Scottd

Had a nasty incident that left my front fender severely cracked. I ground the crack out to about a quarter inch 'V' and laid in Pep Boys purchased fiberglass matting and resin. I reinforced the backside. Repair currently looks like a 'weld' bead about 16 inches long. (only made of fiberglass)

Do I just sand this down and fill the imperfections with bondo/body filler and proceed as usual? Is the fiberglass going to fray out on the edges and have little fibers ruining my finishing attempts? Is fiberglass repair even suitable for repairing what I think is an SMC panel? (IM not worried about brands....Im just making sure IM even using the correct product)

This damage occurred last October and I was in a hurry to get it fixed, so I didnt research the repair as I should have. (I deployed a few weeks later)

Am I heading down the right path or have I already set myself up for a headache?

jnb5101

as long as you used epoxy resin and not polyester the repair will hold. block sand it, spray a coat of epoxy primer to seal and stiffen the 'hairs', sand again and see what it looks like. if it needs more help, the bondo would work, but a flexible filler would be better. go to a local body shop supply store and ask what they have.

Easy Mike

What model year? Stock 68-71 panels are press molded polyester. Beginning with the 71 rear fenders, SMC is used.

Scottd

Body is an 82. The last round of repairs I did were very noticeable. Id spray the primer, let it sit, and the next morning you could clearly see the areas of damage again.

The repair kit is the standard, Pepboys 3M product :
http://www.pepboys.com/product/details/8978406/

What kind of flexible filler is being referred to?

zwede

The resin you used is NOT SMC compatible.

1/4 wide is not enough. It should be 1" wide.

The basic idea of resin & mat is correct. For resin you need either epoxy or polyester w/ SMC additive (dynatron makes one). The mat should be cut in strips, don't shred it and push loose hairs into the repair.

I recommend you grind off your old repair and do it fresh.

Edit: I'm told late C3's used a variant of SMC where no polyester resin works. Better be safe and use epoxy resin.

Easy Mike

Stock 82 panels are SMC. You must use SMC compatible materials. Your Pep Boys link does not open for me.

Scottd

Well SH/T!!!!! Thats going to cause me a serious problem. Ive got a LOT of grinding to do. This is a substantial setback for me.

When you say 1' wide, you mean the width of the repair? The fender split in two...yer saying a 1 inch 'bandage' running the length of the damage?

So, what product should I be using? This seems to be the crucial question here....

Easy Mike

Brand name is up to you, but you must use SMC compatible materials. Read the labels on what you have. Do they state SMC compatible?

zwede

Yes, minimum of 1" wide. Put 2 layers of green painters tape above and below to be your grinding guide.



Here I'm fixing the front edge of a door so it's "half" of your repair. You can see how the tape is placed. When I'm grinding I know to stop when I hit the tape.



In this picture you can see the seam between the quarter and deck. The entire seam has been glassed, about 7 layers of mat & resin. When done this way, the seam is just as strong as the rest of the panel. The key is to give it a wide bonding surface by grinding a very shallow V. The wider you make it the stronger it gets, but takes longer to do your bodywork.

Scottd

Zwede, you are doing exactly what I need to do...(except mines up front...amd my paint job was less than a year old 8*(

Id like to pick your brain real quick.

1) did you lay the tape before or after the glass matt and resin? (Looks like you laid the glass on top of the tape) Is that how your width so parallel? Does your 'V" extend to both edges of the tape?

2) What kind of matting and resin are you using? The only stuff I have readily available is the 3M stuff, so Im going to need to mail order the correct stuff.

Im afraid that because Ive already started (and botched) the repair, that no body shop in their right mind is going to take over now, so Im stuck with my own mistakes and I need a crash course on doing this the right way.

zwede

Ouch!

The tape is on the panels, before (under) the resin &mat.

Yes on all. Without the tape it is difficult to know when to stop grinding. Very easy to grind into the panels. The picture of the rear quarter was taken right before we shot primer. The few small filler spots you see where all the filler that was used.

For rough-shaping the 'glass we used a regular angle grinder with a 36 or 40 grit flap wheel.

Scottd

Im really hesitant to grind a 1" channel down my fender, but I guess I cant make matters much worse.

What brand resin are you using? What kind of fiberglass mat? I dont want to buy the wrong stuff again.

So on a long shot.....what do you think a Shop would charge to repair a 18 inch long 'L' shaped crack ( vertical 6 inches, horizontal 18 inches) and repaint? The paint is a common silver, but has a custom blue pearl clear cote.

Im just wondering if I should do this myself, or if a budget of say, 1500 bucks would suffice for shop repair.

zwede

I used Dynatron 694 but I do not think it will work on a late C3. AFAIK you need an epoxy resin. The mat I liked the best was bondo brand from the local autoparts store. However, an epoxy resin may need a different mat?

Sorry, I have no idea what a shop will charge. You could try over in the paint & body section, ask for "DUB". He runs a body shop and really knows C3 body repair.

jnb5101

any type of glass can be used with any epoxy. this is not a major repair, and is something you can do yourself (except , maybe, the paint). find a local auto body supply store and ask the counter man what he has. they're all ex-body guys and car nuts and like nothing more than to help a diy. my shop even gave me the discount that his large customers received. it's only fiberglass and, worst comes to worst, it can be done over. think of it as a learning experience for when something big happens to your baby.

Scottd

I bought the car 2 months before I deployed. FRESH PAINT.Beautiful silver with blue pearl topcoat. Drop dead sexy paint job. Had it on the road 2 days and a rear tire blowout ripped out a chunk of my rear fender. That was devastating.

1 month before Im about to go away for a year, one of my old school knock off rims falls off the drivers front while im doing 45 and gets shoved up into the fender. I get a split from the rear of the wheel well to almost the door, then straight up. I cried. Honestly cried.

So here I am with the prospect of some serious body repair and painting. Im hesitant on the body work (Ive done more damage than good so far) and I WONT do paint. (If it were a blown valve or wiped cam, Id be fine to do it myself.) Im going to try the avove mentioned tape method with the correct resin when I get home, but Im going to call around and see if any body shops will do it for me within my budget. Im assuming once they see how I messed it up...they wont touch it.

Matching the paint is going to SUCK.

540 vette

I have used the regular resin and have had no problems. I used it to mold in the bumpers on my 77 and 80. The 77 had no problems for theb8 years I had the car and I did the 80 last year and don't see any problems.

CHarper

After the glass is done Dolphin Glaze is what was recommended to me. Putty for a steel bodied cars will not flex and will come off or so i was told. It is a 2 part, very easy to use product for the small blemishes.

540 vette

The "putty" will not come off. I have been doing body work on vettes for 30 years and never saw anything fall off.

Sunstroked

An old sheet metal mechanic once told me, a hole is a hole, doesn't matter the size. It just means your repair is larger. You really need to lay in your repair from the back side. That is your strength, the top side is also structurally sound but ground smooth to blend in. Taper the hell out of it, the longer the taper the greater strength you will impart to the repair. I have totally rebuilt the rt rear fender, and both front fenders as well as the hood surround between the headlights. My car had been in more than a few fender benders, and let's just say if somebody asked the body man if he had ever worked with fiberglass, an appropriate response would be F**k NO! Bondo is not a suitable repair material for glass. Go visit West Epoxy Systems website for some great fiberglass tips. Whether you use their materials or not, but I highly recommend their epoxy system. And I recommend Evercoat vette filler/panel adhesive. It will work on smc and frp. Its not cheap but sands very similar to fiberglass. Personally I don't use the method Zwede uses with the tape, not that it doesn't work, its just that its a hassle and your limiting yourself to between the tapes. Like I said the greater the taper the better. And once the glass is in and sanded you put a coat of the vette filler just like bondo and block the hell out of it anyway. Now, go check out that website and draw your own conclusions. And remember there is always more than one way to skin a cat.

bmprhmpr

Evercoat also makes a SMC resin. I agree with sunstroked, start your repair from the backside. (rough-up back side of fender with 60 grit sandpaper,it will give resin a better "grip") Thats where youll get your strength. Then cut tapper on front side a little into your glass on rear side. Use a good wax and grease remover ( from paint supply store) on surface to make sure its clean before applying resin and mat. Just my 2 cents worth. Good luck.