What causes this crazy brown crazing on a varnished steel square?
I pulled out this measuring square out of my toolbox and was dismayed to realize that it was almost impossible to read the markings because of this haphazard crazy brown "crazing" all over the place.
Can it be fixed?
Strip the varnish, put it in an electrolytic derust tank (I know, it sounds like I'm asking you to do something ludicrous, but I'm running one right now, and trust me, once you have one set up you will find stuff to put it it, it's great) paint/varnish. Or buy a new one for $10 or so.
The crazing I believe is corrosion caused by moisture/air actually getting underneath the finish at a tiny flaw and spreading from there.
nate
Technically, it is called "rust".
You can get rid of it by removing the clear coat on the rule and then either sanding off the rust or removing it chemically.
I had a bit of something called neutra rust a long time ago. It was watery like solution and I used some on a rusting pipe railing and it has not rusted in 15 years or more. I ran out of the stuff and now cannot find where to by more. Anyone have a place to buy it or a replacement for such?
I never thought it was rust. Sure, it's 'brown' ... and the square is steel so it 'can' rust.
But I've never seen rust like that!
Rust usually covers a wide area, and it's rough. This is smooth as silk.
Still ... maybe it 'is' rust as it must be something!
Hi Nate,
I had never thought it was rust, but you're the second person to say that.
Since it doesn't look or feel like any rust I've ever seen, it didn't even cross my mind that it's rust.
Here's a closeup of the crazing. It's almost as if a tiny burrowing animal tunneled under the varnish looking for food to eat!
OK. You're the third person to say it's rust under the varnish.
I have to say, I've seen rust. This doesn't look like rust. But all three of the responses say it's rust - so - rust it must be.
It may be rust in the pinholes of a clear-coat?
It wouldn't be varnish, it would be lacquer. A bit of lacquer thinner will remove it.
Ooops. I don't know the difference between varnish & lacquer.
Looking it up by a variety of sources, Wikipedia included, the difference is interesting ... but after looking that up, I'm still not sure how you know it's lacquer.
Here's how Wikipedia lists differences:
Varnish: oil + resin + solvent always clear usually brushed on slow drying relatively high percentage of solids usually less durable
Lacquer: nitrocellulose + solvent can be tinted usually sprayed on fast drying relatively low percentage of solids usually more durable
Because no manufacturer would use varnish because it dries so slowly. Ditto commercial furniture - lacquer finish.
I don't see it more durable. I also see lacquer as being able to absorb moisture. Ever seen clouding on a piece of furniture top. I had clouding and actual gouging on a car paint finish using one of those bras. Permanent damage. The finish was lacquer.
I have one of those squares that get all rust. I have to try dissolving the rust ever so often. Dam hard to read in any condition.
Greg
Lacquer dries solely by the evaporation of its solvent. No chemical change takes place. When dry, it can be removed with its original solvent
When varnish dries and cures, it combines with oxygen from the air and a chemical change takes place. Because of this chemical change, its original solvent will not remove it.
When you hear that piles of oil soaked rags will spontaneously combust, they are not talking about motor oil. They are talking about oils used in varnishes and oil based paints (linseed oil, etc.) that combine with oxygen (oxidize) producing an exothermic chemical reaction as they cure.
Why wouldn't they use a UV-cured epoxy, or some such? Much faster than any of the above.
probably a phosphoric acid based solution, I'd guess.
nate
Maybe they do, no idea. It would depend on cost I would guess.
It's used on flooring (many coats, even), why not on even a cheap square?
Because flooring sells formore?
Lacquer seems to be a thinner coating. They could easily use acrylic enamel with the hardener, used on practically all cars. It sets up fast.
Greg
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