advice on engraving process
 

Hi,
Looking for some help on choosing a "paint" for a process to enhance
the contrast of an engraving I am going to make on a slab of wood (say
12 inches by 18 inches). It is going to be a copy of a wedding
invitation. Here is what I plan to do:

-surface the wood (my CNC is not flat enough (0.01 inches) over this
distance to skip this step), probably use a rustic slab of redwood or
redwood burl
-coat the wood with some type of "paint"
-engrave the wood (typically 0.06 inches maximum depth for 0.5 inch
tall letters, V groove cutter with variable depths)
-stain or dye the engraved lettering so that it is darker than the
surface
-remove the "paint"
-sand the surface

I am looking for a "paint" that will seal the surface, barely
penetrate the wood and be easy to remove, preferably by sanding. I
don't want to use a planer after engraving, it will damage the edges of
the letters and additionally, the wood will not be flat after the
surfacing step. I am guessing that a latex paint may work, it won't
penetrate the wood too much and should be easy to remove although it
will clog up sandpaper (no big deal). Maybe some kind of wax? Another
idea is some kind of tape that will stay in place and not shift when I
engrave through it? Another option is to not use stain and just rely
on the contrast of the letters. I have done this so far with my half a
dozen engraving attempts, but I think I want a little more contrast for
this piece since it is all text and no illustrations. Another idea I
have not tried yet is to make a lamination of a dark bottom layer and a
light veneer (say 0.03 inches, close to my practical limit for large
pieces) and then engrave
through the light veneer. My first CNC is not flat enough to pull this
off with a piece this large (I am planning for my second CNC to be much
better).
Thanks,
Jaime

wrote:

Looking for some help on choosing a "paint" for a process to enhance
the contrast of an engraving I am going to make on a slab of wood (say
12 inches by 18 inches). It is going to be a copy of a wedding
invitation. Here is what I plan to do:

-surface the wood (my CNC is not flat enough (0.01 inches) over this
distance to skip this step), probably use a rustic slab of redwood or
redwood burl
-coat the wood with some type of "paint"
-engrave the wood (typically 0.06 inches maximum depth for 0.5 inch
tall letters, V groove cutter with variable depths)
-stain or dye the engraved lettering so that it is darker than the
surface
-remove the "paint"
-sand the surface

Jaime...

You might find the discussion at
http://www.talkshopbot.com/messages/315/4716.html?1111624478
helpful. The topic there concerns CNC sign production, but the
process is exactly what you're after.

BTW, I attached an MDF spoilboard to the bed of my CNC machine
and then used the machine itself to flatten the spoilboard work
surface. AFAICT, my work surface is *flat* over the entire 48x96
table. No reason the CNC can't work on itself...

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/solar.html

wrote:
Hi,
Looking for some help on choosing a "paint" for a process to enhance=

the contrast of an engraving I am going to make on a slab of wood (say
12 inches by 18 inches). It is going to be a copy of a wedding
invitation. Here is what I plan to do:
=20
-surface the wood (my CNC is not flat enough (0.01 inches) over this
distance to skip this step), probably use a rustic slab of redwood or
redwood burl
-coat the wood with some type of "paint"
-engrave the wood (typically 0.06 inches maximum depth for 0.5 inch
tall letters, V groove cutter with variable depths)
-stain or dye the engraved lettering so that it is darker than the
surface
-remove the "paint"
-sand the surface
=20
I am looking for a "paint" that will seal the surface, barely
penetrate the wood and be easy to remove, preferably by sanding. I
don't want to use a planer after engraving, it will damage the edges of=

the letters and additionally, the wood will not be flat after the
surfacing step. I am guessing that a latex paint may work, it won't
penetrate the wood too much and should be easy to remove although it
will clog up sandpaper (no big deal). Maybe some kind of wax? Another=

idea is some kind of tape that will stay in place and not shift when I
engrave through it? Another option is to not use stain and just rely
on the contrast of the letters. I have done this so far with my half a=

dozen engraving attempts, but I think I want a little more contrast for=

this piece since it is all text and no illustrations. Another idea I
have not tried yet is to make a lamination of a dark bottom layer and a=

light veneer (say 0.03 inches, close to my practical limit for large
pieces) and then engrave
through the light veneer. My first CNC is not flat enough to pull this=

off with a piece this large (I am planning for my second CNC to be much=

better). =20
Thanks,
Jaime
=20

Try sealing the wood first using wipe on poly or some other clear finish =

coat (or whatever) Then start your carving, then the painting process.=20
Finally plane sand or whatever.



--=20
Will R.
Jewel Boxes and Wood Art
http://woodwork.pmccl.com
The power of accurate observation is commonly called cynicism by those=20
who have not got it.=94 George Bernard Shaw

thanks for the responses, may try some shellac. The shopbot forums are
also a great source of info as well.
jaime