Re: [ATM] Pitch lap

[Guy Brandenburg <gfbrandenburg@yahoo.com>]

This is fairly normal. Gravity will naturally make the
pitch flow to a level position, so you have to FORCE
it to conform to the curve you want.

You will first have to warm it up until it is almost,
but not quite, molten - it needs to be very soft. You
can do this by immersing the lap it in very, very warm
(uncomfortable to the hand) water for a while. Then
put cerium oxide or rouge onto your mirror and press
it down, HARD, onto your lap. This will almost surely
destroy the channels you have made (you did make
channels, didn't you?) but you can open them up again
by pressing them down with a narrow, wet stick of some
sort. I also suggest microfacetting with an onion or
citrus fruit bag. If your mirror is still cold, this
contact will immediately harden the top of your lap.
If your mirror is as warm as the lap, you will have
more time to make things match up, though there will
be more of a tendency for the pitch to stick to the
mirror, which is not fun.

Check the archives for numerous descriptions of this.
Good luck.

--- Cec & Cris <ccabar@bigpond.com> wrote:

> Hi guys
> 
> I just melted the pitch onto my laptool. My question
> is that the pitch came out flat not the shape of the
> mirror. That is there is no elevation in the centre
> so contact with my mirror is not as good as that on
> the edges. Can someone please advise me on this
> please.
> 
> Regards Cristian
> _______________________________________________
> ATM mailing list http://www.atmlist.net/
> 


Guy  Brandenburg
Washington, DC
My home page:
http://home.earthlink.net/~gfbranden/GFB_Home_Page.html
_______________________________________________
ATM mailing list http://www.atmlist.net/