"Re-shaping" fiberglass?

[Alex]

(I put re-shaping in quotes because I'm not entirely certain that's the word I'm looking for...)

Anyways, if one wanted to convince the body to take on a slightly different shape, are there any tips or tricks to follow? I've read a lot of weird things with Cobra bodywork (like putting 100lbs worth of weight plates ontop of it to force it to settle, heat lamps, etc...), just not certain what would be best.

More specifically, I'm working on centering my spyder section. I've got it pretty close at the moment (my front is still a little bit off, but I'm working on it), but the rear is giving me trouble - it's riding very very close to the back of the tire (I can't get a 12mm wrench through there, not touching, but almost). I can't shift the spyder backwards, or else my front tire gets phsyically wedged into the front clip.

I circled the area in question.

So what I did was grab the underside of the body, pulled it back and placed a wooden board between the tire and the body. Then I bolted the rear clip (in that position) to a jig I have clamped on the diffuser (jig is there temporarily so I don't have to drill the mounting hole to locate the hinging setup yet...so it's basically the same thing as bolting it right to the diffuser).

Release the board from the tire, and the rear clip kept its shape (i.e., has sufficient clearance between tire and body now, and the gapping is even).

So that's the summary - I guess my question is what can I do at this point to help convince the fiberglass to mold to that shape? Right now if I remove my jig or unbolt the hinge from the jig, the bottom of the rear clip will sag forward into the tire, so I'd like to convince him to 'loosen' up a bit so he naturally takes on that shaping.

Thoughts from the fiberglass experts? =)

Btw, proof it actually hinges 90* now, eheheh

 

[Chris Huck]

Hi Alex,
You could try heat but it would depend on how "cured" the resin is, what resin was used? Poly or Epoxy? Looking at the pic it appears that the inner surface is just glass, if it were me I`d take the clip off and grind away the back of the offending area with a pad in a grinder (carefull not to get it hot or go through to the gell) Bolt back in place in the correct position, whip the wheel off and re-glass, then leave to cure, it should remain in place when you unbolt from the jig.
regards Chris

 

[Alex]

The only problem with grinding it is that part of the offending area is the bottom portion of the wheel well arch (I re-uploaded the picture and re-circled it; the first one really wasn't clear). It's visible form outside the car, so grinding it would mean you'd basically have to rebuild the bottom portion of the arch to be aesthetically pleasing and contoured (unlike the portion directly behind the tire which nobody ever sees).

After playing 'shift the spyder' for 8hrs today I'm beat .... maybe I'll get lucky tomorrow when I'm fresher and find a positioning of it that's the best of all worlds (i.e., even gapping that doesn't require any massaging into place)

 

[Craig Gillingham]

at least you are getting practice for when you start fitting and aligning the doors. The left and right doors were different on mine symmetrically.
The gapping for the door interior panels and such is compounded when you trim the panels.
Are you happy with your seats as when trimming these it also reduces room everywhere.

 

[Craig Gillingham]

^^^^^^^^ will get deleted hehehheehe

 

[Chris Huck]

Ok, the other thing to do is to flex the arch to where you want it or get a friend to do it while you note where the flex is taking place, I suspect that by looking at the pics it will be on the return on the inner arch and the outer lip? Once you have identified where the flex is taking place this is the area you need to grind back/re-glass, if the outer arch/lip is flexing and you are worried about having to grind the inner side of it, just rough it up with 80 grit wipe with acetone and glass up. It`s really hard to describe not being able to see it, maybe you know someone who knows about glasswork, he`d or she`d be the person to speak to and they`d put you right.

 

[EGLITOM]

Alex

what size rear tire are you using ?

TOM

 

[Fran Hall RCR]

Stock rear tyres are 325/30/19...or 345/30/18 on the track wheels.

Alex has the 19 inch rear wheels but I am not sure about his tyres..

We do leave generous returns on all the wheel arch lips (as you can see in the pics)...these can get close to the tyres until trimmed , also the lower return edge on the tail can be trimmed left to right for tyre clearance in necessary, this is an arbitrary trim line also.

 

[Al Wohlstrom]

Alex, Can you take the rear clip off, bend the piece to where you want it and bond a small piece of aluminum angle to the fiberglass on the underside with cloth and epoxy? When it sets up overnite it should retain the shape. If you want to experiment prior to using the fiberglass, bond it in place with JB Weld, great stuff. If you dont like it, it's easy to grind off.

 

[Alex]

Back to scooting it around today. Failing that, I think bonding something to strengthen it and help keep its shape will be the ticket - for reference, it's not like I have to flex it in half...movement backwards is around 3/8'' or so.

Tires as Fran said may also be playing a role - I went with 345/30/19 which is .4'' larger in diameter than what he recommends .... but really, it's never very fun to follow the rules, hehe :lipsrsealed:

 

[Alex]

After a bunch of prodding, and grinding, and grinding, and even mroe grinding ( ... I wasn't aware you could trim the area, I thought you had to use it as is ) I got the driver-rear even using the factory mounting points (which make the most sense to use) - I have 1 finger width all the way around (front to back of tire). Not a huge amount of clearance, but I don't think the wheel should be wandering around too much there, otherwise I'm going to have a problem, lol. Since it's 1finger width even all the way around, only other way to increase room at this point would be to knock out the wheel well itself, lol.

Now onto the passenger rear - it's unusual because for some reason the rear clip on the passenger side is poking out past the tire. On the driver side, the tire just barely pokes out beyond the clip. Hummmm. It's like a gigantic puzzle, 1 piece at a time to figure it all out.

 

[Fred W Ballinger]

it's unusual because for some reason the rear clip on the passenger side is poking out past the tire.

Have you aligned the wheels by putting a string box (referenced to the car centre line) around the car to make sure the wheels are both the same distance from the centre line and that the wheel base is the same on both sides?

Cheers

Fred W B

 

[Alex]

Not yet, but that does seem to be today's task. Although first I'll squiggle the body around ... squiggling always seems to help, or atleast make me feel better

 

[Alex]

For anybody who cares, 345/19 will fit.

But you'll have to really trim the fenders. Really really trim them.

And you won't be able to leave the control arms in the centre of the brackets anymore.

Buttttt they will fit without having to tug the fiberglass around with a crowbar to get them in

 

[Mesa]

Alex
It's very important with close fitting tires that you do at least a basic alignment on the wheels. One would prefer to align the body to the chassis centerline and not to wherever the wheels happen to be at that paticular monent. It's a good idea to basic wheel align FIRST, then you can see how that relates to the true chassis centerline. Which could save you a lot of grief when you find out the tires were not really in the place they were going to end up AFTER it was aligned for real.

 

[Alex]

I've got my alignment set, using the factory caster/camber, and have set the toe.

It didn't take me too long to realize as i adjusted the alingment, it changed tire tobody distance, hehe....that's why it's taken me 50hrs and counting to get it - want to get it right the first time.

 

[Alex]

oh yea, but I definately see what Fran meant by the body will sit in place and look right when you have it - no need for any tugging or forcing once you find the proper position.