My first jnat

It arrived today, the ozuku asagi from Fendrihan. Got home from work, opened the box and snapped a couple pics then had to scarf down dinner so I could take my son across town for something. It's a nice light gray. Whrn wet it gets a little darker and a couple of faint yellowish stripes become apparent. There is a hairline crack along one side. I was thinking I'd try to get some super glue into it before lapping it. Is this the right approach?
ill update as I lap and use it and try to get things figured out

Very nice! My first JNat (also from Fendrihan) is in my PO box for me to pick up tomorrow.

Congrats! I think my JNAT will be here tomorrow! Scared mailman today. I happened to be on a walk when he pulled up to the mailbox and walked through the treeline right behind the box. He jumped and said, you must be waiting for this! And handed me the PIF I won from BroJohn.

Ypu sure it's a crack?

If you cant feel it with your fingernail it should be ok. Nice looking stone! Its a good idea to seal the sides and back with polyurethane, although thats a hard stone and you shouldnt have trouble with it. Lap it and let us know how you make out. I have an ozuku asagi also and with dmt slurry, you would be surprised at how fast it cuts for such a fine and hard stone. Good luck with that bad boy!

Those cracks are normal.. I would seal the sides with 3-4 layers of clear nail polish so water can't seep in .. And then lap away

How long does it generally take to lap a Jnat compared to a Naniwa, for example?

That all depends on how far its off. Some are fast and some take a long time. Pencil grid it and see. I usually start at 60 grit wet dry on granite surface plate in the sink with the water running a little, then 100, 220, 320 600. In that range depending on what I have. If you are using a dmt, dont bother lapping it higher than the grit as it will only scratch to that level.

buca3152 said:

If you cant feel it with your fingernail it should be ok.

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Thanks. I'll check when I get home. It is very narrow.

Nice looking stone! Its a good idea to seal the sides and back with polyurethane, although thats a hard stone and you shouldnt have trouble with it. Lap it and let us know how you make out. I have an ozuku asagi also and with dmt slurry, you would be surprised at how fast it cuts for such a fine and hard stone. Good luck with that bad boy!

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Thanks. I'm sure I'll be back with some questions when I get some time to use it.
I'll get some polyurethane or clear nail polish soon

My advice or the first time is to hone on your highest grit synthetic and generate a small dmt slurry and try to maintain sharp with the slurry. If you lose the sharp after working it, the slurry was too much or not worked enough. After you do that we can work backwards. Then you can smash the slurry with another blade to black and then finish on it for a smoother result. But I think what Im saying will get you used to the slurry and sharp or dull will tell you whats what. Do you have a tomo?

Tomo en route. I was planning to start with a small dmt slurry as you have been trying to advise seraphim. The razor I was planning to use currently has a coti edge but it won't take much to bring it to a very sharp film edge.

If you mean the fissure that the arrow is pointing to - then that is not 'normal'.
That crack started from an impact to the edge. they can stabilize on their own or run like crazy.
Hardness of the stone doesn't matter one bit here - what matters is stuff that we can't see inside the stone.
Can you leave it alone, and will it never cause a problem?
Maybe.
Have I seen cracks like that cause major grief?
Definitely.

If that stone was mine - I'd force as much CA into that crack as possible. I'd seal over all the distractions along the edge.
I'd seal the sides and bottom most likely.
I'd make darn sure the stone was bone dry before sealing, you do not want to seal water in the stone.
Then I'd lap on w/d - prob 320x - nothing too aggressive. The coarser the paper, the more the stone gets aggravated.
Your stone has already been treated roughly - a little TLC now will go a long way.
If you lap judiciously and don't bump the stone too much you may be able to clear that fissure without causing it to run further.

fissures like that are rarely ever stable for long. Sure - some sit dormant forever. Others sit dormant for a long time.
Others wait till you're honing and let go while the razor is sliding over it.

If you are referring the very long angular line on the other side, that's not a crack.

The crack I was referring to is the black line on the other side of the stone, near my hand. I didn't even notice the one your arrow is indicating. I'll check it out when I get home. I doubt I'll get a chance to do anything else with the stone until next week--busy weekend coming up--so it should have plenty of time to dry before I seal it. Thanks for the tips. Any idea if it would help the CA get into the cracks by thinning it with some acetone?

Not sure if thinning it is good, possible, or whatever. I usually use crazy glue in the little tubes, seems to do ok.
Nail Polish thinned with Acetone can work too - you just want somthing there to hold the place still while you lap.
Ca is stronger though.

The line you're referring to, the black one by your hand is Ke-Suji.
Usually, they're sealed at the mine after cutting. Doesn't hurt to hit them with some CA.

Gamma said:

Not sure if thinning it is good, possible, or whatever. I usually use crazy glue in the little tubes, seems to do ok.
Nail Polish thinned with Acetone can work too - you just want somthing there to hold the place still while you lap.
Ca is stronger though.

The line you're referring to, the black one by your hand is Ke-Suji.
Usually, they're sealed at the mine after cutting. Doesn't hurt to hit them with some CA.

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Yeah good call I thought he meant the long crack... Didn't see the fissure

I guess that could be a crack, but it looks like Kesuji on my IPad.

The ?fissure you spotted is there. It looks like a tiny step-off between layers of stone: one side of the line is slightly (maybe 1/2mm) higher than the other. There is no visible gap or crack. The ca I have is all generic harbor freight brand which I think is a medium thickness. I'll get some thin ca and try to get it between the layers along that line and on the side of the stone before lapping--hobby town or amazon here I come. I'll also drip some onto the black line, just to be sure it is also stable.

Preventative maintenence goes a long way.

Sometimes - the crack just runs though. That's the way it is. Depends on how deep, the stone, etc.
Securing it will help - I've honed out a lot of fissures like that though.
I think it'll turn out well.

Nice stone, hope you get to try it soon!

Me too. I enjoy my job, but hate how little time it leaves for other activities. Otoh, this helps keep the AD's in check

Sometimes, having to slow down prevents me from acting impusvely, and it saves me from making dumb mistakes.