Anti-Corrosion Treatment and Repair
Anti-Corrosion Treatment and Repair |
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Any procedure that disturbs these special treatments, such as panel replacement or collision damage repair operations, may leave the metal unprotected and result in corrosion. Proper recoating of these surfaces with service-type anti-corrosion material is essential.
After repair and/or replacement parts are installed, all accessible bare metal surfaces must be treated with metal conditioner and reprimed. Refer to the GM Approved Refinish Materials book which identifies the paint systems you may use.
The latest revision of the GM Approved Refinish Materials booklet is located on the GM Genuine Parts website at www.genuinegmparts.com.
After a collision, some vehicle structure areas such as frame rails, cross-members and rocker panel sections may need to be repaired. In most cases, the anti-corrosion materials need to be removed to perform these repairs. These materials are classified into two types: Closed Cavity coatings and Undercoat coatings. The primary difference between the two products concerns their drying characteristics. Both are intended to protect the surface they are applied to from corrosion caused by water, salt water or Magnesium Chloride blended de-icing compounds used to thaw icy winter roads. They also can provide a measure of sound deadening.
The Closed Cavity coatings remain sticky to the touch and will seep into seams initially and over extended periods of time. Closed Cavity coatings provide the best corrosion protection inside of rocker panel sections, pillar sections, frame rails, cross-members, doors, rear compartment lids and closed areas of hoods - anywhere that is concealed or closed off to exterior surfaces.
The Undercoat coatings are "dry to the touch" and offer the best corrosion protection and sound deadening for floor pans, wheelhouses, inside rear compartment and underhood areas - anywhere the coated surface is exposed.
Below is a listing of Undercoat coatings and Closed Cavity coatings that GM believes to be reliable. While others may exist, we have found these products, or equivalents to them, can be used with satisfactory results. Always use these products according to their manufacturer"s recommendations.
Undercoating and Closed Cavity Coatings
The following products are available from *Automotive International/Valugard. Contact them at 1-800-543-7156, or at www.valugard.netStock number | Type | Description |
VG-104 | WAX/SOLVENT BASED UNDERCOAT | Traditional Wax/Solvent based Undercoating available in aerosol or spray gun canister Meets OE specifications for corrosion resistance |
VG-076M | HYBRID (SOLV./WATER) UNDERCOAT | Meets OE specifications for corrosion resistance |
VG-140 | WATER BASED UNDERCOAT | Meets OE specifications for corrosion resistance |
VG-101 | WAX BASED CLOSED CAVITY COATING | Meets OE specifications for corrosion resistance |
VG-UCG | CANISTER UNDERCOATING GUN | High quality undercoating gun uses canister packaging of undercoating |
VG-CRG | CANISTER CLOSED CAVITY COATING GUN | High quality coating gun for applying canister packed, closed cavity coating products. IT is supplied with a 30 in application tube with a nozzle for cavity panels. |
The following products are available through your local *3M® distributor. Information about 3M® product retailers in your area may be obtained at 1-866-364-3577 or at www.mmm.com/automotive.
Stock number | Type | Description |
08804 | No Cleanup Water-Based Undercoating - Black | Coarse texture SBR rubber and acrylic applied with 3M No-Cleanup Gun 08801 |
08964 | No Cleanup Undercoating - Black | Smooth texture SBR rubber applied with 3M No-Cleanup Gun 08801 |
08881 | 16 oz aerosol Undercoating | Calcium Carbonate and asphalt based undercoating |
08882 | 17 oz aerosol Underseal™ Undercoating - Black | Rubber based, paintable undercoating |
08883 | 19.7 oz aerosol Rubberized Undercoating - Black | Synthetic polymer based undercoating |
08891 | Rust Fighter - 1 Amber Closed Cavity Coating - quart canister | Synthetic Resin remains tacky seeps into crevices; Applied with 3M Applicator Gun 08997 and Application Wand 08998 |
08892 | Rust Fighter - 1Amber Closed Cavity Coating - 24 oz aerosol | Synthetic Resin remains tacky seeps into crevices; aerosol can |
08801 | No Cleanup Undercoating Gun | - |
The following products are available from *Crest Industries, Inc. at 1-800-822-4100 or www.crestauto.com.
Stock number | Type | Description |
AH-C | HONEY COAT/WAX BASED CLOSED CAVITY COATING | 16.5 OZ AEROSOL CAN AMBER COLORED SEEPS INTO CREVICES AND REMAINS PLIABLE 36 in spray wand with 360 degree nozzle available (WA-HC) |
BZ-BAC BZ-BACB | AMBER COAT/WAX BASED CLOSED CAVITY COATING | GALLON - AMBER COLORED (BZ-BAC) OR BLACK (BZ-BACB) SEEPS INTO CREVICES AND REMAINS PLIABLE APPLIED WITH WZ-GRP GUN AND SIPHON HOSE Flexible spray wand also available (WA-ND) |
AC-R | RUBBER COAT/RUBBER BASED UNDERCOATING, PAINTABLE | 17.75 OZ AEROSOL |
AR-C | SUPER RUBBER COAT/LOW V.O.C. RUBBER BASED UNDERCOATING, PAINTABLE | 17.75 OZ AEROSOL |
BA-C | AUTO COAT/RUBBER BASED UNDERCOATING, PAINTABLE | 28.7 FL OZ CONE-TOP CAN AND GALLON APPLIED WITH GU-C UNDERCOATING GUN |
GU-C | UNDERCOATING GUN | ATTACHES TO BA-C CONE-TOP CAN |
WZ-GRP | GUN AND SIPHON HOSE | USED WITH BZ-BAC AND BZ-BACB |
WA-ND | FLEXIBLE SPRAY WAND | USED WITH WZ-GRP |
The following products are available from *Kent Automotive. Contact them at 1-888-YES-KENT (888-937-5368) or at www.kent-automotive.com.
Stock number | Type | Description |
P60305 | Wax Based Inner Panel Rustproofer - CLOSED CAVITY COATING | 24 oz Aerosol (can apply with 36 in wand and 360 degree nozzle kit) |
KT14912 | Rubber Guard Low VOC Rubber Based Undercoating | 24 oz Aerosol (can apply with 36 in wand and 360 degree nozzle kit) |
KT14725 | Aerosol Extension Wand Kit | 36 in wand and 360 degree nozzle |
KT14796 | Rubber Guard Low VOC Rubber Based Undercoating | QUART - Applied with undercoating gun |
P30025 | Siphon Feed Gun | - |
P86079 | 360 Degree Wand for siphon feed gun | - |
Weld Thru Coating |
Part Number | Description |
4353 | Weld-Through Primer |
*We believe these sources and their products to be reliable. There may be additional manufacturers of such material. General Motors does not endorse, indicate any preference for or assume any responsibility for the products from these firms or for any such items which may be available from other sources.
Seam Sealers |
Sealers are intended to prevent water and dust from entering the vehicle and also are anti-corrosion barriers. Sealers are applied to such areas as rear compartment lid edge flanges, wheelhouse, quarter outer, floor, cowl, roof, and various other panel to panel attaching points. The factory sealed joints are obvious and any damage to these sealed locations should be corrected by resealing. Attaching points of new replacement panels should be resealed. Replacement lids and doors will also require sealing in the hem flange areas.
Flanged joints, overlap joints, and seams should be sealed using a quality sealer of medium-bodied consistency. The sealer used must retain its flexible characteristics after curing and be paintable.
Open joints which require bridging of the sealer in order to close a gap should be sealed using a heavy-bodied caulking material. Follow the label directions for the material selected.
Color application may be required in order to restore repaired areas such as hood, fenders, doors, quarters, lid, roof, engine compartment, underbody, and inner panels to original appearance. When this is necessary, conventional refinishing preparation, undercoat buildup, and color application techniques should be followed.
Deadener materials, spray-on type, are used on various metal panels in order to provide corrosion resistance and joint sealing. They control the general noise level inside the passenger area of the vehicle. When deadeners are disturbed because of damage, are removed during repair operations, or a new replacement panel is installed, the deadener material must be replaced by a service equivalent material. The application pattern and location of deadener materials can be determined by observing the original production installation.
Cleaning of the interior and underbody panel surfaces is necessary when original galvanized or other anti-corrosion materials have been burned off during welding or heating operations. Removal of the residue from burning will require additional care in such areas as interior surfaces of box-type construction and when configurations of the metal panels limit access to interior surfaces.