Alfa Romeo Owners Club of Australia Forum

Technical => 116 Series (Alfetta Sedan/GT/GTV & Giulietta Sedan) => Topic started by: Alfetta77 on October 20, 2019, 08:09:11 PM

Title: Alfetta GTV grilles - what type of plastic?
Post by: Alfetta77 on October 20, 2019, 08:09:11 PM
Hi everyone, I'd like to use a rust converter (Ranex rustbuster - https://www.bondall.com/ranex-rustbuster/) on the jack nuts on my grilles, which have corroded. The thing is, I don't want to damage the plastic, which means I need to know what type of plastic it is - grateful for any assistance from someone in the know. Thanks, Mark
Title: Re: Alfetta GTV grilles - what type of plastic?
Post by: bonno on October 20, 2019, 09:21:43 PM
High probability it’s polypropylene. Just to be sure on suitability, carry out a test by smearing the product on a small section of plastic and see whether no damage occurs after 24 hours.
Title: Re: Alfetta GTV grilles - what type of plastic?
Post by: Alfetta77 on October 20, 2019, 10:05:00 PM
Great - thanks!
Title: Re: Alfetta GTV grilles - what type of plastic?
Post by: john m on October 20, 2019, 11:10:58 PM
Ranex Rustbuster is a must have addition any pre 1990 model Alfa owner. I agree with bonno to test a small amount on the back of the grill.
Cheers
John
Title: Re: Alfetta GTV grilles - what type of plastic?
Post by: 17fitty on October 23, 2019, 03:24:27 PM
Not poly prop but ABS(Acrlonitrile butadiene styrene) and has a very low chemical resistance-as in thinners will melt it slowly as will lots of other solvents.Mainly found in injection moulded vehicle parts ie grilles/centre consoles/some road bike fairings and can be painted easily-hope this helps
Title: Re: Alfetta GTV grilles - what type of plastic?
Post by: bazzbazz on October 23, 2019, 05:04:29 PM
17fitty is correct. You recognize ABS by is rigidity and brittleness. 

Polypropylene is much more flexible and durable.
Title: Re: Alfetta GTV grilles - what type of plastic?
Post by: Alfetta77 on October 26, 2019, 08:51:08 PM
Thanks everyone. Tried a small amount of Ranex for a few minutes - no effect. Tried again for a couple of hours - no effect whatsoever. Looking good to treat the jack nuts - will post some before and after photos.
Title: Re: Alfetta GTV grilles - what type of plastic?
Post by: poohbah on October 27, 2019, 12:00:18 PM
Sorry to hijack the thread, but is ABS the same stuff that the triangular vent covers are made of on the rear quarter panel?

Any idea of the best primer and paints to use for refurbing them?
Title: Re: Alfetta GTV grilles - what type of plastic?
Post by: bonno on October 28, 2019, 08:16:48 AM
Hi Poohbah I have sent you a PM on the refurb method you are after. If you think it is necessary, it is best to create new post so as not to confuse the subject post.