Does mr97 really need to be reapplied every firing?

[Shelley Lewis]

Or is the company just trying to get me to use more?
I haven't had the guts to try using a mold twice without removing and reapplying it, but every time I take it off it seems to be perfect and ready for another fusing. Any experience with this?

[Sharol]

It depends on the mould and your top firing temperature. I routinely get 2 or 3 slump firings from one application on most moulds. Inspect the mould for nicks or areas where the MR97 may have been abraded off though before committing to reusing it.

Sharol

[lbailey]

Same here, 2-3 firings if you're careful and don't nick or scuff it. After those firings I lightly brush off the loose dust with a soft brush, blow it off with compressed air, re-apply one thin coat. All outside with a mask on....

[Laurie Spray]

On casting molds I brush it off with a stiff brush and just lightly spray again. We are distributors for MR97 and I am still learning new ways to use it.
One great way I have discovered recently is that if you spray mr97 on your 1/8" fiber paper that you line stainless steel rings with ....you will get very little spiking from the glass on scrap melts. The glass just slides right down. That is especially nice if you do not have a flat lap or a wet belt sander.
Also I am hearing more and more of people using it on small kiln shelves saying that it leaves a great smooth surface on the back of your glass. I am going to try this in the next few days.

[Drewcilla]

Laurie: Just MR97--no Thin Fire or Kiln Wash?

I've been using Thin Fire but have wondered if I kiln washed my shelf and used Thin Fire on top if the backs of my pieces would be smoother. My shelf if big and heavy and I hate the clean up from kiln wash which is why I don't use just kiln wash.

Thanks,
Drewcilla

[Laurie Spray]

As I said....i have not used it on a shelf yet......but Warren Norguaard (who is the glass artist who started the face book page Fused Glass Fanatics) has said that he does use it on shelves and really likes the finish it leaves on the back of the glass. On a new shelf he gives it a double spray....then just a light mist before each new firing load. A 13oz can lasts a long time and it may be cost effective over thin fire. I have 2 very large shelves also and I roll out thin fire for my production work and love it. I am up and ready to load in 5 min. If you are thinking about using it While the shelf is in the kiln I would drape something over the elements so that it does not get on them. Over time it may be a problem. Just be aware and if you want some send me a message!

[Shelley Lewis]

Thanks everyone!

[misteroldhouse]

I use MR-97 for all of my molds and then just a bare kiln shelf with Thinfire for my kiln shelves. I hate the finish that chipped kiln wash leaves on the backs of my pieces... I rarely re-prime the MR-97...recently I draped 18 9" squares over 4 stainless forms...meaning each one was used 4 times and two 5 times. I sandblasted the martini shakers (my stainless forms) and applied a liberal number of coats of MR-97 and had nothing stick...AND the coating is still fine...I'd slump again without applying.

I agree that if the coating is chipped or scratched or if you can see the mold/form underneath, you should reapply, but otherwise, no need.

Larry