Plastic Repairs

[Banjo]

If your Corolla is like mine, then when they get 40+ years old, the plastics therein, suffer greatly, from age, sunlight, vibration, & generally being removed & reinstalled.

As new replacements plastics, are getting harder & harder to find; then in many cases, there is no option but to try & repair them.  In these days of 3D printing, no doubt some of you have had a go at doing just that, but this post is about asking what the best repair methods & products you have found, from experience.

I was brought up with Araldite, & Super Glue, & recently have used another glue called Gorilla Glue, very successfully, for general purpose repairs.  However, when it comes to plastics, there are best glues for specific types of plastics, or plastic combinations, so it is best to try & identify the plastic, you are trying to repair.

Now, I've got one radio A/C fascia surround to do at the moment.  Actually, it's not out of a Rolla, but an E36 BMW Eurotoy, I recently acquired. Someone, had previously been a "bull at a gate"  trying to remove the radio panel, & broken it badly.

Now I could import a new one at great cost, from Latvia, & hope it is for a RHD rather than LHD, or I could try & repair it.

So luckily, the broken panel has the composition moulded into the rear, advising "ABS + PC".

So I would be very interested, what members have found, that works for them, so we are all the wiser, as I'm sure I'm not the only one that needs this info.

The top products recommended appear to be JB weld Plastic,  Loctite Plastic, & Q Bond.

Below is one website, with some very detailed specific info.

http://weldguru.com/OLDSITE/plasticrepair.html#d 

Has anyone on here used Q Bond successfully ?  Certainly sounds like a miracle product, & is readily available here in Oz on ebay.

Here is a sample of the many utube videos on this subject.

https://www.youtube.com/watch?v=JNeZlh0smuc

Cheers Banjo

 

Edited May 5, 2019 by Banjo

[oh what a nissan feeling!]

I have tried qbond for various things, many people claim that it is just super glue with a filler material like baking soda to fatten up the join.  It does pretty much act in this way,  like super glue it only seems to stick to certain things really well,  it needs a porous surface as well to have any chance of sticking.  

A friend of mine uses a soldering iron to fix motorbike farings, he cuts strips of old farings to use as filler material,  the result is strong, although I have never seen him do the work to know how he goes about it.  Might be worth googling.  

[Banjo]

I got some Loctite Super Glue for plastic today, so will have a go at fixing the broken radio surround on my BMW over the weekend.

I'll let you know how it goes.

Cheers Banjo

[altezzaclub]

I'm sure you've done this before, but scour it deeply on the back face, glue it together with Loctite, and once that is holding it in shape fill the back with Araldite and some matrix, like a strip of alloy or copper wires. Anything to build up the thickness of the panel as Superglue is only surface to surface.

[kickn5k]

https://www.repco.com.au/en/brands/rapid/rapid-fix-dual-adhesive-system-10ml/p/A9477258

Best by a long way. It does seem to work best on plastic I've used it for fairing repairs to fixing the kick panels on the ke11.

[Papay]

I was on a VW kick for the better part of 25 years, and have tried my hand at various plastic modification and/or repair projects.  The most ambitious was a custom Golf Cabrio bumper with shaved lights and other mods.  The best filler plastic you can use is from somewhere else on the same part, say for example an un-needed rib on the inside.  At one time I had one of those plastic welding kits with the different types of plastic rods.  

Overall, I can say that NONE of the projects have been very successful over time.  The key is penetration, just like in metal welding.  No matter how deeply I have tried to fill and keep both sides melted, the end result is always something that looks good but cracks easily later.  By comparison, I have had equal luck with methods like epoxy and gorilla glue.  Most recently I have repaired the brittle headlight surrounding trim on the Papay van, which went about six months before re-breaking.  

There is a product I have not tried, which is more like a mini torch designed for industrial fabrication.  My suggestion is if you're going to do this on a hard-to-obtain cosmetic part, that you reenforce it on the back, i.e. bridge the gap with an epoxy 'splint' to take any mechanical load.