We have been using black oxide screws with our product but want to see if there is a better type of finish. Most screws are 6-32 flat and button head. After a while the color wears away with just age and faster if constantly cleaned.
I have seen painted screws but don't know if you can buy them or have to have someone paint them. We need tens of 1,000's.
Are there any other types of black finishes? Do black oxide stainless steel screws hold up better?
Look through the hand book theres a section that covers coatings. I don't see the stainless holding black oxide any better but they won't rust where it wears off. Parkerizing is the only other black finish that comes to mind. Do they have to be black? Plain stainless would hold up best or crome plated.
I tthink you've painted yourself in a corner (so to speak). No fastener coating holds up long if frequently cleaned. If you desire painted screw heads punch a zillion through cardboard and spray them en-mass - wet paint or powder coat. It costs but if you get the effect you want so what?
If the fastener function is partly appearance and plated or coated don't hold up then you'll almost have to consider corrosion resistant fasteners - or perhaps silicon bronze which is nearly strong as alloy steel and only about 4 times as expensive.
What about Black Chrome ?? or hard Chrome ?? Satin chrome micrometers seem to take quite a bit of handling and not show it, I have always thought it was a flash of hard chrome, looks very similar.
Maybe a picture of the assembled part in question would help produce some more ideas.
They are not cleaned often besides just wiping off some dust. But I have even seen that the black oxide screws left exposed to air in a bin will lose some color after several months compared to keeping them sealed in a bag.
These are custom high-end audio enclosures made from aluminum and anodized. We make them in silver and black. We use SS screws with silver, and black screws with black.
If they are painted, it would have to be a high production process. Punching 10,000 holes in cardboard each month is out. There must be a quick way to paint screws, but it would be better if we can buy them already painted. What I fear about paint is the small internal hex will get clogged up or will chip when servicing. I think all the black painted screws I have seen are phillips head, but we want to stay with hex socket.
May give the black oxide SS screws a try. I checked into black chome on SS a long time ago and I thought it was a more involved complex process? I seem to remember it had to be a special SS to start with too?
There are applied Thermo cure finishes which can be done to small parts in large quantities. The parts are put in a machine which spins like a centrifuge. The coating is put in in liquid form. The parts are bulk loaded into baskets of some type.
A company I worked for did this process but I was never personally involved in it so I don't have more details.
A properly applied Black Oxide finish will not wipe off or fade with time. I suspect you have a problem with the salts or most likely the part prep.The prep has to be done properly or the finish will be fragile and not durable. If you do not have to have a polished finish on the screws make sure they get an acid dip before cleaning and oxiding.Satin or matte surfaces take oxide better than a polished surface.
The standard steel fastener finishes that produce black are black nitrate, black chromate or black nickel. The most durable is the satin black nickel. Refer to finish US15B.
We used to get what our supplier called "marine tech" finish on some fasteners. Some sort of applied coating, you COULD scrape it off, but you really had to work at it. It was for salt-water exposed stuff, and looks good too. A satin black finish.
The BIG problem with oxide is rust... Black oxide rusts, even when it is oxide and oil or oxide and wax.
We changed over to black zinc as the best available anti-rust coating at a sensible price. It will mar, but won't rust.
The Marine-tech was expensice, but that shouldn't bother you in teh audio biz. Not with $600 per foot speaker cable.....
Do you have a link to or a picture of one of these speakers. I'm into audio in a big way and would like to see what your making.
many years ago I had a need for some red screws and could not find a reasonable source. So I had a piece of plywood drilled with 200 holes and placed the screws in each hole so only the heads were showing, then sprayed with a couple of coats of Krylon. let dry, repeat. needed 2000 screws so this was done over a couple of days. Worked pretty good and did not take much time per screw and it held up ok. trick is getting paint on thinly. BTW, I soaked screws in acetone first and dryed them off on paper towels outside. beign in the hole protected the threads. The hole was shallow enough so the head was held above the surface of the ply
[ 09-22-2006, 05:39 PM: Message edited by: surplusjohn ]