Bolt-on vs. Glassed

[draknoir2]

Personally, I would prefer conversion parts to be bolted on, as opposed to permanently fixed with fiberglass/bondo. Might not be movie accurate, but it would be much easier to work on if the parts were removable... and it would make delamination of glass work and bondo from panel flexing and temperature swings a non issue.

Thoughts?

[roadwarriormfp]

Depends which car your talking about.

The yellow cars simply had flare kits their screwed in. The coupe wasn't
If done correctly then there should never be a problem with cracking etc.... Have only heard of one car falling apart in that way...

[mad dan]

Hi draknoir2.
roadwarriormfp is right.
When fitted my roof spoiler and front flares to my BoB Replica I used bolts and quik dry sikaflex. Left that for a few hours and then used pollyester resin and thin fibreglass matting over the top of the fibre glass to bare metal roughed up with a grinder.
I was never happy with the front flares wich I made myself out of chopped up and joined torana flares.
Same with the roof spoiler, never been happy with the shape of it but was all I had at the time.
It took a lot of time and patience to get to that stage and now I have obtained a much better roof spoiler and redone the front flares.
I'll tell you, taking those things off the car was a mission. I could see those things whould never come off or delamenate on their own.
When I fit my better stuff I'll be using the super adhesive sikaflex for even better results.
By the way, I had never used fibre glass in my life before this. I just asked questions to a few boat builders and fibre glass suppliers. Most people will help you with advise or whatever if you approach them properly.

[MFP1]

Some parts of the BOB just have to be glassed onto the body to look right IMO (although you CAN do whatever you like). You can "Get Away" with a cobra boot spoiler as many have, although it is a very obvious deviation from the film. The roof spoiler and rear arches are pretty much "Glass On" only (again unless you use yellow MFP "bolt on" arches).

That said, it is LOTS less work to buy the "Bolt On" kits now available for some of the parts (Ie boot lid, Front Guards (with arches and nosecone skirts built in), and Nosecone), and you avoid any potential problems with delamination or replacing a damaged part the hard way. The boot lid is especially good because folks have a tendency to close the boot with the spoiler.

It is also important to point out that the delamination probelm is as much due to using Polyester resins and inferior cloth in the parts as the attachment to the car (although Bondo is the wrong stuff to use, ad mad Dan points out).

Vinyl ester resins have a much higher TG (Thermal Gain) than Polyester resins do. Vinyl ester is at the same (or close) TG expansion rate as steel, and Poly is MUCH lower. This is especially important when glassing parts onto a BLACK car, if you dont want to watch your expensive paint craze in the summer heat of a carshow anyway (from the diffeent expansions inthe heat). The lay-up techniques like Vacuum bagged lamination, and resin infusion, will also make a big diffrence in the strength, flexibility, and TG of the parts.

If you never leave your BOB out in the sun all day it might not matter for many years, untill the Polyester starts to break down (its elasticity lifespan is also much shorter, ask someone who has restored a brittle old corvette).

Anyhow, if you want the FULL technical explination, talk to anyone involved in Aircraft Composite work, or contact the MMC guys as they are one of the builders who use Aircraft technology in their composite work (dont know for sure which, but I am sure some others do).

[LAST V8]

Hi guy's, here is my 2 cent's worth.Don't cut corner's with product's.You may save a few buck's in the short term but it will bite down the track.Touch wood i have never had delam or peel issues.Have seen first hand plenty of problem's, and i put it down to inferior materials and poor preparation.The movie car look's as good today as she did 20 years ago.That is no mistake.When it comes to resin's and matting i purchase from pro boat builder's.That's where i learned the craft.I mean they can't afford to have problems can they.Like any trade there are a lot of pitfall's and experience is the key.Also don't mix and match paint's and primer's.They are designed to work together.Another mistake people make is to glass and work over previous paint's etc.That is a no no.You must bare metal any glass point's and key in surface area's.You have to create an anchor for the product's to bite into.Air bubbles are your biggest enemy, and if they are there, grind them out and start again.Do it once, do it well, regards Scott.

[madmaxxx]

Scott , have you used any of the new bonding products by duramix or fuser?? Thats what i used on mine and after its bonded and cured the material would rip apart before the bond to me metal would fail.. Not air bubble issues either. My bonds are still 100%.

Jim

[LAST V8]

Hey Jim, i will have to check material brands and will get back to you on that one.Sounds like your doing thing's right if section's would break without lifting off.It all goes down to sound preparation.Avoid any contamanation, measure materials evenly and be mind full of temprature.Also the longer you take the better, allowing for schrinkage etc.Thus the importance of correct mixture's.I only use 2 Pak high fill's these day's, very forgiving and magic stuff to work with.Cost's a bit more but well worth it. Scott.

[ManiacMicky]

I've got an advanced spoilers van front end. Need to modify it and the side panels so they alline with the body and then fit it all up. I'm considering going to a fibreglass fabricator to make the adjustments using reference photo's etc. Hopefully it wont be too difficult. I'm aiming for something like the white coupe on this site minus the flares. I think bolt on is the way to go for practicallity yet glassed looks better.



Looks like this was bolted on, anyway mine will end up something like this but in Gun Metal Grey and black rims.

[mad dan]

Hi micky. is your advanced nose straight or warped like mine? how long ago did you get it and how much did you pay?
Just curious is all.
Dan

[ManiacMicky]

Hey Dan,

I received my advanced nose last March for approx $900 (sideskirts extra). It seems pretty straight and well built.

cheers,
Mick.