12.2.6. Repair of the deformed surfaces
The deformed surfaces repair mechanical or thermal influence on metal, and also filling of dents быстрозатвердевающими plastics or solder.
The rumpled places of plumage straighten, as a rule, manually by means of the special tool (metal, plastic, wooden hammers and various оправок) and adaptations.
Editing with heating use for осаживания (tightening) of strongly stretched surfaces of panels. For prevention sharp вспучивания and deterioration of mechanical properties, panels heat up to 600–650 ° With (cerise colour). Diameter нагретого stains should be no more than 20-30 mm.
Surface tightening make as follows:
– Gas welding, from переферии to the centre of a defective site, heat up metal and blows wooden киянки and a hammer rebuff нагретые places, using flat support or an anvil;
– Repeat operations of heating and осаживания before reception of an equal surface of the panel.
Roughnesses in panels can be levelled by means of polyester шпатлевок, thermoplastic, эпоксидных mastics of cold hardening and by means of solder.
Polyester шпатлевки form reliable connections with the panels which have been smoothed out to metal. They represent two-componental materials: nonsaturated polyester pitch and a hardener which is the catalyst for fast hardening of a mix irrespective of a thickness of a layer шпатлевки. Drying time at temperature 20 ° With – Therefore is reduced 15–20 minutes duration of drawing шпатлевки and there is no necessity to put it in some layers.
Thermoplastic is issued in the form of a powder. The elastic properties necessary for its drawing on a metal surface of the panel, thermoplastic gets at 150–160 ° With.
The surface which is subject to filling, should be carefully cleared of a rust, scale, an old paint and other pollution.
For the best adhesion it is recommended to create on a surface roughnesses by means of the abrasive tool. For drawing of thermoplastic a site which is subject to alignment, heat up to 170–180 ° With and put the first thin layer of a powder, which укатывают a metal skating rink. Then put the second layer and so on, before roughness filling. Each layer укатывают before reception of a monolithic layer of plastic. After hardening a layer smooth out and level metal circle.
The sites of panels of a body amazed with corrosion can be under repair эпоксидными mastics of cold hardening which possess high adhesion, sufficient durability and are easily put on the damaged sites. The structure of mastics includes hardeners, softeners (for increase of plasticity of pitch and shock durability hardened эпоксидного structure), наполнители (for fall усадки pitches and rapprochements of factors of thermal expansion of pitch and metal).
Solders ПОССу 18 or ПОССу 20 are applied to alignment of sites, before filled with solder, escalatings of edges of details and for backlash elimination.
It is better to apply to prevention of corrosion бескислотный a way of drawing of solder.
At considerable damages, panels replace new, with use of contact welding and electric welding in the environment of protective gases.