Ceramic Insulator Glazing Repair
 

On 5/13/2015 10:23 AM, Jeff Liebermann wrote:
On Wed, 13 May 2015 07:59:19 -0700, Jeff Liebermann
wrote:

On Tue, 12 May 2015 10:25:42 -0700 (PDT), Tom W3TDH
wrote:

If anyone has any experience patching the glazing on insulators
so as to prevent them becoming saturated with water I would
appreciate learning how that is done.

No experience, but I would guess(tm) that porcelain sink repair
putting and paint might suffice if the damage isn't too extensive:
http://www.homedepot.com/p/Homax-13-FL-oz-Epoxy-0-04-FL-oz-Hardener-White-Porcelain-Chip-Fix-2-Parts-Epoxy-2164/203086992
(...)

UV cure epoxy is another adhesive that might be worth trying:
https://www.google.com/#q=uv+cure+epoxy
http://www.masterbond.com/products/uv-curable-systems
The stuff is amazing. Smear it on, zap it for about a minute with a
UV flashlight, and it's hard as a rock. My dentist introduced me to
the stuff. There's also UV cure acrylic, but that's not going to work
here. I'm not sure of the electrical characteristics, but if the
chips are small, it probably doesn't matter.
http://www.masterbond.com/properties/electrically-insulative-adhesive-systems


I'm curious about the thickness that can be cured using UV.
If you have an 1/8" layer will it cure through to the bottom?
How thick can you go?
Mikek

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Ceramic Insulator Glazing Repair
 

On Fri, 15 May 2015 10:43:14 -0500, amdx wrote:

I'm curious about the thickness that can be cured using UV.
If you have an 1/8" layer will it cure through to the bottom?
How thick can you go?

It depends on the glue. The clear acrylic is partly UV transparent,
so it will go fairly thick. My guess(tm) is about 1/16" max. The
dentists ceramic had to go on in several layers to fill a cavity. What
amazes me is how quickly it hardens. (I just happen to be at the
dentist's yesterday to get two shallow cavities filled. It was done
in one layer with about a 30 second exposure).

There should be something more definitive on the web. Googling...
http://www.threebond.co.jp/en/technical/technicalnews/pdf/tech15.pdf
This goo looks like liquid or transparent paste. See Pg 8:
"There are many commonly held views regarding ultraviolet-curing
resins. Examples include the view that the maximum curing
thickness of ultraviolet-curing resins is 2 to 3 mm. Under
such circumstances, studies on thick-film curing are
rarely undertaken, and those who participated in the current
study tend to consider it impossible to cure resin with a
thickness of 10 mm... "
The author goes on to claim curing thicknesses up to 30 mm are
possible.

UV15 Product Information
Low viscosity, one component, UV curable epoxy based system
http://www.masterbond.com/tds/uv15
"It typically cures in thicknesses of a few microns to
0.015-0.020 inches in 15-30 seconds or less."
Ok, that's not going to work for filler.

I can dig some more out later. I'm late for an exercise trudge.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Ceramic Insulator Glazing Repair
 

On 5/15/2015 11:37 AM, Jeff Liebermann wrote:
On Fri, 15 May 2015 10:43:14 -0500, amdx wrote:

I'm curious about the thickness that can be cured using UV.
If you have an 1/8" layer will it cure through to the bottom?
How thick can you go?

It depends on the glue. The clear acrylic is partly UV transparent,
so it will go fairly thick. My guess(tm) is about 1/16" max. The
dentists ceramic had to go on in several layers to fill a cavity. What
amazes me is how quickly it hardens. (I just happen to be at the
dentist's yesterday to get two shallow cavities filled. It was done
in one layer with about a 30 second exposure).

There should be something more definitive on the web. Googling...
http://www.threebond.co.jp/en/technical/technicalnews/pdf/tech15.pdf
This goo looks like liquid or transparent paste. See Pg 8:
"There are many commonly held views regarding ultraviolet-curing
resins. Examples include the view that the maximum curing
thickness of ultraviolet-curing resins is 2 to 3 mm. Under
such circumstances, studies on thick-film curing are
rarely undertaken, and those who participated in the current
study tend to consider it impossible to cure resin with a
thickness of 10 mm... "
The author goes on to claim curing thicknesses up to 30 mm are
possible.

UV15 Product Information
Low viscosity, one component, UV curable epoxy based system
http://www.masterbond.com/tds/uv15
"It typically cures in thicknesses of a few microns to
0.015-0.020 inches in 15-30 seconds or less."
Ok, that's not going to work for filler.

I can dig some more out later. I'm late for an exercise trudge.


Your answer satisfied my curiosity, confirming my thought that the UV
wouldn't penetrate very deep.
Mikek

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