holes in everything including you.

chipmaker4130
11-13-2016, 02:21 PM
Why the 'hate' for galvanized? You don't weld large areas of sheet, so stripping the coating off where you need to weld is a piece of cake, and if spot welding or soldering you don't even need to do that. When you're done you have a mostly rust-resistant part. It used to be a pain to get paint to stick but these days that isn't hard to do either.

darryl
11-13-2016, 02:59 PM
I recently got some primer that's supposed to work well on galvanized. Usually the parts I make are angle brackets, corner brackets, etc- just paint, screw in place, and they're hardly ever seen again. The parts I'd be making next are some custom magnetic holders, but have one hole and two bends. Again nothing welded or critical.