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.

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
609.636.5858
www.aerocoat.com

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.

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.

Epoxy Blush Warning

With the onset of cooler, damp weather of late summer/early fall brings the possibility of a troublesome paint problem called Epoxy Blush. Here's what Epoxy Blush is with some tips of how to prevent it.

EPOXY BLUSH

Amine-cured epoxy formulations are widely used in ambient temperature cured coatings, like Mil-PRF-22750. If amine-cured epoxy resins polymerize during conditions of cool ambient temperatures or high humidity, i.e. condensation on the coating, they may develop an amine blush, also called epoxy blush. The amine at the coating surface develops as an oily, waxy or milky film, sometimes amber to clear in color.

The amine component reacts with moisture and atmospheric carbon dioxide to form ammonium bicarbonate and/or ammonium carbamate. This may or may not be visible on the coating's surface but can interfere with adhesion if over-coated. Contractors and inspectors should be alert to this phenomena and test suspect surfaces.

These amine compounds are often hygroscopic and very efficient scavengers of carbon dioxide from the air, even though carbon dioxide is generally present in low concentrations in outdoor environments. In indoor environments with human activity carbon dioxide may be increased 2-3 times. In the presence of gas burning motors (fork lifts, tow motors) and salamanders etc., the carbon dioxide would be even greater. These sources of heat may also produce copious quantities of water vapor resulting is exacerbated blushing problems.

If amine blush/epoxy blush is detected it should be removed. Thorough washing of the surface with water and detergent (contact coating manufacturer) is recommended followed by retesting to ensure complete removal. Recoating is sometimes necessary.

Call me @ 609-636-5858 if you need more information on this problem or how to fix it.  And visit our website, www.aerocoat.com , View our Newsletters, to review our other Knowledge Base articles.

Dick Creek

New Warehouse Opens

Here it is, our new bulk storage warehouse that we will use expresssly for bulk shipping.  The additional space and specialized racking will allow us to add more than 100 pallets of paint and thinners to our inventory. This additional capacity will make it even easier for us to meet our same day shipping guarantee, which simply stated is, "if it's in-stock and we receive your order before 2 PM, we will ship your order on the same day."

Stocked Products

Check link above for a look at our Stocked Products