A while ago @Brandon mentioned engraving sandstone, and we wanted to try it out! So I run a few tests to see what how it worked.
Short answer…not at all like I expected, but could have some really cool results with the right design.
These are the two full designs that I did:
The top coaster is one pass of the laser with transfer paper, the bottom one is 2 passes with transfer paper. The engraved area actually gets lighter not darker with multiple passes. Which is pretty neat, because that would actually give me a lighter color and a darker color to play with in the design.
After a few tests, it was apparent that engraving it once without any transfer paper got me a nice clean bright engrave, and engraving it once with transfer paper gave me a good strong dark engrave.
So I cut out the ‘inside’ of the flower and engraved it once, and then slapped some tape over it and engraved the outlines. and this is how it looked! (Look at the pretty flower, and not my ugly tests. )
I can’t wait to build a design just for this effect. Fantastic suggestion you guys!!
Yeah! So we paper a lot of our material with good old transfer paper. (It is actually usually used for transferring signs and intricate cut outs from the place where you cut it, to the place you want it to be mounted) It can serve the same purpose as covering the material with tape, protecting the wood/acrylic/etc from any smoke damage.
Thanks. OK. I thought maybe from the description above that the dark lettering/flower parts were somehow a function of the transfer paper. Now after reading it again it seems as if burned carbon from the transfer paper are deposited creating the dark outlines?
Very cool! Thank you. Just what I wanted to see.
Gandalf would not allow so many passes. But you sure did a great job demonstrating technique. Thanks.
That is very cool!
It seems like it is bleaching out the colored oxides and leaving white sand.
Is the white area more powdery that the original surface?
If you scuff it does it come off?
I have a bunch of slabs of “picture sandstone” with really pretty colors, I wonder if the effect would be equal across the different color bands…
So many questions so few Glowforges.
That picture stone should yield some great results based on the coasters.
I suspect you are right regarding mineral bleaching.
It will be interesting to see how the effect changes, if at all across different the colors.
So do you use the opaque transfer paper? I’m assuming you don’t use the clear transfer paper ( for vinyl) which is similar to clear contact paper, but rather the mor “paper-like”( for lack of better description) transfer paper? Does the adhesive affect anything ( or rather does the laser affect the adhesive in any way?)
It’s probably something like this:
I use this stuff for vinyl signs and it’s pretty easy to work with. I have the medium tack variety, but low tack might be better for laser applications–you want the tape to stick to the item, but you also want it to come off really easily.
If you are applying a big piece of tape, it is helpful to buy or make a dispenser, unless you have extra hands.
Not counting shipping, this stuff is about a dime per square foot, at least if you buy the 24" x 100 yd roll.
This is almost certainly the hematite cement (which provides the red color) being converted into other minerals. The actual quartz grains that make up most of the sandstone are probably not being effected. It would be interesting to see how far down this effect carries into the rock and if the cementation is disrupted enough for any of the grains of work free. This is probably not the case as the primary cement is going to be either quartz or calcite, probably quartz though, with the hematite being deposited by fluid flow after lithification (the cementing together of the individual sand grains) of the sandstone. The dark marks are certainly residue from the transfer paper, there’s nothing to oxidize in the sandstone.
Welcome to the Forum, @sociogogue and can’t wait for more of your knowledgeable posts!
Thank you! Being a geologist it’s easy to sound knowledgeable on this subject I’m definitely interested to see what I can do with different types of stone when I get mine!
Thank you for including a link. This is very helpful when you don’t know anything about the product. Prices seem very reasonable too.