repairs on plastic parts

[peterb]

hi ive had a bit of a look at the shit box project were no spanners have been used only a hammer and chisel to undo screws,nuts,bolts,allen bolts . ive a few broken plastic bits cracks mostly ,side panels,seat front mount missing, number plate bracket cracked can they be repaired ?

[JonW]

Have a search on here there are lots of us doing repairs to things. I also did an article on my website about using a soldering iron, and also use Wurth replast as well. All depends on the plastic of course and not all repairs products are equal, some are just junk. Do not fibreglass a repair... ever. lol

[shaunthe2nd]

Be careful, I had some PVC drain pipe glue I'd been using on some gutter downpipes I'd been bonding and thought that would be ok to use it to repair a 4L0 side panel which had a slight crack.
I bonded a stiffener on the inside of the panel, after 2 days it had softened and rippled the outside of the side panel and it looked like it had been overheated, which it hadn't.
All this after an expensive paint job. grrrr.

[JonW]

Yes glue is a strange thing as the plumbing type glues melt the OEM plastic some can keep melting and eating if its the wrong stuff.

Has to be said that a lot of the plastic repair glues re junk really, only use stuff that proper repairers use and know your plastic. ie you cant use cables ties as the filler for on an LC side panel... but if youve an old panel thats trashed, youve got lots of spares. As usual with welding, clean is your friend.

You can also pay a pro to do the work, but has to be said that these old brittle plastics will kick your butt as the yanks say, soon as youve fixed a crack, another one appears.

[ERic350]

I normaly use MEK (Methyl Ethyl Keton) with good results and very strong repair. 1 liter will cost you about 10 euro's and is enough for the rest of your life :-)
How to use... A small piece of fairing or a Lego brick (the kids toy) is solved in some MEK. Clean crack and apply the stuff well. The solvent evaporates in a day or so. Leaving a strong connection. Provide the necessary fresh air, because the stuff stinks.

[nobby62]

Try plastic welding, no glues required and you end up with a solid fused repair. First scrape the paint away from the affected area. Then get a soldering iron and press it into the crack and slowly work your way along the length of the crack using a prodding motion to create a rippled fused repair... don’t let the soldering iron get too hot as you will make the repair brittle, if it starts to smoke its too hot, keep unplugging it to keep the temperature low, as long as it melts the plastic its hot enough. If you have a piece broken off or a hole to fill you can use some filler strips. Get a cheap black paint tray from BandQ for £2.99, cut it into strips and use it as filler, its the same material (abs). Sand it down afterwards and then fill and paint. The repair will be as strong as original material.

[paulincayman]

I've used the ABS cement , thick black goopy stuff, which is quite different to the regular PVC plumbing cement. This was on modern Ducati plastics . Someone else can say if older LC plastics are ABS or not.
Good luck with the project.

[petenofear]

There is lots of ways to do this lots of people have there own ways ,

The way I have done it and still do now ,

With cracks I file out and then use a 2 pack glue , Mitre Bond, and fill the crack with it , it works a treat , Then use wurth 2 pack plastic rubber filler to fill the crack , flat back then skim with some normal car body filler ,

If I have some plastic missing like on my Rd125lc belly pan topic I put up plus my RD350 f2 project topic I have up ,


I have some spare fairings I have cut bits off and shaped to what I need , then stuck on with mitre bond then feathered in with wurth plastic filler , it has worked a treat for me and I have done lots with good results,.

[pdxjim]

As paulincayman has said, I use plumber's ABS cement and fiberglass cloth on the backside for strength.

I may try the MEK or soldering iron to fuse the crack first next time, as it's difficult to get the thick cement down in the crack all the way to get a good bond.