Advice / help with fiberglass repair! (Page 2/2)
cliffw NOV 12, 09:30 AM

quote
Originally posted by 82-T/A [At Work]:
She used a sander to sand down the paint, expose the "glass" and drilled holes along the cracks.



I thought one would drill holes at the ends of the crack, not along the crack.
82-T/A [At Work] NOV 12, 09:46 AM

quote
Originally posted by cliffw:

I thought one would drill holes at the ends of the crack, not along the crack.




I instructed her to do both. The end of the crack I think will help stop further cracking, but my thought is that along the crack (a few here and there) would provide a greater place for it to bite into the material. I'm going to go out and check to see how it dried... 13 hours later...
82-T/A [At Work] NOV 12, 09:56 AM
Ok, so... not happy with the results.

The stuff is very flexible. I ordered exactly what was mentioned in the other thread, specifically for SMC... and it's more like hard rubber. The stuff just peels off. This is what I used: https://www.3m.com/3M/en_US/p/d/b40071610/


What the hell do I need to order to fix this, this stuff clearly wasn't the right stuff, even though it says it was for SMC?

[This message has been edited by 82-T/A [At Work] (edited 11-12-2024).]

82-T/A [At Work] NOV 12, 10:15 AM
Ok, I just bought this stuff... https://www.eastwood.com/ev...in-quart-100864.html

It's far more like the fiberglass resin that I remember using with my uncle when he restored his Corvette... and it dries as hard as a rock, which it is supposed to. I'm really frustrated I wasted my time and money... on the other 3M crap. That's not for SMC... even though it says it is. That's for like bumpers and flexible crap. I am so pissed. I mean, not like raging pissed... but would like to hear from others who have used that stuff. Maybe I did something wrong?
Neils88 NOV 12, 11:25 AM
The first stuff you used works well on flexible SMC panels. The flexibility stops it from cracking. However, it's not the right stuff for structural repairs. The second stuff you bought is the correct stuff. Don't be afraid to grind down deep into the area to remove all old repaired/ damaged material. Feather well into the good material, then build up with layers of mat fiberglass and the SMC resin.
82-T/A [At Work] NOV 12, 11:57 AM

quote
Originally posted by Neils88:

The first stuff you used works well on flexible SMC panels. The flexibility stops it from cracking. However, it's not the right stuff for structural repairs. The second stuff you bought is the correct stuff. Don't be afraid to grind down deep into the area to remove all old repaired/ damaged material. Feather well into the good material, then build up with layers of mat fiberglass and the SMC resin.




Thanks Neil... that makes sense then. Ugh... ok, well, that was a practice run. Haha...

thanks!
RCR NOV 15, 04:54 PM

quote
Originally posted by 82-T/A [At Work]:

Ok, I just bought this stuff... https://www.eastwood.com/ev...in-quart-100864.html

It's far more like the fiberglass resin that I remember using with my uncle when he restored his Corvette... and it dries as hard as a rock, which it is supposed to. I'm really frustrated I wasted my time and money... on the other 3M crap. That's not for SMC... even though it says it is. That's for like bumpers and flexible crap. I am so pissed. I mean, not like raging pissed... but would like to hear from others who have used that stuff. Maybe I did something wrong?



Sorry to look in so late. I've always used the EverCote when bonding to the SMC panels. I'm still concerned on the structural strength of EverCote and glass matt and having it bond to that crack. It looks like the break is in a high stress area where the hinge mounts. Are you using a wing on the back? That will increase the stress on that area. If you get rid of the springs and go with struts, you might have a better chance on not recracking the repair.

Bob
82-T/A [At Work] NOV 18, 08:03 AM

quote
Originally posted by RCR:
Sorry to look in so late. I've always used the EverCote when bonding to the SMC panels. I'm still concerned on the structural strength of EverCote and glass matt and having it bond to that crack. It looks like the break is in a high stress area where the hinge mounts. Are you using a wing on the back? That will increase the stress on that area. If you get rid of the springs and go with struts, you might have a better chance on not recracking the repair.

Bob




Never too late, thank you for the advice. I was able to strip off all the old green stuff that we'd put on the other day. For the most part, it peeled off. I was able to get a hold of an area where I maybe hadn't removed the gelcoat, and then used some pliers to carefully peel it off. It tore up some of the fiberglass / SMC that was underneath, which I think is actually a good thing, because it exposed more material that the new stuff can bond to rather than a perfectly smooth surface. For the rest of it, I had to use a box cutter, and / or a sanding disk.

I ended up mixing the fiberglass / SMC resin with the hardner, and applied multiple layers of pieces of chop mat over the areas that I had dug out. I then layered a couple of larger pieces over what I had repaired. I checked it last night (after it had been drying for a couple of hours), and it was really warm, but rock-solid.

I'm going to look at it again. I figured what I'll do is sand it down just a little bit, and then use plastic filler to fill in the holes, and then prime and paint the entire back.


As for the break... it's weird. It was broken before I got it, but I THINK what happened is that someone was towing the car backwards, and the trunk flipped up and backwards, causing it to break backwards. Really weird. The top panel has zero damage at all, but it looks like they re-bonded it to the decklid, and they had installed two metal brackets (which I removed). They hadn't done ANY fiberglass repair at all... not even glue... just attached two metal brackets over it. It has a luggage rack, no spoiler.


I think it should be ok. I'm going to check it out tonight after work.