Colorfull coasters - The Idea

[Kimb0]

Hi

I have an idea and want to know from the craftsman out there if it will work please

I want to engrave a coaster and fill the engraved area with acrylic paint, the problem is there are a few colors so i thought to engrave the fist color, take it out paint it and replace the coaster and go to the next color, to prevent charring of the edges i thought to cover the coaster with masking tape before i start

The problem i am having is how do i replace the coaster on exactly the right spot for the next colors, maybe a small piece of wooden dowel in the center in the reverse side and a hole in the waste board were the dowel will fit, and when i am done just sand the dowel flush. What do you think?

[kibodwin]

I have done something similar... I engraved the whole design as deeply as I could and then masked off the parts I did not want painted the colour I wanted, painted, masked off the painted part and any other part not wanted to paint and continued. It would depend on your design though. when finished painting, sand and seal.
Worked ok as I only wanted different coloured letters...

[ggallant571]

Alignment brackets and homing'/limit switches get the laser to a fraction of a millimeter. What medium are you etching?

[Kimb0]

ggallant571 i am working on plywood

[ggallant571]

For my less than successful tries:
  1. Stained and sealed the surface prior to etching. Keeps the soot from settling on the work surface.
  2. Applied a layer of brown masking tape (blue does not burn).
  3. Split the image into individual burn colors.
  4. Used a strong directed air stream.

Painting is one of my many weak suits. Zero skill is pretty close to most accurate. This applies to both brush and paint so it is likely that the poor finished results are due to that endeavor.

I did try to regulate the burn intensity to minimize the char. This also reduces the depth of cut. Did try a low power pass to just burn the tape. Perhaps multiple burn passes would help.

One of the problems I had was removing the tape. Especially when the width was small (< 2mm).

I am willing to try almost anything relative to laser etching and have a few images that might be good candidates. Please post you progress and feel free to ask questions. There are some pretty talented artisans on this forum who supplied me with lots of assistance.

[Kimb0]

Thank you ggallant571

Yea me and the brush is not very good friends, well we have not met before but i hope we can work together

I will post, the laser should be here tomorrow, then is is building and setup, then hopeful by the new week i should be up and making new friends.

I sat last night and saved all the different sections with the same color in the same bmp so that they can be engraved at the same time

I will post here as i progress

[nc]

I am doing this by:

1) Putting "paper tape" to mask all the surface / be aware of poisoned air from the glue! I have separate room, filtered by active carbon air cycling system.
2) Lasering just in "OUTLINE" mode based on vector graphics in PDF / DXF.
3) Unmasking & remasking parts for paint applicated by spray.
4) Painting by spray colors.

By this you will avoid to put it under laser more than one-time.
Its almost impossible to aim the laser (or any other CNC machine) once you touch the material.

I've build up some simple "shaped tools" for some situations when I need to be as closest I could to the original position of material.
But its because I combine routing/milling with laser engraving so on final product the common difference of 0.5mm (best achievment i have) is between line of laser and the edge of material which our human eyes does not detect so easily.

Usualy if you want multicolor on wood / you will do it by decal printing technology - much more cost effective way.

There is one other way how to achieve very nice result.
Its based on chemical proccess of toner.
First you printout reflected image on LASER PRINTER.
Than you apply the paper printed side down on the wood and put some pretty aggressive chemical on the upper side (backside of the print).
After some time and layers of this chemical, you "just" scratch out the paper by some knife carefully (very time consuming)

Toner is transfered by chemical on the wood and stays there.

Very nice solution for large pieces!
I've found some people doing this, but here in EU, the chemical is sold only to subjects with special licence, so the final product is a bit ilegal.

nc

[ggallant571]

@nc - Are you burning the wood or just cutting the mask?

[nc]

@nc - Are you burning the wood or just cutting the mask?

Both at once. Mask is the paper tape. There are just black lines in the wood. Easy to remask by tape again + almost unable to cover by paint.

[ggallant571]

If I understand correctly, the dark burn line will outline the paint. Do you have any sample pictures?

[Kimb0]

FFS .. I forgot today is a public holiday, so the waiting for the courier continue

[ianchia]

John Trotto (forum member @jtice) shares his secret sauce for his painted laser engravings on YouTube here:

https://www.youtube.com/watch?v=DkAlnwfDCzY

His tips and a jig that holds your coasters in place for accurate registration on separate engraving passes should be what you need.

Best,

- Ian

[Kimb0]

Hi Ian

Thank you, that vid is the one that gave me the idea at the start

[nc]

@Ian - thank you for reminding me who should I thank to again and give credits for this knowhow
@Kimb0 - original thread where the Jtice's secret was shared with us / https://benboxlaser.us/index.php/topic,786.45.html

@jtice - thank you again! 

[Kimb0]

Thank you nc

he courier was here today so i am building at the moment, i recon tomorrow my friendship starts