Plastic welding

Howie · Post by **Howie** » Mon Apr 12, 2010 8:46 pm

Hi all, does anyone know what type of plastic is used for the kr1's fairings?

I've just bought a plastic welding kit & had a look all over my fairings but cannot for the life of me find any kind of reference on the panels

I'm pretty sure there should be a letter(s) like PP or PE stamped somewhere, am I just not looking in the right place?

Howie

twostrokesmoker · Post by **twostrokesmoker** » Mon Apr 12, 2010 9:03 pm

Howie
I found some letters on mine, they read S H I T P L A S T I C, hope this helps

That wasn't very helpful was it

Sorry pal, must be the sun affecting me ed

Howie · Post by **Howie** » Mon Apr 12, 2010 9:09 pm

No not very helpful, but funny.

Howie

Oh & very true

smithyrc30 · Post by **smithyrc30** » Tue Apr 13, 2010 5:48 am

All the fairing panels on the KR1 and 1S are ABS.

Are you using hot air or a 'hot metal' (like a soldering iron) welder?

I've found hot air works really well on 'new' plastic (stuff which is less than a year old) but not so well on anything older than that. The plasticiser leaches out over time and UV exposure and the weld joint/interface becomes a stress raiser and they crack quite easily. (The hot air does not help because it also bleeds out the plasticiser).

The hot iron type mixes the weld rod better with the 'old' plastic and your joint is more stable. Also the amount of heat used can be less so you get less distortion and you can repair smaller parts more easily.

Use a filler rod as well. You can use old fairings but these have issues with the plasticiser and the weld becomes very brittle as a result.

Finally, when I have done a weld I always give the panel a very hard shake and bend. If you can hear the plastic cracking or creaking, it will fail . Most likely after you have had it painted and just bolted it into place....

Howie · Post by **Howie** » Tue Apr 13, 2010 6:32 pm

Thanks Smithy,

The kit I bought uses a soldering iron & comes complete with rods of all sorts of different plastics.

And thanks for the tip about shaking & bending

Howie

scooble · Post by **scooble** » Tue Apr 13, 2010 7:23 pm

I had a go on my Aprilia fairing with a gas soldering iron. Used a strip of the same plastic and worked it into a channel I had cut with a dremel. When set, it looked as if the plastic just 'sat' on top of the channel I had cut and could peel away without much provocation - suffice to say, the weld failed.

was thinking of using JB weld as that seems quite sticky.

salty · Post by **salty** » Tue Apr 13, 2010 10:27 pm

I used ABS from an Ebay Plastic Welding Kit (£7.99) - practiced on a cracked side pannel - following the instructions (making the crack into a V then filling it) then tried to break the panel to see how strong it was.. stronger than the rest of the pannel - not sure how they stand up to vibration re-opening the crack - but it seems very strong. Smells a bit if you do it in the house and makes you lightheaded - recommend the garden table

Salty

smithyrc30 · Post by **smithyrc30** » Wed Apr 14, 2010 1:27 am

I forgot to mention as with any sort of welding the temperature is quite important.

If the plastic you are working with is starting to bubble, it is way too hot. This will cause the weld to fail as you have broken the molecular chains in the plastic.

The fumes, particularly from ABS are a bit nasty, a well ventilated work area (garden table) is recommended.

Scooble, JB weld won't do the job for any length of time. The problem with plastic is, it is full of plasticiser to make it, well, plastic.... JB weld is a surface bonding agent and does not react with the plastic, so as the plasticiser leaches out over time the joint fails and it comes off.

The only stuff you can buy that will dissolve ABS is a liquid called MEK (Methyl Ethyl Ketone) This will stick ABS together, but again you will need a filler rod, because the plastic shrinks when you use MEK.

It sounds like you either did not heat the panel enough to get the filler to bond, or the filler was not the same as the panel. Pretty much all panels now are marked somewhere (they have to be by recycling laws). The ones marked GF are the worst to do. They contain glass fiber filler of varying percentage to stiffen the panel, but because of this they require a high temperature to melt them, and the control of the weld is difficult. Kawasaki used GF panels on the ZXR range form 1991 through to 1996, and they are a right PIA to work on.

If you are using a soldering iron type one, try to work from the middle then an end then the other end of the work piece. This will prevent over stressing the crack/join. Always drill the end of any crack/join and over fill. Oh and I always melt the panel first and then add the filler to the panel. Not sure if any instruction mention this, but getting the panel hot first seems to make a very good weld. Maybe I'm a bit odd too, but I do the reverse side first and then vee out the outer surface and do it again.

Oh and make sure you get all the paint off before you start. Paint and plastic do not make good welds!

Dieseldog · Post by **Dieseldog** » Mon May 31, 2010 1:58 pm

Hi,
Anyone had any success plastic welding a 2 stroke oil tank

Hopefully should be able to get doner tank for making filler rods.
Need to modify mine to fit round new mounting point - shock top mounting on 350 valve project.
Would hot air or soldering iron be best

Cheers any help wolud be gratefull.

zebsp · Post by **zebsp** » Wed Jun 02, 2010 8:34 pm

I've used the plastex or (in UK) plastech stuff on two bikes and the results were fantastic.

I watched some videos on youtube before playing with it. I built up a complete new tab after hittingt the worlds biggest bastard grouse thingy and fixed a crack in a top fairing. I played with a few test pieces and tried to pull them apart and snap them and the stuff is just excellent.

Fumes smell good to!! seroiusly open a window if you use it. My wife is a dentist and she says it's like the stuff they use to make false teeth, if they're like my mothers, they get a lot of stick.

tescr500 · Post by **tescr500** » Wed Sep 14, 2011 7:46 pm

Hi tip of the day, make sure you drill a small hole at the end of the crack stops it going any further cheers.

Howie · Post by **Howie** » Wed Sep 14, 2011 8:34 pm

Since my initial post, I've been 'welding' plastic quite a bit.

Wouldn't say I was an expert but pretty much everything Smithy wrote is spot on (top man =D> )

It appears that the two most impotant factors in a good 'weld' are initial heating of the area & cleanliness of the the area.

I've just 'welded' an ear back on my Kr1 fairing (it had broken off completely by the mirror fixing) & using Smithy's bend/shake method, it appears to be stronger than the opposite side. This is also with bridging a gap on the upper part of the 'weld'.

The area needs filling to get a good finish but the 'weld' is strong. Next thing is to 'weld' a section onto one of my inspection panels. Ho hum, its a good job I love my Kr1

Post by **500bernie** » Wed Sep 14, 2011 8:55 pm

Hi Howie,
No photos?
Cheers
Bernie

Howie · Post by **Howie** » Wed Sep 14, 2011 9:01 pm

I'll pop some on tomoz fella

twostrokesmoker · Post by **twostrokesmoker** » Wed Sep 14, 2011 9:38 pm

Hey Howie, seeing as you are now our "Resident plastic welder" can I book my Rayban's in as I broke them in half on my hols