Conventional wisdom has it that PVC is not paintable. That’s a reasonable statement. Had I not spent six years researching painting uPVC I’d say the same thing. So: Can PVC be painted?
The fact is that uPVC and cPVC (PVC from here on) are difficult to paint. The reason is, is that PVC has a low surface energy. All materials and liquids have a “surface energy”. The scientific unit of surface energy is Dynes/Centimeter . For purposes of discussion I will talk about the surface energy, SE, of water and how it relates to PVC.
Water has an surface energy of 72DYNE (DYNE is short for Dynes/Centimeter) and PVC has an surface energy of 41DYNE (list of the surface energy of various polymers). Since water has a higher surface energy (SE) than PVC, it will bead up and roll off like: “water-on-a-ducks-back”. In order for the water to “stick” or “wet out” onto PVC, PVC has to be treated to raise the SE of the PVC above the SE of water. Can this done? By the average consumer?…well…no…but don’t give up yet, and read on… The average consumer can do two things to increase the SE of PVC, the first of which is to sand the surface lightly. This will remove the surface waxes to a degree (learn about surface waxes and learn what PVC is made of) and create more area for the water to wet out. We recommend you use Green Scotch Brite because sand paper will load up very quickly with the surface waxes on the PVC. This raises the SE; the second way to raise the SE is to wipe the PVC with Acetone. Acetone is detrimental to PVC. If one were to immerse PVC in Acetone, it would break down the molecular structure over time and destroy the PVC. This, however, can be a benefit when preparing PVC for painting. The Acetone does two things: (1) it swells the surface making it slightly more porous and (2) it disperses the surface waxes that are inherent on the surface from the extrusion process when it is manufactured. So, Acetone will also raise the SE of the PVC.
There is another piece of the equation that has to be considered. Even if a consumer prepares the surface as described, the SE of PVC will never reach the SE of water (with these techniques)–which is 72DYNE. And with all the best preparation, the SE of the PVC will be variable due to the waxes that are external and internal to the PVC. To combat this, paints made of a blend of acrylic and polyurethane, (i.e., special latex paints) have been formulated with additives to reduce the SE of the liquid paint. These additives reduce the SE of PVC paints down to 34DYNE, which is lower than the untreated SE of PVC.
In theory one would not have to treat the PVC if the paint has a surface energy below the PVC; but there’s a problem with theory–reality. Empirical results suggest a combination of good surface preparation and a paint coating with a low SE, can result in good adhesion of paint to PVC.
There is a lot more to it than that: the paint formulation is actually a cacophony of chemistry. Every micro ingredient and every pigment change, can change the adhesion of the liquid paint to the PVC substrate, but that’s beyond the scope of this article. Suffice it to say that the paints developed for the PVC niche have been tested for adhesion on PVC each and every time a change is made to the formulation.
Yet another layer of the Onion to remove
At MGM we subject the PVC to a flame treat process that can raise the surface energy from 42DYNE to above that of Water’s 72DYNE.
To try to better explain it. When the surface energy of PVC is raised to this type of energy state, the liquid can “wet out” into all the “micro pores” of the plastic. These “micro pores” can be thought of as “micro anchor points” to which the paint can adhere.
In our flame treat process, we subject the PVC to a very lean burn flame of natural gas. The temperature of the flame is roughly 5000oF. At these temperatures a low temperature plasma is created. In effect the excess oxygen in the flame is heated to the point of ionization. Which means that the oxygen loses an electron and becomes a positive ion. In this state the oxygen is very very reactive and wants to bond to another atom or molecule. In our process the O+ is introduced next to the PVC and bonds to the PVC. The result is the surface energy of the PVC is raised tremendously. There is another benefit of the flame process which is to remove the surface waxes on the PVC, raising the surface energy of the PVC.
So, whew… there you have it. PVC can be painted, but it has to be prepared correctly and it needs to (note: I said needs to, not has to) be painted with paints that are formulated for PVC. As yet another side note, there is a subdivision close to our company that has PVC windows that were painted with ” garden variety” big-box paint, and it is still on the windows after ten years. I would not scrape it with a house key, but would you do that to your car?
At MGM we also put reflective pigments in the paint so that the PVC will not rise above it’s distortion temperature of 140oF. (note: for dark colors PVC has to have reflective pigments)That’s another article, so stay tuned.
With our reflective pigment paint you can paint your windows with black paint and not have distortion issues–you can “bet-your-sweet-bippy” on that one. (I’m showing my age here, sorry ’bout that.)
At MGM Industries we have merged the markets between Clad-Wood windows and vinyl windows. Take a look at the MGM 8017 Series Double hung. This window looks exactly like a contemporary aluminum-clad or vinyl-clad wood window, but now you can get better performance at a fraction of the cost.
Can PVC be painted: ABSOLUTELY!!
always time to read. love what you are doing and this article was very educational.
All the best
Terry
Hey Terry, thanks for the comment. That means a lot that you like the article.
Does your Daddy know that you are so dang smart? He may get a notion that the acorn could not have fallen too far from the tree, and come back out of retirement just to savor this action. Think of all the quality fishing time that will be wasted by such a development. Soooooo, maybe it’s riskier to put all this onto the website. Just the same, I agree with it, as all that “social media” stuff seems full of wackos, if you ask me. Better cred on our own site. And as for you Dad, just tell him from me cause this is one of the few things I’m an expert on, “Marshall, when tempted by a work situation, JUST SAY NO!”
Dad’s the smartest of us all because he is in Mexico fishing for Large Mouth Bass. Don’t that say it all…
Abe:
Good article. Looks like the “geeks” (Terry and Pete) will be all over it.
Joe
Abe,
Thanks for tech info on the paint technology. Have been around the plastics industry more years than I will admit, so duly impressed with your presentation.
This is the most straightforward and logical explanation of the science of painting plastics I’ve read. Plus, PVC may be among the toughest “cats” (yes, aged term, years showing) in the plastics arsenal.
As always, you hit a timely topic that builds more positive consumer confidence in PVC windows in general while enhancing the marketing potential of the painted features. Well done!
Ken Fullick
Hill Design Products, Inc.
I was getting a sample of a PVC part. As it turned out my supplier has only clear. In my application everything works “but” clear, I have to glue it and it will look ugly.
So basically your answer is, “do not attempt to paint it”.
And if I do? Use acetone. And what readily available paint would you recomend?
William,
I am not sure of your question. I wrote to you off line about paint supplier options. We are in the process of installing a $40,000 computerized color matching system. With this system we will be in a position to offer paint to you. For budgetary purposes the paint will be in the range of $130/gallon. I do not mean to imply that you should not paint your PVC, however, if it is exposed to direct sunlight, be aware of the heat gain issues associated with the infra-red heat from the Sun.
I have tabletop CNC machines for which I am making enclosures from a black PVC (walls) and clear acrylic. I’d like to paint the PVC a light gray to aid lighting and vision. Or, I might try laminating thin sheets of gray ABS to the PVC with 3M Super 77. Wondering if you might have suggestions before I proceed?
Thank you much.
Brian,
I would lightly scuff with Green Scothbrite and then wipe with Acetone. On the cheap: a latex paint and experiment. Little more expensive: We have a primer that I would be willing to sample you at no charge. If the adhesion is better than your latex experiment, then we would be willing to sell the primer to you. We have it mixed for us at an industrial paint manufacturing company. They only want to sell in 25 gallon minimums. We could sell you in one gallon pales. The cost is in the range of $75.00 I don’t know how well the primer will stick to your formulation of PVC. I have found out that the micro ingredients in PVC have a big impact on the adhesion of paint to PVC. We have worked with our uPVC supplier and found a formulation that allows paint to adhere. Working to optimize the adhesion of paint to PVC is really a pig-in-a-poke/iterative process to find the right combination to work with each formulation of PVC.
We have manufactured a dye for PVC. Check out our website for this product. This is a patented product which is owned by our company.
Can I use the PVC DE-GLOSSER of the type I use to prepare PVC coupling for glueing? …. the purple stuff. And what paint do I use: Poly Urethan or Epoxy or any other type / brand.
Please let me know real fast.
thank you
Peter
Peter,
I have never used the “purple stuff” as a primer and I do not know if it will work. If the application you are considering is exterior, then I would not use epoxy because it will not resist the UV. Polyurethane will work. Our paint is a blend of polyurethane and Acrylic. Acrylics adhere to PVC well. Polyurethane is a very durable plastic. I would lightly scuff your PVC with Green Scothbrite and then wipe it down with Acetone. PVC has different minor variations between different formulas so my recommendation will work better on some PVC’s and work less well on other PVC formulations. We have found that differences in “heat stabilizers” (different micro ingredients) can affect the adhesion greatly. These compounds are put in the PVC formula so that the extruders can process the power PVC through the extrusion process. At our company we have found this out because we extrude and experimented with formulations until we found a heat stabilizer additive which did not adversely affect the adhesion of paint.
I came across your information and I was very impressed with your knowledge. The problem that I have is that I leave in Wisconsin and I am unable to find any dealer in this area for your products. I am about to install 5 Walsh Tundra (we live in WI)
windows that I would like to paint with a Bronze exterior finish. Can you give me any suggestions on paint that could be purchased from either a big box store of from maybe a national chain that I could find locally. I would am not sure which paints would have the reflective pigments in them. Any help would be greatly appreciated.
Steve
Steve, You can buy reflective pigmented paint at Sherwin-Williams. You will probably have to ask the manager to research the SKU for this paint and he/she will have to order it. Actually I am not sure if they will sell it at a retail store. We have used it in the past, but we purchased it through the SW industrial division. Sometimes these two divisions do not communicate very well. The SW product does not adhere well initially, but it will improve over time. At least that was our experience. If you can not get it locally and you really want it, then you can order it from our company. It is $130/gallon.
Greetings Abe.
Your article is very interesting. We are purchasing a holiday home all the exteriorer window and doors are Black PVC, whilst the building is less than 5 years old the black PVC has faded to grey. Firstly have MGM manufactured a black paint, and if the answer is yes can I obtain this product in Southern Ireland. I have used Acetone in a manufacturing proccess and can see that it would give adhesion to PVC. ( Acetone is a dangerous product extremely flamable and due care should be taken when using this product). Good luck with your research.
Regards.
Richie.
Richard,
Yes we have manufactured a UV stable black paint that has reflective pigments. Right now our paint is not available in Southern Ireland. I have had contact with Sidey in http://www.sidey.co.uk/ . George Mckenna is the General Manager there. His company might be able to help you. I do not know whose paint he is using but he knows what kind of paint you need to use. If George can not help you, I suppose we could send it over there, but I think the freight would be very expensive.
Thank you,
I used PU paint for painting the PVC cabinett (Bath Cabinett), but I have some bubles on it after painting. I used filters, dryer and anti-silicone but the problem not solved.
Do you have any suggestion?
Pooya,
The simple and quick answer is that you have some contamination in the paint. However, I looks like you already suspected that. Is there a way for you to contact the technical support for the particular brand of paint you are using? For example, if you had purchased our paint, I would contact our vendors for a possible solution. It could be solved by various additives: maybe a de-foamer, maybe something else. If the paint vendor has good customer support, that would be my first suggestion: call the technical support and ask if the recommend an additive in their paint to counteract the bubbles your are experiencing. I can not recommend anything specifically because I do not know the chemistry of your paint.
I’m interested in purchasing some of your paint for PVC, in royal blue and yellow. Please advise on colors, sizes, pricin.
Carla,
Pricing is $175 per gallon. I can send you a color card by mail if you send me your snail mail address. Go to Uncle Omer’s Paint for a Digital version of our standard colors. We can color match you your sample if you send in a color standard. We have X-rite color matching technology, so the color matching will be done in-house by our color technicians.
Hi Abe, thanks for your time.
I make recycled lamps out of PVC, and am very interested in what you have written regarding painting PVC. The obvious reason being is that i want to sell my lamps in multiple colours As the PVC im using is a sky blue, i will need to paint them to get the desired colours. Can you advise me on the best method?? Possible products i should use here in Australia, if you have a distributor here for the products you use, or other products potentially available here. The lamps are for interior use only and am looking for a product with a variety of colours.
Any information would be greatful, and compliments on your fantastic research.
Regards Dax Knight
Dax,
We use some expensive preparation technology to raise the surface energy (surface tension) of the PVC by flame treating with an oxidized flame. You probably do not have access to this, or can’t justify the Capital expense. So I would lightly sand with Scothbrite or equivalent. Use compressed air to blow off the surface, then wipe with acetone. Since your product in indoors, you will not need heat reflective pigments. Any high quality latex paint should work.