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Need screw heads painted reliably

Q. I'm a homeowner who's been looking--without success--for relatively small (#6 x 1" and #6 x 1-1/2") white-colored, trim head screws. The #6 x 1" screws are for use in fastening white-painted wooden door stops to white-painted wooden door jambs on pocket doors, and the #6 x 1-1/2" screws are for fastening the wooden pocket door jambs to the rough wooden framing. On pocket door installations, the use of screws on the trim pieces is recommended by the pocket door frame and track manufacturer to simplify removing the trim pieces if and when it becomes desirable to service or replace the pocket door trolleys and/or remove the door for some reason, such as to refinish it.

None of the screw manufacturers I've researched make trim head screws in white in the two sizes I want, but I've been able to find some who make the size I want with either a black oxide or a black phosphate finish, so I've resigned myself to having to buy one or the other and painting the heads white after installation.

I'm using the doors as entry doors into bathrooms equipped with showers, and I'm well-aware of how steel bathroom door hardware--however finished--inevitably develops rust, so I want to use a white paint on my trim screw heads that will last as long as possible before it, too, inevitably rusts.

Q1) Which of the two available finishes--black oxide or black phosphate--holds paint best?; Q2) What should I do to prep the screw heads before priming and/or finish painting them?; and Q3) Assuming I prime the screw heads with an oil-based primer--which, to a homeowner like me, seems like the most logical thing to do--does it matter whether the finish paint is oil-based or water-based?

Mitch King
- Summit Hill, Pennsylvania
February 25, 2023

A. Hi Mitch. Neither black oxide nor phosphatizing has much corrosion resistance without oil or wax, so my guess is those screws will have some amount of oil remaining on them. Any solvent ought to remove the bulk of what's left, sufficiently at least for an oil based primer. Black phosphate is probably somewhat better for paint adhesion.

I think oil based primers and latex finish coats will be compatible, but a peak is worth a thousand finesses, and a try is worth more than a thousand opinions. Put a dab of your primer on one screw, let it dry, and put a dab of finish paint on it. Luck & Regards,

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

⇩ Closely related postings, oldest first ⇩

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RFQ: I have a vendor painting screws. The screws are 6-32 slotted oval heads. Only the heads are painted. It is being done manually. We seem to get high PPM due to volume of screws being painted. 200 million plus parts per year! I am looking for vendors that paint fasteners in high volume.

We are also experiencing adhesion problems. At least perceived adhesion problems. Some of the screws finish is chipped off! This seems to occur during transit or perhaps in bowl feeding the parts to the application. I am looking for an adhesion specification - ASTM D3359 seems too stringent. It also seems to deal with larger painted areas.

Can someone help?

Hank Merkle
Greenville, South Carolina

Ed. note: Sorry, this RFQ is old & outdated, so contact info is no longer available. However, if you feel that something technical should be said in reply, please post it; no public commercial suggestions please ( huh? why?)

"Zipper: An Exploration in Novelty"
by Robert D. Friedel

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A. You should contact a company named [deleted by editor, apologies] in Italy they specialized in painting equipment for screws and zippers. They work with a german company who manufactures a proprietary paint for such application and probably they can guide on who might do the job for you in the USA.

carlos dreszer
- bogota colombia

Hi Carlos. Thank you. Hopefully Hank can proceed based on the technical portion of your reply. I apologize that we must delete public commercial suggestions but time has proven that we must ( huh? why?).

We apologize that we can't be all things to all people, but we are a site where people can share camaraderie & technical information, readers can request private contact from suppliers, and advertisers can offer their products if they wish. But public brand & sourcing suggestions and free advertising just don't work on this semi-anonymous, no registration required, site.


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

A. Zinc plate and color chromate might be an option.

James Watts
- Navarre, Florida

thumbs up sign Hi Hank. James may have a great point. If the colors you need suit a chromate conversion coating (black, gold, dyed in pastel colors) you can eliminate a whole process and the costs and defects by just having the zinc plating shop chromate them in the color you need.


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

Industrial Process for Painting Screw Heads

Q. We need to paint fastener heads. We'd like to know what is being done in the industry to paint millions of screws, but the head only. Our requirement is to Zinc plate the fasteners and then paint in different colors the heads. The paint should be oven cured. How can we do this? Like I said, there are millions of parts and we need a productive system.

Any help will be greatly appreciated,


Enrique Segovia
- Monterrey, N.L., Mexico

? Some questions. Do you need powder paint or liquid paint? Do you want to make it by your own of you are looking for a supplier that can make it for you?

Jorge Hernandez
- Guadalajara, Jalisco, Mexico

A. Hi Enrique. The screws can be phosphatized for good paint adhesion, then it should be reasonably straight forward to use vibratory feeders to align them in some sort of bandelier and roll-coat them and bake them.

Luck & Regards,

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

Q. I want to paint the heads of screws.

A method is to put them into a pegboard and spray paint them. This works well for hundreds to thousands, but I want to paint tens of thousands.

The present method is to put each one in a hole of the pegboard by hand.

Is there a better way?


Ken Wilkinson
homeowner - Rio Linda, California, USA

"Mechanized Assembly: fundamentals of parts feeding, orientation, and mechanized assembly"

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A. It's hard to picture a homeowner painting tens of thousands of screws, Ken -- that sounds more like an industrial application. The reason it matters it that there are relatively simple industrial solutions called "vibratory bowl feeders" used in all sorts of sorting and assembly applications, but I'd rather doubt that vibratory feeders and automated bandeliers would be applicable to a homeowner's needs. Please clarify. Good luck.

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

thumbs up signThank You Ted.

Well, I must admit it. The screws are used at work. About 100,000 a year. I really wanted to know an answer so I won't wind up doing a mind numbing job for a week or two. I was afraid that if it was described as a company problem I wouldn't get an answer.

Your answer gave me the "key words" to access a flock of possibilities. I expect you have saved me a lot of grief. Thanks again.

Ken Wilkinson
- Rio Linda, California, USA

! Glad to hear we could help get you started. Vibratory feeders are used in high volume production all the time. It is relatively simple to separate/singulate and orient bulk parts with a vibratory feeder so that a robot or a linked machine can pick them up and insert them.

By 'relatively simple' I mean that an experienced automation engineer has little difficulty designing the gates and stops and linkages to orient the parts; and once it's done it can be very reliable. Certainly not saying I could do it :-)

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

Want to paint screws in-house

Q. PAINTING SCREW HEADS. We are a rollforming company offering 18 colors and sell about 15000 screws a day and want to start painting our screws as it is very hard to keep 18 colors in 4 different lengths in stock. We can get plain screws but nobody wants to show us what equipment we need as they want to sell painted screws.

Norman H [last name deleted for privacy by Editor]
Rollformer needing screws - Kitchener, Ontario, Canada

Ed. note: Sorry, this RFQ is old & outdated, so contact info is no longer available. However, if you feel that something technical should be said in reply, please post it; no public commercial suggestions please ( huh? why?)

A. I am not sure if there is a modern way of coating screws but the old way was to place several hundred screws into a tilted barrel (like a concrete mixer) with sufficient liquid paint - once barreled they would be strewn out across wire mesh. The type of paint air-dry or stoving? The art in this is getting right the amount of paint necessary to coat but not flood.
The process also includes centrifuging to remove excess paint - sorry I do not know if this is part of the barreling or a separate process outside the barrel. You could make your own with a one gallon bucket with a top to evaluate the process.

Terry Hickling
Birmingham, United Kingdom

A. I have a distant recollection that this was done in an oblique barrel (like a concrete mixer), and the paint was added a bit at a time in the form of a spray or spritz.

jeffrey holmes
Jeffrey Holmes, CEF
Spartanburg, South Carolina

A. Seriously, why would the paint shops help you to take some of their business away?
That said, there are paint material vendors that might sell the information to you or to make you a licensee for their material.
Do a web search on "dip spin". Include the quotation marks or you will be buried in hits.

James Watts
- Navarre, Florida
November 12, 2008

A. Hi, there are automated machines for painting screws/rivets of any size, easy change out for colour change. They pre-prime, bakes between it painting.

Mike Prendergast
- New Zealand
October 22, 2011

Screw Head Paint Chipping

As a sheet metal manufacturer that uses various types of screws (screw heads) for our products (Phillips, Torx-Pin, One-way vandal proof, Hex, other security type screws), we often run into problems where our finished product is powder coated, and the zinc-plated screws that are shipped loose to the customer to attach the product to the wall (heads being visible and part of the architecture of a room)are powder coated as well. We run into 2 problems - the coating easily chips when a screw driver or other is used, and the powder coating itself reduces dimensions of the drive type, so for example, a hex key will no longer fit into the head of the screw after coating. Is there another finishing process that can be used to resolve these 2 issues? Our standard color is "white"..

Any input is appreciated. I'm thinking there might be another coating or finishing process for this application.

Thor Lane
Product Design Engineer - Los Angeles, California, USA
May 28, 2008

A. Hi, Thor. Electrophoretic lacquer (e-coat) is much thinner and will solve the dimensional problem. It may offer greater hardness or better adhesion as well, but that is less sure since these factors depend upon a number of parameters in both technologies.


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

Q. We are a construction fastener distributor. At present, we send out all our painting jobs to an outside contractor, but are considering putting in the equipment to do this in-house.
I am interested in what equipment you use and whether you manufacture the equipment or are a user.

David Laquer
- Warrington, Pennsylvania
March 10, 2012

Multiple threads were merged: please forgive repetition, chronology errors, or disrespect towards other postings [they weren't on the same page] :-)

Q. I want to come up with a system to paint screws which will have the best bonding properties. I currently use a self-etching primer and an acrylic paint. I use a heat lamp to bake but am not sure if I am doing this properly.

Donald Orsburn Jr
Home Improvement - Grand Junction, Colorado USA
March 26, 2014

A. Hi Donald
When you said "Home Improvement" I'm not sure whether you meant you are a homeowner improving something in your house, or a business involved in manufacturing screws for home improvement. Obviously, some things may be practical for one case and not the other. The best way to prepare screws for "best bonding properties" is to phoshatize them.
Luck & Regards,

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

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