Thermark "lifetime"

[Matt Carlson]

I understand Thermark and similar materials, deposit on the metal itself, and doesn't "etch", but how "securely" does it stay on the metal? I assume using steel wool will remove it, but how wear-resistant is it? Meaning, if it's handled daily, is it going to wear pretty quickly?

[Bruce Volden]

Back in 1995? I made my first SS sign for a local business. Back then the stuff was called Cerdec. The sign is 12" X 10" and mounted on his outside entry door. It sits on the East side so it gets full sun til about noon.

This sign looks like day one--maybe the SS has slightly discolored after all this time but it's hard to tell.

I also do a lot of knife marking and have made the occasional mistake (spelling)----NO---steel wool will NOT remove this stuff, however a 3/4 hp Baldor buffing station will. DAMHIKT

Bruce

[Dave Sheldrake]

It's pretty good stuff as it causes a chemical reaction in the surface of the metal rather than just sticking to it.

Normal washing up liquid (I'm not sure what it would be called in the US but here one of the brand names is Fairy) also works on stainless steel in much the same way (it's the selenium that does it) but does take a bit of fiddling to get the power settings right (but is very cheap)

best wishes

Dave

[Dan Hintz]

Steel wool will remove it... but you'd be standing there for quite a few hours working at it. It takes abrasion techniques to remove it (sandpaper, steel wool, scraping, etc.)... simply rubbing by hand will not remove a well-placed mark. There is no chemical reaction going on, it is simply a physical bonding between the metal's surface and the glass frit in the Cermark.

[Ernie Balch]

I can directly mark steel with my laser but am concerned that reflections back down the beam line will damage my laser. I understand that some lasers use polarization to prevent damage but I assume that chinese lasers do not. Does anyone have information on the damage potential of marking highly reflective metal surfaces?

[Gary Hair]

how "securely" does it stay on the metal? I assume using steel wool will remove it, but how wear-resistant is it?

Same way that you can empty the ocean with a teaspoon, Cermark will come off with steel wool.

[Bruce Volden]

It is my understanding and experience that it will not come off with steel wool! In order to remove Cerdec/Cermark/Thermark.....effectively from a high quality steel it will be necessary to remove the steel ALSO.
Perhaps it looks "gone" but holding it so light reflects from different angles you will still be able to see where you have engraved. Steel wool will not work. 240 grit buffing compound and a buffing wheel will and even this will take a few minutes to look "new" again.

Unless I have been doing it all wrong for some time now?

Bruce

[Dave Sheldrake]

Polarisation makes no difference to back scatter sadly. RF lasers produce polarised beams , DC lasers don't (unless they have reflective phase retarders installed)

Lens's used on metal have an anti reflective coating applied to both sides of the lens but this is usually only really any good on higher quality lens's.

Backscatter damage can be minimal or technically absolute, while highly highly unlikely it can in theory damage not only the final lens but all the way back to the tube as well.

Phase Retarders, Blanking windows, beam combiners, beam expanders can all be manufactured with AR coatings one side, they are all subject to backscatter damage in the wrong circumstances.

In general the biggest danger is from liberated metallic particles flowing up and hitting the final lens causing physical rather than optical damage.

best wishes

Dave

[Matt Carlson]

Thanks guys, I appreciate it! Sounds like this is the right stuff for my application!

[Dave Sheldrake]

It's a chemical bond not an adhesive bond.

Adhesive bonds rely on surface imperfections to hold via a filling agent (glue) chemical bonds change the properties of the surface to hold otherwise the chances of getting a bond on a "glasslike" surface would be minimal to impossible. (it's the principle reason it's unwise to glue stuff onto a corroded surface using adhesive bonding)

Anything can be removed/reduced with anything given enough time, friction and pressure.

1000 monkeys / 1000 typewriters / 1000 years kind of argument and in real terms pretty much academic.

best wishes

Dave

[Mike Null]

It is a heat bond not a chemical bond if it makes any difference.

[Dave Sheldrake]

http://www.thermark.com/content/view/16/86

http://www.thermark.com/TM_Images/How%20It%20Works/Glass_on_Metal_Bond_w.jpg

Heat is a catalyst resulting in a chemical polar covalent bond between metal and coating due to the unequal sharing of electrons between nuclei. It's resistance to removal can be calculated by the covalent radius of each atom in the molecule to determine strength.

Short version? it ain't coming off very easily :)

best wishes

Dave

[Jesse Anderson]

The 1.1 gigawatts required to produce enough energy to power the flux capacitor to remove the Cermark mark is not sufficient to remove the mark.
So a DeLorean jacked up with a giant grinder wheel attached... With enough force should remove the Cermark....:confused: