About 4 years ago, LDC introduced the first, and still the only, brush plating hard chrome. This development went against all of the brush plating industry's accepted knowledge. Most people are still skeptical about the merits of the LDC-HTC³ Chrome.

The reasons for the resistance are many, but they can probably be
broken into two categories: history and resistance to change.

History: For over 30 years, EVERYONE in brush plating was told you can not brush plate with hard chrome. This was true, until
LDC introduced HTC³, Hard Trivalent Chrome. No other brush
plating suppliers can offer you a working brush plating hard chrome. But they will sell you a poor imitation.

Resistance to Change: Many long time brush platers have not adjusted to HTC³'s unique, but critical, operating parameters. Before
delving into these particulars, let us start with some background information.

If your are reading this newsletter, you are probably well aware of the many advantages brush plating offers the bath/tank chrome plater.

Brush plating is portable; it requires minimal masking; it reduces downtime and production delays; it usually requires little disassembly; it allows for exact thickness control; it does not require chemical analysis and adjustment to the plating solution. These are only a few points.

But, brush plating has its limitations. And, in the past, that included no hard chrome plating capability. There is a huge market of applications that simply must have hard chrome. No substitute will be, or should be, accepted. Now, with LDC-HTC³, many of these applications are possible.

What makes hard chrome so special? Hard Chrome has many unique properties that no other plating deposit can equal. These include:

• Extremely hard deposits
• Low coefficient of friction
• Excellent wear resistance
• Corrosion resistance

LDC-HTC³ supplies these properties, plus it is a trivalent chrome solution. Tank or bath hard chrome plating is done with hexavalent chrome.

Hexavalent Chrome is near the top of the EPA's hit list. Hex Chrome is toxic, HTC³ is not; Hex Chrome is a carcinogen, HTC³ is not; Hex Chrome is an oxidizer, HTC³ is not; finally, Hex Chrome baths are extremely corrosive (pH 0 - 1.5), HTC³ (pH about 7.0) is not. Therefore, because of the EPA's continued crackdown on Hex Chrome bath platers, the opportunities for brush platers who have  HTC³ capabilities are growing daily.

You can assure your customers that they do not have to sacrifice deposit properties by switching to HTC³ Chrome. As a matter of fact, in several independent tests, HTC³ has  repeatedly proven to have much better wear resistance than traditional Hexavalent bath hard chrome.

HTC³ does have its limitations:  complex and intricately shaped parts   are impossible to plate and very thick deposits are impractical.

Having listed many of the reasons why a.full service brush plating shop should add LDC-HTC³ to its plating arsenal, you must consider the following points.

LDC-HTC³ is unlike any other brush plating solution, in that there are several, set in stone rules/parameters which must be followed to achieve success (if you want to produce a functional/engineered hard chrome deposit and not just a color change/cosmetic change):

• The solution must be heated and maintained during the entire operation at 165° - 175°F (73° - 80°C)
• The solution must be pumped to the anode
• Red scotchbrite must be used as the anode wrap
• Graphite (preferably) or platinum clad niobium anodes must be used
• An LDC Porta-Plater heater pump system (or equivalent) that is brand new/never used with any other material must be used
• If"thieving" tape is required, lead tape should be used

In addition, here are some important dont's:

• Do not filter solution
• Do not use stainless steel anodes, heaters, or solution containers with HTC³
• Do not let the solution overheat and evaporate
• Do not attempt to machine or grind HTC³ (polishing and
  blending of the deposit is permissible)

Because of the cost, HTC³ will not replace all bath chrome plating, but a lot of applications, now make sense to brush plate. We suggest keeping the chrome deposit thickness to less than 0.002" (50 microns). But, if an application requires a heavy deposit, just use copper andlor nickel to build-up the required thickness, grind or polish the surface to the desired finish leaving the part 0.0005" - 0.001" (12-25 microns) undersize, and then plate with LDC-HTC³. Depositing just 0.0002" - 0.0003" (5 - 7.5 micros) provides all the hardness and wear resistance required for most applications. In addition, thin deposits on steel/iron will pass the copper sulfate test.

Hopefully, this information has helped you better understand the commitment required and the endless potential offered by LDC-HTC³ Chrome.

LDC is in the process of planning a series of 1 day chrome training sessions to be held in Norfolk, VA. If you are interested in attending please contact LDC or W.R. Associates for further information.

This newsletter is published by W.R. Associates, Inc.
All rights reserved. Copyright, 1998.