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View Full Version : Thermark application/removal



Andrea Weissenseel
05-23-2009, 11:16 AM
Today I engraved a couple stainless trays with Thermark. Since I don't have a compessor I tried a couple different methods to apply with brushes or sponge. The sponge works OK for small items i.e. cutlery, but it didn't work out to good on the larger area I did today, so I tried with different brushes. The best worked a brush that you use for stencils but it soaks up a lot of the Thermark.

How do you apply it ? After washing off the Thermark I also noticed a lighter "stain" in the spot where the Thermark was applied.

I previously read "no picture - it hasn't been done " :D so here it is. this was done for a customer they give it clubmembers as an Award instead of plaques, that's a pretty good idea I think - people get an Award an something they can use every day

Mike Null
05-23-2009, 11:51 AM
I believe you can buy a portable spray device (I forget the name) that will allow you to spray it on. I'm not pleased with results when I paint with a brush.

Stephen Kane
05-23-2009, 1:25 PM
I use a very fine brush eg camel hair, with light strokes. Typically I am doing one offs and spraying does not make sense for me.

Stephen

Rodne Gold
05-23-2009, 2:03 PM
Staining is a big problem ,the way to minimize this is to apply , dry asap under lights , laser and wash off immediately ..ie let the stuff stay on the metal for as short a time as possible.

Frank Corker
05-23-2009, 3:21 PM
Rodney has it right, the reason for your staining is that it was on far too long. Dry it off as soon as you can and only apply it when you are ready to laser it.

Tony Lenkic
05-23-2009, 4:53 PM
Mike - Are you refering to "PREVAL SPRAYER".
I use it most of the time.

Another option is sponge brush that come in different widths.

Joe Pelonio
05-23-2009, 6:13 PM
I use a very fine brush eg camel hair, with light strokes. Typically I am doing one offs and spraying does not make sense for me.

Stephen
Same here, then airbrush for larger quantities.

Gary Hair
05-23-2009, 6:36 PM
Staining is a big problem ,the way to minimize this is to apply , dry asap under lights , laser and wash off immediately ..ie let the stuff stay on the metal for as short a time as possible.

Ferro, the Cermark manufacturer, also recommends spraying it a bit farther away from the item to be marked. This allows it to partially dry on the way to the item and will reduce staining. You can also heat the item up a bit to expedite drying.

Gary

Mike Null
05-23-2009, 8:08 PM
Tony

Thank you. That is what I was thinking of.

Rodne Gold
05-24-2009, 2:46 AM
In terms of application , the ideal is to get as thin a coat as possible on the material without streaking or gaps.
Degreasing the item prior to spraying/applying is a must
I use paasche airbrushes , thin the material with water and use a few drops of wetting agent on it (cheap dishwasher liquid without any additives like lemon or lanolin)
clogging is a problem and the siphon bottle doesnt work well so we use the gravity hopper and often use another bowl of water to declog
We reclaim overspray by spraying in a perspex box and reclaim the material in the washoff bowl and the de clogging bowl.
Our problem is that we do large quantities of stainless marking and the cost of the marking material becomes an issue if we "waste" it in terms of profitability and price. Often you can waste way more material you apply with sponges etc and fail to factor the waste in when pricing.
Apart from that , the uniform thin application means we can go a lot faster with engraving and get superior results.
We have found that thickish or less than perfect application requires more power and less speed and often even after this , the abraision resistance of the mark is less than ideal.
If I am doing multiples , I always use a test piece and have a standard test - 30 strongish rubs with a scotchpad should satinish or brush finish the underlying material but not affect the mark.

andy blackett
05-24-2009, 3:37 AM
The Cermark LMM comes in an aerosol spray tin which works really well. Its a bit messy though, we always put lots of sheets of newspaper down when doing it this way.

We also use a gilding brush to apply it to small plates, means we can do the whole piece with one stroke.

Andy

Andrea Weissenseel
05-24-2009, 4:54 AM
I applied it just before I put them in the laser and washed it off directly after, maybe the coat also was to thick ?

The "stain" is nothing that messed up the trays just a bit lighter area, I probably was lucky that I cut me a paperstencil as where to apply the Thermark so the lighter spots have a circle/rectangle form - also noticed that in that area the metal reacted different with water when washed off. Water pearled off in "normal" areas, and stayed pretty wet where the Thermark was.

That portable spray might be an option as well as a can of air for my airbrush, but at the moment with doing not so much of metal items and only small areas I think with spraying I waste more than I apply. Thanks for your tips :D

Tom Bull
05-24-2009, 10:04 AM
Perhaps what happened is the thermark actually cleaned off something that was applied to the tray. We use cerium oxide to clean glass when it has to be really, really clean and I can see how the thermark would have similar cleaning properties. Perhaps the "stain" in this case is actually just cleaner than the surrounding area that still has a protective coating of some sort that caused the water to bead up. Just a thought.

Richard Rumancik
05-25-2009, 10:45 AM
I see a few people are trying to apply LMM (Cermark or Thermark) without an airbrush. When I first started with Cermark I tried paint brushes etc but never had good results with uniformity. It just does not "stick" so a subsequent brush stroke can wipe away the previous one.

One method that seemed promising for applying small patches of Cermark with minimal waste was the following:

1) place a small piece of Kodak lens cleaning paper on the metal to be marked.
2) apply a few drops of denatured alcohol (same as you use for diluting the Cermark) on the lens cleaning paper

This will wet it down and it keep the paper from moving.
3) Apply the Cermark over the lens cleaning paper wth a small brush. The fact that the paper has tiny fibres creating a "grid" will allow for a much more even application of Cermark. As usual, apply a minimum amount. The pre-applied DNA on the paper will dilute the Cermark a bit and help it flow.
4) Once the lens paper is "painted" in the area to be marked, let the Cermark dry as usual.
5) Laser as usual.

This technique showed promise. I did not find significant degradation of the image due to the presence of the lens paper. At high resolutions it is possible that the lens paper may result in a poorer image, but I did not test it extensively at high resolution.

Once I got an airbrush, I did not do much further experiment. Also, I haven't done much Cermark recently. However, for one-offs or samples it can take a lot less time than setting up an airbrush. Perhaps some members might be motivated to try it and report what kind of results they get.

Mike Null
05-25-2009, 11:54 AM
Richard
Interesting idea. Do you think transfer paper could be used instead of lens paper?

Gary Hair
05-25-2009, 4:31 PM
Richard,
That's bordering on ingenious! I have always broken out the airbrush, even for the small, single item jobs, and it's a pain, but the results are so much better that I still do it. I am going to give your method a try.

Mike - I don't think xfer paper will work, it may be too thick compared to lens cleaner. Maybe kleenex or t.p. would work?

Gary

Richard Rumancik
05-28-2009, 10:22 AM
The material that you use needs to be very "open cell". The Kodak lens paper is probably about 95%+ air space between the little fibres. "Paper" probably isn't the best term for it, it is really a very open tissue. As a result, there is plenty of coverage for the Cermark. I found that the Cermark probably seeps under the fibres, aided by the fact that the tissue is porous and wet from DNA. Since you really only need a small amount of Cermark to get a mark, it seemed to work okay in the experiments that I ran.

I wouldn't try standard tissues however as I doubt that they have the same amount of open space between the fibres.

If you try "painting" Cermark on a piece of stainless you will probably have an exercise in frustration. You think it is covered; then you brush it once more and leave a streak of thin Cermark. Then you can go back and forth fixing forever. If you do get it covered, the thickness probably will not be uniform, which is not conducive to a uniform mark.

To determine if this process will work at higher resolutions and to determine if the lens paper is degrading the quality of the mark would require some time-consuming tests, and some good magnification. I haven't tried to do that sort of comparison.

But if anyone does try this method I'd like to know what sort of results they get.

Dan Hintz
05-28-2009, 11:12 AM
The material that you use needs to be very "open cell". The Kodak lens paper is probably about 95%+ air space between the little fibres. "Paper" probably isn't the best term for it, it is really a very open tissue. As a result, there is plenty of coverage for the Cermark. I found that the Cermark probably seeps under the fibres, aided by the fact that the tissue is porous and wet from DNA. Since you really only need a small amount of Cermark to get a mark, it seemed to work okay in the experiments that I ran.

I wouldn't try standard tissues however as I doubt that they have the same amount of open space between the fibres.
No interest in running a test myself, but I'm willing to bet if you peel that lens paper back there will be very little Cermark on the substrate. My guess would be the laser is simply vaporizing the minimal lens paper, allowing the Cermark to do its job.

Regardless of the "science" behind it, it's still a novel way to mark a small piece... I like it.