PVAc wood glue laser cut

[Marc Pod]

Hi,

is it safe(for laser) to use wood glue containing PVAc(polyvinyl acetate). Epilog says in their manual that you should NEVER engrave or cut any material containing PVC or vinyl. When engraved, a corrosive agent is produced that will destroy your machine.

Thanx
Marc

[Richard Rumancik]

Marc

When it comes to laser cutting, probably 99% of the components produced during the lasering process would be hazardous to your health. To give a definite answer as to what is acceptable and what is not is difficult. To read an MSDS and determine what can be cut safely is also very difficult, as you have to know what concentrations of chemicals are unacceptable. This is not always known conclusively, even by the experts in the field.

PVC is unique in that it decomposes and produces hydrochloric acid, which is bad for health as well as bad for the laser. The acidic vapors, should they get on your lenses, motion components, etc, will cause corrosion.

The PVA (polyvinyl acetate) molecule does not have any chlorine in it, so without being a chemist, I can assume that hydrochloric acid would not be produced. It may very well produce toxic gases (like most materials) but the key with all laser cutting is to ensure you have a good ventilation system to remove the products of lasering so that you are not exposed to them.

The glues used in the manufacture of plywood are probably more toxic than PVA glue, as they often generate formaldehyde gas. Again - ventilation is the key.

Some people on this forum have cut thin vinyl (.003") using their laser. I won't tell you that you should or shouldn't, as you will put your warranty at risk if you do. The logic for permitting thin vinyl seems to be that there is negligible material actually being decomposed. Assuming you have proper air assist, the lens should be protected. Then it would depend on whether your exhaust system can remove the hydrochloric acid vapors without condensation on any machine components. Your ventilation system would be exposed to the gases as well. If the air intake is high enough the actual concentration in the exhaust stream would be small when cutting vinyl.

PVC will actually mark quite well with a CO2 laser (it tends to make a contrasting golden-colored mark.) See the Synrad site and look at the applications info (search on vinyl.)

In the book "CO2 Laser Cutting" by John Powell, he says "The only safe way to deal with PVC cutting requests is to persuade the customer to change to another material." He does not address sign vinyl specifically. Some industrial laser companies do cut PVC, however. Presumably they are set up to properly handle the acidic vapor and neutralize it.