Plastic Welding advice

Old 12-17-11, 07:11 AM
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Plastic Welding advice

I'm going to be doing custom work to a pair of headlights. Normally I could bake the headlight until the glue softens up and then pull the light apart, but I cannot bake this set of lights apart so I will be cutting them open. To close them back up I plan on on using the speed welding technique, as well as coating the seam with some sort of weatherproof adhesive as its absolutely important that its completely water tight. My questions are, do you think this would be the best technique? What plastic do you think the clear plastic cover on headlights are made of? Is it absolutely necessary for me to match the welding rods to the type of plastic i'm welding? I was looking at the welding temperatures for a few different types of plastic, and some are 300C, 350C up to 650C+. Is it absolutely necessary to weld at exactly that temp, or is there some play? That would decide if I go with a cheap $25 heat gun, or a $400 variable temp heat gun. A few of the cheap ones are dual temp, at 300C and 600C, and im wondering if I can get away with this. Also, I will have to purchase a reducer to fit a speed welding attachment to the heat gun. Are the connecting parts of reducers and speed welding attachments all a standard size? Thanks for your help.

Just as an FYI, the following is a picture of where I will be making my cut and weld

Old 09-30-13, 07:07 PM
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Get the right tool for the job

Get a real plastic welder. You can go with one with a little compressor in it. It works fine, but get one off of craigslist or ebay unless you have 800 bucks. Laramy is good. SO is Kamweld. You must have the correct filler rod. You cant weld dissimilar plastics.
Old 09-30-13, 07:47 PM
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Welcome to the forums.

Slightly off topic....

When I had a mobile electronics store there was a few times we had to drill holes in the plastic headlight chamber for a strobe bulb insert. Since the lens is polycarbonate it was easily charged and the plastic "sawdust" would stick all over inside the housing. It would take a long time to get it all out.

Since you'll have your lens open it'll be easier to clean but be careful as the inside of the lens as well as the reflectorized parts scratch very easily.

Good luck on your project

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