Air brush tips ????

[Randy Digby]

I have an anodized aluminum product that is close to 200 sq. in. that I will be using CerMark LMM6000 to mark various text, lines, and etc. The aerosol application works well but I'm having to paint a lot of area that will not be marked. I figure that if I convert to air brush application I can cut the CerMark usage by 40% to 50%. I have never used an air brush but understand the process. I am not an artistic person but am mechanical minded. I already have an air compressor so the initial purchase cost of equipment should not be that high.

What I am interested from the Creek are tips in the application of CerMark by air brush such as:
Tips for mixing correct ratio.
Can I leave the mixture in the air brush spray bottle?
Do you stir or shake to mix?
If the base material dries up, can it be made usable again by adding DNA?

Along with the other tips I need but don't know that I need them!

Thanks for you time.

[Dan Hintz]

I use about a 10:1 ratio, so very dilute. There's no issue with leaving the mixture in the spray bottle during use, but you won't want to store that way as the DNA will evaporate. You can give it a good shake to remix after it has been sitting for 5-10 minutes, but if it has been there for a few hours you may need to stir. No problem with re-wetting dried Cermark.

[Niklas Bjornestal]

Why are you using cermark on anodized aluminium, cant you just engrave it as it is? And does cermark work on the anodized aluminium?

[Mike Null]

I would buy a single action Paasche airbrush. I got mine for about $15 at a hobby store. I've also used HF air brushes but the Paasche is superior.

Just practice for a minute or two with water in the glass and you'll get the hang of it.

[Randy Digby]

I use CerMark on clear anodized aluminum to get a black mark and, yes, I have very good results with it on anodized aluminum.

[Randy Digby]

Thanks Mike. I'll try to locate a supplier close by or look on line. McMaster Carr sells a couple of airbrush kits but they don't disclose the brand.

[Dee Gallo]

Randy,

I agree with Mike, the Paasche single action is the best one for the job. I might also recommend you get the #3 tip/cone because it is easier to clean and will give you an even large area spray with less finesse than the typical #1 tip.

cheers, dee

[Tony Lenkic]

Here is another tip for you.

Once you have a graphic setup completed you can draw boxes in the area that will be lasered. Give those boxes cut line, apply cheap transfer paper on your plate, cut the boxes out, remove inner parts where graphic falls in and now you have minimum area where to coat your work piece with Cermark rather than guesstimating.

[Randy Digby]

Thanks Mike and Dee on the Paasche suggestion. I'll try our local Michaels tomorrow. If they don't carry it, I'll order from Paasche or Amazon site.

Great idea Tony. I just drew cut boxes on one I have to do tomorrow with a spray can. That will save a little material, even using the aerosol can. It sure will make it better when I start airbrushing. I was going to do a fast engrave pass to mark the areas but I like your idea better.

Long live the Creek!

[Richard Rumancik]

I use CerMark on clear anodized aluminum to get a black mark and, yes, I have very good results with it on anodized aluminum.

Randy - Lots of people have given up on aluminum with 25/30 watt machines as it just sinks the heat away too quickly, and adhesion is poor. But I'll bet most people have been using bare aluminum. Seems like you may have solved the adhesion problem by using the anodized material - but I assume that you still need to go really slow?

[Randy Digby]

Richard, I do get good marks on anodized aluminum--finally. It wasn't easy getting there. Forget the long hours of watching the laser do it's thing and then watching the mark wash off, the nights I got up out of bed to try something different, and then loosing my last couple of hairs, I finally arrived at this solution:

Coat material with CerMark LMM6000
Laser at 100%P (30 watt machine) and 40% speed (100% = 110 in/sec - I think)
Apply a second coat of Cermark to the marked areas.
Laser again at the above settings.

I could probably do one pass at 20% but if there is a light area due to inadequate CerMark coverage, I would have to recoat and laser the problem area. My current method kind of washes out the application error, since I have a small chance of applying a light coat in the same area twice. Thus the reasoning for going to airbush application so I can reserve the CerMark for the marked ares with pin-point (well, a little wider than that) application.

I tried masking and then cutting the mask today as suggested above but ran out of time before I could find a point where I could cut the transfer tape and not mark the aluminum. I will try that again later.

I'll try to attach a pic of some of the mark. The text in the pic is about .300" high.

[Richard Rumancik]

OK, thanks for the info. Seems like aluminum is inherently difficult to mark with Cermark.

Just a couple comments - I think you may have some trouble "kiss" cutting the masking without leaving a mark. It may not show perpendicular to the part but you may get a witness mark under certain light conditions/angles. I would be cautious.

Generally I have used mylar stencils to place my Cermark. I draw the stencil pattern over the part leaving some margin for error on the graphic cutout. There should be some registration method (flush to two edges, cut two holes, or whatever, depending on the part.) I cut the stencil; then I hold the stencil in front of the plate and airbrush through the "window" in the stencil. You might need a couple paper clamps depending on the part size.

If you felt inclined you might be able to recover the Cermark off the stencil although I have not usually bothered. I have not had good success reconstituting Cermark after it dries up. One small particle of solid material will plug your airbrush and then you have wasted a lot of time. I would suggest that you keep the Cermark wet with DNA while in storage. It will tend to dry up even in closed airbrush bottles. Maybe a Saran seal would help.

The other thing is that I have not had good success with the high dilution rate some people use. I want to see a uniform opaque coating. If I can see metal through the Cermark, there is not enough Cermark there. You can't get a black pixel if there is nothing there to bond - at least, that's how I see it. If there are missing pixels it will give your graphic the jaggies.

[Randy Digby]

Thanks to the Creek for all the good info on my airbrush quest. The Paasche equipment is on order from Amazon and I should be up and running in a couple of weeks.

[Dave Johnson29]

Coat material with CerMark LMM6000
Laser at 100%P (30 watt machine) and 40% speed (100% = 110 in/sec - I think)
Apply a second coat of Cermark to the marked areas.
Laser again at the above settings.

Randy,

What I suspect is happening here is that the first pass is actually burning through the anodizing and exposing the bare substrate as with normal marking on colored anodizing. Even though it is clear anodizing, there will be clear-color (water) trapped in the anodized surface that is being boiled off with the first laser pass.

The second coating and pass is then applying the cermark to that base material. If you can get reliable registration of the material, try doing the first pass without the cermark, then spray and do the next. Basically what you are doing but with one less application of cermark.

[Richard Rumancik]

Randy, I think Dave is on the right track. When you proposed using Cermark on clear anodized I thought you were bonding to the anodize layer but now I think not. Ferro does not spec the LMM6000 for use on anodized, only bare metal.

But I did notice something when I went to their site - the product LMM6046.
http://www.ferro.com/NR/rdonlyres/45...14/LMM6046.pdf

Also see the Thermark site
http://www.thermark.com/content/view/40/78

I never noticed this before - I haven't seen it discussed here. It is apparently intended for use on ANODIZED alum. (works on bare and anodized ONLY- no other metals.) The fact that they have a separate product for use on anodize tells me something. I don't know if they give out the 5 or 10 gm sample bottles anymore but you could ask. Thermark also mentions a tape product. Again, most people here use the paste but Thermark says the tape is better for 6046.

But note the the caution on the Thermark site - they say LMM6046 it is a "challenging" product to use as it has a narrow process window.

So if you don't want to try 6046, I suggest you follow Dave's advice - hit it fairly hard in the uncoated state to expose the aluminum, clean, apply Cermark, re-register, and laser. Right now the first application of Cermark is probably just acting as if it were contamination on the first pass.