Another Newbie Question

[Oddisgood]

Hello

I've just been looking into handing building a bottle.

I came across a suggestion to use vinegar instead of slip to bond pieces together.

And another to use WD40 to help release a mould.

 

Would neither of these things contaminate the clay or effect glazes later?

[Chris Campbell]

Vinegar added to water is sometimes advised to help bonding ... Don't know if it works but vinegar is cheap and you only need an ounce or so per quart ... So why not? It does not seem to affect much down the line in my experience.

 

As to WD40 ... Well, that is something people advise for everything that sticks in any area of your life! : - )

I would not want it in my clay or on my molds because I really dislike the petroleum smell ... It does not go away.

As to what it does down the line? Others might know more.

[Crusty]

A lot of people use Vinegar in different ways. I keep it simple, i use a toothbrush and water. I rub the brush where i need to attach and it makes slip for me..

 

Im not sure about WD40- it might give you trouble if you under glaze the piece when green... There is a lady that i know that does mould work, she just dampens the mould with a sponge before she uses it..  I would assume it would be safest to bisque it first so the oils can burn out.. I dont think i would use it myself, most clay related materials use water or water based materials..

[oldlady]

i use WD-40 to "release a mold" but not in the way this question seems to be running. W ater D ispersal formula number 40 does have an odor.  i do not have such a sensitive sense of smell so it doesn't bother me.  it does NOT have an effect on the clay because it dries up.  it does NOT prevent sticking of additions,  hurt or otherwise cause problems with adding colors, slip, underglaze or glaze.  i have used it since early 1990 and cannot speak highly enough about its benefits for potters.  i am talking about LIQUID WD-40, not spray-on.   i know potters who use a spray on cooking oil.  that appears really pointless and silly to me.  it is OIL!

 

i use WD-40 to release glass, plastic, metal, any other non-porous shape i have used with clay on top of, inside of, touching in any way.  NOT PLASTER which is porous and will release itself from the clay at some point in the drying stage.

 

it is hard for new people to know enough to ask more questions when they hear something said by a more experienced potter.

 

i wish i could move something from the gallery to here but i cannot figure out how.  in my gallery under POTS you can see long trays drying inside white ceramic trays used as molds.  these were white glazed ware sold in department stores for people to use for food on their tables.  totally non-porous.

[Joseph Fireborn]

I use vinegar exclusively to add attachments like handles and lugs to my pots. You add vinegar, scrape the area, it makes a vinegar slip. Then do same thing for other side then press. Let sit like 2-3 minutes and its firmly attached.

[Chilly]

Like Old Lady says about WD40 on non-porous moulds. I use the spray stuff, works fine.  I've even recycled clay that was covered in the stuff after unsuccessful stamping and there was no effect.  Never get it near plaster moulds though.

[LeeU]

I use the original Murphy's Oil Soap, 50-50 mix with water for mold release. 

[glazenerd]

Vinegar is organic- burns off. WD-40 carbon- burns off.  I have used Pam spray oil when making molds. Once they have sat a few days, I torch off the oil. -- in a kind and orderly fashion of course. Actually I like LeeU's idea.. will have to try that one.

 

nerd

[oldlady]

lee, you are talking about making new PLASTER molds, right?  when you make a mold of something in plaster for the first time, murphy's is the separator.  is that what you are talking about?

[Chilly]

lee, you are talking about making new PLASTER molds, right?  when you make a mold of something in plaster for the first time, murphy's is the separator.  is that what you are talking about?

 

Old Lady, we are on the same wavelength.  I was going to ask the same question, you beat me to it 

[drmyrtle]

Oddisgood,

 

Just to be clear, plaster molds are dynamic tools. By this I (we, see above) mean that a plaster mold does more than form the shape, but also absorbs moisture from the slip or clay. Using any oil substance (WD40, Vaseline, silicone-a non carbon oil-, etc) will ruin your mold for absorption by blocking the surface 'pores'. As you cannot bisque plaster, the oil stays in your mold. Murphys soap will not block the plaster, and is ideal when making the mold, but not necessary when using the mold.

 

For non plaster molds, others here have much more experience. I prefer using cornstarch lightly dusted on the non porous surface, or even strips of paper. IMO, WD40 is a toxic solvent, and shouldn't be casually used in your processes.

 

P.s. Old lady, the white paint anecdote may explain the disappearance of a dark cat, and the appearance of a calico in the neighborhood...

[1515art]

for mold release, using rubber stamps and making sprigs i like to use olive oil cooking spray. spray a bit on and wipe off the excess oil, i keep it off the areas to be joined when sprigging although it might not interfere with the joint.

[LeeU]

Old lady...yes, when making new plaster molds.  

[oldlady]

drmyrtle, i have rechecked the WD-40 msds info online and found that to have any toxic effects, the user has to be really incompetent or is deliberately misusing the product.  i did learn that it is flammable.  since i do not smoke, have no friends who smoke have no flames, candles etc. that is not important to me.  my studio is always well ventilated and i do not object to the slight smell.

 

when i read your post, i ran over the "IMO" just before your reference to toxicity.  i am sorry that we disagree with its use in pottery studios.  if someone has small children who investigate dangerous things (any kid) that might be a reason to use something else.  

 

i have never known cornstarch to work.  it cannot be sprinkled and if it piles up, its pile becomes texture.

[Callie Beller Diesel]

Cornstarch works if you put it in an old sock, and then use it like a pounce bag. I've not found it necessary to use a release on plaster.

[oldlady]

thank you, callie, it would never have occurred to me to make a pounce with cornstarch. i put it in a salt shaker with rice. didn't work.

 

a great thing to do with a sock, actually a nylon stocking, is cover a shape and use it as an interior mold. the nylon prevents sticking and making a square vase over a piece of wood is easier than joining slabs at corners. lifting out the wood form is simple, just pull up the stocking and the wood comes out.