In terms of purchasing parts for a body kit I was told that plastic is better than fibre glass because you can repair it if necessary. Is this so?

Also which is better quality overall?

Thanks

I don't know with regards to bodykits, but I do know a bit about plastics and fibreglass in general, which might give you a few tips.

Firstly, fibreglass is also known as fiber-reinforced polymer (FRP) or glass-reinforced plastic (GRP); as you can see, it is a plastic, but with glass-fibre reinforcing. This is supposed to increase it's strength.

BUT fibreglass uses either polyester or epoxy resins (plastics), both of which are hard but brittle; hit it hard, and it'll smash.

Don't really know which "plastics" are used for bodykit moulding, but most likely would be either ABS, polypropylene, or polyurethane. All of these are generally quite resilient.

As for repairing; personally I would imagine that fibreglass would be the more readily repairable, but also the more prone to needing repair. ABS and polypro would probably require plastic welding, which basically involves melting new strips of plastic onto the bit that needs repairing. As for urethane, I'd tip it being the most resilient of the bunch, but repair could be a nightmare if it was ever required.

A note also, that unless a kit is mass-produced, finding something in ABS or polypro would probably be very hard, due to the costs of manufacturing and moulds. Fibreglass and urethane would have lower initial costs, but higher production costs; good for small runs.


PS. As an example, your bumpers are probably either ABS or polypro; they're churned out in the thousands.

PPS. Overall quality would be impossible to say, a well-made fibreglass kit could be 10x better than a cheapie Chinese "plastic" kit, or a professionally made plastic kit could be 10x better than a backyard fibreglass job. All depends on how much time and effort they put into it, without cutting corners.

Rogue_streak is spot on. Most car bumpers are made from polypropylene(PP). generally this is more flexible and durable than fibreglass, however fibreglass is far easier to repair as you can replace large damaged sections of it with ease, where as polypropylene either needs to be plastic welded or repaired with some of the 2 part epoxies available. low volume production parts (like ralliart kits) are sometimes made from Polyurethane(PUR from memory) or ABS as the cost of moulds and the like is far lower than PP, and it is not financially viable to make such small runs of parts from PP.
Polyurethane and ABS is slightly more brittle than PP but still more resilant than fibreglass, which can crack(sometimes just the gelcoat) quite easily. saying that, Polyurethane and ABS is a bitch to repair as the normal techniques used on plastics (ie plastic welding) generally dont work(there is a new 2 part epoxy from Terosan that is very good though).
In order of which would be preferable on a car that sees regular use, i would say PP first (which would only be factory kits) followed by fibrglass(for its ease of repair) then Polyurethane or ABS (stronger than fibreglass but hard/costly to repair), unless your very careful with your car, in which case Polyurethane or ABS would be prefferable to fibreglass for its better fit and finish.

...and then there are variations on the theme. For example the genuine Mitsu Ground Effect kit is all ABS (it's actually stamped into the kit).

Having come from nice flexible BMW kits I gotta say I am not real pleased that my GE kit is ABS. But I would have that any day over fibreglass. 'Glass requires real expertise from the manufacturer to avoid waves and ripples in the final finish. Ditto with the final gel coat. Poor glassing often has lotsa little pinholes in it. Painters hate these as you can spend hours chasing all the pinholes and filling them, so getting a a good paint finish is much harder than other plastics. Fibreglass also stonechips much more readily than the other plastcis simply because the resin coats make it so bloody hard, where the other plastcis we are talking about have 'give' in them (which might mean small marks in the paint from stones, but not gouges in the plastic like you will get in 'glass).

All that said, fibreglass is without doubt the easiest to repair....

Just to clear the air, not sure about standard magna bumpers but all body kits (vrx, ralliart, ground effects) are ABS plastic.

Rogue streak is spot on with his description of the 2.

Which one would i choose for a body kit?

Plastic. As Rogue Streak said fibreglass is strong, BUT it is very brittle. One wrong scrape and bam you've lost half a bar. Whereas with plastic it'll bend a fair bit before it'll actually be damaged. Then when it is damaged, it'll usually only be split somewhere near a mounting point, which is easily repaired by plastic welding (cost you about $100).

But not to totally discount fibreglass, it is generally cheaper to make than plastic kits so that may outweigh the benefits of plastic.

Just to clear the air, not sure about standard magna bumpers but all body kits (vrx, ralliart, ground effects) are ABS plastic.

Rogue streak is spot on with his description of the 2.

Which one would i choose for a body kit?

Plastic. As Rogue Streak said fibreglass is strong, BUT it is very brittle. One wrong scrape and bam you've lost half a bar. Whereas with plastic it'll bend a fair bit before it'll actually be damaged. Then when it is damaged, it'll usually only be split somewhere near a mounting point, which is easily repaired by plastic welding (cost you about $100).

But not to totally discount fibreglass, it is generally cheaper to make than plastic kits so that may outweigh the benefits of plastic.
LET'S FACE IT NO ONE WANTS TO LOSE HALF A BAAAAAR

Thank you all for your very informative responses. I just wanted to know as I am picking up a TL VRX front bar, nose grille, light inserts and side skirts later this coming week. Its all genuine un-prepped Mitsubishi plastic and so I just wanted to find out.

I would imagine that genuine VRX body kit parts would be pretty good quality, however I did hear that they would be just as good as the standard TL ES front bar which I think is pretty durable.

should look great you just can not beat plastic body kits, no vrx rear bar ??

i have had 2 cars with fibreglass front bars and both have ended up with cracks in them from hitting things. but on the other end of the scale i had the missus pulsar nose down in a drain (long story, but i was doing a 3 point turn 1 night while driving round looking at flood water and couldn't see the drain) where it was resting on the front bumper (the stock one) and had folded it back against the radiator support. when we got a tow out it just popped back into place. it left a tiny kink in the little edge that is inside the guard.

and had folded it back against the radiator support. when we got a tow out it just popped back into place.OT, this is something to look out for when buying a second-hand car; because standard plastic bumpers can take quite a whack, deform and pop back into place, a seemingly good bumper can actually be hiding significant structural damage behind it.

I remember quite a few years ago reading how I think it was the Pontiac Fiero's were using plastic body panels, that could take a fair hit and just pop back into shape.

X Trails have plastic front guards

should look great you just can not beat plastic body kits, no vrx rear bar ??

I was only planning on getting the vrx front bar, nose grille and light inserts (no lights yet) and the guy is throwing in a set of side skirts for nothing. Am also getting wheels sometime too so i have to be strategically incremental in adding things to my car to keep my wife onside:D

I was only planning on getting the vrx front bar, nose grille and light inserts (no lights yet) and the guy is throwing in a set of side skirts for nothing. Am also getting wheels sometime too so i have to be strategically incremental in adding things to my car to keep my wife onside:D

"What's that honey? No, thats the front bar that was originally on it. Of course i'm sure."lol

OT, this is something to look out for when buying a second-hand car; because standard plastic bumpers can take quite a whack, deform and pop back into place, a seemingly good bumper can actually be hiding significant structural damage behind it.

I remember quite a few years ago reading how I think it was the Pontiac Fiero's were using plastic body panels, that could take a fair hit and just pop back into shape.
in my case there was no structural damage as it happened at about 2kmh. i just slid down a ditch about 50cm deep. but you make a valid point.

but then in my skyline......... just kidding, LOL

"What's that honey? No, thats the front bar that was originally on it. Of course i'm sure."lol

lol exactly, and then...

'what no, the car has always had 18" black wheels whatdya talkin' about?, it must have been the angle you were looking at them from or the time of day and the position of the sun in the sky.' :D

followed by

"oh that noise when i change gears is nothing. just turns out something was blocked, that's why it didn't make that 'psssh' noise before"

LOL

but then in my skyline......... just kidding, LOL

haha nice 1 smart asslol

Just to clear the air, not sure about standard magna bumpers but all body kits (vrx, ralliart, ground effects) are ABS plastic.

ABS hey? Then wtf can't I weld a TJ bumper? They can't even weld a strip of parent material back onto themselves. I hassled out a mobile bumper repair guy and he said they're made of some recycled bitsa plastic feedstock. Real handy for our insurance premiums........

ABS hey? Then wtf can't I weld a TJ bumper? They can't even weld a strip of parent material back onto themselves. I hassled out a mobile bumper repair guy and he said they're made of some recycled bitsa plastic feedstock. Real handy for our insurance premiums........

he's wrong. you can plastic weld a standard TJ bumper. i have done it before.

he's wrong. you can plastic weld a standard TJ bumper. i have done it before.
My Ralliart front bar was split, cost me $100 to get it repaired and they used plastic welding. So yeh it definitely can be done.