Switch to full style
Post a reply

What to do? - Crack in a Natural Stone

Thu Jul 04, 2013 3:26 pm

Hi Guys,

Here's a 20X pic of an Aono Aoto I dropped in the sink a time or two. As gratitude for my fine care, its developed a crack :o

If I leave it, I am fairly sure it will split the stone. I'm thinking if I super glue the seam of the crack, it will likely stabilise the stone and when if I ever wear the stone to the seam, I can use a diamond plate to grind through it so it doesnt interfeer with sharpening.

Has anyone any experience with this sort of thing? Any suggestions?

Image

Thanks

Re: What to do? - Crack in a Natural Stone

Thu Jul 04, 2013 4:16 pm

In my unfortunate experience cracks in natural stones tend to occur from rapid drying of the stone or going from wet to dry too often.

My Monzen recently experienced some rapid drying and nearly cracked in half, I talked with Ken Schwartz on what to do and decided to seal the sides and bottom to help hold the stone together. I should have used epoxy or a better sealant because Shellac didn't work too well. It sealed the stone and looked great until I put it in water which the shellac did not react well with. It seems to be breaking down the coating as it has gone from clear to white and will probably peel off in a few days :(

Re: What to do? - Crack in a Natural Stone

Thu Jul 04, 2013 5:19 pm

I did not notice the crack until this am. Dropped it last week. Am wondering if mine was drying related now. Am wondering if these stones need more care than the synthetics in general.

I did super glue mine. Seemed to work okay. That said, the stones I assume expand and contract, so maybe a more flexible glue would be better. Oh well, will live and learn.

Re: What to do? - Crack in a Natural Stone

Thu Jul 04, 2013 10:07 pm

A tip I once heard recommended is to coat the sides of the stone with lacquer or epoxy (some kind of waterproof sealant), followed by a layer of paper towel, followed by another layer or two of lacquer to create a fiberglass type reinforcement effect. I have personally not attempted this, but I thought it had some logic.

Josh

Re: What to do? - Crack in a Natural Stone

Thu Jul 04, 2013 11:10 pm

Hi Jason, forthosewhotoil, et al,

The Aoto as far as I can see is an inherently soft stone made up of compacted Aoto stuff. As such, I'm thinking its inherently fragile, at least to a klutz like me, so I'm thinking reinforcement as you suggest might be a good plan.

Epoxy would be good. West System 105 / 207 is completely clear.

Am thinking that on top of some cool something might be the ticket.

Options include:

Wood
Carbon Fiber
Fiberglass ( would be invisible under the Epoxy )
Cloth
Fiber ( like manilla, paper, etc )

If you put it on the sides, eventually as one wore the stone, the tops of what ever was laminated would become exposed, so what ever one laminate it with would have to be inherently water proof, or porous enough to be impregnated with the resin so as to avoid rot.

I think Ken had a stone broken in shipping that he stabilized by wrapping it and then mounting it to glass.

What do you think?

Re: What to do? - Crack in a Natural Stone

Fri Jul 05, 2013 12:22 am

Ken and I talked briefly about this a bit back, so he definitely has some experience that I consider valuable. I hope he hops in soon as this is all second-hand information that I didn't take careful note of.

I remember him using something paper-like so you didn't have gnarly fibers coming loose when you eventually flattened the stone down into the reinforced sides. I seem to remember him using marine spar varnish as well.

Re: What to do? - Crack in a Natural Stone

Fri Jul 05, 2013 12:48 am

It's tissue paper that you would use, don't want to use fiberglass as it would release into the slurry as the stone wears.

The crack should mostly close up once put back in water (mine did).

Re: What to do? - Crack in a Natural Stone

Fri Jul 05, 2013 4:33 am

Jason,

Thanks for the reply.

Are you saying tissue paper as in blow your nose paper, or tissue paper like crape paper you might get cloths packed in?

Re: What to do? - Crack in a Natural Stone

Sat Jul 06, 2013 6:03 am

I had a cracked hakka stone. I used some tissue paper (the fairly light stuff used in packing or wrapping) and polyuerethane to seal off the sides and the bottom to reinforce the stone and prevent the crack from getting bigger. I applied about 2 layers with tissue and 4-5 layers of the polyuerethane. Seemed to work OK, but I used some colored tissue paper so I can't really observe what's going on with crack. Also, the polyuerethane seems to peel away from the stone in places along the top surface when I'm rounding the edges with a diamond stone.

I was thinking about getting shellac until I read what Jason posted above.

I read somewhere that it might be a good idea to seal the sides of all your natural stones.

Re: What to do? - Crack in a Natural Stone

Sat Jul 06, 2013 3:26 pm

Heres what I came up with.

Image

I love wood and stone together. Given that I had some very dense naturally oily, read waterproof, wood on hand, I thought how about making bolsters for the stone to stabilize it. When I wear the stone down to the bolsters, I'll hit them with a router to lower them and all will be well..... in theory anyway...... you know how theory goes...... it will probably all fall apart but it will look great doing it :lol:
Post a reply