Engraving through paint on wood

[John Bion]

Recently I have had a number of requests to engrave through white painted MDF, however each time I get a lot of smoke damage, I could mask the entire sheet but would rather not do so if possible. Is there any type of paint that the lasers do not “dislike” as much as others?
Thanks.
John

[Dave Sheldrake]

Less air assist and top extraction John, the air assist will blow fine particulates back onto the surface.

cheers

Dave

[Mike Null]

I would suggest lowering the power and increasing the speed to the limits that it still gets the job done.

I think your problem is not so much the paint as the mdf.

[John Bion]

Dave and Mike,
Thanks for your comments. I had already turned air assist off but top extraction is a great idea, I will have to concoct that :) Why I did not think of that beats me :(
Thanks Mike, I will give that a try, even if it takes a couple of passes it would be worth it.
Kind regards,
John

[Mike Null]

John

Something I do when engraving leather is to use a neutral paste wax on the entire piece. This seems to make cleanup somewhat easier. You might give it a try.

[Matthew Grant]

Smoke damage, or just residue? That fast orange stuff that epilog suggests does a pretty amazing job of removing tar as far as I am concerned. I got it in Lowe's near the tools/sawblades.

[Dave Sheldrake]

For a small diameter extractor (inch or so) try a screamer, they move lots of air and can be moved about easily.

cheers

Dave

[John Bion]

For a small diameter extractor (inch or so) try a screamer, they move lots of air and can be moved about easily.
cheers
Dave

Hi Dave, Do you mean a regular shop vac?
I was thinking of installing a 1/4” flexi-pipe into my gantry for this type of work, the reverse of the air assist :) I don’t think it would be too much of an impediment - but I have not had a chance to stop and try anything today. Your thoughts?

Mike, I wondered about something to give it a clean wipe off too as the type of paint used simply absorbs the smoke right down to it’s ‘roots’ - well smoke damaged.

Thanks again for your help.
Kind Regards, John

[Dave Sheldrake]

Na a screamer John ...sometimes called an Air Mover or Air Amplifier

http://www.brauer.co.uk/acetal-adjustable-airmovers-s263.aspx


http://www.youtube.com/watch?v=E5FOalm-Xo8&feature=plcp

I have them fitted to mine for top extraction if I have to do any engraving, work very well at removing smoke and debris.

cheers

Dave

[David Somers]

Dave,

That looks like some kind of ventuuri effect operating it through the small fitting on the side of your larger tube? I assume you are pumping compressed air in through the small tube? Do you know how much is needed to be effective? Did you make this or is it a commercial unit? Do you know why the sky is blue? (figured I would get as many questions in as I could....! <grin>)

Dave

[Dave Sheldrake]

It is indeed Dave, many different types available and take between 2 cfm and 12 cfm depending on what size is used. Yup compressed air through the inlet tube at between 40 and 100 psi. Nothing in them to block so just clean them by flushing through with water / solvent.

cheers

Dave

[Dan Hintz]

Vortex cooler action... wonder what the temp of the incoming/outgoing air is.

[David Somers]

Cool Dave! That seems like a pretty efficient use of air flow from your compressor? Thanks!

Dave

[Bill Cunningham]

If you you don't want to mask (masking over a clear sealer - two coats with a light sanding between them would be my first choice)use a enamel paint or something like Krylon White, once it's dry you can laser through it, and clean it up with something as simple as Windex..

[Mike Null]

Dave Sheldrake

Can you post a picture of how your vacuum assist is installed?

[Dave Sheldrake]

Hi Mike,


Will do soon as I get into work, I used a tiny screamer, some 1 inch flexit tube and chain link conduit (the same way the Chinese machines run wires along the gantry)

cheers

Dave