Marine: Corrosion Resistance in a Challenging Environment

How to protect Aluminum Boats from Salt Water Corrosion – By Tim Cabot, President of DCHN

Salt water marine is considered to be one of the toughest environments for aluminum, as salt-water and galvanic conditions are a perfect recipe for rapid corrosion.

Given our long history with manufacturers of military, commercial and yachting hardware due to our location in Rhode Island, DCHN is an excellent and long-standing provider of both conventional and proprietary anodic and conversion coatings suitable for marine applications.

Due to the unparalleled control of our process lines and use of certified and independent testing facilities, DCHN can provide Mil-A-8625 Type II and Type III anodic coatings that reliably meet MIL spec salt water spray corrosion specifications. DCHN offers a broad range of dye coloring and sealing techniques to meet your specific needs.

MICRALOX, Salt Water Corrosion, Corrosion Protection

For superior salt water spray resistance, DCHN provides MICRALOX® partially crystalline anodic coatings that have gone over 15,000 hours at an outside lab without showing evidence of corrosion.   (Download our white paper on Microcrystalline Anodic Aluminum Oxide Coatings: A Revolutionary Basis Technology for Corrosion Protection) In addition, MICRALOX® has unsurpassed hard coat performance, does not use heavy metals, and is RoHs compliant. Apart from the anodic coating, DCHN is able to carry out very detailed hand masking accurately and economically using both clear and yellow chromate conversion coatings in conjunction with anodic coatings or on their own.  It also offers a range of printing and marking services, including SANFORD PRINT, conventional screen printing, and laser marking.

Whether you are producing a rail, block, hydraulics, travelers, electronic casing, or other marine hardware, DCHN has an anodic and/or conversion coating that meets your needs.

© 2014 Tim Cabot, DCHN All Rights Reserved

 

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12 Proven Tips to Save Time and Money for Aluminum Anodizing, Hardcoat, and other Metal Finishing Services.

Best Practices, Tips and Techniques in Anodizing and Metal Finishing – By Tim Cabot, President of DCHN

Too often companies who require anodic coatings and other metal finishes fall into communication breakdown due to the many things that the metal finisher requires to do a high quality job effectively and efficiently. A lack of helpful communication often times results in delayed deliveries, greater costs, quality issues, disputes and needless anxiety.

There is really no reason to find yourself in this situation. In fact, take a look at a synthesis of best practices for anodizing and metal finishing in the attachment  “12 Tips to Save Time and Money” and stop worrying. Click Here.

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This is No Fish Story for Real – The MICRALOX® Salt Water Fishing Reel

By Tim Cabot – President of DCHN

MICRALOX, Aluminum Anodizing, Fishing Reel

Untarnished MICRALOX® Coated Fishing Reel.

We never set out to make fishing equipment corrosion resistant, but if salt water is messing up your fishing reel, we have a story to tell. MICRALOX® was developed to solve the problem of corrosion and discoloration for aluminum medical equipment that requires regular cleaning and sterilization.   As many companies have learned, conventional aluminum anodizing just does not perform in these applications, especially where high pH cleaners are used.

Our parent company’s outside board of directors, many of them with years of experience in medical device and equipment manufacturing, have provided some excellent guidance that along with the inherent strength of the coating has led MICRALOX® to become the fastest growing new anodic coating technology in over thirty years.

Somewhere along the line, however, an important line was crossed by one of the outside board members.  Advise and consent was ditched in favor of skunk works projects, and little known to me, one of the board members was able to pursue his outside passion  – salt water fishing – with a MICRALOX® coated fishing reel.

As all of you anglers know, most reels are made out of aluminum, and they are all coated with decorative Type II aluminum anodizing.  And no matter how well you wash down your equipment and the end of the day, the fishing reels usually start to corrode within months because of the salt water.  So imagine his delight and my surprise when Bob Rabiner, one of our board members, arrived with a perfectly beautiful and completely untarnished MICRALOX® coated reel that he claimed is used all the time but doesn’t show the use.  It’s been over a year now and the aluminum reel looks perfect. Apparently it was an inside job orchestrated by the COO of DCHN, Jack Tetrault, who is another fisherman.  Thank goodness they do not have more expensive hobbies.

Click Here to request a sample of MICRALOX® on aluminum

© 2014 Tim Cabot, Sanford Process Co., All Rights Reserved

 

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Metal Tolerance Guidelines as it Relates to Different Aluminum Hard Coat Technologies.

Insightful Guide to Quality Product for Metal Finishing Manufacturers  ~ By Jack Tetrault, President of Sanford Process Co. 

March 19, 2014, Woonsocket, RI

Regardless of how experienced the manufacturing company that buys hard coat or other anodic finishes on aluminum is, there seems to be misunderstandings about what they need to do to insure that their tolerances are held during the finishing operations. Often, I see the same assumptions made and the cost of these assumptions can be high. Considering just the coating thickness, without considering what tolerance the finisher needs or what material they need to remove to provide cosmetic appeal to the part can be the stake in the heart of a quality product. Click here to see our white paper on Metal Tolerance Guidelines as it Relates to Different Aluminum Hard Coat Technologies. This can save you many headaches.

© 2014 Jack Tetrault, Sanford Process Co., All Rights Reserved

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Anodizing Racks: When It Makes Sense to Purchase Part Specific Tooling.

Selecting the right Anodizing Rack designs for Anodizing that Produce Better Results : From Jack Tetrault, President of Sanford Process Co. 

Woonsocket, RI (February 14, 2013)

It’s probable that you have never given any thought to the material or the design of the tool that your aluminum part will be racked on for anodizing or hardcoat; and for many of you, that’s fine. However, since a well-designed rack can cut your anodizing lead-time, lower your finishing cost, and provide for higher and more consistent quality, it is something that should be considered.

When is it appropriate to design a part specific rack you ask? The answers are more complex than can fully be addressed here but if you process the same parts over and over, are concerned with cost and quality, or you want specific and well placed racking, specialized tools may be the answer. High volume is NOT the only reason to consider specialized racks but is certainly a reason as well. I have worked with many customers to design racks that specifically address concerns they have about their parts regardless of volume.

Usually, specialized racks means titanium racks. Titanium racks have long life because they are not consumed by the chemistry and they do not need stripping after anodize. They can be specially designed with a variety of fingers, clips, and other contact points, and be sized to maximize the volume of parts that can fit in a tank.  They can also be designed to hold the part for superior rinsing and drainage, and protect the part from damage during travel.  Consequently, a well designed rack is an effective way to improve process capability (ie, better quality), lower finishing costs by increasing tank utilization and avoid stripping requirements, and produce faster turn times by maximizing loads while designing the tooling for quick racking and unracking.  The issue is that these titanium racks for anodizing can be very expensive given the cost of the material and the specialized cutting and welding processes to construct them. Generally speaking the pay back period of a titanium rack is about [500 uses].  The lead-time for a titanium rack is usually about 8 weeks after the design is finalized so the use of titanium racks requires a bit of planning as well.

On the other hand an aluminum rack is relatively cheap, are easily assembled and disassembled, and can be quickly designed to accommodate a great variety of part shapes and sizes.   The lead-time of an aluminum rack is usually a day or so as a full service anodizer should have some capability to produce racks in-house on short notice. Lastly aluminum is a more conductive material than titanium that allows more current to flow through the same contact area.  This is especially important for hard coat where the current can be up to 60 Amps per square foot.  On the downside, while flexible and quick to organize, aluminum racks are seldom a perfect fit for the part but rather adjusted or adapted to the piece. While aluminum is less expensive than titanium, it is not cheap, and aluminum racks must be stripped after each anodize cycle because they become coated along with your parts.  (A coated rack has much higher electrical resistance that makes it unsuitable as tooling.) Further the rack loses material and strength after each stripping process. This usually shows up first in the fingers or clips that end up not holding the part tightly.   Typically an aluminum rack isn’t used more than 5 times for anodizing after which the tooling is discarded.  Apart from the cumulative rack cost, there is also the issue of the time it takes to strip the rack. In addition, since aluminum racks are not specialized to maximize production quantities, turn times can be longer than optimal even if there only moderate part volumes.

aluminum racks, anodizing racks, titanium racks, titanium anodizing racks

Anodizing Rack Parts

The purchase of tooling is always done in conjunction with the metal finisher who will coat your parts.  The reason is that the tooling should maximize tank production that is dependent on both the tank size and the capacity of the rectifier used to drive the anodizing process.  Secondly, the metal finisher will need to work with you to understand where the part can be racked to accommodate both the part weight, overall part surface area, and electrical contact requirements. Lastly, the metal finisher needs to think about the orientation of the part to make sure that there are no cavities that will form air pockets, can’t be drained, or doesn’t allow for complete rinsing.

Fortunately, there are thousands of specialized racks designed for a variety of products and working with your metal finisher you may find a great solution that delivers better results. Cost, quality and productivity are at stake.  Any questions don’t forget to “Ask Jack” (jtetrault@d-chn.com)

©2014 Jack Tetrault, Sanford Process Co., All Rights Reserved

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Can I really get a true anodic hardcoat that exhibits vivid, crisp and true color?

Sanford Process Quantum® Hardcoat Colors vs. Traditional Hardcoat and Color Anodize – From Jack Tetrault, President of Sanford Process Co.

Woonsocket, RI (February 6, 2014)

“Can I really get a true anodic hardcoat that exhibits vivid, crisp and true color?”  This is a question we get asked over and over and the answer is…..”Yes” – if you have a vendor who uses a Sanford Low Voltage rectifier. Without it, you will either get a very thin hard coat, a dull lifeless color, or a type II anodized product that is being passed off as hardcoat. Here’s why:

Conventional hardcoat is produced by using an electrolyte at 32˚F while applying a current density of 25 – 50 amps per square foot (ASF) to the aluminum being anodized. This process will yield a natural color (“Natural” Hardcoat) that is usually a darkish grey, green or brown depending on the aluminum alloy (and your eyesight) at thicknesses of .0016” – .0024” (mil spec thickness).  Even at a thickness as low as .0007” on most alloys, the coating will have a noticeable shade undertone. Given the discoloration of the oxide, it is impossible to dye the coating and have the color be true, crisp or even recognizable as it was intended.  For example red may appear dark burgundy or maroon. This is a reality because anodic coatings take on color through dyes that flood the anodic coating pores before sealing.  Unlike pigment chemistry found in powder coating for example, dyes work by coloring the base material in the same way as dyes color fabric.  Like a fabric, the dyes require a bright substrate to produce a bright color – otherwise, the resulting color will be dulled or darkened to the degree the substrate is dull or dark.

In order to achieve true, crisp colors, the anodic coating must remain clear or translucent before dying so that when the dye is absorbed into the pores it will show its true color, such as, fire engine red, sky blue, orange-orange, etc. Type II anodize does exactly that because of the process conditions. It stays clear at thickness as much as .0009” BUT it is not hardcoat as the current densities are very low. Consequently, Type II anodize is very easily scratched and abraded.

Sanford Process Quantum® Hardcoat Color Anodizing

Sanford Process Quantum® Hardcoat Color Samples

Sanford Process QUANTUM® hardcoat, on the other hand, can produce CLEAR hardcoat that can be dyed to beautiful colors. There are NO other systems in the world capable of producing this type of coating that can pass military specifications for hardness, thickness, and corrosion resistance (i.e., certified as hardcoat) for medical, marine and military applications.

An easy way to check whether you have a Type II anodic coating versus a Sanford Process QUANTUM® hardcoat is to run the point of a sharp knife over the surface.  A Type II coating will gauge over time while a hardcoat will blunt the knife – in fact, you may see lines on the hardcoat that is metal from the knife.  (You can wipe these lines off.) So don’t pay for a thoroughbred and get a donkey. Make sure you get the wear resistance and quality you are paying for.

See the difference yourself, request samples of Sanford Process Quantum® hardcoat Colors by clicking here.

© 2014 Jack Tetrault, Sanford Process Co., All Rights Reserved

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Having Anodizing Issues with Aluminum Castings?

Insights to Anodizing Solutions For Die-Casting Aluminum Alloys – Jack Tetrault, President of Sanford Process Co. 

Woonsocket, RI (February 4, 2014)

Aluminum Casting

Aluminum Die-Casting Part Anodized by Sanford Process.

A recent correspondence I received related to difficulties with hard anodizing a cast aluminum product. The cast part was receiving a black hardcoat anodic coating. The company was experiencing several consistent problems trying to finish this part, and none of their regular vendors could solve the problem.

First, the part needed to be finished with an intense black color with no un-anodized spots or discolorations. Second, the product had to be capable of passing MIL 8625 Type III salt spray specifications for hardcoat anodize that are normally expected of wrought alloys.Lastly, the product had to be finished economically.

Aluminum Casting

Aluminum Die-Casting Part Anodized by Sanford Process.

After reviewing the criteria and possible solutions, DCHN, along with its sister company Sanford Process Corporation, was able to engineer a process that enabled the customer to meet its company’s specification without costly additional steps like impregnation. Sanford Process Plus® Low Voltage rectification process along with a “secret ingredient” solved the problem.

“The Sanford Corporation PLUS® and the “secret ingredient” enabled us to create an oxide film of nearly flawless character,” according to a DCHN process engineer. This coating offered the perfect solution to achieve a deep black color and meet the salt spray resistant requirements demanded by the end user. Because the process had only a few added steps, the additional cost was kept to a minimum.

The lack of a capable process that caused the customer missed deliveries, sub-par quality, and significant lost dollars in returns, wasted time, and scrapped parts were all eliminated by the DCHN and Sanford Process technical staff.

When it comes to castings, we have “solutions”. If you would like to schedule a 15 minute engineering review, please submit your request at ENGINEERING REVIEW.

© 2014 Jack Tetrault, Sanford Process Co., All Rights Reserved

Posted in Aluminum Anodizing - Type II, Aluminum Anodizing - Type III, Aluminum Casting, Uncategorized | Tagged , , , | Leave a comment