Guide for Evergreen Marine Airbags Repairing-Interview with Evergreen Maritime

When there is air leakage, identified the crack propagation by visual inspection on the marine airbags to check on the rubber characteristic by determine the surface whether seriously aging (fatigue fracture and sticky surface).
There are two ways of patching, which are hot and normal temperature sulfuration.
Now we introduce the hot sulfuration as follows:
1. Clean up thoroughly inner and outer marine airbags to ensure totally clean especially on the outer wall surface. Don’t immerse into the water more than 10 miutes before patching.
2. Marking/indentified the air leakage area by extending “wound” part outward 15mm.
3. Patch ply depends on the size of flake leakage area.
If leakage area approx. 100mm or propagating fracture 50-70mm will be patched with 4-6layers.
And it’s better to equipped “+” cushion of Nylon.
Note:
The material of interleave should be same with marine airbag. And the angle of line also should be same with the marine airbag body.
The first layer of interleave is ordinate. Length= length of “wound” + 50 x 2m
The second layer of interleave is bias. The angle should be same with marine airbag’s body. And it should be 20mm bigger than the first layer.
The third layer of interleave also is bias. The angle should be contrary with the second layer. And it’s 20mm bigger than the second layer. The 4th-6th layers is analogy.
Circular angle is required around the interleave. The semi diameter is 40-50mm.

4. File the flake leakage area by sand paper in single way direction for several times to ensure clean & smooth surface surrounding the fracture area. Remember to clean it again with compressed air.
5. The whole process should ensure there is no unwanted particular embedded and dry up the air bag surface. Then brush up some 502 glue with glue mixture of pure rubber material: petroleum base chemical of 1:8.
6. patching process - use prepared mentioned layer to patch.
7. Vulcanizing press process - using the rack structure indicated below to carried out vulcanizing process by heating up to 135 ± 5℃; press the flake leakage area with 0.08-0.12 Mpa pressure for 40-50minutes.
8. Inspection - Check the patching area to ensure the tight agglutination. Then inflate the air bag for final checking.