What type of plastic are CRM fairings?

Post Reply
hpm
Site Supporter
Site Supporter
Reactions:
Posts: 41
Joined: 23 Nov 2009, 14:53
What type of plastic are CRM fairings?

Post by hpm » 13 Feb 2010, 21:56

I have got some second hand plastics that I am restoring from a painted finish. I have cleaned the paint off and found that both rad shrouds have cracks around the mounting holes. I want to glue them but most glues say don't use on Polypropylene or Polyethylene. I know some tanks are Polyethylene but after looking on other sites they suggest MX plastics are nylon anyone know for sure?

What have others used on cracked plastics?? I have read araldite works ok and others have used something called Polymorph which is nylon based :?:

I found this but think that is for race fairings not MX ones??
Plastic welding isn't the black art that some people (usually those who want to charge you for their plastic welding services ) seem to think. All you need is a soldering iron and an old plastic coke (or similar) bottle. Soft drink bottles are made of the same material as most bike fairings.

Use the soldering iron to melt to the two sides of the crack together, and use thin strips of the coke bottle as filler to build up the repair on the inside for strength. This is a far more satisfactory repair than using epoxy or fibreglass as either of these two can separate from the fairing later on.

Done carefully, you should be able to repair the fairing to a good enough standard that the crack is close to invisible from the outside, and won't need painting.

User avatar
xander
Visitor
Visitor
Reactions:
Posts: 53
Joined: 26 May 2008, 19:40
Location: Bath
Re: What type of plastic are CRM fairings?

Post by xander » 15 Feb 2010, 12:19

I have no idea what plastic type the fairings are but I've just used araldite on a crack on the radiator shrouds and have had no problems with it. As far as I remember from my schooldays polymorph isn't a type of glue. It's a thermoplastic that can be melted in hot water or with a hairdryer and shaped into whatever you want. I can't see it being of any use for repairing a cracked fairing as it isn't adhesive.

hpm
Site Supporter
Site Supporter
Reactions:
Posts: 41
Joined: 23 Nov 2009, 14:53
Re: What type of plastic are CRM fairings?

Post by hpm » 15 Feb 2010, 14:12

xander wrote:I have no idea what plastic type the fairings are but I've just used araldite on a crack on the radiator shrouds and have had no problems with it. As far as I remember from my schooldays polymorph isn't a type of glue. It's a thermoplastic that can be melted in hot water or with a hairdryer and shaped into whatever you want. I can't see it being of any use for repairing a cracked fairing as it isn't adhesive.

Thanks Xander

Apparently if you heat polymorph past the 60-65 degrees it turns into a goo that is very sticky.

User avatar
knackeredMk1
Super Moderator
Super Moderator
Reactions:
Posts: 4184
Joined: 03 Nov 2006, 17:41
Bike Owned: Modified Mk1
Re: What type of plastic are CRM fairings?

Post by knackeredMk1 » 15 Feb 2010, 14:29

All plastics are polypropylene - took a while to check.

Really difficult to glue cracked plastics. I've even tried 'plastic' glues. The best way I've found to use is epoxy (Aruldite) where under minimum load, or welding with a bit of waste plastic when under load. To weld you need a soldering iron. Get it hot but not too hot to burn/blacken. Then sand down and use filler designed to be used with plastics. Prime, paint (satin not gloss) or sticker.

hpm
Site Supporter
Site Supporter
Reactions:
Posts: 41
Joined: 23 Nov 2009, 14:53
Re: What type of plastic are CRM fairings?

Post by hpm » 15 Feb 2010, 16:33

Thanks Steve, I 'll try araldite on the back then as the cracks aren't to severe and only on one of the mounting points on each piece so should be ok.


Post Reply