Plating barrel danglers and other maintenance problems

A. Jeff: You want to use polypropylene or Teflon for most applications and stay away from nylon, which tends to embrittle. Good luck from PlaterB

A. It sounds like either the new parts are nylon as Berl suggests or, possibly that they used to be straight Teflon (resistant to everything) and they are now glass-filled Teflon (which won't hold up to hydrofluoric acid).

A. Hello Jeff, the "sleeve" you are describing was available in a material that was nylon based. This worked well for many years. The introduction of acid based solutions replacing cyanides caused a problem with this product as the acid base would attack the nylon and make it a gummy looking appearance with severe wear. This product was changed to a polyethylene based material with excellent lifespan. Your note does not state the details, but if the material is white it could be a number of starting products. If it is a "brittle" material, it may well be nylon. Teflon and polyethylene are more "bendable" of a material. Ted, news to me, glass filled Teflon?, well, you'd think it would wear better but the problem (on our end) was never the Teflon wearing out, it was the Teflon sticking to the hanger hub and wearing the barrel. is the glass Teflon a better choice?, again, it's news here      

A. Nylon will dissolve quickly in HCl. As you describe, nylon will first turn a chalky white.

A. Hi, Ron. One supplier I was with tried various materials for the bearing surface of the idler gear. In other words, the idler rotated on a stationary shaft, and the polypro the idler gear was made of wore too quickly, and the bore hogged out, etc., So we wanted a replaceable bushing and we tried many materials. For that particular application Teflon proved to be too soft, it would "flow" out under the heavy load. We had about equal life from glass-filled Teflon and from UHMW polyethylene.

A. Hi Ted, well,that makes a little more sense here,I thought you knew someone trying it as a barrel end bushing. My best experience for gear bushings is u.h.m.w. it seems to be the most tolerant, although delrin works good as well if kept from the solution. c.y.a ... ron

A. Hi Brian. Sorry, I'm not quite clear on whether the dangler knob gets worn out too quickly or the insulation on the dangler cable gets abraded too fast. I don't know what your green plastic is, but UHMW-PE is an exceptionally abrasion resistant plastic and should be available in a thin walled soft tubing that you could slide as a sleeve over the commercial dangler. (Of course, you need a good fit or the screws will insinuate themselves between the sleeve and the dangler insulation).

A. If the problem is wear of the cable insulation there is a dangler design which coats the portion in the cylinder with heavy vulcanized rubber. This has proven more effective than sleeves. If you would like the manufacturers name, our company distributes this product.

A. Dear Brian: I understand perfectly. We have also had this problem. Our solution is we used semi flexible plastic tubing about 1/8" thick as a sleeve around the cable. You must take the cable off and sleeve it from the bolted side. Works great. KH

A. The dangler problem you are experiencing is common for those companies doing sharp screws, etc.

1). you should be able to order danglers from your supplier with a clear flexible p.v.c. sleeve or jacket , measure from behind the head to where the dangler passes thru the barrel on the inside + a half inch or so. Get a couple of sample to try out first.

2). consider a center rod contact assembly, this is a 1" dia. 304 ss bar going straight thru the barrel with 304 ss "hairpins" bent from 1/8 x 1" material, evenly spaced, use 1" id pvc pipe to cover the exposed areas between the hairpins. connect the SS to the barrel contacts with 3/4" dia. copper solid, cover the solid copper with either plastisol coat or heat shrink and electric tape in a pinch. These components are commercially available thru most equipment distributors as a "center rod contact assembly"

A. Hi, Kevin. Electropolishing of the stainless steel dangler knobs can help to passivate them and smooth them so that this undesired metal buildup will have less tooth and can be more easily removed. Also, you should make sure that the plastic sleeves are in very good condition so no more of the metal is exposed than absolutely necessary, and certainly not the ends of the braided copper cables.

You might also talk to manufacturers who specialize in danglers.

Sorry I didn't mention this. The dangler knobs are not stainless steel. They are golden in color, unless they are a special type of stainless. Should we use stainless?

I'm an electrical engineer that knows nothing of plating, but I have to keep the line running. No one is really familiar with the technology. Heck how do you electro polish? Understand I'm stuck in a hard place, I can't buy material or talk directly with suppliers, but they want me to look at the process to see if it can be improved, which I've done with other parts of the business. The people who do the buying don't ask about new processes, stuck in the 'it works why fix it' mode.

Thank you for your help.

A. Although they might not be stainless, I'd bet they are despite their golden color.

I can't give you advice about what waves you should or shouldn't make, but you can't fix anything without making changes. You should probably buy new danglers from a plating equipment supplier rather than fixing & home-brewing them.

You might see if your employer will spring for a training course in electroplating, offered by the American Electroplaters & Surface Finishers Society or by Kushner Electroplating School. Or you might attend a few local evening meetings of the AESF; there is a branch in Philadelphia. Good luck.

A. Get proper danglers. We do zinc plating and ours are made of copper cable rubberized outside - it prevents the buildup along the cable and only the contact ends are exposed metal. We don't clean them at all - no need! they get a bit "plated" but once they go back to acid pickle they come out like new.
We get ours through a local electroplating distributor.

A. Hi Al. We appended your inquiry to this thread because I believe that a manufacturer of 'plating barrel danglers' or 'plating racks' could easily design a really proper cable arrangement for you.

Regards,

A. Hello, you can use Ticlad (titanium over copper), it's pricey. I would suggest a titanium EAR off of the basket, and then a cable connection coated with air dry plastisol.

A. Hello John,
Brass or copper dangler tips work well. The shape and size of tips must be compatible with your parts to be plated, as well as media. Arc burning can be caused by improper contact within the barrel and parts are not rotating freely, and getting stuck around the dangler tips. Barrel speed, load capacity and current also play roles. When I was in the field I had to ask myself "what has changed in my process to cause this problem?" This meant going back to the drawing board, monitoring and checking everything related to the process. Good Luck.

A. Hi Nick. First off, make 100% sure that your analysis of the problem is based on personal firsthand observation because it is indeed almost impossibly strange that a dangler could remain buried within a heavy load of parts and produce this problem, but have the problem go away when the rotation is stopped.

May we assume that the knob end of the dangler is stainless steel? Have you tried reducing the barrel rotation speed to see whether the problem persists or gets better as you get closer to the rotation off scenario? I would suggest buying a couple of danglers from a different company to see if anything weird, like wrong knob MOC, intermittent contact between knob and cable, etc., might explain the problem. I tend to doubt that chemistry or temperature causes the problem, but if it's not defective danglers or a short circuit, I would investigate the rectifier situation -- sometimes single-phasing can cause weird problems.

Regards,