part to be removed.
（
5
）
Apply the patch to the intended position and press it tightly, draw a line along the edge
of the part to be removed and cut it out, using methods like gas cutting or excising
according to the actual situation, and then align the patch with the excised area.
（6） Weld the seam by gas welding or carbon oxide protection welding. Spot-weld it at a
pace of 30-50mm to fix it and then weld it again in a certain order after beating it
smooth. For seams requiring welding of higher strength, doulble-sided welding is
prefered.
（7） Smooth the welded seam by beating it with flat hammer, release the welding pressures,
and then shape it and polish the seam with a grinding machine.
4.4. Restoration of Wrinkled Parts
Depending on the damage extent of the plate work pieces, the wrinkles are divided into “live
wrinkles” and “dead wrinkles”. The “live wrinkles” are slight ones and can be directly removed by
beating the convex part with a hammer. The “dead wrinkles” refere to seriously damaged parts.
Since the wrinkles are folded and pressed against each other, so if you hammer the most convex
part, the wrinkles would get even more seriously and harder to release, hence the name “dead
wrinkles”. The principle of correcting the wrinkles is to spread “dead wrinkles” first so that they
become “live wrinkles”, and then “live wrinkles” are converted into convex-concave shape, and
finally restore the damaged parts just as you deal with convex-concave damages. The repairing
steps are as follows:
（1） First use support-draw method to apply a correcting force in the direction opposite to
that of the impact at the wrinkled part of the plate work, and then spread and ease the
wrinkles.
（2） Remove the wrinkled plate work and lay it on a platform and then, beginning with
the inner side of the wrinkled area, pry up the wrinkles with a proper prying tool and
heat the “dead wrinkles” one by one with a welding torch at the same time. Finally
all “dead wrinkles” are pried up and eased and converted into“live wrinkle”.
（3） Beat and smooth the “live wrinkles” from the inner side outward. The hammered
spots should be near the most convex part of the “live wrinkles”. At the same time
make sure the platform can support every beaten spot. When the wrinkles in one side
of the plate are almost smoothed, turn it over to beat the other side till all wrinkles are
completely spread out.
（4） Measure with a templet, and at the same time heat and beat the convex-concave part
to restore it to its original shape.
（5） When the vehicle body is assembled, test with a templet again and make finer
correction to achieve the final requirements.
（6） The seriously damaged wrinkles that can not be restored can be excised and repaired.
4.5. Welding of Four Doors and Two Covers
When welding the door panel, choose proper welding methods: gas welding (oxygen and
acetylene welding), CO
2
shielded welding, manual arc welding, resistance spot welding, braze
welding and so on. Besides, in order not to reduce the original strength and durability of the vehicle
body, try to adopt the welding methods used in manufacturing the door panels, and the dimensions
and types of all weld joints should be similar to those used by the original manufacturer.
As for appearance and quality, no burnt-through spots, half points, cracks, a lot of burrs or
other defects should exist at the welded parts. The welded surface should be smooth and
nice-looking, no obvious twist or deformation is allowed, and the indentation depth should be less
than 1/5 of the plate thickness. Flat spade and iron hammer can be used to carry out non-destructive
tests of the welded spots’ strength. Insert the flat spade between two welded spots to see if they are
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