Procedure Manual No. AT 101 Original Issue Date: September 19, 1989 Revision: 8 Date: June 1, 1997 PROCEDURE FOR APPLICATION OF PRIMER/FILLER/UV BARRIER PROCEDURE AT 101 – PF – ALTERNATE 3 For those involved in fabric covering in situations where compliance with sound environmental practices is difficult or impossible Air-Tech offers its non-toxic water based emulsion alternative #3 as a primer filler base coat for the fabric. All steps up to the application of the #3 primer coat are identical. After the fabric and tapes are installed move the assembly into the paint area for application of the flexible primer/filler/UV barrier. 1.
To ensure the primer attains the maximum wetting and adhesion the entire fabric covering must be cleaned with Air-Tech Fabric Wash RF 4020 Rev. 3. The surface should be allowed to dry at least 30 minutes before primer application. 2. To the clean fabric surface apply a thinned coat of Air-Tech PFUW 1050 using either a foam brush, paint pad, mitt or squeegee. The objective of this first thinned coat is to penetrate the fabric weave and gain adhesion to the fabric. If the material has a tendency to pinhole when applied wetting the fabric prior to this first coat with a distilled water moistened lint free cloth or sponge will eliminate the pinholes.
The primer PFUW 1050 can be thinned with distilled water. 3. After the first coat is dry a second cross coat should be applied to the surface. This coat can likewise be applied by foam brush, pad or by spraying using either an airless, HVLP or regular air pressure type spray gun. After drying this second coat should be sanded smooth with 280 – 320 grit. Do not sand over rib stitches, rivets, etc. but rather scuff these areas with a 3M Scotchbrite Pad #7447 (3M Bldg. Svc. and Cleaning Products Div., St. Paul, MN 55144). 4. Apply a third coat of PFUW 1050 to achieve coating thickness as desired. Apply only enough material as necessary to fill the weave as a base for the color coat.
Excess material is never a good idea on fabric. After drying sand surface smooth as in step 3 using up to a 400 grit in preparation for the color coat. Notes: a. Do not allow PFUW 1050 to freeze. b. When applying any water containing coating ie. PFUW 1050 temperatures should be above 50 F and humidity below 70%. To achieve these curing conditions a heated area may be necessary. Remember, that for the coating to cure successfully conditions must be such that the water will evaporate therefore the need for these conditions. c. Like aircraft dope this filler coat is softened and/or swelled by certain ketones, alcohols and aromatic solvents. Keep them away from the surface.
This primer is not affected by fuels, oils or other liquids normally found around an aircraft. 5. Primed and sanded surfaces are now ready for topcoating with selected color. Make sure certain material is fully cured and dry, normally one day at 70 F and less than 70% relative humidity, prior to topcoating. Follow manufacturer’s instructions during application.