PVA Plastic Available in Paste or Gel?

Sorry for the confusion.. I meant Polyvinyl Alcohol and not Polyvinyl Acetate which should really be abbreviated as PVAc..

Ugh!

At the risk of inciting a verbal riot:

During my tenure of 10 years as the plant manager of a chemical plant where all sorts of adhesives were manufactured, the term "PVA" was used to denote Polyvinyl Acetate and Polyvinyl Alcohol was referred to by the complete expression "Polyvinyl Alcohol". In written form "PVA" denoted Polyvinyl Acetate and "PVAl" (lower case L) denoted Polyvinyl Alcohol.

This seemed to be the use within the whole industry. Our site made PVA based adhesives in 5 gal pails up to tank truck quantities daily. Most of the products were for industrial use but some of them were consumer products still used throughout the world with very familiar brand names.

Good Luck, Old Salt

You ramble on too much. This sometimes happens when one knows the subject well.

I think PVA is commonly used for both materials, which leads to this type of confusion.

ramble on too much?

I hardly know what I am doing... you are the one who introduced me to this material in a previous post... thanks

I have learned that it can be done from powder and water mixed in the right proportions at the right condition...

At the risk of being a complete bore: Polyvinyl alcohol is the only polymer I know of, for which there is no monomer. Any attempts to synthesise vinyl alcohol produce the isomeric structure, acetaldehyde. Polyvinyl alcohol is therefore made by the hydrolysis of polyvinyl acetate.

Doesn't bore me.

You are too kind!

Your rambling,

Bazzer

Correction: "You are" or "you're," but absolutely not "your."

They sell it here...

http://www.johnnealbooks.com/prod_detail_list/67

http://www.chemistrystore.com/Chemicals_G_R-Polyvinyl_Alcohol.html

http://www.soapgoods.com/Polyvinyl-Alcohol-p-713.html

Dupont's data sheet for their PVAlchohol product says it is soluble in hot water and not cold. Apparently there are some applications where this property is desirable. They gave examples.

OP, do you really want to go with the PVAlchohol gel/paste or are you open to alternatives? Please tell us more about these gaps that need temporary stopping.

I am open to alternatives.

The gaps are just slots in a machine part that needs to be covered, and then painted and then cleaned.

Poly vinyl alcohol (PVA) is soluble in water and Poly vinyl acetate (PVAc) is not soluble in water. I have both poly vinyl alcohol and acetate ink or paste you can use as temporary gap filler. I will recommend PVAc for temporary gap filler if you can use solvent like acetone to clean and wash away . This is one of the typical solvent in electronic industry along with IPA.

Let me know what you will like to know about the ink

The ink?

Is there a reason for your preference barring the solvent used?

Since I developed ink to mask area which we do not want to plate and also to have touch up ink after plating so one can avoid striping and plating

PVAcetate is solubilized as part of the manufacturing procedure for most of the popular PVA glues. It just depends upon how and when it is done.

These adhesives, the popular ones of the "glue-all", "school" and "carpentry" types are manufactured by adding water to an open head steam jacketed reactor (sometimes referred to in the industry as a "kettle"). The PVAcetate and a few minor components are then added and heated till the PVAcetate is dissolved in the hot water. Next the PVAlcohol is added quickly to the brew, along with a few more minor components, and brought up to a mix slightly higher in viscocity than the desired end result. By now the mix is at room temp because there is much more Alcohol than Acetate in the mix. A sample is taken for viscocity and additional Alcohol and/or water is added if necessary to reach the desired viscocity.

The resultant product is then packaged in the desired container, be it a 4 oz squeeze bottle up to a 4,000 gallon tank truck. The product must be protected from freezing unless the procedure added some Ethylene Glycol, common anti-freeze, to the formula.

PVAcetate can be dissolved in water if the mix is heated prior to use. This resultant mix is too hot to handle with unprotected hands so take precautions.

Good Luck, Old Salt

Will masking tape work?

No, I don't believe that would work for what I am doing?

"No, I don't believe that would work for what I am doing?"

Just reading along - you have gaps that you want to fill, then paint, then clean.

Why?

Like; why a water soluble gap filler?

Is it meant to wash out from under a paint coat?

Or do you want it water soluble because the paint is water based?

Why not paint-able silicone or epoxy, even hot glue?

Why are you painting?

At some point you have to realize WTF U are trying to do, and why, is a bit relevant to the input.

Why?

Because I want them to be there.

Is it meant to wash out from under a paint coat?

YES

Or do you want it water soluble because the paint is water based?

Paint is not water based.

Why not paint-able silicone or epoxy, even hot glue?

It won't work.

Why are you painting?

Because I want to.

Ok, So this substance provides a temporary bridge for paint to adhere to, which is then not required.

So, presumably the gaps bridged by a paint membrane have some functional role.

Would it be a problem if the substance did not fully wash out?

_{(This question is 'application' oriented as 'feathering' of edges/surfaces may trap 'substance' inaccessible to solvent - resulting in a larger, or smaller, membrane span than desired)}

The word is diffusion..

Not washing out

Feathering will not be an issue..

Are you asking all these questions because you have a solution to propose..

It would be more fruitful if you put you ideas up and I could give more targeted discussions..

I tend avoid guessing at a 'solution' until I fully understand why what is wanted.

Experience has taught there is not necessarily a functional link between 'why' and 'what', passed a presumption by someone based on limited, or specialised, understanding of available technology options.

Yes 'diffusion' is a great word. It also infers a static, or un-accelerated by agitation rate.

This discussion should stay on the subject.

The gaps are small, and i have calculated Pe <<1, Diffusion will dominate transport.

Therefore, agitation or 'washing out' does not seem to be a viable option. This is why Pval, which is soluble seemed to me a good option.

Also, share you solution ideas if you will.

"This discussion should stay on the subject" What is the 'subject'?

Diffusion can only reduce to a residual distribution greater than zero. I.e. less than 100% removal.

But, no I don't really care what the 'master plan' is, so lets try to get 'useful';

Define "small" - width, length, depth - meters, feet, millimeters, microns, choose your poison.

What are we sealing against? gas, liquid, vapor?

What pressure is involved?

What temperature is involved

Is there a flammability issue - during processing or by evolution of solvents later in service.

What is the size of the area that you need to mask?

Is there a difficult/complicated geometry that needs to be dealt with?

What material is the machine part made from?

What type of paint is it?

Will the component be subjected to any other processes in between masking and painting?

What sort of quantities are we talking about?

Are there any time constraints?

Any skill limitations or difficulty `in ensuring that masking is applied per instruction every time?

Does it really have to be painted?

What if it isn't masked and just totally painted?

What is the size of the area that you need to mask?

small, just a prototype for now, 2sq. in... 1/8" deep, 1/16" wide gaps

Is there a difficult/complicated geometry that needs to be dealt with?

NO.

What material is the machine part made from?

Aluminum.

What type of paint is it?

Regular paint.

Will the component be subjected to any other processes in between masking and painting?

NO.

What sort of quantities are we talking about?

1.

Are there any time constraints?

No.

Any skill limitations or difficulty `in ensuring that masking is applied per instruction every time?

No.

Does it really have to be painted?

Yes.

What if it isn't masked and just totally painted?

It needs to be painted.

Have you tried "Paint be Gone" gap filler from Lyndoor Industries?