Re: [ATM] Quandry over steel washer tool

["Peter" <peter@kitgear.com>]

Hi Mark,

My 2 cents are...

The washers will wear very slowly because the grit embeds itself into the
soft metal.

As suggested I would also skip the washers altogether and use a cast iron
ring about 1/2 the diameter of the mirror to hog out the glass. You should
be able to hog it out to 75% of the sagitta in about 2 hrs if you can get
some rougher grit such as #36 or 60 grit, 4 hours if you continue with #80.
I would then cast a new tool to match the shape of the glass then epoxy the
tiles to it. Don't forget to add a plastic sheet between the tool and the
mirror otherwise you will never get them apart. That tool should last
through all of the grits.

There are many ways to get a good mirror but that is what I would do.

Feel free to ask as many questions as you want.

Regards,

Peter

-----Original Message-----
From: atm-bounces@atmlist.net [mailto:atm-bounces@atmlist.net]On Behalf
Of Mark
Sent: Wednesday, December 20, 2006 8:16 PM
To: atm@atmlist.net
Subject: [ATM] Quandry over steel washer tool


Started today, a 12" plate blank using a stone tool topped with steel
washers.

Unfortunately, when I made the tool, I didn't realise that the washers had a
bit of variation in thickness.  If
I had, I would have put them on the blank and poured the stone over them.
But, as it was, I made the
stone "blank", then epoxyed the washers to its top.

So now, after 6 hours of hogging with #80, only about 1/3 of the washers are
showing contact and
the blank is not deepening very fast.  Have about 10% of the sag after the 6
hours and the wear
is not well centered.

Should I gut it out and continue?  Should I trash the tool and start a new
one?  I have no more washers but
I do have 1x1 tile...but I've heard that tile is not the best thing to start
a flat blank with.  I do have another
38 pounds or so of Hydrostone :-)

Any help is appreciated!

Mark
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