Fiberglass body wheel lip body prep

DanEC · #1 (**permalink**) 03-09-2010, 04:04 PM

I'm doing body work on my ERA and started trying to prepare one of the front wheel lips. They left it full when they trimmed the body out of the molds so I ground the return edge back to a uniform 5/32 inch thickness. This is the thickness of the exposed edge looking at the wheel well. I will then round that off to simulate the original rolled edge.

Question is - the fiberglass is pretty thick in this area and the thickness of the lip's return to the inside of the wheel well is from 3/8 to nearly 1/2 inch thick. I had planned to lay that back along the inside of the fender to again somewhat simulate the original's rolled edge. But, that is going to be a lot of fiberglass to grind out and I don't want to get it too thin and brittle. I'm looking for examples of how others have finished the fiberglass wheel lip, or how some of the better body and paint shops are finishing them.

Thanks

Dan

strictlypersonl · #2 (**permalink**) 03-10-2010, 04:56 AM

Do you know how hard it is to take a picture of an edge?

The cars here have a fairly consistent edge diameter of about 3/8".

cobrajeff · #3 (**permalink**) 03-10-2010, 05:55 AM

I wouldn't try to reduce the fender thickness too much. Just simulate the rolled edge on the outer edge, then blend it back. You'll want to smooth it back far enough that probing fingers won't feel any glass matt texture.

Most people will be using their eyes and fingers to check out your fender lips - few of them will have calipers, so they probably won't realize how thick the material is.

I glued 3/8" thick closed cell foam to the underside of the fenders to protect from rocks being thrown up by the tires.

regards,

Jeff

289ERAkit · #4 (**permalink**) 03-10-2010, 06:37 AM

Build the inner edge up with short hair glass(evercoat in a can)...then sand to a rolled edge. Yup...it takes a while. A sanding drum kit would be in line for this job. Use just a little glass...don't get carried away...less is more.

DanEC · #5 (**permalink**) 03-10-2010, 08:57 AM

Well - let me try a couple pictures of my own to make sure I don't get too carried away here.

This shows the flush edge I currently have on the first wheel well I turned down with a sanding drum. It's a little fuller than I thought - just slightly less than 1/4 inch. Bob's 3/8 inch has me a little worried as I'm already a little below that on this face although when I roll the edge in the thickness normal to the fender will probably still be 3/8 inch or so at least.

This shows the lip return - except I hit it with the sander and probably have removed 1/8 to 3/16 inch thickness from it already. I'm trying to get an idea of how much I need to take this down in thickness to lay the rolled edge back on the inside.

Do I look to be on the right track or have I gone a little too far? Pictures of finished cars like CobraJeff's give an impression of a fairly knife edge fender lip but that just may be the photos.

Thanks for the responses.

289ERAkit · #6 (**permalink**) 03-10-2010, 11:53 AM

I would not take away ....just add to the inner edge.

w-lewis · #7 (**permalink**) 03-10-2010, 12:10 PM

To simulate the rolled look and feel, I had my builder take a strip of copper wire and bond it to the fender edge. Since it's been about 8 years, I don't recall what type of bonding material he used, but I could ask him if necesary. The finished product looks and feels very good.

DanEC · #8 (**permalink**) 03-10-2010, 05:36 PM

Bob - does this look like it will get me to something similar to the finished cars in the shop? Not a great sketch but maybe better than a picture.

Thanks

Dan

strictlypersonl · #9 (**permalink**) 03-11-2010, 03:55 AM

Looks good to me.

DanEC · #10 (**permalink**) 03-11-2010, 07:43 AM

Quote:

Originally Posted by 289ERAkit

I would not take away ....just add to the inner edge.

The fiberglass is so thick behind the wheel lip that I can't see needing to add anything to it - other than just a skim coat of plastic filler to cover the fiberglass mat texture and sanding/grinding scratches after cutting it down.

There may be more glass thickness in this area after they changed up their molds a couple years ago - I don't know?

Dan

DanEC · #11 (**permalink**) 03-11-2010, 07:48 AM

Quote:

Originally Posted by strictlypersonl

Looks good to me.

Thanks Bob. I'm not scared of fiberglass work but I don't want to have to re-do something I could have avoided in the first place.

Dan

DanEC · #12 (**permalink**) 03-12-2010, 02:26 AM

Quote:

Originally Posted by cobrajeff

I wouldn't try to reduce the fender thickness too much. Just simulate the rolled edge on the outer edge, then blend it back. You'll want to smooth it back far enough that probing fingers won't feel any glass matt texture.

Most people will be using their eyes and fingers to check out your fender lips - few of them will have calipers, so they probably won't realize how thick the material is.

I glued 3/8" thick closed cell foam to the underside of the fenders to protect from rocks being thrown up by the tires.

regards,

Jeff

CobraJeff - Do you have a picture of the forward fender edge also? What would you say the radius or diameter/thickness of the very outside rolled edge to be on your car? It looks pretty small in your picture but as Bob said, it's hard to get the perspective in a picture.

Thanks

Dan

cobrajeff · #13 (**permalink**) 03-13-2010, 05:14 AM

Dan -

Sorry, but I am 1,000 miles away from my ERA, soaking up the Florida sunshine - and I don't have a picture of the forward edge on my laptop.

The edge of my fenders is about 1/4" thick, and has been massaged to look and feel like aluminium rolled over a 1/8" thick rod.

regards,

Jeff

Snakebit · #14 (**permalink**) 03-13-2010, 09:45 AM

I took a short block of wood and drilled a 1/2' hole through the center. Cut the block in half through the center of the hole. Use the 3M paper with the sticky backing and press the sand paper in the half moon shaped hole to round the edge. You can use a amall piece of PVC pipe cut in half also. I used this method using different pipe diameters to round the fender lips, front grill opening, dashboard edge, and rear cowl edge. Worked great using the sticky back sand paper. Buy it by the 3" wide roll and save money. Hope this helps.

DanEC · #15 (**permalink**) 03-13-2010, 12:53 PM

Quote:

Originally Posted by Snakebit

I took a short block of wood and drilled a 1/2' hole through the center. Cut the block in half through the center of the hole. Use the 3M paper with the sticky backing and press the sand paper in the half moon shaped hole to round the edge. You can use a amall piece of PVC pipe cut in half also. I used this method using different pipe diameters to round the fender lips, front grill opening, dashboard edge, and rear cowl edge. Worked great using the sticky back sand paper. Buy it by the 3" wide roll and save money. Hope this helps.

Thanks Snakebit and CobraJeff for the tips. I lucked out and made a visit to Keith Crafts shop yesterday and he had a nearly finished Super Performance in the garage that I got to closely look at and lay my hands on the fender lip. A close look is worth many pictures. That helped a lot and I will probably try your wood block tool. Boy, there is a lot of fiberglass left on these ERA fender openings to remove. But I understand why they do that. I think I'm going to have to go to something more aggressive to do the bulk work and save the sanding drums for the close in work before going to the sanding block.

Thanks again.

289FIA · #16 (**permalink**) 06-30-2011, 04:10 PM

Quote:

Originally Posted by DanEC

... I think I'm going to have to go to something more aggressive to do the bulk work and save the sanding drums for the close in work before going to the sanding block.

Thanks again.

Dan, been reading this topic with interest. What did you finally do/use for more aggressive trimming?

DanEC · #17 (**permalink**) 06-30-2011, 05:00 PM

289 FIA - I used drum sanders (about 1-1/2 dia from memory) to work the raw opening back to my masking tape line. I also used them some to bring down a few areas on the inside where the fiberglass thickness was a little too great. After getting it down to my masking tape line I just ran the drum back and forth on the opening radius to smooth it up until it looked good to the eye and by feel. I used the scotch sanding discs (about 2-1/2 inch dia) in my drill to bevel the inside and outside edge of the lip to form a rough circular contour. I used the wood block with a 1/2 inch hole in the edge (discussed above) to finish sand it to radius. After that it came down to some hand work to touch up any areas that didn't seem to be quite even or true to contour. The fiberglass thickness on my car varied quite a bit around the wheel lips - typically thicker along the top part of the lip and thinning out quite a bit at the bottom. I evened it up a little around the top and floated about 2-1/2 inches inside the lip with filler and sanded it smooth. I sanded the inside of the wheel opening and filler mostly with a 6-inch piece of swimming pool tube with 180 and 220 sandpaper wrapped around it. I probably should have worked a little more evening up the thickness around the lip on the inside but I hated to thin it down a lot for fear of weakening it. Mine are probably a good 3/8 inch thick diameter along the top and and around the side - and stout. They are never going to crack except from hitting something hard. I found this to be kind of nerve wracking because I was afraid of taking too much off and having to re-glass the lips. But, it worked out fine. By the way - pick up one of those smaller diameter swimming pool tubes and cut some various lengths. They are great for sanding inside curved areas.

289FIA · #18 (**permalink**) 07-02-2011, 11:07 AM

Thanks Dan.

You've given me some ideas. I have a small electric body saw that should help with the bulk removal. Afterwards I’ll block down to the tape guide then round it off with the ½ inch semi circle. I’m not sure I’m qualified to use a barrel sander for this task. In my hands, damage is imminent!

Inside fenders with the pool tube should be just right. Off I go…

Thanks again.

Al

DanEC · #19 (**permalink**) 07-02-2011, 03:11 PM

Quote:

Originally Posted by 289FIA

Thanks Dan.

You've given me some ideas. I have a small electric body saw that should help with the bulk removal. Afterwards I’ll block down to the tape guide then round it off with the ½ inch semi circle. I’m not sure I’m qualified to use a barrel sander for this task. In my hands, damage is imminent!

Inside fenders with the pool tube should be just right. Off I go…

Thanks again.

Al

For some reason I didn't immediately catch that your building an FIA - with a differnt fender lip detail - Duh. But some of the above might still help. Get some high quality filter masks to wear. Goggles are not a bad idea also. I hate grinding fiberglass and I sure don't recommend breathing any of it.