kristinanoel

Red iron oxide. It's in about half of my studio glazes. Sometimes it's the main colorant, in others it's used to tone down the brightness of other colorants. No other oxide can make as many colors RIO, it just depends on glaze formula, temperature, and firing method.

Iron oxide is the main colorant in practically every glaze i make.  Rutile would come second not as a colorant but just for the effect it has on glazes. 3rd cobalt ox or carb.

not an oxide but a carbonate, copper.      would someone who is the chemical expert in your area please explain the difference between oxide and carbonate for those of us without your education?

No new questions in the pool, folks! 
QotW: All things considered, What coloring oxide would you not be able to work without?
My favorite oxide over the years has been the most simple. . . iron oxide. I like so many other oxides and their uses, but nearly everything I do has some bit of iron in it. It softens so many other oxides, and works well in washes over and under glazes, and I find it versatile in so many ways that I can not imagine being without it.
best,
Pres

You can boil down glaze to thicken it in a kitchen pot-then apply the thick glaze to get the same results

I JUST tried this with some pieces, know just how you feel.
I was trying to salvage some cups that had crazed - would have just thrown them out but I'd spent a lot of time on an exterior detail and hope springs eternal. 
Unsuccessful Tactics
I tried laundry spray starch and hairspray - neither worked for me.
The glaze kind of stuck to the spray in a patchy way, kind of like when a soup with dairy will form a skin as it cools,  and then it moved around unevenly on the surface, sliding down the sides. 

Tried heating my ware in the oven to 175 degrees and dipping, the layer of glaze that stuck was way too thin.
When I tried reheating and adding a second layer, the first layer came off in places, dripped funnily, and made a mess. 
Successful 
Using commercial brushing glazes actually worked well - they are much thicker and stickier than my own glazes (and probably a little dehydrated, to boot). I was able to add multiple layers - took a very long time to dry, hours, but it worked and did not come off or drip. 
Outcome
While I didn't like the way the refiring came out (I only had a few old glazes I had stopped using for a reason) theoretically, if I'd had a clear or better color, it might have worked. The application was fine and the new glaze fused with the existing glaze and corrected the crazing, I just didn't like the way it looked. 

I JUST tried this with some pieces, know just how you feel.
I was trying to salvage some cups that had crazed - would have just thrown them out but I'd spent a lot of time on an exterior detail and hope springs eternal. 
Unsuccessful Tactics
I tried laundry spray starch and hairspray - neither worked for me.
The glaze kind of stuck to the spray in a patchy way, kind of like when a soup with dairy will form a skin as it cools,  and then it moved around unevenly on the surface, sliding down the sides. 

Tried heating my ware in the oven to 175 degrees and dipping, the layer of glaze that stuck was way too thin.
When I tried reheating and adding a second layer, the first layer came off in places, dripped funnily, and made a mess. 
Successful 
Using commercial brushing glazes actually worked well - they are much thicker and stickier than my own glazes (and probably a little dehydrated, to boot). I was able to add multiple layers - took a very long time to dry, hours, but it worked and did not come off or drip. 
Outcome
While I didn't like the way the refiring came out (I only had a few old glazes I had stopped using for a reason) theoretically, if I'd had a clear or better color, it might have worked. The application was fine and the new glaze fused with the existing glaze and corrected the crazing, I just didn't like the way it looked. 

I put the starch spray in just a dinky plastic spray bottle and then painted on the glaze.  It definitely took longer to dry between layers than normal glazing but nothing crazy. 

Thank you SO much for your response. I really appreciate you laying it out the way you did and being so thorough.  Bummer that you're re-firing didn't come out how you wanted! Those finicky kiln gods.
I tried the heating method also and was really disappointed with the results. The glaze was so thin and it was literally impossible to handle even to wipe off the bottoms because it just smudged off in my fingers leaving blank spots. 
I made a homemade corn starch spray by warming 2½ cups water with 1½ tbsp corn starch, bringing to a boil and then letting cool. I sprayed the pieces all over and it worked remarkably well! The glazes really stuck to it after I let it dry on the pieces. And they also did not smudge at ALL when handled. As long as the re-firing is successful then I think this may be a good method! 

The holes won't affect the firing.

Am feelin' compelled to reiterate...
Material the motor/fan assembly is connected to can act as a sounding board.
The ducts can act as resonator tubes.
A large portion of the noise may be emanating from the intakes and exhaust.
My kiln vent is fairly quiet, however, the secondary system (overhead, for heat and any escaping fumes) is rather loud; I have some ideas for reducing the noise.
Any road, please do post an update with your findings/results OP!

The can handle two kilns, so yes on one kiln they are starved. They work, though. Thousands of these out there functioning as intended...

Yeah, measured on a two kiln setup, they end up starved. They work, just not able to move near their design air because of the high losses on the suction side. This is fine for their design, since all the production motors are externally cooled just generally not good for a fan that cools itself such as an in-line fan.  If you hook up a 100 cfm in-line fan, it will not discharge 100 cfm drawing through a few 1” holes. The dual Orton setup was measured at 14 cfm total discharge on a  100 + cfm rated fan. The inlet size was 3 - 1” holes on each kiln so six 1” holes or about 4.5 square inches. A 4” diameter pipe is about 12.5 square inches so no surprise, a big restriction.  In their defense, they don’t need anymore since airflow through the kiln is way less given a 1/4” diameter hole or two into the kiln.
They are starved because of the inlet restriction, which is fine for their use and design. Not necessarily for a quiet in-line fan that gets cooling by the air through it though.

Mine is really loud as well and I was really bummed about how loud it was,  but as far as bothering the neighbors, i would say there is NO way someone could complain about that level, our HVAC is WAY louder than that and it runs all the time.

Thanks for all of the great advice - my new plan is to find a suitable inline fan motor to swap out, keeping the rest of the apparatus, the collection cup and hose, and see if that is a better solution. 

If you swap for an in-line fan and use the same kiln pickup, the existing mixing box is usually very undersized to let the proper amount of air through the fan. In-line fans are self cooled, you could try an in-line fan rated for dryer booster service to deal with the starved condition, but these are often rated in the 200 Cfm rangę, so nosie and overkill become your issues. This type of fan can be enclosed for noise, but it must cool itself with enough exhaust air. 
When we actually MEASURE the air that can make it through the commercial units its  generally on the order of 1/10 th the fan rating. No surprise since the pickup area is usually  a fraction of the 4” diameter it would need for full flow.. The mixing manifolds on the commercial units are generally too small and therefore do not allow much  room air to enter. This is fine with an externally cooled motor, but an in-line fan needs this to cool itself. Not an issue as long as you pay attention to temperature of the units and folks often find a goof proof easy way to let more room air in. I have seen folks simply install a 4” open T fitting above the kiln  and still get enough suction at the kiln connection to perform as originally designed.

yeah, it's much more invasive than I would have thought!  it's already in the unattached garage, so it's as separate as can be expected. Nobody's working in the building, so the benefit was purely for the ware, not people breathing. 
If I can't replace the fan, I probably just won't use it. I was thinking it'd be good for evening out the temperature in the kiln and providing a better oxidation atmosphere, but there's no way I'd ask neighbors to put up with that noise for hours on end, not to mention that I'd never be able to fire early in the morning or late at night. I (stupidly) hadn't considered the noise factor. Not worth it. 
So bottom line -  anyone considering the envirovent, make sure you take the noise into consideration!

That sounds normal to me.  It's just a simple squirrel cage blower, so not the most advanced  blower technology. When they go bad the bearings wear out and they make a lot more noise than that. I couldn't hear it in the video, but if you're getting any additional noise from vibrations in the wall, you could put it on the floor on a piece of foam to isolate it more.

THIS IS BRILLIANT!
Thanks for the great tip!