Russ

One thing you can do to increase your success. Put your dry dry pieces in an oven at then turn it on to 200f for an hour. Then slowly bump the temp up to 250 for a bit and then let cool. This will remove the physical water and give it a better chance to make it thru a pit firing.
Ive also done this on top of a wood stove and had the same good results in both pit and sawdust firings.

One thing you can do to increase your success. Put your dry dry pieces in an oven at then turn it on to 200f for an hour. Then slowly bump the temp up to 250 for a bit and then let cool. This will remove the physical water and give it a better chance to make it thru a pit firing.
Ive also done this on top of a wood stove and had the same good results in both pit and sawdust firings.

Don't forget to put a cookie under your experiments!  Lin

Experiment experiment experiment. Give it a try with many variables and see what works the best. Dont forget to document and mark what was done to each test piece.

Ive used portland cement as a glaze for many years.  Mixing a small amount at a time and using it within an hour works best.  I then fire it to c10 and it looks quite similar to a runny ash glaze.  Portland is comprised of lime, magnesium, iron ox, and silica.
Like Callie said its not something you want to mix alot of because it sets fairly fast.
 

Ive used portland cement as a glaze for many years.  Mixing a small amount at a time and using it within an hour works best.  I then fire it to c10 and it looks quite similar to a runny ash glaze.  Portland is comprised of lime, magnesium, iron ox, and silica.
Like Callie said its not something you want to mix alot of because it sets fairly fast.
 

Ive used portland cement as a glaze for many years.  Mixing a small amount at a time and using it within an hour works best.  I then fire it to c10 and it looks quite similar to a runny ash glaze.  Portland is comprised of lime, magnesium, iron ox, and silica.
Like Callie said its not something you want to mix alot of because it sets fairly fast.
 

The slip has not moved. The color of the brown clay is coming through the slip where it is thin. You need more coats of slip.

If your choices are pottery plaster or plaster of Paris, use the pottery plaster. PoP won’t stand up to the level of moisture and it’ll crumble. 
 
I personally lay a bedsheet over my wire shelves and lay slurry out on that. 

Your handles have lost plasticity due to the drying you are doing. When your pots shrink, the pot shrinks more than the handle but the handle has already mostly dried. I would imagine the cracks are in the same place at the arch of the curve? Try putting the handles on right after trimming the pot, join them with slip or magic water, reinforce join, use you damp finger to pull/shape the handle and set aside for the next one. When done cover all with plastic over bat and then let dry. All IMHO
 
best,
Pres

"Sticky" is an indication that organics are present. A particular kind of humus called Ord is commonly found in natural clay. Ord is many times more plastic than bentonite: which makes clay "sticky." Have you dissolved any in water? If so, any dark particles float to the top? Without pics, I have to assume your "dark" description means dark gray? If so, most likely you have magnetite (iron) in your clay. Magnetite will fire a terra cotta color at cone 06, and turn deep brown at cone 6. Iron disulfide (pyrite) also follows that color transformation. Hematite (iron) will keep more of its terra cotta color at cone 6. Sheering in this case is most likely a lack of fine particle clay: which you indicated it has a sandy feeling. Add 20% OM4 or equal ball clay, and see if the sheering improves. Remember to let is sit 5-7 days after you mix it in; takes a bit for plasticity to develop.
Yes, a sheen can be an indication of vitrification: but it can also occur on the surface from out gassing of inorganic materials. I am making the assumption that is magnetite from your color description. The most common iron source in the USA is iron disulfide (pyrite); which on occasion can be a dark grwy color pending organic levels or other minerals in the deposit. If you fire iron disulfide quickly, you will get a sheen from sulfur off gassing. Without pics, sort of a guessing game at this point.
Tom

My hunch is that there is too much sand in the clay.  I would have suggested you test the clay first before adding that much sand. 
Has the sand been washed? I've never worked with sea sand but I wonder if it adds salt to the clay? Do you know the mesh size of the sand? A smaller mesh would have less impact on plasticity. 
 

Thanks for the tip Rae! I also just invested in a hepa air purifier so hoping that calms me down a little too. My studios usually tidy, it's just because I sleep in what's basically the same room that I've become so concerned. 

We have been using E6000 to attach D rings to wall hangings.  Use a liberal amount of adhesive and let it cure fully before hanging.  In our experience, E6000 has proven more secure than epoxy.

Ive found out thru experience thats its not the glaze fit but rather the clay body that cant handle the sudden temp shock. Thru research and long conversation with Tony at digitalfire we came to the conclusion thatthe clay body I was using had an unusualy high amount of silica.... micro crystalline silica.  A change in the Hawthorn clay ore body prooved to be the culprit.   This led me to completely change the clay body Im currently making and using now.  With the clay body I have now I can take a mug straight from the freezer and pour in boiling water with no detrimental effects...

Put them in the coldest part of your freezer overnight then into the sink and straight away pour boiling water into them.
I just looked at the specs for that slip, it has a posted absorption figure of 2.89% which is high for ware like mugs. I would run your own absorption tests with it, ideally it should be below 1.5% for functional pots that will be used with liquids.
What's your glaze recipe? If it's a low expansion one then that combined with thin walled pots could be exacerbating the problem. Sometimes it's not just one thing that causes a problem but a combination of factors. 

Ive found out thru experience thats its not the glaze fit but rather the clay body that cant handle the sudden temp shock. Thru research and long conversation with Tony at digitalfire we came to the conclusion thatthe clay body I was using had an unusualy high amount of silica.... micro crystalline silica.  A change in the Hawthorn clay ore body prooved to be the culprit.   This led me to completely change the clay body Im currently making and using now.  With the clay body I have now I can take a mug straight from the freezer and pour in boiling water with no detrimental effects...

Ive found out thru experience thats its not the glaze fit but rather the clay body that cant handle the sudden temp shock. Thru research and long conversation with Tony at digitalfire we came to the conclusion thatthe clay body I was using had an unusualy high amount of silica.... micro crystalline silica.  A change in the Hawthorn clay ore body prooved to be the culprit.   This led me to completely change the clay body Im currently making and using now.  With the clay body I have now I can take a mug straight from the freezer and pour in boiling water with no detrimental effects...

Sounds like it's probably clogged up inside. Time to take it apart.

Skutt phone support has been excellent (in my experience); have your serial and model numbers ready.
The wheel head should be solid (zero play) and run absolutely vertically true (less than a .001" of run out).
If you've already tried removing the wheel head and reseating it, maybe try that again in the other position (180 degree turn). Carefully clean and inspect the shaft - the tapered contact portion and the pin; inspect the wheel head's tapered contact and slots; relube with anti-sieze; mount in the direction opposite (per the directions in the manual, "...opposite direction the wheel will be spinning..." ); compare how much the wheel head rotates until lock against the slot (the manual indicates "...about a quarter turn...") is achieved.
Likely you've already done all that.
Please do post back an update 'bus!
My Skutt wheel does run a bit louder than some others, but not by much.
I bought it "used," however, it hadn't actually been used; it quieted down a bit after logging some hours.

Yep an old modified plaster mixer outside and a pugmill. The clay ingredients from my formula are weighed out in proportion and put into the mixer in 100 or 200lb batches and dry mixed for a few minutes then water is added. Clay pulled out and put in 40 gal trashcans and wheeled inside and run thru the pugmill. Pugs of clay are placed in another trashcan and covered with plastic at each layer. Been doing it for years. I once bought a box of clay in the late 80s but none since.

Yep an old modified plaster mixer outside and a pugmill. The clay ingredients from my formula are weighed out in proportion and put into the mixer in 100 or 200lb batches and dry mixed for a few minutes then water is added. Clay pulled out and put in 40 gal trashcans and wheeled inside and run thru the pugmill. Pugs of clay are placed in another trashcan and covered with plastic at each layer. Been doing it for years. I once bought a box of clay in the late 80s but none since.

Yep an old modified plaster mixer outside and a pugmill. The clay ingredients from my formula are weighed out in proportion and put into the mixer in 100 or 200lb batches and dry mixed for a few minutes then water is added. Clay pulled out and put in 40 gal trashcans and wheeled inside and run thru the pugmill. Pugs of clay are placed in another trashcan and covered with plastic at each layer. Been doing it for years. I once bought a box of clay in the late 80s but none since.

Yep an old modified plaster mixer outside and a pugmill. The clay ingredients from my formula are weighed out in proportion and put into the mixer in 100 or 200lb batches and dry mixed for a few minutes then water is added. Clay pulled out and put in 40 gal trashcans and wheeled inside and run thru the pugmill. Pugs of clay are placed in another trashcan and covered with plastic at each layer. Been doing it for years. I once bought a box of clay in the late 80s but none since.

With all due respect I disagree.
Yes, the Daniel Rhodes recipe is an old one; it is also has the benefit of being used for decades with success.
Given that the OP is from Iran one cannot assume they are using materials with the same composition as is available elsewhere.
Recipe for the ^04 wet clay slip I posted above contains 5% talc. Even if the OP's supply of talc contains trace amounts of iron it isn't going to alter the colour of the slip noticeably, far more likely to have the significant amount of iron coming from the ball clay. A zircon opacifier will negate any deleterious effects said iron might impose. 
Porcelain casting slip recipe I developed contains 2% talc. It does indeed act as a flux as my extensive testing showed me. Absorption figures dropped by 0.5% with the addition of it. At ^04 the talc could very well be acting in another capacity than a flux.
If you are referring to the new CimTalc that Laguna is supplying, analysis below.  Silica, magnesium, calcium and alumina, no iron.