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Fibreglass bonnet qn

Posted: Mon Jul 06, 2009 5:56 pm
by chimpboy
Hi, never done anything in fibreglass really, so... if I were to get a fibreglass bonnet, and wanted to add a small bonnet scoop to it, how hard would it be to get a fibreglass bonnet scoop and make the finished item a one-piece, all fibreglass thing rather than bolting the two together?

Is it as simple as cutting them, joining them (how?), and then cleaning up?

... edit: while I'm at it, what's the legal status of fibreglass replacement panels anyway? I know people bolt on fg mudguards etc; is this strictly speaking legal or is it in the grey zone?

Posted: Mon Jul 06, 2009 6:15 pm
by want33s
Joining a glass scoop to a glass bonnet with glass is probably the best way to do it.
Join from underside and fair it in on the outside with a mix of resin and microballoons.
AFAIK fibreglass guards and bonnets are legal..
Doors may be another story on late model vehicles originally equipped with anti-intrusion bars.
OZ-East make complete fibreglass bodies for 40 series cruisers and they are legal. Lots of 75's have fibreglass roofs.

Posted: Mon Jul 06, 2009 6:39 pm
by bru21
I was asked a while back to glass a scoop on his bonnet, and I said hell no.

To do something like that is a lot of work - even more so without being a pro.

I would imagine it would take about 3 weekends on and off to get something worth painting.

Why not just fit a bolt on scoop like a GU one or similar.

In theory a glass bonnet is not legal as it will affect the way a vehicle will collapse on a crash. In reality you will probably get away with it.

Posted: Mon Jul 06, 2009 7:57 pm
by Matt_85Lux
I know in Qld they have to be ADR approved to be legal

Posted: Fri Jul 10, 2009 8:09 pm
by thehanko
Personally I would do it by getting any glass scoop which fits the bonnet then cut a hole a little smaller than the scoop as if you were going to bolt it on. ( the hole would need to be the same as the inside cut out of the scoop)

then personally I would glue it on using resin between the bonnet and scoop, then glass from the under side up into the scoop so it doesnt need to be perfect as with a slight sand it will never get seen.

Then simply blend the top into the bonnet with the glass bubbles / resin mix mentioned above.

any mug should be able to do the glass work involved in this method in a hour, then add sanding time which will depend a little on how good your job is and how well you can sand stuff.

if you want any of this clarified then pm me as i might not look at this thread again.

As also mentioned above to actually run glass ontop of the bonnet and onto your scoop would be a fair bit of work in order to get it blended well enough so as not to be noticable as it will make the area around the scoop a little higher. So avoid this method unless your keen for some work.

Posted: Fri Jul 10, 2009 9:47 pm
by RN
Wasn't there a guy on this forum selling fibre glass guards doors and bonnets. The bonnets could be had with a scoop already glassed in.

Can't find the link but I think he was in Geelong.

Posted: Fri Jul 10, 2009 10:13 pm
by hillbilliywheelchair

Posted: Sun Jul 12, 2009 10:51 am
by RN
Correct.

Posted: Sun Jul 12, 2009 11:55 am
by fool_injected
Matt_85Lux wrote:I know in Qld they have to be ADR approved to be legal
Bonnet scoops/projections may be fitted to a vehicle
provided the driver’s vision is not restricted under
normal operating conditions with the driver’s seat
located at its lowest and rearmost position.
Bonnet-mounted scoops/projections must meet the
following requirements:
• When a 165mm diameter sphere is placed on the
bonnet in front of the scoop (or bonnet projection)
and rolled backwards until it touches the scoop, no
forward point of the scoop or point of contact between
the sphere and the scoop must lie above a horizontal
plane passing through the centre of the sphere.


page 9 http://www.transport.qld.gov.au/resourc ... icles2.pdf

there is some pretty pictures to show you how test, easy stuff
I think theses are the standard specs for all states (ADRs)

Posted: Sun Jul 12, 2009 5:33 pm
by hando
anyone know what the NSW RTA thinks about this???? i'd love this stuff but still want to be legal and covered by insurance

Posted: Sun Jul 12, 2009 8:21 pm
by fool_injected
hando wrote:anyone know what the NSW RTA thinks about this???? i'd love this stuff but still want to be legal and covered by insurance
My link above is the same for NSW

Posted: Sun Jul 12, 2009 9:13 pm
by LuxyBoy
So what are the rules regarding just making your bonnet taller :?:
That way you could put an intercooler over the top of an engine without body lift :idea:
Or you could raise the bonnet so your spotties aren't above it, which impedes your vision and makes them illegal; but by raising the bonnet height you are impeding your vision still :?

Posted: Mon Jul 13, 2009 8:14 am
by want33s
LuxyBoy wrote:So what are the rules regarding just making your bonnet taller :?:
That way you could put an intercooler over the top of an engine without body lift :idea:
Or you could raise the bonnet so your spotties aren't above it, which impedes your vision and makes them illegal; but by raising the bonnet height you are impeding your vision still :?
In Qld you can make a bonnet "HUMP" as tall as you like as long as it complies with the specs stated above AND from a standardised drivers eye level you can see the road surface no more than 11 metres in front of you.

Posted: Mon Jul 20, 2009 9:33 pm
by Fglass
Hi chimpboy,

It is a very easy job to do what your asking. There is some right advice and wrong advice on here.
First you need to locate where your scoop will sit and mark.
Then cut your hole so the scoop sits neatly in the cut out.
make sure you grind the fibreglass and gelcoted surfaces of the bonnet and scoop so new laminate will adhere.
use masking tape to make a bridge between the to edges of the hole in the bonnet and sit the scoop on the tape.
use a few strips of fibreglass to join the scoop to the bonnet, when it sets you can turn the bonnet over and fibreglass the join from the inside it wants to be about 50mm ether side of the join and 2-3mm thick.
when this has cured turn the bonnet back over and make a v in the top side of the join you want this about 30mm ether side of the join and 2mm deep using a grinder. You will grind the tags off you put on there to start with.
Cut strips of fibreglass and build up the V. When cured, sand and fill any lows with body filler.

If you don't V and fibreglass the top side it WILL CRACK through the paint.

Cheers Jase.

Posted: Mon Jul 20, 2009 9:39 pm
by chimpboy
Fglass wrote:Hi chimpboy,

It is a very easy job to do what your asking. There is some right advice and wrong advice on here.
First you need to locate where your scoop will sit and mark.
Then cut your hole so the scoop sits neatly in the cut out.
make sure you grind the fibreglass and gelcoted surfaces of the bonnet and scoop so new laminate will adhere.
use masking tape to make a bridge between the to edges of the hole in the bonnet and sit the scoop on the tape.
use a few strips of fibreglass to join the scoop to the bonnet, when it sets you can turn the bonnet over and fibreglass the join from the inside it wants to be about 50mm ether side of the join and 2-3mm thick.
when this has cured turn the bonnet back over and make a v in the top side of the join you want this about 30mm ether side of the join and 2mm deep using a grinder. You will grind the tags off you put on there to start with.
Cut strips of fibreglass and build up the V. When cured, sand and fill any lows with body filler.

If you don't V and fibreglass the top side it WILL CRACK through the paint.

Cheers Jase.
Hmm, since you're two minutes up the road from me I just thought of an even easier option I could go with ;)