How do I repair a cracked fender?

[Sandra H.]

Any good advice on how to go about repairing a crack, not
surface crazing, but a real one?
The crack is about 6 inches long, partially repaired, lower edge of front fender, above the wheel well.
From what I've read it appears I need to remove the old repair (mesh and something(?) to glue it together) and start over.
What works best to put it back together? Or if there are any good books out there on fiberglass repair, I would like to read them.
Any ideas?
Best, Sandy

[Terry D.]

Re: How do I repair a cracked fender?

Sandra
There are lots of books about fiberglass repair. There are even a couple for sale at the NCRS store. If it were me I would check at the library first, most have plenty of books on the subject. It would take too much time to try and explain that repair here.
Terry

[Jim H.]

Re: How do I repair a cracked fender?

There is a book out there which covers this subject called "Chevrolet Corvette Restoration Guide". CC sells it.

http://www.http://www.amazon.com/Chevrolet-Corvette-Restoration-Motorbooks-Workshop/dp/0760303258/ref=sr_1_15?ie=UTF8&s=books&qid=1231780353&sr=8-15

[Pierre J.]

Re: How do I repair a cracked fender?

Cracks at that location are common on C1's. Usually caused by the wrong number of shims under the rad. Ask me how I know?

Pierre 34410

[Chuck S.]

Re: How do I repair a cracked fender?

Any good advice on how to go about repairing a crack, not
surface crazing, but a real one?
The crack is about 6 inches long, partially repaired, lower edge of front fender, above the wheel well.
From what I've read it appears I need to remove the old repair (mesh and something(?) to glue it together) and start over.
What works best to put it back together? Or if there are any good books out there on fiberglass repair, I would like to read them.
Any ideas?
Best, Sandy

Hi Sandy, a good book is really what you need. Eckler's once published a good one. Last I heard, it was out of print, but I understand you can still find one on ebay occasionally.

You're on the right track. You'll need a mini-grinder with 36 grit disc to grind off the old repair and prep the area for repair. You'll need tinted resin to match your Corvette (The Corvette Image), fiberglass mat and a fiberglass repair roller to roll out air bubbles (Ecklers or other Corvette vendors), MEKP catalyst (available at home stores), latex gloves, disposible "chip" brushes, and acetone as a cleanup solvent,

You have a C1, and some of the older C1s used fiberglass mesh as reinforcement. Unless the C1 guys say you have to use it for originality, I wouldn't use fiberglass cloth or mesh for reinforcement even if it was used originally. As the repair ages, you may begin to see the mesh pattern in the fender surface.

As you said, begin by grinding off all the old repair down to original fiberglass. Taper grind both edges of the crack beginning about 2" from the crack, and tapering to almost zero thickness at the crack edge. The sides of the crack should be aligned perfectly in the relaxed condiiton without support; if not, support the fender from behind to make the edges align.

Cut three to four layers of fiberglass mat to cover the taper ground area. Some say to tear the mat, as it gives you better "feathering" of the layers, but I say "horse feathers"...use scissors to cut the mat to fit. Use old expendable scissors as the glass fibers will dull them. Scissors give you precise control of the shape of the mat pieces, and allows you to build in "feathering" by cutting each layer about 1/4" smaller all around than the previous layer. This permits the "thickness" of the repair to work with the taper grind to give you more uniform repair thickness. In my opinion, "feathering" of the repair is moot anyway...you will have to grind the finished repair to contour.

Mix polyester resin, and saturate a the largest piece of mat with resin. Brush a coat of resin onto the ground area, apply the mat piece, and roll the mat layer. Repeat these processes until all the layers have been laminated.

Once the top surface of the fender is repaired and the resin cured overnight, the same repair procedure should be done to the inside (wheel well side) of the fender for strong repair that doesn't crack again. The inside will be in closer quarters, and somewhat more difficult as a result, but I would not compromise.

Allow the resin to cure overnight. Now the artistry begins...grind off everything that doesn't look like a C1 fender. You want to have the fiberglass slightly below correct contour so you do your final precision finish with body filler. I have attempted to do zero body filler repairs with limited success...I found it was much more difficult and time consuming to work the fiberglass, than simply grinding it down below contour and using body filler for final finishing.

[Sandra H.]

Re: How do I repair a cracked fender?

Hi Pierre,
As much as this sounds like the common kind of crack, I do know this happened at about 45mph on packed snow.......swapped ends and did a little off-roading, details I don't know. Do know it wasn't a head on impact, just deep snow (that probably saved her life).
No other damage was done to the car, though.

Thanks Chuck, what you describe makes perfect sense to me and I can do it. Thank goodness that's the only glass damage on the car.
Best, Sandy

[Ray C.]

Re: How do I repair a cracked fender?

Hi! Sandra

I have a copy of Eckler's Complete guide to Corvette Fiberglass Repair. Yours if you want it, email me your address.

Ray

[Jeffrey S.]

Re: How do I repair a cracked fender?

The tool I found most useful in doing small glass repairs, like this, is my dremel tool.It gets in small spaces is easy to control ,and with a little practice you can repair holes and cracks like a pro. I also use west system resin as you can get it with pumps that eliminate the guess work in mixing resins,which can cause resin that dries to fast,too slow,or never or worst catches fire. Also whenever I grind I hold a shop vac next to the dremel and I never have a problem with itchy glass dust all over myself.Hope this helps Jeff

[Sandra H.]

Re: How do I repair a cracked fender?

Hi Jeff,
Thank you for the tips......I have dremels and a variety of grinders around here.
Didn't know epoxy came in easy-to-use tubes. But, fire? No one mentioned fire before. This is good to know.
I took Ray up on his very gracious offer of the book.....Thank you Ray.....so have confidence that I can get the job done.
Best, Sandy

[Ridge K.]

Re: How do I repair a cracked fender?

Is this a great board, or what!
Why is it, that everytime I sign in, there are five to ten "guests" viewing, that are not members? Looks like these guests would want to join the NCRS, and join in on the fun and camaraderie.
And, annual dues are cheap. It's the best deal in this hobby.
Ridge

[Bill I.]

Re: How do I repair a cracked fender?

Sandra, as I recall from doing some boat fiberglass repairs back in the 70's, the resin does not like wood as a place to mix it. I used a piece of plywood, and it got HOT. Suggest glass. Bill.

[Bruce C.]

Re: How do I repair a cracked fender?

Sandra, as I recall from doing some boat fiberglass repairs back in the 70's, the resin does not like wood as a place to mix it. I used a piece of plywood, and it got HOT. Suggest glass. Bill.

I second that...and don't use cardboard for either your resin or your filler.

Good luck !!!

[Jeffrey S.]

Re: How do I repair a cracked fender?

The west system I mentioned is not in tubes , you can purchase pumps that fit the cans that make getting the correct proportion of resin to catylist correct much easier, sorry for any confusion. Also boat repair has been mentioned , don't use woven fiberglass material like they use in boat manufacture. You want to use what they call matt . the fibers in it don't have a disernable direction and is what the cars were originaly made of. Hope this helps Jeff

[Sandra H.]

Re: How do I repair a cracked fender?

Thank you Jeff,
Clarification is really good....what I know about fiberglass up to this point is that it catches on fire.
Best, Sandy

[Monte M.]

Re: How do I repair a cracked fender?

Sandy,
Just my two cents. As you mix more resin, you will get better at it. You want to be careful not to mix in too many air bubbles. It will just make for a better repair and easier to cover if you do not end up rolling out all the little bubbles of the previous layup.

I do not want to get too complex, but I actually put my mixed resin in a 5 gallon bucket I have set-up with a plexi-glass cover and air hose fitting. I pop the mixed resin in the bucket, pop the cover on, turn on an old A/C vacuum pump I have, and within a few seconds, all the air bubbles boil out of the resin. It just make it much easier to work with when there are no air bubbles.

You can see "fiberglass resin out gassing" on You tube and see what I am taking about.

Take your and I am sure you will do just fine.

Also, Chuck has it right. Make sure you do the back side as well. It is a far better job.