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Stephen Hanlon
12-06-2014, 4:21 PM
Hi All,

Just after a couple of tips on clean up of the paint filled signs I have to do. The signs are around 850x300 cnc engraved to 0.3mm deep and then I paint fill with enamel paint. The clean up is getting a bit messy and the surface is not cleaning up to the original state (getting a smudge, stained look). I am cleaning up using metholated spirits (alcohol), but am open to other ideas..

Can you give me some suggestions on the best way to attack this issue.

Much appreciated.

SteveH​

Bill George
12-06-2014, 4:50 PM
Did you varnish or clear coat a couple of times before engraving? I use spray lacquer. Then again after to seal the letters before the color? Mine are of the size I can run through my drum sander to take off any excess paint.

Joe Pelonio
12-06-2014, 5:20 PM
Apply high-tac transfer tape before routing, then paint fill and peel off when dry. The transfer tape will not stick well to unfinished wood, if you are leaving it natural, then sanding after the paint is dry as Bill suggested works.

Mark Sipes
12-06-2014, 5:32 PM
Maybe I read the title wrong but I believe the material is aluminum "anodised" clear. sanding is not an option, is it?

Kev Williams
12-06-2014, 5:50 PM
I've engraved and paint fill a lot of anodized aluminum over the years, but I've never clearcoated any...

Your satin finished aluminum, did you buy it from an engraving supplies distributor, or did you do like me and have a sheet metal shop make it from scratch to order?

Made from scratch can have quite a rough finish, very hard to remove paint from. Most "pre-fab" anodized aluminum is quite smooth, and shouldn't be too tough to remove paint from.

I'm not sure how you're applying the paint? How I've always done it is to brush it in, then squeegie off the excess so only a thin film of residual paint remains.

How we clean up afterwards: First, you need some old- or new- 100% cotton sheets. I still have about 3 queen-sized-beds worth of old sheets my mom stored away for years. She saved them just for this purpose.

Second, an eyedropper jar filled with denatured alcohol.

Next: I have a chunk of plexiglass, 1" thick x 2" x about 7" long. On one side I have fully taped to it, a 1/16" thick piece of dense shipping pad. The others side is plain and smooth. All edges have been sanded just enough to remove the sharpness. What you do with the plex, is to tightly wrap, with your hands, about a square-foot piece of the cotton sheet around it. This is your 'paint removing pad'. Depending on what you're removing paint from will determine if you'll use the padded side or the hard side. You'll have to experiment. It's basically just a sanding block with a sheet around it. I'm sure an actual sanding block would work too! (I just have a lot of old plex around here)

Now, take your eyedropper and dribble about 5 or 6 drops worth of alky on the face of the pad, pull the sheet tight, then start scrubbing off the excess paint. The paint on the surface should come off, the paint in the engraving should stay put, because the cotton is smooth enough to not dig-down into the engraving. The alky will dry out fairly quickly as you work and the sheet will pick up paint, so you need to reposition the sheet on the plex as you go. You may need more or less alcohol, you'll figure that out as you go too. Nice thing about alcohol is it's slow to break down the paint within the engraving, so usually, you can get the cotton pretty wet, if it helps.

You can also use stronger chemicals-- naptha and mineral spirits work better and faster than alky, but they quickly break down the engraving paint, and sometimes the scrubbing will pull paint from the engraving and make things worse. If you use water based paint, Windex can usually be used to clean up afterwards, or alcohol.

If you need something with more "give" than a hard sanding block, we use those black 'sponge' sanding blocks from Harbor Freight. They work real well on certain items, because you can really tighten the sheet around them. Just be sure all the edges are covered!

And don't throw the sheets away when you're done. Run them thru the washing machine. They can be washed and reused several times before you need to throw 'em...

Stephen Hanlon
12-06-2014, 6:41 PM
Hi Kev,

Thanks for the reply.....The 1.6mm aluminium sheet is cut to size from a 2.4mx1.2m sheet and the finish does look to be rough. That is the issue that I am having, the paint looks to be staying in the fine grooves. I am running test pieces using enamel and acrylic paint and have tried acetone, alcohol and other bits and pieces to help, but no great luck as yet.

The method you outlines above it pretty much the same that I use for all of my other engraving, it just seems that this material is giving me issues.

I am also going to look at syringing it in, so as to not flood and wipe the whole piece. This may take longer, but will reduce the clean up time.

Bill George
12-06-2014, 10:24 PM
My Bad I miss read as being wood, could not see how you could have paint bleeding on aluminum anyway,

Mike Null
12-07-2014, 10:41 AM
I think I would try the transfer tape and squeegee it on then roll it after engraving but before painting. The engraving is very shallow so that may be contributing to the problem.

Kev Williams
12-07-2014, 9:14 PM
Paint is extremely hard to get out of sanding marks. Sounds like you're doing everything right. If Acetone isn't cleaning the surface, that's a rough surface! If you haven't tried mineral spirits, you might give that a shot...

I've found for rough surfaces, Rustoleum water based acrylic is easier to remove than thinner based enamel. It dries quickly, and as I mentioned above, Windex -or Fantastik- using the cloth n' block trick works quite well, as long as the paint is dry but not fully cured. Alcohol works better after that. Maybe an alky-windex mix might work. Anyway, I just know that enamel will be extremely hard to remove from a rough anodized surface.

If you haven't finished all the engraving yet--- try waxing the material with some kitchen wax, or pure paste wax before engraving. It will create a buffer between the paint and aluminum and may make paint cleanup easier (sometimes it helps, sometimes not so much)

And finally, if you're going to use the syringe route-- I've never been able to paint worth a darn with a syringe unless it's BIG engraving, I can never 'regulate' the paint flow, I always end up overflowing the paint out of the engraving. And the air bubbles, I always get air bubbles!

What I use is round wood toothpicks. I take a round toothpick and slightly sand the end, making it slightly bigger, nice & round. You must make the tip bigger, the paint won't come off a sharp pointy tip, it just hangs onto the thicker wood above. Size the tip of the toothpick to fit what you're filling, bigger end for larger areas, etc... takes a little practice. I have about 4 different sized toothpicks all ready to go. To paint, dip the pick about 1/8" into fairly runny enamel-- you want it thin enough to come off the toothpick and flow out when you touch what you're painting, but thick enough to stay ON the toothpick until you do... Carefully touch the tip into what you're painting, and the paint will leave the pick and fill the engraving. Yes, it takes a lot of dipping, but not that bad, especially when it works well. I've painted engraving this way for years, and, I use a lighted magnifying glass, it really helps. With a little practice you'll find you can paint fairly quickly, and you'll have hardly any cleanup at all. And the cleanup time saved helps cancel out the extra time spent painting...

Scott Shepherd
12-07-2014, 9:53 PM
Kev, have you ever tried the paste type acrylic paints instead of the liquids? After using it, I avoid liquid at all costs. The awesome thing about it is that it shrinks a little when it dries, so you can take a business card and spread it into the engraving, then, as it dries, it shrinks below the surface slightly, which makes clean up nice.

Bert Kemp
12-07-2014, 9:59 PM
Scott do you mean the the tubes of acrylic paint, I just ordered some from amazon, I would normally have gone to Hobby Lobby or someplace but I needed a few bucks more to get free shipping on some stuff.


Kev, have you ever tried the paste type acrylic paints instead of the liquids? After using it, I avoid liquid at all costs. The awesome thing about it is that it shrinks a little when it dries, so you can take a business card and spread it into the engraving, then, as it dries, it shrinks below the surface slightly, which makes clean up nice.

Scott Shepherd
12-07-2014, 10:18 PM
Scott do you mean the the tubes of acrylic paint, I just ordered some from amazon, I would normally have gone to Hobby Lobby or someplace but I needed a few bucks more to get free shipping on some stuff.

Yes, Bert. I can't believe how long I fought with the liquid paints. I love the tubes of acrylic paint. Start collecting business cards everywhere you go because they work great to squegee off the excess paint. I have stacks of business cards I use for that. Once the paint dries, a little DNA on a paper towel works great. Not so much in this case, because it's a rough surface, but it general, it works great.

Bert Kemp
12-07-2014, 11:25 PM
Cool I mostly try to fill baltic birch, not that I do a lot of it. I clear coat sand clear coat again sand mask engrave paint , clear coat a final time . Even with 2 coats before I paint I still get some bleeding into the fine grain, maybe the paste paint will be better.


Yes, Bert. I can't believe how long I fought with the liquid paints. I love the tubes of acrylic paint. Start collecting business cards everywhere you go because they work great to squegee off the excess paint. I have stacks of business cards I use for that. Once the paint dries, a little DNA on a paper towel works great. Not so much in this case, because it's a rough surface, but it general, it works great.

Scott Shepherd
12-08-2014, 8:55 AM
I can't speak for paint filling baltic birch, I don't do any of that.

Kev Williams
12-08-2014, 10:57 AM
I'll have to give the tube paint a chance- back in the old days my mother and sister did all the painting, and they had tube acrylic paint, but never used it. Probably because it didn't work well for what they were painting and their cleanup method. Because of that I've never tried the stuff. I'll have to pick some up and see how it works on certain parts. Like rough matte finish 2-way radios f'rinstance ;)

Business card squeegie, they work good, but I like something a bit more long-lasting. I've tried a lot of things as squeegies- Bondo spreaders, engraving plastics, old credit cards, they all work real well, but the edges always wear down quickly. What I found that never seems to wear out: those gold colored "premium" vinyl sign squeegies. I don't know what they're made of, but we're using some going on 5 years of vinyl sign and paint squeegie duty and they just never wear out. They're not very pliable, so they maybe don't squeegie quite as well as some other items, but real close. And their no-maintenance longevity more than compensates...

My all time favorite-ist squeegie: the phone book. Tear off the cover and keep it on your paint table. For small, flat engraved parts, like 3" square or less, just gob on the paint, then turn it upside down and swipe off the excess across the phone book. You'll be left with only a slight smear to clean off later. Just tear off the pages as needed. And-- when the same parts have dried for a few minutes, start a clean page and drip a couple of drops of DNA or mineral spirits on the top half of the page. Now "wax on" the part across the page from top to bottom, from wet to dry. Done. Depending on your parts you can do several per page. Just add drops and/or change out pages as needed. Works like a charm, BUT-- certain paints work better than others, some don't work at all. I've found some enamels are like snot, and smearing across the phone book just pulls the paint out of the engraving as well. Find paint that stays in and cleans up well. One 2" thick phone book will last for years! :)

Here's one of the squeegies, the wife & I have been using this one for at least 3 years, and I've never trimmed or sanded the edges...

301804301805

Bill George
12-08-2014, 11:14 AM
Gee, almost afraid to post since its aluminum instead of wood.

But anyway go to your nearest discount auto supply store and look for the plastic squeegee/ putty / applicator/ knife they use for applying Bondo or body filler. You can always cut down the larger size to make smaller ones.