How to Repair and Welding Motorcycle Plastics

Today I am going to tell you, how to build a motorcycle from plastic bottles. That was a joke, of course. In reality, I will tell you today about welding of a plastic.

There are so many professional devices for welding of a plastic, such as soldering stations, extruders, plastic welding rods… But in fact, that is not necessary. And you can weld a plastic by usual tools, everybody has in his garage. You need to know for this just two key factors. The first is a type of a plastic you are going to weld You need to weld it just by the same type of plastic. The second is a temperature range for welding it.

Generally, you can find plastic type marking on the back side of the part. It may be letters marking, here it is “PP”.

Or it may be digits in a triangle, here it is “05”. Normally this type of plastic is used for the dirtbikes. For the roadbikes normally ABS plastic is used.

You can see appropriate marking on the part. Here you can see samples of the marking on the everyday things. There is a PP marking on this cap. So it can be used as a donor for our part. Any schoolboy from Europe knows this table, because they are sorting garbage according to it.

From the back side of the part we need to weld a crack by a flat profile rod. Let’s do these rods from our donor. Before welding of the cracks it is good to check the temperature regime on the not important sector of the detail.

Let’s degrease plastic for this. The best is to use a heat gun with a digital control of the temperature and a small nozzle.

The temperature of the welding for PP plastic should be about 400 Celsius degrees. The patch was torn off by rather big effort. But I think, I need to rise up a temperature for a better diffusion. Now the temperature is correct, the patch cannot be torn off.

This cheese cap plastic is rather thin.

It is better to use motorcycle plastic; it is thicker and more durable. I have already prepared rods made from it. The result is not so beautiful. Don’t be so strict, this is my first time. The target was to fixate the cracks, and it was reached!

Now we need to make a groove along the cracks by dremel, to weld the plastic on the front side of the part. If you don’t have a dremel, you can make a groove by metal file or by angel grinder.

It is good we used a plastic of another color on the back side. So we can see the depth of the groove we need to do. The front side of the part I will weld by exactly the same plastic.

I made this rod from an old fender. It looks much better after polishing. I think for training motorcycle it is good enough. And if you cover it by a sticker, it will be looking great. The durability is many times better in comparison with sewing of the part by nylon ties or by a wire.

By the way, I need to say, the part was damaged very much. The crack was very long and branchy. I am sure it was impossible to repair it by nylon ties. If you heat up the part after repairing, it will be looking better, it will be glossier. So what guys, let’s do a crush test and check a durability.

Should I break it? On my mind the crush test has been successfully finished. Riders often break a visor, when they fall down. It is almost impossible to find a visor for your model of the helmet of the same year and color. That is why the repairing of a plastic will be very useful here.

Unfortunately, there is no any marking of a plastic type on the visor. And it is good a have a visor from the similar helmet, which I will use as a donor. The visor is painted, that is why the paint should be removed. Donor part was also cleaned by me. And I am going to cut off a piece of it.

May be it is not so beautiful, but it is fixed. I think it is rather good for “smart hands”. It is ready for installation. I use this very cool professional skid plate from Moose Racing. I like it so much.

It protects not only a frame, but also a rear suspension linkage.

You can slide on it very good over the obstacles. A few motorcycles have been ridden by me, and the skid plate is still the same. But unfortunately this piece was broken off because of my fault. I drained an antifreeze with the installed skid plate.

Let’s try to repair it. The price of a radiator shroud is about 25 dollars and the price of this skid plate is about 150 dollars. That is why the repairing of it is much more interesting and profitable. Unfortunately, there is no plastic type marking on this part. I was a little bit sad about this.

I found in the Internet description of it. And directly in the first string written that it is made from High-Density PolyEthylene (HDPE). This corresponds to number 2 of this table. I checked the Internet where it is used. And it is very common everywhere.

For example, plastic bottles caps are made from it. Or even in a hardware supermarket you can buy special plastic rods.

HDPE plastic should be welded under another (higher) temperature. That is why we need to test it in advance. So my friends, we did a trial welding by special rod and by plastic bottle part.

Let’s check, how durable it is. It was very difficult to tear it off. The rod was broken down. The weld withstand. The bottle was not welded so well.

It is much more difficult to weld by this bottle plastic. It is difficult to keep correct regime of the heating. I think after getting some experience it is able to weld by this plastic.

We did a correct welding, not from a first attempt. We came to the following regime.

We adjusted a heat gun to 580 Celsius degrees. Installed thin nozzle. We did a point heating, and you need to heat up more not the rod, but the part. The rod should go down by itself under your downward pushing of it. Similarly we did a trial welding of ABS plastic by ABS rod.

Having above experience we did it from the first time. As you can see the joint is very strong and it is impossible to break it out. So we did a first welding, we fixated the piece. Now we are going to make additional welds to get strength. Here we have welded outside of the joint.

Now you see some strength in the joint. And it is left only to fill the gap from the inside. The welding has been finished. Now we need to polish the joint to get beauty and to check the quality of the weld. You can see that the joint is monolith.

From the above experience, I can tell you that the polypropylene (PP) does not need fine tuning of the welding regime.

And that is why it can be easily welded. HDPE plastic is not so easy to weld it. But after having some trials, everybody is also able to weld it. We still don’t know from what material the visor is made.

But it has been also welded successfully. The only difficulty here is the material is thin and it bends during welding. In case you don’t want to do this crap, you can buy brand new parts at good prices from Stuntex guys. So what, my friends, I repaired all my parts in Stuntex studio, by their tools. I am super glad.

The result is great. The strength of the parts is equal to brand new. And they look many times better than brand new. And with this work we can get a grand prix at international expo of modern art. Write comments about my bad hands.


Perform general repair and maintenance work on motorcycles Assist with washing and detailing motorbikes Diagnose problems with motorbike transmissions Troubleshoot issues with knocking and shimmying Handle maintenance tasks on fuel lines and tires Perform fluid change tasks and ensure that bolts are lubricated properly Confer with customers to determine problems with motorcycles to determine issues Start motorbikes in order to assess impending problems Inspect motorbikes to figure out repair needs Work with apprentices and mechanics in order to diagnose and fix problems Perform both preventative and regular maintenance on motorcycles and mopeds Select appropriate tools to handle repair procedures

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