Proper Welding Techniques - General Considerations - Drader W30000 Instructional Manual

7. Proper Welding Techniques – General Considerations
Consider these variables when welding plastics.
Plastic should be at "room temperature" for at least 24 hours before it is welded.
Material
In order to achieve quality welds, ensure that the
welding rod matches the parent material. For example,
match polyethylene with polyethylene rod and match
polypropylene with polypropylene rod.
Do not expect a quality weld if the parent material and
welding rod do not match.
Heat
Each plastic melts within a certain temperature range.
When you drift outside this zone, the weld quality
diminishes.
Some people turn up the heat in order to weld faster,
yet they sacrifice weld strength. Do not be tempted to
weld faster by raising the weld temperature!
Pressure
Pressure allows the plastic molecules of the materials
to mix. Best bonding occurs when there is a physical
mixing of the plastics.
Pressure, when too high or too low, reduces weld
quality.
Time
Plastic needs a time to melt and time to cool down.
Do not speed up the cooling time. After welding, plastic
molecules need 24 hours to come to a complete rest.
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