Reinforcing 'glass rear panel

[Guest Z-rific]

Here's the low down...

 

I have flares (body panels) in the rear that start under the door, flare out to the top of the wheel well, then go horizontally straight back and wrap a little around the rear. They add a good 3 to 4" out from stock fender. I have taken about 2" of metal from the well.

 

Now, I have an area behind the wheel where there is an open void between the old quarter panel and the new flare. Half way between the back of the wheel well and the rear, the fiberglass flare needs reinforcing, as you can push it in.

 

I plan on riveting sheetmetal between the old fender and new behind the wheel to cover this opening, but before I do, I need to reinforce this void.

 

What suggestions do you guys have?

[Guest Anonymous]

If I understand the problem: you removed about 2 inches of the old fender wheel wheel radius which caused weakness. Dan Juday solved this problem with his flared fenders.Go to Eric Nyerlins site web page and scroll to pictures of Dan's project 240 Z rebody project.The picture has detailed instructions.You need to get the original inner fender and outer fender back together the way Dan did by slitting and folding over(if you still can) or by either joining additional sheet metal to them by screws,pop rivits or welding. After the inner and outers are fully joined back together , you can seal them together like Dan did by using this aluminum backed putty tape.

[Guest Z-rific]

TZ, yes this is what I did, but that's not the problem.

 

I now have a "pocket", if you will, between the old body panel and the new flare behind the rear wheel. If you are at the driver's side, for example, and look back without tire on, you can see a big gap behind the wheel well between the original panel and my new flare/panel.

 

My new fiberglass panel is bonded and riveted at the top edge. It is very sturdy, except for where this pocket is. You can push on the new panel and get some movement. So I was going to brace this area between the new and old panels, and I can't decide how.

 

Afterwards, I will rivet sheet metal right behind the wheel to cover the opening to this gap.

 

If I had a digital camera, I would email you the image and it would make sense.

 

I was hoping you or Dan J would have some advice.

[Guest Anonymous]

So you are a perfectionist LOL...Labor intensive requiring a lot of member input. Dan J, Racer X,Blue Oval Z.etc..You may need to remove the flares to fabricate a mounting lip or flange to the interior of the flare to fill the void.Here is one method Before removal Mark or scribe the current fender radius to the inside flare surface. Obtain some 6 inch or less wide roll of thin electro galvanized roof sheathing from Home depot to make a flat(fiberglass) mold for the flare mounting flange.A 3 to 4 inch wide strip of sheathing would be ideal to fabriacte a flat mold for a fiberglass mounting flange. Ruff up and clean thoroughly around the scribed mark on the inside of the Flare. Bend a 90 degree angle in the middle of the sheathing about the approximate length of the "scribed" radius inside the flare.With tin snips fit the sheathing to the scribed line so the slit and snipped part of the angle lays flat against the fiberglass while the uncut side runs alongside the curvature of the scribed line. Attach the sheathing with short dry wall screws to the inside flare on the slit side of the sheathing (flat "mold").On the continous non cut side, attach masking tape to the surface of the fiberglass at least 2 inches from the sheathing.Get some polyester fiberglass resin and fiberglass mat. Hand shread the mat into tiny pieces and wet it in uniformly in place with catalyzed resin over the scribed radius line on the flare between the masking tape and the sheathing. This initial strip of fiberglass secures the new mounting flange to the flare (and this area needs to ruffed up and cleaned thoroghly)..The shreaded mat will have wetted fiberglass hairs extending onto the metal sheathing(which is desirable). Keep building this strip with a few successive layers of shreaded mat. Begin applying the shreaded mat to the metal sheathing with about 3 successive coverings of mat which will begin to slightly fill in with hairs the 90 degree angle crated by the flare and the the uncut side of the formed metal sheathing.Now directly apply shreaded mat to the the angled center of the sheathing and flare to finish the new mounting Flange. After the fiberglass cures remove the dry wall screws and the sheathing which will leave you a substantial uniform flange permanently attached on the flare to mount to.This new fiberglass mounting flange will provide a lot of strength to the flare You can screw a strip of the roof sheathing to the new flange on the flare and to the radius of the cut fender weel opening to cover the VOID I hope this makes sense.BTW you may want to go to aluminum sheathing to fill the void because the "no stick" electro galvanized is great for making "flat molds" but nothing sticks to it. You can use the paintable black undercoationg to dress the covered "voids"

[Dan Juday]

Wow, that is way more complicated than my plan. I'm not dissin' you bro. I'm just too lazy for that much work.

 

My plan: The Datsun wheelhouse is made in two pieces, an inner and an outer with a convienient seam right down the middle to use as a guide-line. I will make a template out of several pieces of cardboard taped together that will fill the space between that seam and the inside suface of my 'glass fender. Then I will remove the template and cut one piece of aluminum sheet. on the edge that contacts the fiberglass I will slip on that generic flexable weather striping edge stuff. They make some that is just the edging with the metal inside without any actual seal attached to it. I will then fit the piece into the opening and pop-rivit it to the steel wheelhouse with a little caucking to seal it. On the edge that contacts the fiberglass I will just use a bead of silicon to glue it to the fender. Quick and easy. The rubber edging will keep the aluminum from abrading the fiberglass.

 

Not an original idea. I saw it on a cobra kit.

[blueovalz]

I filled my quarters (the void between the unibody quarter and the new wider fiberglass one) with minimally expandable foam. Get a good quality foam as the cheaper ones will shrink a small amount with time. Other than that, the only way I can see to stiffen the fiberglass is to add strips of glass to the back side, which sounds like it may be a bit tight back there to do this easily.

[Guest Z-rific]

TZ and Dan,

 

Thanks for your replies. I have much respect for you guys buuutttttt....

 

Terry gave me the reply I was looking for. It's not the wheel wells, it's the void between new and old body panel back towards where the rear side marker was. I wanted to fill or brace it to keep the fiberglass solid. I was wondering if there was some kind of foam to put in there without causing rust problems.

 

It's my fault that I didn't describe the situation well.

 

I will be welding or riveting the fender and inner fender to retain strength. If I rivet it I will go back over it with glass.

 

Thanks guys. Now to find this foam....

[Guest Anonymous]

web page Sooner or later some one comes up with an answer that is sustainable (Blue Oval Z bats about a 1000) 1-877-477-7823......Closed cell foam..Aircraft Spruce has a free catalog... Poly-cel 100 polyurethane foam in a spray can maybe sourced locally or in the bulk can "X-30 Expanding Foam" two part mix

[Guest Z-rific]

Thanks TZ.

 

If this stuff gets wet, will it be okay? I'm not sure how well I can waterproof that area. And condesation if probably imminent.

[blueovalz]

Kudos to RacerX. The foam filler I used was then undercoated (again, like he said, after sanding it smooth) to completely seal the water out. This combo has withstood the test of time. When you get through doing this, the underside of your wheel well will have a professional look and feel to it.