View Full Version : Air brush tips ????

Randy Digby
02-12-2010, 11:18 PM
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
02-12-2010, 11:24 PM
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
02-13-2010, 4:18 AM
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
02-13-2010, 5:40 AM
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
02-13-2010, 9:18 AM
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
02-13-2010, 9:20 AM
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
02-13-2010, 11:23 AM

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
02-13-2010, 7:25 PM
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
02-13-2010, 11:53 PM
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
02-14-2010, 9:10 PM
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
02-14-2010, 9:54 PM
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
02-14-2010, 11:16 PM
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
02-15-2010, 9:24 PM
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
02-16-2010, 10:24 AM
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.


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
02-16-2010, 10:58 AM
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.

Also see the Thermark site

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.

Randy Digby
02-16-2010, 11:53 AM
I tried the 6046 early on when TherMark sent me a sample. I never could get a dark mark with it. The sample they sent was the paste/ink, so I may have better reults if I tried the spray - a test for another day. On second thought, I still have some of the sample and I will try it when I get the airbrush going.

I know the 6000 is advertised for stainless but it works good for me on anodized. I have been using the tape in the past but I have to use open fonts (batang) and make the font line width .015" to get a mark. Solid font (arial) of any size does not yield consistent marking for me with the tape. I also have to run it at 100/20 which is about two hours on my part. When you add 10 minutes for a marking run and then 15 minutes to apply tape and 20 minutes to clean the board afterwards, it gets to be a long process. I can paint the board in about a minute and clean it in about two minutes...much better.

My Speedy 100 registers very good. When I use the tape, I run a fast pass to mark the areas for tape application and then re-run it at marking levels. I have never had a registration problem after doing this many times.

I'll test the burn before coating as suggested above just to see. It makes sense and it would same a lot of coating material. I'll let you know how the test turns out.

I'll try TherMarks suggested material for anodized again, but right now I've got a process because it gives me a pure, consistent and repeatable mark - and that's a good things if you knew what I've been through for the last several weeks trying to settle this process down and meet customer orders at the same time. It's really bad when you pull a part off the laser after one or two hours and discover that it is "almost" god enough to send to the cuatomer.

I'll test some more an post the results - thanks gang.

Randy Digby
02-16-2010, 6:54 PM
Ok, made time to run some more tests. I made a couple of runs where I lasered the part first at full power and fairly fast (one at 60% and one at 100% speed), applied the CerMark spray and then lasered again at 100% power, the first test at 40% speed and the second at 30% speed. Although neither sample had the "snap" or "crisp" appearance as the two coat process, both results are acceptable and I will probably attempt customer runs at those settings. The good side is I should use half the coating with this method. I want to see how the full part looks using this process before I'm completely happy but it looks promising.

Thanks for the great suggestions.

Dan Hintz
02-16-2010, 7:39 PM
Randy, is your re-registration perfect? If not, you'll be trying to Cermark edges that have not been cleaned of the anodizing, leading to fuzzy edges.

Randy Digby
02-16-2010, 7:56 PM
Dan, no fuzzy edges. When I talk about "crisp" look, it's hard to explain, but a close comparison would be to say that the two coat application gives the appearance of a glossy finsh to all of the marks and the single coat application gives a matte appearance. Both the two coat and one coat methods I have tested require removing the part from the laser and then replacing it after applying the paint for the second run. One reason the two methods stand out as different to me, I think, is because I ran both tests on the same plate and the marks are adjacent to each other. If I had separate parts in hand, it might be harder to tell them apart - at least, that's what I'm hoping for.

Dave Johnson29
02-16-2010, 8:55 PM
Hi Randy,

For the first pass without cermark, check the recommended speed and heat settings for colored anodizing. I suspect the speed is too high and you are not boiling out all of the water trapped in the anodized layer.

To laser mark colored anodized stuff, you have to boil the colored water trapped inside the small capillaries created during the anodizing process. Going too fast will not clean the capillaries out properly.

Also the substrate for the 2nd pass will transfer heat away faster so try slowing down for that too.

Randy Digby
02-16-2010, 9:15 PM
Hi Dave,

Yea, it's a juggling contest between Cermark usage and time in the machine. I have an acceptable and repeatable process at - coat, 40%s, coat, 40%s. The first priority is to eliminate the second coat (without increasing machine time) of CerMark since that is a direct cost of the process. The second challenge is to reduce machine time (not direct cost - other than power usage and laser life - since I am self-employed) to reduce the bottleneck that results when processing one of these parts. The ultimate solution to the bottleneck is additional laser resources, which I will do as a last resort.

Dave Johnson29
02-17-2010, 11:22 AM

Can't agree with the juggling act. To me it is a matter of getting the best practical result. By that, I do not mean do everything slow and perfect, but rather get the best practical result for the requirements.

If I was doing this project I would first define settings for a good clean bright white finish for colored aluminum. That defines a clean substrate, your canvas to work with.

Then I would do the cermark spray and find the best practical set up for that. Rushing through the first pass to save time will affect the outcome of the second pass.

I am not trying to preach to you here, but I have been an Engineer pretty much all my life and there is only so many right ways to do things. Step by step is the most important approach. Get the first step right before moving to the next step.

If you are happy with the money you were getting for the former double-coat process, then that single coating saving will allow for slower speed for the first step. If the new approach is taking too much longer, then explain to the customer and say you will have to up the prices a little to give him an overall better job. Most customers aren't stupid and they understand you get what you pay for.

Just one old man's opinion. :):D I have run my own businesses for more than 30 years, all were successful and all made a bag of bucks for me when I sold them.

Randy Digby
02-17-2010, 11:40 AM
No problem Dave, just the terms we use to arrive at the same end may be a little different. I'm a retired process engineer myself having spent 37 years in the plastics industry (blown film and expanded polystyrene thermoforming) and have spent many long days, weeks and sometimes months getting a process to the point where it is sustainable, repeatable, reliable and profitable - providing a quality product which meets the customer's needs and his budget.

Now at 60 years old, I'm going to learn how to use an airbrush and move to the beach and do tee-shirts!! Yea, right. That got a laugh out of my daughter said when I told her. :-)

This is a great forum for exchanging/sharing ideas and methods.

Thanks for your input.