Friday, November 22, 2013

Metallic mil-spec Topcoat Spraying

Metallic Mil-Sec Coatings


Don’t Spray Like This

In spraying most mil-spec coatings topcoat colors our painters get into a nice routine of spraying a certain way that brings us satisfactory results.  But there are a couple of metallic colors in the Federal Standard 595 color deck that you can’t spray the usual way at least without getting out-of-spec color appearance. 

There are 650 colors currently in the 595 color deck.  But 4 of those colors are metallics:  17043 gold, 17178 silver, 27043 semi-gloss gold, 37200 flat silver.  And one of those colors, 17178, is used fairly often for aerospace coatings applications.   If you spray 17178 like you usually spray Mil-PRF-85285 solid colors with 2 wet coats, you will probably think you have received a bad batch of paint.  This color in both Mil-PRF-85285 and in Mil-PRF-22750 has come up in more complaints than any other color.  And upon further investigation the problem usually comes from the improper spray techniques.  You can’t spray metallic colors the same way as you spray the rest of the solid colors in the 595 deck. 

Instead Spray Like This

Metallics must be spayed in 3 deliberately light passes with the spray gun.    Painters with automotive paint experience have an easier time with these metallic colors because they have had experience with spraying metallic paints during their automotive careers. 

Other keys to spraying metallics:

Proper mixing: Follow the recommended mix ratio to the letter.  If allowed use some thinner as this will help to achieve better atomization.

Low fluid delivery: Lower your fluid delivery to 1/2 to ¾ that you used for solid colors.  Look for fine atomization to reduce mottling & to bring out the metallic.

Multiple Passes: Start with light tack coats, cross pattern (1.0-1.5 mils Wet)

Allow 1-5 minutes flash.  Build film slowly with light coats, again cross coating.

Do not allow film to get too wet. (3.0-6.0 mils wet).  To bring out bright metallic fog the last coat from minimum 1 foot distance.  Total DFT should be 1.5-2.0 mils for optimum gloss and color consistency.

Consistent basecoat or Primer color: Always do original color match on the same substrate you’re your customer is going to use.  Gray primers impart darkness and blueness, buff primer brings out yellow color.

Increased the distance from object to be painted:  Painting too close with metallics will cause mottling, edge pull, darker color.  Keep spray gun further back.

Agitate metallic paints often: Before mixing paint and catalyst, agitate metallic base component well.

After paint is reduced for spray, swirl cup gun gently before each coat.  Or for large volume applications an agitated pressure pot is suggested.

Monday, July 15, 2013

Last Call for Silica Flattened CARC Topcoat

 The US Army is taking the final step toward eliminating the use of silica as flattening agent for its Chemical Agent Resistant Coating (CARC) products.   October 1, 2013 will be the deadline after which the Army lab will no longer accept silica-based flattened CARC for testing. This change has been expected for some time. There have been contractors and agencies that have fought this change but the change is inevitable. What this means specifically is that the MIL-DTL-53039 type I and type II products and the MIL-DTL-64159 type I products will no longer be available. In their place will be a wide variety of polymeric-beaded flattened products.
AeroCoat will be very proactive and has already started to inventory many of these new technology type products.   Specifically, we will stock the 53039 Type IV or Type IX in the following colors: 383 Green, 686 Tan, 34031(Type IX), 34201, 36231, and 37038 in quarts and gallons. We will inventory more colors of the 64159 type II including 383 Green, 686 Tan and 37038. 

In addition aerosol cans for touch-up (Type VII) are available in colors 383 Green, 686 Tan, and Foliage Green 34160.
  Please let us know if the products you anticipate needing are not on our list. We will certainly consider stocking these for you. And don't forget to talk to Jesse about the possibility of blanket orders which is a very effective way to reduce your costs for these more expensive items.

Please feel free to call me regarding your concerns and questions about these changes.




Thursday, March 14, 2013

The Legend of the brand Alumigrip™

The Legend of the brand Alumigrip™

Recently an article was written announcing the birthday of the brand Alumigrip® which stated that Alumigrip was officially born on  March 14,1968 making the brand 45 years old today.   For those not familiar with the Alumigrip brand name Alumigrip has been the standard of the aviation industry for high performance polyurethane topcoat color for painting of aircraft for a long time. The name Alumigrip is synonymous with paint for airplanes and is almost a generic term for aircraft paint much like Kleenex is generic for facial tissue.

That article appeared in the AkzoNobel magazine publication, REFLECTIONS Issue 13, page 6.  For your interest the REFLECTION magazine is linked here.  AKZO is the current owner of the Alumigrip brand by reason of their purchase of the aerospace and marine businesses of U.S. Paint in 2002. The article in Reflections magazine shows some graphics common during the period when Alumigrip was born.  The article quickly transitions into talking about the current technology of the Alumigrip product line which now includes a high-solids version and a base coat/ clear coat product line for general aviation aircraft painting. But there is a lot more to the Alumigrip story that was not told in the Reflections article. Here is an account of the word-of-mouth history of the Alumigrip brand written by two salesmen who were actually there to experience some of the Alumigrip history.

The legend of Alumigrip as it was handed down over the years comes from U.S. Paint where the product initially was developed.  The following article is “legendary” in that some of the actual facts about the events discussed are no longer traceable. So this article is based on the conversations that have transpired and the recollections over the years and may or may not be completely factual.  But this story is certainly part of the legend.

Alumigrip is believed to be the first two-component polyurethane commercially developed for use on commercial and general aviation aircraft in North America. 

Polyurethane polymers as a chemical class were around since about 1937 having been developed by Otto Bayer and his coworkers at the laboratories of I.G. Farben in Leverkusen, Germany, according to Wikipedia.   Initially, work focused on the production of fibers and flexible foams.   With development constrained by World War II (when PUs were applied on a limited scale as aircraft coating), it was not until 1952 that polyisocyanates became commercially available.  Commercially available polyurethanes for aircraft came much later.

Mr. Joe Dilschneider the President and owner of US Paint, (then known as U.S. Paint Lacquer and Chemical Co) a small industrial coatings manufacturer located in St. Louis, MO became acquainted with the technology as result of a chance meeting in a bar with a representative from the Bayer Company while Dilschneider was on a vacation in Germany. 

As legend has it the man from Bayer was describing a problem that was prevalent as a result of the development of the new chemical for the aviation industry developed by another St. Louis company, Monsanto. That chemical was called Skydrol® and was a phosphate ester liquid used for the hydraulic controls in aircraft.   Skydrol had many wonderful characteristics that made it a good hydraulic fluid for that application but acted like a paint remover to the aircraft paints and coatings of that time.   The legend continues that this conversation was the inspiration for the commercial development of polyurethanes to be used for painting airplanes.   Mr. Dilschneider went back to his laboratory at US Paint and presented his chemists with the challenge of developing a coating which would resist attack by Skydrol.   Dilschneider directed his team to look at the Bayer technology thinking this might be a viable commercial use for this largely unused type of coating. 

In 1964 Monsanto, McDonnell Douglas, and U.S. Paint teamed up to paint the first Douglas DC-9 with what would become Alumigrip.  As the St. Louis connection continues it should be noted that first DC-9 was delivered to Ozark Airlines, which was headquartered in St. Louis as well.  This ultimately led to the development and introduction of what is believed to be the first commercial product used exclusively as an aviation paint, which was called Alumigrip.   Through the 1960’s US Paint built on the success of its new product and developed strong business relationships with McDonnell-Douglas, Lockheed, Beechraft, and Cessna, among others.  Dilschneider acted on the early success with the DC-9 and made a deal with Bayer where US Paint was the exclusive importer to the US for Bayer’s patented curing agent technology for the product. 

In the late 60’s Dilschneider sold US Paint to Grow Chemical Corporation.  Under Grow ownership and Disschneder’s directing US Paint continued to develop polyurethane coatings.  The Alumigrip brand was introduced and the market for the technology continued to develop.  During the 70’s US Paint, though maintaining a strong relationship with Douglas Aircraft in Long Beach, CA began to concentrate its efforts on the business and general aviation markets.  By the end of the 80’s Alumigrip was almost exclusively used in business aviation –for many years it was the standard coating for private jets and other executive aircraft produced by Beech, Cessna, Lear Jet, Gulfstream, Falcon, and Sabreliner just to name a few.  The product was not limited to passenger air planes however.   Sikorsky used Alumigrip exclusively for application on helicopter fleets.  Also Air Tractor appreciated the toughness of the coating which allowed them to use their bright yellow color to coat their crop dusters. 

US Paint had a long list of celebrities with what seemed to be bizarre requests for special colors.  These included matching colors on countless logos, fabrics, cocktail napkins, china jewelry and parts off of various types of planes, boats and automobiles.   During the 70’s and early 80’s it seemed as if every day’s mail had another sample of something to match for someone’s aircraft.   By now more than 5,000 colors had been formulated in the Alumigrip line.  Please see below one of the earliest color cards of the Alumigrip standard colors.  VINTAGE COLOR CARD, circa 1975.

Also interesting is the shown ad below, circa 1984, which speaks of the pioneering aspect of Alumigrip and features one of US Paint’s most beloved salesmen ever, Orville Wilbur Wright, a descendent of THE Wright brothers.  Orville ad for Alumigrip

In the 1990’s low VOC. requirements for aircraft coatings caused US Paint (then owned by Nippon Oil and Fats of Japan) to take another look at the commercial aviation market and they developed High Solids Alumigrip which quickly developed a following among the world’s airlines which continues today under the direction of Akzo Nobel.  Today Alumigrip is again being used to coat air craft of every type and size. 

Nick Hall                                                          Dick Creek

VP Sales                                                                                                 President

AWLGRIP North America                                                        AeroCoat Source, LLC


Monday, June 25, 2012

MIL-PRF-22750 specification update

Revision G issued

On September 12, 2011 the specification for Mil-PRF-22750 was updated to Revision G. This was the first revision in almost 20 years and changed the specification in many ways.  The spec now makes distinctions for various levels of performance.  Now included in the spec are designations for Types, Classes, and Grades, none of which were ever relevant in the prior revisions.  Rev G has four different Types as well as two Classes and two Grades. The callout for this item now has become very complicated.  For example, a typical Hentzen product PIN number, Part or Identifying Number, would read as follows:  M22750-2-H-A-001G-17925, meaning it is Type II, Class H meaning high solids, solvent base formulation as opposed to Class W which would be water base formulation, and Grade A, for this one gallon kit of color 17925.  Here is the link to the latest revision of this spec  for those who are interested in all of the details. 
Questions should abound.  Feel free to direct your questions/comments to me here or give me a call @ 609.636.5858.

Dick Creek
AeroCoat Source, LLC.

Tuesday, April 17, 2012

Surprisingly Simple Suggestions for Gloss Conrol of Semi-Gloss Paints

Factors for Gloss Control of 2-Part Semi-Gloss paints.

Two-part epoxy and urethane mil-spec finishes with semi-gloss levels of gloss are especially tricky to get correct and consistent gloss readings from because the gloss range for this class of paint is relatively wide, 15 to 45 degrees of gloss for urethanes like Mil-PRF-85285, and 15 to 30 degrees of gloss for epoxies like Mil-PRF-22750. Any slight variation of key variables can change the gloss dramatically.  Here are two of the most important variables to control to get consistent and correct gloss readings:
Homogeneous Part A.  Shake Base Thoroughly.

Shake base for at least 5 minutes on a paint shaker

A paint shaker should be used for preparing the Part A of the paint for mixing and use.  Some of these 2-Part paints are heavily pigmented and the pigment and the flattening paste tend to soft settle.  By agitating the Part A’s for at least 5 minutes all soft settling and large paint particles will go back into solution and assure a smoother paint job and a homogeneous mix resulting in consistent paint properties including gloss.  The flattening paste must be consistently dispersed throughout the gallon, otherwise you can get high gloss from the top of the gallon and then low gloss from the bottom.

Check bottom of Part A can with stir stick for settling.

After shaking for at least 5 minutes and before mixing the two parts together check the bottom of the Part A container with your stir stick to make sure there is no sediment on the bottom or in the corners of the can.  If you find sediment this means that the can must be shaken or stirred for a longer period of time.

Mix Ratio. Very Important.
Check for the proper mix ratios (See the Product Information Sheet & the Product Label)

Mix ratios are always stated as parts per volume.  So, for example, a 3 to 1 mix ratio means 3 parts of Part A to 1 part of Part B by volume and the measurements must be accurate.  Most Part B’s of 2-part paints are full gloss materials so that even a slight mistake in the mix ratio will quickly change the gloss reading of your final paint job. 

For mixing less than full containers a mixing cup with gradations and/or a mixing stick come in handy to get the ratios correct and accurate.  Accuracy in measuring is important and will insure that the paint dries properly, and has the stated gloss, and will insure that the coating develops full performance properties.

To view AeroCoat's complete line of epoxy and urethane mil-spec topcoats click on AeroCoat's Stocked Products List.

Dick Creek
AeroCoat Source, LLC

Tuesday, March 20, 2012

Mil-PRF-85285 Revision E Announcement

MIl-PRF-85285 Revision E Issued

Revision E to this very important specification, Mil-PRF-85285, was issued on January 12, 2012.  But not to worry.  Almost nothing has changed for the users and specifiers as a result of this latest revision.  The only change as a result of this Rev is that an additional burden has been placed on the paint manufacturers themselves to further limit the amount of VOHAPS in the formulations of paints made to this specification.  VOHAPS are Volatile Organic Hazardous Air Pollutants and these objectionable ingredients are slowly being phased out by government and industry wherever possible.  You should see new production batches of this material arriving soon labeled with this new revision letter but otherwise unchanged.

The Mil-PRF-85285 specification describes Polyurethane Coatings for use on Aircraft and Ground Support Equipment and is AeroCoat’s featured line of products.  Currently, AeroCoat has the ability to ship any color of nearly 450 colors of Type I material and 175 colors of Type II material on the same-day-as-ordered basis.   For further details please check the list of 85285 Available Colors on AeroCoat’s website.

Tuesday, March 6, 2012

The mil-spec, Mil-DTL-53022, recently issued Revision E.

Revision E of Mil-DTL-53022 was issued on 19 January 2012 and gives the paint user more choices in specifying this epoxy primer because this revision adds Types IV and V to the spec which are higher performance products than the earlier Types I, II, and III. (Type I is not listed in Rev E so it can't be used on new contracts but is still available and sold as Rev D.)  The higher performance in Types IV and V is evident in the salt spray resistance of these products. Whereas the salt spray resistance of the Types I, II, and III is 336 hours, the salt spray resistance of Type IV and V is 1,000 hours. (The Type V product is essentially a touch-up kit.) These new Types are an effort by the specifying agency, the Army, to upgrade the performance of paint systems that use this primer.  A key phrase early in this specification says "Whenever one of the coating types is not cited in a relevant contractual document or drawing, select type IV."
Mil-DTL-53022 Type IV Epoxy Primer
AeroCoat is now stocking all of the types of this primer except the Type V touch-up kit. For your own copy of the latest copy of this new spec click the non-secure but safe download link, Mil-53022. And to check out the list of all of AeroCoat's Stocked Products on our website please click this Stocked Products link.