LaserUser.com Forum (formerly RDWorksLab)

Hello,
i have a little bit problems with cutting acryl, after i spray painted it.
When i cut the Acryl without color, there is no problem, but after i have colored it black and cut it,
i have always a flame where it cuts.
The problem is, the flame burns the color at the Acryl.

What can i do against this?
More Airflow thru the laser ( where the lense is located )
More speed and power, less speed less power ??

Have you any good expieriences with that?

Thx
Matthias

I'm not sure if this will be helpful, as my method is a type of reverse of your project.

Consider to use a glue stick (Purple Elmer's glue stick from 3D printing) to coat the surface of your work after it is painted. The glue stick is used because after about four coats, it serves to protect the surface, yet washes off easily with hot water.

You would want to create a test piece to determine if this will work for you and the glue sticks are not very expensive and should be easily located in the school supplies area of many stores.

I say this method is a type of reverse, because I use the glue stick before I engrave, then apply acrylic paint to the engraved areas. After the paint is dry, washing the glue stick removes any deposits and over-marking from the paint.

For your project, the glue stick may not prevent the flame, but if applied in multiple coats (I use four to six) with dry time between coats, the glue should prevent the discoloration.

Thanks a lot for this Idea. I will try.

Is the Flame normal ??

Matthias Roschk wrote: Sun Jan 19, 2020 Thanks a lot for this Idea. I will try.

Is the Flame normal ??

I've not had any flame when engraving painted acrylic. Does the paint have metallic flakes in it (like automotive paint)? Is the paint properly cured?

I have done an experiment where I painted white acrylic with dark brown Krylon (brand) spray paint. Then I lasered off the paint to reveal the white underneath. There were no flames. But I didn't have to use a high power because I was engraving, not cutting.

You could try masking over the paint (using masking tape) before cutting / engraving.

Hello,

on engraving i have no flames.

BUt on cutting the painted material.
Maybe you are right and the color spray has metallik flakes in it, but i dont know.
I have coverd a test piece with Frog-Tape and then it works perfekt.
The anoing work comes after that .. pealing the frog tape from the little pieces

Can you try to CUT a black spray painted 3mm Acryl ?
I cut with 10mm and 65-70%.

Matthias