Aerospace Coating Prep Essentials: Thinners, Adhesion Promoters, and Curing Compounds on GSA Advantage

GSA Advantage continues to revolutionize the way government contracting officers and procurement professionals buy materials and products for their teams. And their preferred partner? Greenwood Aerospace. 

Conveniently located near the nation’s crossroads, we are proud to serve the military and federal government by providing leading aircraft parts, rotables, and hundreds of consumables from the industry's leading brands. 

Here is our take on the essential aircraft-coating thinners, adhesion promoters, and curing compounds, all of which are easily sourced through GSA Advantage. 

Aircraft Coating Preparation Materials

The foundation of all successful aircraft coating systems is proper surface preparation. We cover the most important categories of coating preparation materials, which we have made available via GSA Advantage. 

These include:

- MIL-T-81772 type II

- qualified thinners

- solvent cleaners

- degreasers

- adhesion promoters

- curing compounds

These have been sourced from manufacturers whose products meet and exceed the most rigorous MMI-L-PRF standards and OEM standards. 

Engineered for use across a full spectrum of aircraft surfaces and the most common substrates, from aluminum airframe structures to composite paneling and even polyester top coats and sensitive avionics adjacent areas. These products will work for you. We have products for:

- field touch-up operations

- fades or isochronal level repairs

- other shop repairs

- and even depot-level maintenance

All products linked through GSA Advantage are available from Greenwood Aerospace. We are an AS9120B-certified distributor committed to sourcing compliant materials through approved manufacturing channels. Our AS9120B certification reflects our constant adherence to the aerospace industry's highest quality management standards for distribution. We firmly believe in traceability, shelf-life compliance, and proper handling from the manufacturer to the end user. 

Key Specifications & Certifications

MIL-T-81772 Type 2 designates thinners that are made specifically for epoxy-based aerospace coating systems. These have defined evaporation rates, flash points, and solvency requirements. 

We carry PPG Aerospace/PRC DeSoto's DEFT IS-237, which you can find here.

This is a MIL-PRF-22750-compatible system that works with select polyurethane systems using type three thinners. It remains the specification choice for dedicated polyurethane applications like MIL-PRF-85285. Always consult the aircraft technical data and the manufacturer's TDS before crossing any coding chemistries, and make sure they are approved for the area and aircraft. 

These products are DOT hazard class 3 (flammable liquids) and are governed by 49 CFR, with air shipment restrictions above the limited quantity thresholds. Keep that in mind when ordering. Most qualify as ECCN EAR99 through export contacts, particularly FMS programs, which should be reviewed with your export control officer. 

Product Formats And Packaging

MIL-T-81772 Type II Epoxy Thinner

DEFT IS-237, Clear, MIL-T-81772 Type II Spec Epoxy Thinner, Gallon — PPG Aerospace / PRC DeSoto | MFR PN: MIL-T-81772 TY2 | GSA Item: DEIS237XXXMIG11B. Available in single-gallon format, suited for shop-level use and low-volume spray applications.

MEK-Based Cleaners & Paint Thinners

MEK 7401 Arposolve Cleaner & Paint Thinner, 5 Gallons — Univar Solutions | MFR PN: 16131797. Single 5-gallon pail format, ideal for sustained shop operations that require frequent surface wipe-downs and equipment cleaning.

Solvent, MEK Arposolve MEK 7401, Gallon, Pack of 5 — Univar Solutions | MFR PN: 16131795. Pack-of-5 gallon configuration offering flexibility for distributed storage or multi-station use without committing to a full pail.

Skykleen 1000 Solvent Cleaners

Skykleen 1000 Solvent Spray, 16 oz, Pack of 5 — Eastman | MFR PN: 1000 | Vendor PN: SK160Z-PKG5. Aerosol spray format in a pack of 5, best suited for targeted spot cleaning, tight access areas, and field maintenance kits.

Skykleen 1000 Solvent Cleaner, 5 Gallon Pail — Eastman | MFR PN: 1000 | Vendor PN: SK5GL. Standard pail quantity for general shop use; compatible with wipe, immersion, and spray application methods.

Skykleen 1000 Solvent Cleaner, 54 Gallon Drum — Eastman | MFR PN: P3410401 | Vendor PN: SK54GL. Bulk drum format for depot-level operations, high-throughput maintenance lines, or base-wide contract stocking. Requires compliance with flammable liquid storage requirements per NFPA 30.

Degreasers

Degreasing Solvent, MIL-PRF-680 Type III, Gallon — Vantage Specialties | MFR PN: MIL-PRF-680 TYPE III. Single gallon format of a specification-qualified degreaser suitable for aluminum, composite, and ferrous surfaces prior to primer application. Lower VOC profile than MEK-based alternatives, making it suitable for environmentally sensitive facilities or operations with solvent-use restrictions.

Procurement & Supply Chain (Greenwood Aerospace)

Federal agencies, defense contractors, and military maintenance operations can source MIL-T-81772 Type 2 epoxy thinners, approved cleaners, approved degreasers, and other related coating-preparation materials directly from Greenwood Aerospace through GSA Advantage (see links above). 

If you have any additional questions about procuring these products, contact us at gsasales@greenwood.aero or call 580-865-6000 / 833-GSA-EBUY (833-472-3289). We will also help you out with product availability, bulk orders, or expedited shipping. 

Surface Preparation for Aircraft Surfaces

Surface compatibility must be verified for the specific substrates in question, whether they're aluminum skins, composite panels, composite skins, or other common substrates. All finishes respond differently to preparation chemicals and mechanical processes, and for adhesion to be properly achieved, this must be a known quantity first.

Adhesion preparation, which includes scuffing with appropriate abrasive media or, where specified, adhesion scoring, is required for epoxy primers and some topcoat applications to ensure mechanical bonding. Coating systems that include film-thickness targets and thinning ratios must be confirmed before any spray application begins. 

Cleaning To Remove Grease

Cleaning to remove grease should begin with a pre-wipe using an improved aerospace solvent, MIL-T-81772 Type 2 Epoxy Thinner (where permitted by the manufacturer). Dedicated degreaser like MIL-PRF-680 Type 3 Solvents from Vantage Specialties. Use these to break down grease, oil, and heavy surface contamination.

For seriously stubborn deposits, MEK-based cleaners like Univar's Aprisolve MEK 7401 are effective solvents on all common aerospace substrates. Acetone may be referenced in some technical guidance, but should only be used where explicitly approved because it can attack certain coatings in composite resins. 

Compatibility With Sensitive Surfaces

Composite parts, painted parts, and specialty finishes need special care during surface prep. Aggressive solvents like high-concentration MEK and some epoxy thinners can soften paint layers, attack composite resin matrices, or lift specialty coatings if applied without verification.

Before you wipe or spray, always do a spot test on an inconspicuous area of the surface and let it dwell for a bit to see if there’s any adverse reaction. Product selection should be guided by the manufacturer’s documentation, class designation, and approved substrate list. In regulated maintenance environments (FAA repair stations, military depots, AS9100-certified MRO facilities), compatibility verification must be documented on the work order, and the SDS and TDS must be on file to support airworthiness and quality audit requirements.

Safety, PPE, And Compliance

As with all chemicals used in industrial environments, the SDS is mandatory to be reviewed before any solvents, cleaners, or thinners are used. It must also be located in the shop area where it will be used.

Personnel have to understand the hazard classification, exposure limits, first aid procedures, and any required PPE before handling commences. Respiratory protection is required whenever solvents and epoxy thinners are sprayed or used in enclosed spaces. Also, make sure there is appropriate ventilation in those areas. Chemical-resistant gloves, safety eyewear, and coveralls are standard for handling and application tasks. 

Spill containment equipment, namely absorbent materials, containment berms, and non-sparking cleanup tools, must be staged in any area where flammable solvents are in use, in compliance with NFPA 30 and OSHA 29 CFR 1910.

All solvent products covered in this guide carry a DOT hazard class of 3 (flammable liquids) and require appropriate labeling, segregated storage in a hazmat locker, and hazmat-certified shipping. We are experts in hazmat shipping and can guarantee they will arrive as scheduled. 

Environmental And Regulatory Considerations

Coding preparation materials that are solvent-based, carry measurable VOC or volatile organic compound content, and are subject to EPA regulations. These are under 40 CFR part 59, and all state and local air quality rules that may impose even stricter limits are also applicable. Buyers need to confirm VOC compliance data in the products' SDS before the products are used in regulated facilities.

Disposal of spent solvents, contaminated wipes, degreaser residue, and grease-laid materials must follow EPA hazardous waste regulations under RCRA (40 CFR parts 260). 

And again, follow all state-specific requirements. Never dispose of solvent materials through standard waste streams. Licensed hazardous waste contractors should be engaged for collection. 

Procurement Through GSA Advantage from Greenwood Aerospace

Choosing the right product should be simple. Grime combined with moisture is a destructive force and usually leads to poor adhesion of paint and sealants. Using the right promoters, thinners, and degreasers is extremely important for the overall paint system to operate as it's supposed to for your fleet.

But sourcing approved materials to remove contaminants is only the first step. You also have to be able to procure it through approved channels. As a Native American-owned company and a small business in a rural area, Greenwood Aerospace checks a number of those boxes. We also streamline the process by sourcing these products on GSA Advantage, making it faster and easier for you and your team.