So I'm building my father in law a gun and he is a retired cement finisher.

I want to have a simple cement truck engraved on the mag well of the lower, but no one local does firearms (or has before).   My question is for decorative purposes only how powerful of a laser would I have to have to etch the finish on the lower?   Would etching be enough to show up or look good throughout the life of the firearm? or should I look into physically having it engraved?

If it is anodized a 30 watt CO2 laser (as found in many trophy shops) will do fine.

Most of the white with no depth designs you see on black anodized lowers are done this way.

Do it yourself. Lots of videos on YouTube too.

You probably have most of the needed stuff laying around the house. Tons of people on etsy can make you a stencil.

If the lower was still in the white it would be easy to etch with a battery charger, vinegar and water.

With a finish on it, you'll need to use a laser.  

https://www.youtube.com/watch?v=qTks3y8vu-4

Yeah I figured laser was the way to go. There is local store that does laser for trophies. With the advice above about 30w working for just an etch I'll give them a call and see what they can do.  I've got a couple cheap lowers that I wouldn't care if it didn't work on the first try.

FYI I am an 07 FFL that does laser engraving everyday on guns.  [email protected] for quotes