Engrave Shin Guards made of K-Resin and EVA?

Beyond the Manual
#1

Have a friend who wants to put his kid’s name and player number on his shin guards.

The guards say they are 69% K-Resin and 31% EVA. It’s definitely a hard shell. They want to mark on the orange material.

EVA is Ethylene-vinyl acetate and appears to be ok to cut or engrave but I don’t know what K-Resin is made of. I find “SBC” but that’s where I get lost. What is this stuff?

Secondly, if I engrave/score this, what will we even be able to see? Just light cuts in the plastic? What would you fill in score lines with so you can read the numbers? Clearly they’ve done something here with the Nike Swoosh.

Thoughts?

shin-guards
shin-guards.jpg1000×1000 237 KB

#2

http://www.sun-prosper.com/spec/MSDS-KR03.PDF seems to be the location for a (possibly older) MSDS. If that’s the stuff it doesn’t seem to have any obviously hyper-evil decomposition products.

How well it engraves or scores is anybody’s guess, but it’s likely you’d have to go over the areas with ink or paint to get them to stand out. That picture looks like the put a decal on it.

#3

ANYTHING vinyl is NO! It releases chlorine gas which can liquefy your lungs. Don’t do it.

It also will corrode any steel in the machine.

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#4

Vinyl typically refers to PVC, which is absolutely not safe to cut on a laser, but EVA should be laser safe. As always, the MSDS is a more appropriate source than my poor opinion.

#5

It’s the vinyl in pvc. Do not laser anything with vinyl. Ever.

#6

I always thought it was the CHLORIDE in pvc that was a no no. Lots of posts on here of people that have done eva foam on their laser.

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#7

PVC is not laser safe, as you correctly identified. Traditionally, when people use the term vinyl as a product name, it releases toxic gases harmful to people and equipment.

However, vinyl, as part of a chemical name, can be used in products (such as EVA) that are in fact laser safe with proper ventilation; i.e. they don’t release chlorinated gases.

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#8

No, it’s the vinyl.

I will never risk it.

#9

Certainly your call. We all have to make safety decisions for ourselves, and our families, since these are often sitting in homes.

My point was that there are plenty of people that successfully and safely cut EVA.

#10

That statement seems to contradict every discussion I have read on the topic of distinguishing vinyl in itself and PVC with the chlorine added.

Chlorine makes hydrochloric acid which eats up the components of the Glowforge and is fairly toxic to breathe. Vinyl is a combustion hazard and often doesn’t laser well but there has been a consensus that EVA is fine.

Help me understand why you think that vinyl products are all unsuitable.

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#11

So you wouldn’t use your laser to cut any paper glued together with that ubiquitous white glue, PVA ?
After all, that’s polyvinylacetate, and, heaven forfend, it might even have polyvinylaclohol in it.

Truly said that ‘a little knowledge is a dangerous thing’

:upside_down_face:

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#12

Although I’m new to the glowforge, I’ve been into lasers for about a year. I do research a lot. Not saying that the information is always spot on, but the research I’ve done points to this.

http://atxhackerspace.org/wiki/Laser_Cutter_Materials

I also sell mounts for diode lasers on a cnc machine. I’ve been a part of a few laser groups to.

Again, all I can do is give the warning, pass on the information from my research, and have my own opinions. My advice and opinion will always be DO NOT LASER CUT VINYL. that’s all I’ll say on the subject. No angst, just my advice.

#13

Phil, while a fountain of useful knowledge on the inventibles forum is mistaken on this issue. The reason to avoid burning vinyl is that we’ve come to use it typically to mean PVC. After burning, chlorine makes HCl when mixed with the water vapor in the air. It’s highly corrosive.

EVA on the other hand does not make a corrosive gas in large quantities like PVC. It does make some of the same dangerous substances that all of the things we burn do (wood, acrylic) since it is made out of similar stuff.

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#14

And by similar stuff, I mean carbon molecules which vary quite a bit. However, when burnt, you get carbon monoxide, hydrogen cyanide (very dangerous, but in very small quantities), and other organic compounds you don’t really want to breathe in quantity. So vent well to the outside.

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#15

A vinyl record will do the same. It is the vinyl.

#16

Vinyl records are PVC which we call vinyl.

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#17
#18

PVC = vinyl
Vinyl = pvc

Again, I could very well be wrong with the material in the post at the top, but you will never catch me lasering anything that contains vinyl in any form

#19

Yes, vinyl often refers to PVC which is why you should avoid. But that’s English common usage. Vinyl in chemistry does not necessarily mean PVC. And the vinyl in Ethylene Vinyl Alcohol is not PVC and is fine to laser.

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#20

You are correct. I’ve been lasering for years and teach laser operations. But I’m not about to argue with experts on the internet or with people’s varying tolerances for risk. There are other “non-harmful to the machine” compounds as you’ve noted that are the result of lasering but are not especially healthy for people which is why we vent outside. Some folks feel that even a trace of cyanide or formaldehyde or a host of other combustion byproducts are too much exposure and won’t laser them. That’s ok. But that should be a personal decision of acceptable risk vs a blanket statement of suitability.

That’s coming from the viewpoint of someone who has to breathe exhaust-laden city air and also loves the taste of a charcoal grilled steak so my tolerance for bad chemicals may not be normal :slightly_smiling_face:

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