Author Topic: etching slate  (Read 444 times)

donwatson

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etching slate
« on: September 23, 2020, 04:17:54 AM »
I am trying to etch a piece of slate and it cuts a groove fairly deep. It doesn't show a white etch like I see on this site with pictures from the regular engravers

ggallant571

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Re: etching slate
« Reply #1 on: September 23, 2020, 08:07:11 AM »
Not all slate is etchable. I have 4 boxes of grey slate (free) that are immune to the diode.

I typically use at least 3 pixel wide lines.

Are you doing an outline? Try raster filled image.
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donwatson

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Re: etching slate
« Reply #2 on: September 24, 2020, 02:07:25 AM »
Thanks George,
I have completely lost the plot and and have been too long away from the engraver.
I did this etch yesterday and it cut pretty deep but not what I wanted. I will have another go today (after advice from Zax) and will get it right.
take care
Don W
EDIT Pic_3 I have a vector outline that gives a nice neat outline and looks deep, I then enable Sketch (Filled) with a 0.2  gap in the Advanced Menu. and have run 2 passes in raster. This is what it looks like. This is the reverse of the slate so I have plenty room to trial my efforts. It doesn't seem to be very deep, just rough ?? and I would like to see it lighter coloured to match the picture on the front.
EDIT 2 I think the slate may not be slate as I think it is melting the stuff. It cuts a fine vector line deep enough but then when I raster it it seems to melt ??
Don W
« Last Edit: September 24, 2020, 11:08:20 AM by donwatson »

donwatson

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Re: etching slate
« Reply #3 on: September 26, 2020, 02:30:37 AM »
I have finished trying what I can for the moment. I don't seem to be getting anywhere with this. I have attached the last 2 pics of what I have done. Pic_03 is the various results from an outline burn and various number of raster passes and Pic_05 is the result of trying to paint the design with white acrylic paint. I will give it a rest for now as I don't seem to be getting anywhere with this project.
Thanks for looking.
take care
Don W

ggallant571

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Re: etching slate
« Reply #4 on: September 26, 2020, 06:45:24 AM »
Not all slate reacts nicely to diode lasers. I have 3 large boxes (free to me) of gray slate that is immune.

Sealing the surface first helps improve the contrast. The coated slate appears darker while the burn is more gray. I suspect the difference fades with time.

Post your source file and I will take a peek.
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donwatson

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Re: etching slate
« Reply #5 on: September 27, 2020, 02:10:06 AM »
Thanks George,
The man is coming to see the results today. It is no fault of mine that this has not worked too well The material is NOT slate, it is reconstituted slate i.e. a mix of ground slate and resin. He can decide if he wants the results as is or take the piece away.
Strangely enough I had a call from someone, just this week, asking if I would etch a piece of slate with a Celtic Cross ??. I told them about the difference between the slate options and have not heard back from them.
Thanks for the offer to look at the setups, I think the piece is 380 x 255 with a picture on it and the etching needs to be restricted to a space at the top and the bottom. I run the raster twice and then the vector to make sure it's tidy, not sure that's the best way to do it.
Thanks again
Don W

ggallant571

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Re: etching slate
« Reply #6 on: September 27, 2020, 08:14:55 AM »
Don,

There are a lot of 0.2mm burn line segments in the james_watson_raster.nc file. The resolution is also set at 0.2mm. I don't know the algorithm used by T2 to convert image resolution but I find that 0.1 works better on slate. I also find the the minimum line length needs to be 0.3mm.

If it is possible post the source art work. James Watson any relation???

George
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Zax

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Re: etching slate
« Reply #7 on: September 27, 2020, 08:28:47 AM »
He isn't using an image, it's Sketch (vector) which is then being converted to raster. He could bold the font to help the thin sections or use 0.1  or 0.15 resolution (obviously much slower).

I'm not sure what he is expecting though, as it appears the "slate" is just melting and going dark so probably won't get any better with more overlap.

ggallant571

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Re: etching slate
« Reply #8 on: September 27, 2020, 09:37:11 AM »
I'm not familiar with "Sketch".
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Zax

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Re: etching slate
« Reply #9 on: September 27, 2020, 10:53:21 AM »
Sketch is part of T2Laser, the drawing applet that allows you to do simple text and designs either alone or combined with a loaded image / file.
« Last Edit: September 27, 2020, 10:54:08 AM by Zax »

donwatson

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Re: etching slate
« Reply #10 on: September 27, 2020, 11:04:59 AM »
Thanks chaps,
I have finally caught up.
It is a piece of reconstituted slate (slate dust and resin) and does not etch like slate. It melts the top few thou of the stuff and then it solidifies again.
I have attached a picture of the front where he wants the etching to be placed and he has announced that he would like it to be white ?? the same as the picture.
Any ideas on painting it white 'like the picture' ?? I tried yesterday to etch through a covering of masking tape and painted it white and it worked fairly well but the acrylic paint seeped under the tape in places and looked horrific when I peeled it off.
Thanks for the help chaps.
take care
Don W

Zax

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Re: etching slate
« Reply #11 on: September 27, 2020, 11:23:19 AM »
Etching masking tape may be the best solution but I would use spray paint (several very thin coats). I guess you could try real slate and see if that gives you the desired result.

ggallant571

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Re: etching slate
« Reply #12 on: September 27, 2020, 11:28:56 AM »
If I understand correctly you are adding text to an existing etching, Any idea of the process used to create the originate etching?
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donwatson

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Re: etching slate
« Reply #13 on: September 28, 2020, 02:05:40 AM »
@ggallant571, I don't think the original is etched. It looks as if it is a sprayed on paint finish.

@Zax, I have a friend that customises motor cycles and he suggests masking tape and a couple of fine coats of paint. I will do another trial  etch through masking tape and hand it to him to work his magic. If he is satisfied I know what to do.

This whole project has been a nightmare due to the fact I received the wrong information and material to start with.
Thanks again for the help
Don W