How to Weld Thermoplastic
Prepare plastic components., Ensure that all soils are removed., Use a face mask when performing this task as this process can create a fair bit of dust.,Once the part has been properly cleaned are prepared, we are now ready for the "Tacking" step...
Step-by-Step Guide
-
Step 1: Prepare plastic components.
Poorly prepared plastic components will lead to weld failures.
As with all forms of welding, cleaning of plastic components prior to welding is as important as any other welding preparation in achieving strong, structural welds. , Any paints, oils, greases and even UV degradation must first be removed prior to welding.
With large parts, eg.
Bumper bars, washing the part is usually a good start.
This will ensure we are removing any atmospheric soils, eg.
Mud, Traffic films etc .
Use a soft sponge with warm water
- don't use any industrial detergents as these can also introduce film coatings that may also affect the welding results.
Clean all the painted surfaces right back to the parent material.
Paints and other remaining soils should be removed easily using a standard abrasive wheel (sanding disc) with any high speed air drill or electric drill will do the trick.
A grinding disc will make quick work of this process, but be warned
- plastics yield easily to abrasives, so take care you don't end up damaging other sections of the part where the wheel can 'catch' and 'drag' across the component. , Other methods for preparing plastics include
- paint scrapper, sharp blade, clean wire brush...,,, Take care when using the rotary burr, as plastics will yield easily to abrasives.
Ensure you use adequate jigging and support, to prevent the rotary burr from 'digging in' and running across the plastic being repaired.
When "V"ing is complete, you are now ready for the "Tacking" stage. , Unlike metal welding, where tacking is carried out at the ends of the welding area, Plastic Welding requires "Tacking" to be carried out where ever you intend to place welding rod. , Set the required welding temperature on the welding tool using the guide provided.,
1.5 minutes), select the correct welding rod (see our previous Tech Tip covering "Plastics Identification").
Cut the start of the welding rod to a point.
This will help with the initial flow of the weld rod.
Use a pendulum motion to evenly heat the parent material and the welding rod.
Feed the welding rod into the welding area, while curving the tail of the weld rod away from the welding tool.
This will help you control the rod feed during welding and will allow the operator to observe the material flow during welding. , Welding should be carried out in one continuous run along the length of the area to be welded.
Welding speed should be adjusted to the point where you observe a slight 'wash' at the sides of the welding rod.
Ensure that your pendulum motion is providing even heating of both the parent material and the welding rod throughout the weld run.
When complete, allow the plastic component to cool completely before attempting to trim or clean up the welding area.
This is important as the plastic will not be at full strength until completely cool. , Trimming & sanding can now be carried out if required., The term "Speed Welding" gets its name from the fact that it is a relatively fast process compared to that of the "Pendulum Welding" technique., Select the correct "Speed Welding" nozzle to suit the corresponding welding rod profile
- these are available to suit a range of welding rod profiles , Once up to temperature, simply insert the welding rod into the Speed Welding nozzle and apply a downward pressure on the welding rod itself.
Apply approx.
2.5
- 3 kgs of downward pressure, forcing the welding rod through the speed welding nozzle and into the weld area.
The welding tool will only need to be supported, as the force on the welding rod will move the tool along the weld area with ease. -
Step 2: Ensure that all soils are removed.
-
Step 3: Use a face mask when performing this task as this process can create a fair bit of dust.
-
Step 4: Once the part has been properly cleaned are prepared
-
Step 5: we are now ready for the "Tacking" step.
-
Step 6: Apply a "V" groove to the weld area: Weld plastics components relies on a number of factors - Surface Preparation Good joint interfaces Plastics Identification / Correct welding rod selection "V" Grooving
-
Step 7: using the rotary burr Tacking Correct welding temperatures Welding technique
-
Step 8: A Rotary Burr is used to provide a "V" groove along the weld line.
-
Step 9: Tack plastics: Tacking of plastics components prior to welding
-
Step 10: helps the welder to achieve two things - Good joint interfaces and Alignment of the plastic components prior to main welding The "Tacking Nozzle" can be used to ensure close joint interfaces and alignment of broken parts.
-
Step 11: Fit the standard nozzle (LE100303) on the welding tool.
-
Step 12: Once up to temperature (from cold
-
Step 13: this takes approx.
-
Step 14: Do it all at once.
-
Step 15: Finish it.
-
Step 16: Use the "Speed Welding" technique for long weld runs.
-
Step 17: Fit the standard nozzle on the welding tool.
-
Step 18: The Speed Welding nozzles are an easy push fit onto the standard nozzle.
Detailed Guide
Poorly prepared plastic components will lead to weld failures.
As with all forms of welding, cleaning of plastic components prior to welding is as important as any other welding preparation in achieving strong, structural welds. , Any paints, oils, greases and even UV degradation must first be removed prior to welding.
With large parts, eg.
Bumper bars, washing the part is usually a good start.
This will ensure we are removing any atmospheric soils, eg.
Mud, Traffic films etc .
Use a soft sponge with warm water
- don't use any industrial detergents as these can also introduce film coatings that may also affect the welding results.
Clean all the painted surfaces right back to the parent material.
Paints and other remaining soils should be removed easily using a standard abrasive wheel (sanding disc) with any high speed air drill or electric drill will do the trick.
A grinding disc will make quick work of this process, but be warned
- plastics yield easily to abrasives, so take care you don't end up damaging other sections of the part where the wheel can 'catch' and 'drag' across the component. , Other methods for preparing plastics include
- paint scrapper, sharp blade, clean wire brush...,,, Take care when using the rotary burr, as plastics will yield easily to abrasives.
Ensure you use adequate jigging and support, to prevent the rotary burr from 'digging in' and running across the plastic being repaired.
When "V"ing is complete, you are now ready for the "Tacking" stage. , Unlike metal welding, where tacking is carried out at the ends of the welding area, Plastic Welding requires "Tacking" to be carried out where ever you intend to place welding rod. , Set the required welding temperature on the welding tool using the guide provided.,
1.5 minutes), select the correct welding rod (see our previous Tech Tip covering "Plastics Identification").
Cut the start of the welding rod to a point.
This will help with the initial flow of the weld rod.
Use a pendulum motion to evenly heat the parent material and the welding rod.
Feed the welding rod into the welding area, while curving the tail of the weld rod away from the welding tool.
This will help you control the rod feed during welding and will allow the operator to observe the material flow during welding. , Welding should be carried out in one continuous run along the length of the area to be welded.
Welding speed should be adjusted to the point where you observe a slight 'wash' at the sides of the welding rod.
Ensure that your pendulum motion is providing even heating of both the parent material and the welding rod throughout the weld run.
When complete, allow the plastic component to cool completely before attempting to trim or clean up the welding area.
This is important as the plastic will not be at full strength until completely cool. , Trimming & sanding can now be carried out if required., The term "Speed Welding" gets its name from the fact that it is a relatively fast process compared to that of the "Pendulum Welding" technique., Select the correct "Speed Welding" nozzle to suit the corresponding welding rod profile
- these are available to suit a range of welding rod profiles , Once up to temperature, simply insert the welding rod into the Speed Welding nozzle and apply a downward pressure on the welding rod itself.
Apply approx.
2.5
- 3 kgs of downward pressure, forcing the welding rod through the speed welding nozzle and into the weld area.
The welding tool will only need to be supported, as the force on the welding rod will move the tool along the weld area with ease.
About the Author
Kathleen Wilson
Writer and educator with a focus on practical home improvement knowledge.
Rate This Guide
How helpful was this guide? Click to rate: