Sealing slate

Has anyone tried sealing slate coasters? Is it necessary? I hunted around the forum and didn’t see any direct recommendations.

This may just be because of my poor searching skills, I dunno. Please take pity on me if I missed something obvious :slight_smile:

1 Like

I guess there may be a good reason to seal them, but I’ve never sealed my coasters and they work fine. I do use a mineral oil wipe on them before engraving to give a nicer contrast, but nothing afterward. (I use the same stuff you’d use on a cutting board.)

Good effort trying to search it first too! :+1:t3: :slight_smile:

5 Likes

If you want an easily applied, durable sealant, try Thomson Water Seal in a spray can.
Any condensation from a glass will bead up on the surface.

1 Like

Any before and after pictures or with and without images?

1 Like

Got any pix of a mineral oil treated piece?

I wonder if I could do it after the fact? Does the slate feel oily after?

1 Like

No but the image disappears from my experience. I have a really nice black (dark gray) cheeseboard with a hidden image :smile:

4 Likes

You wipe them with oil before cutting? I guess I thought that would cause more burning? I don’t know, it was just something I would not think about.

You do just a thin wipe before engraving. Just put a little bit on the rag, quick swipe and done. It just barely coats the top surface making it a little darker and giving more contrast when you engrave it. If you put it on afterwards it kind of defeats the purpose and would darken your engraving as well.

**Edited to add-- It only takes a very small dab of oil. You don’t want to saturate the slate, just give a light coating. Rub it in well, then wipe off any excess. The tile should be darker, but not slick with oil. The oil will continue to absorb and won’t be greasy in a day or so.

2 Likes

I’m at work right now, but I’ll check to see if I have any non-oiled pieces at home to compare with.

1 Like

I will add that any food grade cutting board mixture works as well such as a beeswax / mineral oil mix. It will coat the slate but doesn’t seal and close off the surface like a synthetic lacquer or sealant would.

2 Likes

Stone isn’t really burned away in the same way wood and other fibrous material is. Stone particles are basically desenegrated by the laser. If you use too much power and the pulverized pieces get too hot, they will melt into little glassy globs that stick to the surface of the slate.

5 Likes

Learn new things all of the time. Thanks for that. I had no idea.

1 Like

That makes sense that it leaves the engrave highlighted against the now darker stone. I’m going to have to try it when I get back (on a business trip).

1 Like

OK, here’s an example. Please ignore the very low lpi crappy engrave as it was just a contrast test. @PFI-Guy

14 Likes

That oiling really makes a difference.

4 Likes

Yeah that’s huge. Next time.

2 Likes

I’ll be danged… It never occurred to me to pre-treat slate (or post- for that matter). Looking forward to comparing straight mineral oil to a beeswax & oil board conditioner. :sunglasses:

4 Likes

Yep, I oiled after and lost the image.

aFu_ComputerUser

8 Likes

Oh cool, you’ll save me buying beeswax conditioner to test. I’m leaning towards beeswax being better than straight mineral oil, but I really don’t have anything scientific to to base that on other than bees are cool lol. Let us know what you find out.

2 Likes

Funny you should say that… i did a first purification run on some wax today!
Here is a 500gm block!

9 Likes