SS mesh melt: black & white specks

[lmartine]

Hi,

I have two questions wrt the mesh melt that I did last night. I used a SS mesh (304) with 1/2 holes.

1- black specks

I had read on this board that SS 304 flakes but that these flakes can be brushed off the surface. Some of the black flakes are embedded in either the top of bottom surface (see circles in the two pix). I guess I could dremel them out. But I am more concerned with the ones that are embedded within the glass (see squares in the 2nd pix): these are a lost cause and I will have to avoid them when I select the inserts for my plates.

I hammered the heck out of the SS mesh this morning to ensure that all loose flecks are gone. Anything else I should do to ensure that my next melt mesh comes out OK?

2- White specks
I did the melt on a ceramic fiberboard (I had a bad experience with my first mesh when the kiln wash became embedded in the glass...). There are several 1-3 mm diam. chunks of white material. It does not look like glass. These are also embedded and could be drilled out. Are these fiber material? Anything I can do to avoid this next time?

If you look closely (pix 2), the bottom is peppered with white small specks. I do not have access to sand blast equipment. Would a 10 h soak in pickling vinegar (7% acetic acid) remove them all or I need something stronger?

Cheers!

Lucie

[Steve Immerman]

Was this a new sheet of mesh, or mesh that you had used before and cleaned off?

Steve

[lmartine]

Steve,

I had used this SS screen twice before.

I first fired it at 1400F by itself to ensure that it would flake as much as possible. The shelf was covered in black flakes. I then used the screen for my first mesh melt (to 1650F): it did not flake as much and there were certainly no flakes embedded in the glass.

Thus, this was this screen's third time in the kiln. I adjusted my schedule (600 dph to 1550F hold 120 min then anneal slowly) as most of the glass had already melted at 1550F.

Lucie

[Steve Immerman]

Lucie-

The fact that the mesh has been fired before is why you are getting black specks. The first time you use the mesh, it doesn't spall until it cools. By that time, the glass had hardened enough that any black specks just land on the top if the melt and can be brushed away. But, since it has been fired previously, it can spall and drop little bits at any time during the firing process, so some of the bits get embedded in the glass. The only way I have found to prevent this is to sandblast the mesh between firings to remove any loose flakes of metal. This is time consuming enough, that I've resorted to using a new piece of mesh for each melt.

Steve

[lmartine]

Steve,

Which SS mesh do you use? I could not find any here, only galvanized metal. So I ordered SS perforated sheets. They cost approx $30 a square foot, so I cannot imagine using a new one each time ( ).

Lucie

[Steve Immerman]

http://www.clearwaterglass.com/Tutorials/MeshMelt.html

Steve

[Stephen Richard]

Cynthia MOrgan has also published on her blog another way to make a stainless steel mesh. She uses ss rods pushed into fire brick to make the grid. Easy to replace, usually easy to find rod. See her blog Morganica for more information

[Georgia Novak]

Steve Immerman: In your tutorial you say you can use hardware cloth, but the zinc coating if toxic. My kiln is in a machine shed and fumes would not be a problem. Would zinc coated hardware cloth be OK to use? Georgia

[wped-tv]

Those specks get carried to every nook and cranny in the kiln on those hot air currents so make sure you clean well. It only takes one to make you curse.