Acrylic Engraving Colour Fill - Best Results?

Almurray42 · August 14, 2022, 8:35pm

Hi All,

I’ve been trying to achieve a Decent colour fill on my Acrylic Engraving, but can’t seem to get it right, Just wondering what people have found that works the best? I have done some searches and looked at old topics but can’t seem to find the answer I need…

Material Specs: Acrylic (Cast) 3mm - Engraved Shapes/Text

What I’d like to achieve:

A Colour Fill of engraved text or shapes that leaves a Glossy finish flush with the surface of the rest of the acrylic.

Already Tried:

1: Nail Polish

First thing I tried was Nail Polish, which worked surprisingly well, but I Learned the hard way that cleaning off the excess with Acetone was not a good idea as it cracks the acrylic - Lesson Learned, Should have done my research!

2: Spray Paint
Second thing I tried was spray paint - This was OK, but the paint doesn’t properly penetrate fine engravings or lines.

3: Water Based Acrylic Paint
I then bought some water based acrylic craft paint and tried to use this. I Masked the piece using application paper (Masking tape) and then engraved through. I flooded the engraving with the Acrylic paint and waited for it to dry. Unfortunately, I had slight bleed and also found that it would crack/pull out the infill… AND it must shrink as it dries as it wasn’t as flush as when applied.

I also tried Acrylic paint without using mask, by flooding it, scraping excess while wet and then cleaning the remainder with a damp cloth… This seemed to pull the paint out of the engraving. This also left a dull (Not glossy) finish to the coloured infill.

So, Has anyone found a tried & tested method to colour fill with High quality results on acrylic?

I’ve heard of Oil based enamel paints, 2 part epoxies & Colour Tint etc etc and there are also places that sell what they claim to be an acrylic colour fill paint… but I want something that is readily available and not massively overpriced.

Look forward to hearing suggestions and seeing results! Thanks in advance.

Kind Regards;
Al

jkwilborn · August 15, 2022, 12:26am

along with rubbing alcohol are solvents to acrylic. It will just get worse looking over time.

This is going to be the issue, I think. I haven’t seen anything that will get into the lines, that will harden and you can easily wipe off the acrylic.

I lase off the mirror coatings and usually paint the back of them. The paint never looks like the side it’s spreayed on, I believe it’s the ‘rough’ glass the lasing leaves…

Good luck, I’ll be watching…

zaxes · August 15, 2022, 6:35am

Engraving speed and power (wats) ?

Almurray42 · August 15, 2022, 8:53am

Ha, Yes - I have also used Isopropyl Alcohol to clean and this seems ok, but maybe I should avoid this if it will cause surface blemishes/cracks over time? Thanks for the heads up.

Ultimately, it doesn’t have to look “As Good” as the polished acrylic surface, but at least nice & Flat.

Will definitely be posting updates here of what I try & Results!

Al

Almurray42 · August 15, 2022, 8:54am

Using K40 At 150mm/s & 25% power

Edit: and 0.08mm Interval

zaxes · August 15, 2022, 6:53pm

The low speed does include excesses forces in the material, and cracks appears with the time. I engraved the acrylic with speed 500, 50 watt power, and 0.1step. After that, whatever paint from your above, i used spray acrylic paint. Here is the result.

jkwilborn · August 15, 2022, 8:06pm

These are acrylic ‘condiment’ cups. Purchased at the same time. I used the one on the right with isopropyl alcohol, it was in there less than 20 minutes. The cracks started appearing the next day and grew. Took over more a week for it to subside…

It hasn’t leaked, but you can see the cracks appear to go all the way though.

Almurray42 · August 16, 2022, 4:22pm

Well, I’d better stop with the IPA.

I think I need to get myself some of this Stuff, Antistatic and apparently very good for acrylics, anyone used this?

Almurray42 · August 16, 2022, 4:23pm

These look great! Did you pre-mask then peel after spraying?

I’ll try increasing the speed too.

Almurray42 · August 16, 2022, 4:25pm

Update: I’ve ordered some UV curing Resin, and a UV light… Don’t know if it’ll work but might be fun to at least try! Will post results when it arrives!

jkwilborn · August 16, 2022, 4:26pm

Just thought I’d post what it did to the acrylic. We used to get a meguiars brand polish that we used when I flew sailplanes. Worked great on the canopies.

Good luck

Almurray42 · August 17, 2022, 7:05pm

Update: Tried the UV Resin… Would not Recommend! It stinks, and doesn’t cure anywhere near as fast as claimed even under a very strong UV light! Think i’m going to go back to the Acrylic Paint method, but with some decent quality Paper Application Tape & Some Gloss Acrylic Varnish on top. This time, I’ll actually post some results photos in case anyones interested… If not, well i’m just talking to myself!

jkwilborn · August 17, 2022, 10:02pm

We’re always up for photos…

zooms · August 21, 2022, 3:44pm

At work we made large acrylic racks to hold specialized scientific glassware. They would put the whole thing in the sanitizer that used isopropyl alcohol. They would last a few months, but then would come back with cracking and crazing and would be falling apart. Alcohol, especially with laser cut parts that have stressed edges, can have a severe effect over time. The corners of the finger joints were always the worst. Keep in mind the different alcohols have different characteristics, so ethanol (denatured alcohol) may be less aggressive compared to IPA.

At work we also made signs out of acrylic. We would leave the protective cover on the acrylic, engrave as lightly as possible, then spray paint. It leaves the letters slightly recessed, but looks pretty slick and is super easy. You could try a few coats of filler primer (or even spackle/Bondo) then paint. Maybe even try coloring acrylic resin and pouring that in the engraved area. I’m not sure if that shrinks, or how easy it would be to clean up the excess, but it might be worth looking into (especially compared to UV resin).

carat · January 10, 2024, 10:50pm

Hey @Almurray42 , how did you end up going with your final test?

I’m currently doing to prototyping to try and get a premium finish with a paint fill technique.

The best fill ive found is using an artist quality guache acrylic as its heavily pigmented and gets good coverage. However when removing app tape it sometimes peels out of finer engravings.

I’ve also tried engraving deeper and then screeding on a gesso medium with pain mixed into it to achieve colour. This takes time to dry but is by far the best finish yet except it scratches out I’m going to apply a spray on seal to it today to see if this eliminates it. I havent heard of anyone using this product before so will keep doing some test to see if i can master it as it looks pretty amazing.

If you ended up settling on a technique would you mind sharing?

Most people i know use Posca Paint Pens and it looks pretty crappy. I love that you’re thinking outside the box trying to find something amazing.

Rob_H · January 11, 2024, 6:42am

Hi Cara,
If you want to colour acrylic engravings with metalic paints it might be worth trying wax paints like Rub N Buff. There is a bit of a learning curve to getting a clean finish,but it is very forgiving also. I have found that the best solvent to use to remove the excess is coconut oil. After painting I seal it with a couple of coats of carnauba wax. Here are some of my finished samples;

Cheers,
Rob