[Things]

Yeah, as the title says, always get this annoying film of residue on the surface I'm engraving, which is a pain in the @ss to remove, even right after engraving. How do you all deal with it?

[SPC-laser]

hey,did you use the honeycomb or blade work table? like the blow picture.

[xabungo]

I wash the acrylic with neutral Soap, dry it and in the borders I clean with Isopropyl alcohol, but can't use too much, just a little.

[Exsecratio]

IPA and a toothbrush Dan,

It won't melt the acrylic but will break the bond between the residue and the main material.

Avoid Acetone,MEK etc, it just melts it

A quick spray with silicon oil before engraving also helps it prevent sticking.

best wishes

Dave

[Things]

Thanks guys. I've been trying engraving with the paper still left on, and it seems to work just fine.

Speaking of acetone melting it, I'm actually trying a little experiment at the moment using it to try glue a few pieces together, interesting to see how it goes. I'm pretty sure the commercial acrylic glue is just acetone and dissolved acrylic.

[LeeWay]

No. Not Acetone. The commercial stuff is Methyl ethyl ketone. MEK.
It is in the Weldon 16 that I use, but doesn't appear in Weldon 3 for some reason. I thought that was the main ingredient it it as well. Here is that MSDS.
McMaster-Carr

[Things]

Wish that Weld-on stuff was available more easily here in Aus, seems like something you can really only order online

I'm glad acrylic is so versatile in a laser cutter though, I attempted to cut some ABS today and it was horrible. Even with ventilation the laser filled up with smoke rapidly, and just the smell from the small amount of leaked smoke gave me one badass headache for over an hour. I then found out it produces hydrogen cyanide - not doing that again!! At least until I can beef up the exhaust fan anyway.

[Awardmasters]

Naphtha (lighter fluid) will clean up acrylic easily and do no damage. It also works on most of the engraving plastics, but should be tested first.

[Exsecratio]

MEK can be used as a glue but in it's pure form is restricted in some countries (you wanna see what it does to your lungs)

Commercial Acrylic glues are a mix of Dichloromethane and Acetic Acid. (the well known PK1 is just that)

Dichloro can be used alone but causes stress cracking on extruded materials, the Acetic acid acts as a binding agent and reduces the cracking (but doesn't prevent it totally)

ABS is nasty, PVC is worse!! it liberates Chlorine Gas as well as a number of other nasties

best wishes

Dave

[Things]

Yeah, not even gonna touch PVC, can turn your machine to a rust bucket in a matter of days!

Wish ABS cut a bit nicer though, many project boxes are made out of it I might try experimenting with faster speeds and lower power, just doing multiple passes to see if I can avoid melting it so much. The amount of smoke it produced was ridiculous, and to think, if I was directly exposed to that, the risk of being killed within minutes!

[wwendorf]

Use denatured alcohol, AFTER the part cools down from lasering. It disintegrates the residue and cleans the surface without any after effects as it dissipates very quickly.

Wade

[LeeWay]

I know what you mean about the ABS smell.
I built a 3D printer and print with ABS sometimes. The smell isn't overwhelming, but something I do ventilate well. I like printing with PLA much better. It has a sweet smell. Almost like caramel cooking.

MEK is the main ingredient in the Weldon 16 that I use. It comes in a tube an is akin to plastic model cement. Vent well with any of them though. Rather than an adhesive, MEK and others are really solvents. They melt the plastic an actually weld them together rather than adhere them. In the #16 stuff, it actually is the solvent with plastic already dissolved in it to make it thicker. It is stronger than the thin stuff because of this. I use this to fill larger gaps too.

For clean up on polycarbonate in the rare event that I need it, I use a product called "goo gone." It works great.

Goo Gone® - 8 oz. Bottle S-18415 - Uline

[Things]

Last night I cut a couple squares out of 2mm acrylic, and used some acetone to try glue them together. This morning the bond is actually surprisingly strong. Being only 2mm and minimal surface area, it's not insanely strong, but for what it is! Actually takes a bit of force before I can see it start flexing.

[LeeWay]

Any solvent that will actually melt the material and evaporate will act like that.
Some better than others.
The actual solvent cements that are available are formulated for best results. Other solvents can work pretty well too.

The thin stuff isn't as strong of a bond as the thicker stuff, but the thin stuff will creep into crevices and go exactly where you want it. The thicker stuff will squeeze out on you. So each type has its uses.
I have a glass syringe with a flexible teflon needle that I use for the solvent type and just apply directly from the tube for the thicker stuff.

[Things]

Yeah, I need to find a little needle to apply it with, it's a pain trying to get a small blob on the tip of a scalpel and drip it into the crack. I found an online place in Aus that has the weld-on stuff, might give that a shot, but not really expecting an insane bond on 2 90 degree pieces of acrylic to begin with

[Bec Weir]

Yeah, I need to find a little needle to apply it with, it's a pain trying to get a small blob on the tip of a scalpel and drip it into the crack. I found an online place in Aus that has the weld-on stuff, might give that a shot, but not really expecting an insane bond on 2 90 degree pieces of acrylic to begin with

Hold off on that purchase Dan.
You may find an extra something in the Post early next week that will do the job.



Bec

[gtoal]

IPA and a toothbrush Dan,

It won't melt the acrylic but will break the bond between the residue and the main material.

Avoid Acetone,MEK etc, it just melts it

A quick spray with silicon oil before engraving also helps it prevent sticking.

best wishes

Dave

I had cut acrylic for the first time today (at the free Fab Lab attached to our local university). The Lab supervisor strongly recommended removing the protective film. I was a bit disappointed that the piece I cut and for about an inch around it was marked with the deposit of burned-off acrylic. When I got home I googled for the problem and this site was the first and most informative hit. So I headed out to CVS and bought a small bottle of Isopropyl Alcohol (after seriously wondering for a few minutes whether you could have really meant India Pale Ale) and tried to clean up my test cut. A light buffing with a soft lens-cleaning cloth and a light sprinkle of Isopropyl was doing nothing; so I made sure the cloth was actually wet by holding it against the neck of the bottle; after a few minutes of more intense rubbing, I now noticed 3 things: 1) the smoky marks were lifting; then 2) the surface was picking up small but noticeable micro-scratches; and finally 3) the piece was starting to develop significant cracks starting on the edges.

So after some more Googling I discovered that "laser-cut acrylic edges are brittle and under a big mechanical stress, and will crack with solvents or alcohol" - exactly what was happening to my piece.

My conclusion from all this is that by the time the work piece has been besmirched it is too late - in future I should insist that we cut any acrylic while still covered by protective film.

G

[fixtureman1]

It sounds like you are cutting extruded acrylic if it has a plastic film

[gtoal]

It sounds like you are cutting extruded acrylic if it has a plastic film

Probably. It was the cheapest sheet I could find at Michael's, which I bought just for an initial test. The label didn't say either way, and I didn't know enough about the material to know that a protective film implies extruded. (I did know the difference between extruded and cast - but none of the sheets available were specifically marked, not just the smallest one, so I could have bought one of the expensive sheets and found it was the same material... I guess the conclusion is to order online and not in a local store...)

[ZASto]

Laser cut acrylic does not like to be touched with any kind of alcohol. IPA is the reason for cracks.