PIPER AIRCRAFT
PA-42-720(Advanced Trainer)
MAINTENANCEMANUAL

A. Storage(continued)
18.Repair Patch (Quick Cure Method) (continued)
(g)Apply one brush coat of 82C32 cement to clean buffed area of cell. Do not not apply beyond buffed area. Allow to dry from 10 to 15 minutes.
(h)
Repeatstep (g) with second coat.

(i)
Repeatstep (g) with third coat.

(j)
While third coat of cement is wet, apply fabric patch to damaged area as follows:

(1.) Dip patch in clean MEK and shake off excess solvent.
(2.) Lay patch into wet cement. Make sure patch is centered over damaged area.
(3.) Smooth out patch using a relatively dry brush. Work from the center of the patch to the

edges to remove all trapped air.
(k) Apply final coat of 82C32 cement over patch. Spread cement at least 1/8 inch beyond fabric patch.but not beyond buffed area.
CAUTION: NEVER APPLY A HEAT CURE TO 82C32 CEMENT.
(I) Allow repair to air cure for a minimum of 6 hours at a minimum temperatureof 70°F before moving cell or exposing the cell to fuel.
(m)Check repair after cure time to ensure cement is cured. If sticky proceed as follows:
(1.) Remove repair patch and all cement.
(2.) Repeat steps 1 thru 12. Make sure cement is not out of date.

(n) Check edges of repair for looseness:
(1.) Trim loose edges if less than 1/8 inch radially.
(2.) Bond loose edges if more than 1/8 inch radially.

NOTE: Channels or voids running from center of patch to edges are unacceptable.
(o) Performfuel cell leak test (refer to testing fuel cells).
19.Sealing Metal Surface Fittings
WARNING: DO NOT ALLOW ALODINESOLUTIONTO COME IN CONTACT WITH HANDS, EYES, OR CLOTHING.
(a)
Rub roughness off the affected area with a fine file or fine emery cloth.

(b)
Clean metal surface using a clean cloth dipped in Methylethylketone.

(c)
Moisten the cleaned surface with a clean cloth dipped in water.

(d)
Apply undiluted alodine1200 solution to the affected areawith a small nylon brush.

(e)
Allow the solution to dry until a light golden color appears.

(f)
After a coating has been formed, removethe excess solution by wiping the surface with a clean water moistened cloth.

(g)
Wipe dry.

EFFECTIVITY: 040-999

PAGE24
Jan10/9028-10-00
PIPERAIRCRAFT
PA-42-720(Advanced Trainer)
MAINTENANCEMANUAL

A. Storage(continued)
20. FuelCellAccessoryReplacement
(a)Obtaina curedrepairaccessoryfromthecellmanufacturer.
(b)Marklocationofoldaccessoryandpreservemarkingsforguidelinesto locatethenewpart.
(c) Removetheoldaccessoryasfollows:
(1.) Graduallylooseningan edgewithabluntprobe-likeinstrument.
(2.) Grasptheaccessorybythelooseedgewithpliersandgentlypeeltheaccessoryoffthe cellwallfromtheblindsideofacelllaptowardtheexposededge.Becarefulnotto pull thecelllapopenwhilepeelingaccessoryoff.
NOTE:Removaloftheoldaccessorywillprobablyleaveanunevencavityandsurface.
(d)Buffthecellsurfaceundertheaccessorywithemeryclothto smoothroughnessandprepare forcement.
(e)Buffandwashthecontactsurfaceofnewaccessory.Washthecellsurface[refertorepair patchheatcuremethodsteps(b)thru(d)).
(f)
Applymixed5923Crepaircementto bothsurfaces.Levelthecavityleftbytheremovalof the oldaccessory.

(g)
Rollthenewaccessoryintoplace.Placepaddedplatesinpositionto ensureadequate pressurewhenclamped.Useacellophaneseparatorto preventthecementfromstickingin thewrongplace.

(h)Cureaccessorywitheitheraircureorheatcuremethod.
EFFECTIVITY:

28-10-00
28-10-00 Jan
10/90
PIPER AIRCRAFT

PA-42-720(AdvancedTrainer)
MAINTENANCE MANUAL

A. Storage (continued)
21. Repairof Fuel Cell Defects
(a)
Repair blisters as follows:

(1.) Trim loose or ragged material from affected area.
(2.) Apply an outside and inside repair patch.

(b)
Repair holes, punctures,cuts, tears and deep abradedareas as follows:

(1.) Trim loose or ragged material from affected area.
(2.) Apply an outside and inside repair patch.

(c)
Repair loose edges as follows:

(1.) Buff loose edges and contact surfaces with emery cloth. (2.) Wash buffed area three times with Methylethylketone. (3.) Apply two coats of 5923C mixed cement to each surface. (4.) Clamp and cure. Either method may be used. (See repair patch.). (5.) Trim loose edges if less than 1/8 inch remains.

(d)
Repair inside loose fitting flange as follows:

(1.) Buff the edge of the flange and the contact surfaceunder the flange. (2.) Apply 5923C mixed repair cement,cellophane,padded plates and clamp. (Refer to repair patchheat cure method.)

(e)
Repair looseness against metal as follows:
　
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