Full Version: Color fill on rotary engraved aluminum
From: basehorawards [#1]
22 May 2006
To: ALL
I searched the archives and found some good information and I found a thread that spoiled the mood around here for a while. But what I did not find was the answers to these questions:
1. When you are going to color fill (flat black spray paint) rotary engraved aluminum signs do you use a mask?
2. If so what type? I tried to use a paper mask on some wood once and did not get the results I expected. I did not get a clean cut on the mask so the color fill had whiskers.
3. If you do not use a mask how do you get the paint to stay in the recesses when you clean off the excess?
4. What type of cutter would you use? The signs are 5" x 3" .040 aluminum giving maintenance recommendations. There will be about 12 lines of gothic text and a border around the edge.
I would prefer to use Cermark but this customer has very specific requirements that he has to meet and can not get his boss to let him change the way things are done.
From: Dave Jones (DAVERJ) [#2]
22 May 2006
To: basehorawards [#1] 22 May 2006
I saw a tip on a woodworkers forum about color filling wood through a mask. They suggested spraying it first with clear acrylic through the mask, let it dry, then spray the color. That prevents the color from bleeding through the grain and creating whiskers.
From: Harvey only (HARVEY-ONLY) [#3]
22 May 2006
To: basehorawards [#1] 22 May 2006
See post 2340.14 for additional information.
This technique will work on aluminum also.
From: basehorawards [#4]
22 May 2006
To: Dave Jones (DAVERJ) [#2] 22 May 2006
Dave,
That does works when laser engraving but on the rotary it actually tore the mask instead of cutting it so the paint went places on top of the wood it wasn't supposed to go not just seeping into the rays and grain lines. I did not try it on the wood as it was already finished.
I need to practice more on wood on the rotary engraver when I find time.
So much to learn and only one lifetime to learn it.
From: basehorawards [#5]
22 May 2006
To: Harvey only (HARVEY-ONLY) [#3] 22 May 2006
Harvey,
I did read that post. That was the one that Michael got so upset about that he left us. I was hoping someone would say that would work on the aluminum. This customer is one of my few industrial clients and I would like to be able to do anything he throws my way.
I am going to get some aluminum and give it a go.
Thanks for your help.
From: Semi-Accurate Engraver (LONEHAWK) [#6]
23 May 2006
To: basehorawards [#1] 24 May 2006
What you will need:
Medium sized syringe.
small piece of melamine coated wood. (for being very straight and not warped.)
Automotive enamel paint and accompanying thinner.
Smooth flat toilet paper.
1. Make sure your engraving is minimum 12 thou to 15 thou deep. (Deeper is ok if it suits your job). Make sure there is absolutely NO burr on the engraving.
2. Use a car paint (enamel based, eg. Sherwin Williams or something like that). Also, get the same name brand of paint thinner as the paint you get.
3. Use a syringe with the needle point flattened on a grinder so that its end is like the end of tube and not the 45 degree slant end to point they come with. You will also need to acquire a syringe that Varsol or mineral spirits does not attack immediately.
(check your local medical supply store). Even the "tough" syringes are only good for use on that day, by the next day you will have to throw them out; unless you buy a glass syringe but they are more expensive and take a little more skill to use.
4. Thin an amount of paint so that it drips from a small stir stick almost like water. (use acrylic for stir sticks or wood. Do not use cut offs of gravoply as it starts to melt/is attacked by the paint thinner). 60% paint, 40% thinner usually works but you may have slightly different results. The important thing is that the paint "flows" out of the suringe nicely and into the engraving.
5. Filter the paint into another jar with a fine mesh paint filter. (the paper ones you get from any paint store will do). This is important for a smooth finish when paint dries.
6. Fill the syringe about half way with thinned paint and carefully fill engraved areas. (this will take a little practice to get used to but not much). Don't worry too much about over spill as the next step will fix. If you get any large blobs of over spill, squeegee it some with some small pcs of bristol board type paper so it doesn't dry as a blob. Any thin overspill is ok.
With automotive enamels, you can even let the paint dry overnight and clean the next day. The engraved areas should be filled at least 3/4 to the top. (approx.) Less than that and you will get "bare" spots in the engraving, once it has dried, because the paint has been thinned.
For Clean up:
1. Cut yourself a nice peice of 1/2 inch melamine wood about 5" x 3 1/2 " (Approx.)
2. Wrap it smoothly a few times with some very smooth toilet paper. Not the kind with "quilted" or "lot of absorbing cushions" etc. Smooth and flat as you can find.
3. After the paint has dried (with enamel-based car paints you're usually good after about half an hour to an hour) wet one side and slide it over the engraved area to be cleaned. Use very slight pressure, do not "push" down hard. Just very slight pressure is all you need. Slide the "cleaning block" over once or twice then unwrap a layer of paper and repeat till clean. The paper must be fairly "wet" , if it is not wet enough with the thinner it will actually just soften and want to draw out the paint. This step is why no burr on the engraving is so important. The paper will shred if there is any burr.
4. Let dry again for about 20 minutes.
This may seem like a difficult process when it's all typed out and read like it is here; but after you get the hang of it, it goes pretty quick. The results (specially if you have the right kind of automotive enamel) are awesome!
We fill all our engraving into metal this way and have taught a few other companies how to do it as well. The reason we use automotive enamels is we've found they dry very hard and seem to last the longest.
Tremclad can be used the same way with 2 big exceptions. First you thin it with Varsol as it's a varsol based paint. Second and VERY important, you CANNOT clean it the next day. With tremclad, once you've filled the plate, clean it up no later than 3 hours later or you will have an extremely hard time getting the paint off without using actual paint remover solvents.
Make sure--if you store the paints you thin down for repeat jobs-- to store in good jars with great seals so they don't get skins or dry out too fast. Again, tremclad will develop a skin in a very short time so store it for maximum a month or so then make new batch.
In this way you will never need to worry about masks of any kind. This is just the way if you have intricate engraving or other situations where a mask isn't gonna work well. Spaying the engraving with automotive lacquer-based paint, then cleaning with lacquer thinner with the "cleaning block" method above will work in a lot of situations too.
Lacquer will not attack anodizing or hard coloring. Not sure about all, but most other finishes it will or may attack.
Good luck and agian, I hope this has been a help to some.. :-)
EDITED: 23 May 2006 by DGL