Vinyl/PVC/Plastisol Coatings & Their Primers

A. Michael,

A good primer is hard to come by. It is essential to proper bonding. Look up "stop-off lacquers" on the internet.

Plastisol
on eBay

(affil link)

A. Hello, Jean-Francois. It sounds like you are interested in "plastisol coating". This is usually done by a dipping process onto a properly primed substrate, although it is also possible to spray it. There do exist air-dry plastisols, but the better plastisols are oven cured. Any plating rack manufacturer will have plastisol dipping capability, but this site is for technical issues, and we don't recommend specific vendors. Good luck.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

A. Hi Jean-FranÁois!

Re your question, WHY vinyl, why not other 'coatings'? Why the colouring? What's the environment?

The most expensive but the toughest coating is called PLASTISOL. This calls for a liquid PVC monomer into which one dips the product, then lets it drip 'dry' for a short while, then one puts this into an oven to cure. Tough, resilient, very acid/alkaline resistant coating. Not a smooth, perfect finish and far thicker than paint.

As far as paints are concerned, ask your local paint people. They would have a far better colour choice but not necessarily vinyl!

Hope that helps you un petit peu.

A. Here in the U.S., I know it's possible to have vinyl dye ⇦ on eBay or Amazon [affil link] custom blended if this is what you're looking for. Specifically what I have had done recently was a combination system. It was a Dupont branded vinyl dye in a Sherwin-Williams packaging aerosol system.

Spray on just like spray paint, I'm sure something like this can be formulated in larger quantities and packaged more accordingly to your needs. Consider contacting Sherwin-Williams Automotive division if this sounds like the product that might be of help to you. It's nowhere near as thick as a plastisol coating. It's very thin, dries quickly and can be blended in a very wide range of colors.

Just offering you another option in case the plastisol coatings aren't exactly what it is you were talking about.

A. This type of coating is typically used on parts that are exposed to very corrosive environments, and also on tool handles, and wire form products.

A. Dear sir,

A good prime coat is top priority. I use T-100, a Miccro product by Tolber. It works great for PVC.

A. Hi folks.

You can read the technical data sheets and the safety data sheets for such products to get the general information on such formulations, or read on as it's further discussed on this page. But as the suppliers discover improvements they almost invariably retain them as proprietary information rather than publishing them.

If you're going to buy the plastisol rather than formulating it yourself, you can buy the primer from the same sources rather than formulating it yourself if you wish.

But if you really wish to do the chemistry yourself, Google Scholar Labs offers this very deep search of the literature:
"Formulation of primer for plastisol coatings".

Luck & Regards,


Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Need quick confidential answers? $25
Need project assistance? $100/hr.

A. You exactly follow the procedures from the plastisol vendor. Basically, abrasive blast the part, heat it, dip or spray in a "primer", reheat, dip or spray in plastisol. Remove extremely slowly from the dip and bake for the given time/temperature. Too low a time or temperature and it is not cured properly. Too long or hot and it chars or discolors and later cracks.

Hi Felipe,

What James W. says sounds 100% perfect and hits the nail right on the head ! ... but go the manufacturer first of all, as he suggested. ...but I didn't know that one had to use a primer. Iggerance iz blizz.

Plasti Dip



on Amazon or eBay
(affil link)

A. Hello, Who Jang. If this is for personal use, you can try simple commercially available dips. For good adhesion make sure the tool handles are spotlessly clean; light sanding to restore activity to the surface would be best.

If that doesn't offer sufficient quality for your needs, you can look for a plating rack manufacturer. Most plating racks are plastisol coated for extreme corrosion resistance and electrical resistance, so they are set up to offer this coating service at top quality to you. Good luck.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

A. Hi, Hank. Although it might be possible to improve the plastisol coating formulation for somewhat better adhesion, the principle is absolutely correct that good adhesion requires an oven-dried adhesive primer, as you'll read repeatedly on this page. Plus, galvanized and stainless steel are notoriously difficult to get good adhesion onto.

I can't comment on whether a 40-60% increase is appropriate to the extra steps (I don't know what has to be changed because I don't know they were doing before) but your company contracting with a supplier who does not even guarantee general fitness to purpose is rather strange. Further, what happens if they come back yet again telling you that now the adhesion to stainless is okay, but the galvanized needs a zinc phosphate treatment first at yet another 40%?

Personally, what I think should be done is you should have sample parts stamped locally, and plastisol coated locally, and testing done locally to insure that they are satisfactory, then complete process specifications drawn up before a contract is placed. You can get great quality from China -- Apple & others certainly do -- but you can also get far lower quality that you're likely to find in the USA.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

A. Hi Hank, I think the adhesive that your supplier refers to is a primer made by vinyl chloride terpolymer; its carbroxyl group can provide good adhesion to metal. Something like a deep drawn can; without a prime, ink cannot maintain adhesion during deep drawing process.

A. Hi, John.

If the finish performed well for 10 years, that's not bad. If the finish is now peeling, actually curling away from the pipe, I doubt that any paint or plastic will fix it.

I think your choices are to:
- paint bare areas for color match, while expecting the problem to get worse.
- remove all the vinyl and repaint the pipes in situ
- replace the poles with new factory painted/powder coated poles, or remove them for factory painting

You could paint the bare areas for color match and then wrap the poles in something like clear packaging tape or industrial weight plastic wrap (the stuff they use to hold pallets together). If you start at the bottom, and the top is out of reach of kids' prying fingernails, there is at least a chance of a few years service from that. Note that this is just brainstorming from a guy who hasn't tried repairing backstop poles :-)

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

Hi Aniruddh. Plastisol will only adhere to a very clean and metallurgically active surface, preferably with some "tooth", and properly primed. Many plated surfaces have been handled and are full of fingerprints and not clean; often made of metals like nickel that deliberately form very passive surfaces. Plating is often 'self-leveling', i.e., designed to eliminate any "tooth"; and release agents like chromates are sometimes on the surface.

It is possible to o a pretreatment sequence for good adhesion of plastisol on plated surfaces, but it is unfortunately not realistic to expect good adhesion of plastisol onto plated surfaces without serious effort.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

A. Air dry plastisol that I am aware of is not tough. There are some spray can vinyls that are not bad, but a bit on the hard to find. You can find "brush on" at most auto stores.
You might want to try the spray-on_rubber that is currently advertised on TV. It is carried by most of the big box stores. Saw two in the last month.

A. Hi Brent,

Large factories presumably made those traps and coated them in huge volume, keeping labor costs low. It's a sad truth that labor is so expensive that refurbishing things is often cost-prohibitive.

You could inquire of a plastic coater like a plating rack manufacturer what they would charge to recoat them, but due to the labor involved with low volume, I'm not confident that they can re-coat them for less than the price of new. But stainless steel crab traps ought to last forever.

Luck & Regards,


Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Need quick confidential answers? $25
Need project assistance? $100/hr.

A. Hi Doug,

Although this thread emphasizes the importance of adhesion, if a component is both small and simple in shape, maybe the 'shrinkwrap' aspect of plastisol coatings will suffice.

Luck & Regards,


Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Need quick confidential answers? $25
Need project assistance? $100/hr.

A. Hi Erv. If the PVC coating is done right, there should be no problem at all. PVC coating of even plain carbon steel makes it acid resistant for difficult duty. However, if this 'cable' is repeatedly wound tightly on a drum, or used in some other way which might crack or split the coating, then it might not be satisfactory.

Vinyl coated cable and stainless cable are commodities available from a hardware store, but I don't know if vinyl coated stainless cable is as readily available.

Regards,

Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

A. Hi Mr. Burn. Such primers are solvent-based 16% to 24% solids, and oven cured. As others noted, stop-off lacquers can be good primers. The steel must be meticulously cleaned by blasting or cleaning and acid dipping. The primers are usually supplied by the same vendor who supplies the plastisol.

Primer manufacturers are not going to post their exact formulas, but part of the reason applicators are not helping each other with formulas here may be that it misses an important point, which is that someone is obligated to guarantee that the overall process meets specifications & requirements; if you do not have a primer supplier certifying such compliance, you as the coater are left with that obligation. How will you test and certify adhesion (not to mention the other requirements of the coating) yourself?

Freely available old MIL-P-20689 [link is to free spec at Defense Logistics Agency, dla.mil] explains the whole process. You could also obtain copies of the technical data sheet and safety data sheet from established vendors of the primer, or even small samples of it for reverse engineering ... but when you were done you'd not be able to assure your customers of anything unless you establish your own testing program. Best of luck!

Regards,

Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey