Well, don't know about that. Never used it and never will - if its indeed polyester based. It might be ok but I know epoxy for sure is good for early and later C3's. There is no question about it so I don't plan to risk anything else, no matter what the advertising says.

 

So they are lying in their advertising and all the guys on here that have used the resin for SMC panels are not being truthful.



Of course you have done alot of body work on Corvettes and are speaking from experience.

 

Don't take it personally, I was just saying how I feel about it. And no need to twist my words. You can use whatever you want. Hope you succeed next time.

 

I don´t take anything personal on here. I started the thread to see if anyone has the same experience as I did. One guy did. He did the same job as I did. No body skimped on supplies or used the wrong product. I am sure others have had the same problem but haven´t seen the thread.

But you still didn´t answer my question, have you done body work on vettes where you have tried different product and have had different results. Reading and doing are two different things.

 

Don't know what else to tell you, from the information given, it seems as if you have classic polyester shrinkage, that's what you're seeing when the temp changes, not stress cracks.

 

If it was polyester shrinkage there would be ripples in the paint, right. I really don´t think you understand what the problem is. It is the same ghost line that you get when you over lap weld quarters. No polyester used there.

I have been working on and doing body work on vettes for around 40 years and have never seen this.


And how much body work have you done.

 

For what little it means, I've been doing corvette body work for more than 40 years, had a crash shop with frame machine and painted hundreds of them over the years. Back then it was midyears where poly resin was fine as long as the method was correct.
And yes, I've run into what you call ghosting from other painters not used to resin methods.
Black is unforgiving, everything has to be perfect.

I started using epoxy years ago.
Stinger12 here, with his rebuid thread and glass obsession has even experienced it's advantages over poly and it's his 1st rodeo.

 

I guess you have as much experience as I have had. And I never ran into this problem. I don´think there is anything to do with shrinkage here. I have seen body work shrink and this isn´t it. Like I said if it was shrinkage you would be able to see it and feel it.

The funny part is, the front bumper dosen´t have the problem and neither does the top of the rear bumper. And neither did any of the other vettes I molded the bumpers on.

 

But you surely seem to take offence to suggestions others have to offer. I don't quite understand the hostility. I am sure you have extensive Corvette repair experience but surely even you can learn some new stuff without taking a dent into your superiority? Like you did less than year ago when you realized not all resins are the same .

I've done Corvette glassfiber jobs since 1989 and other glassfiber jobs since about 1982. And also some carbon stuff in last few years. My latest job was to repair a C3 battery box which had a major hole in the bottom, finished 2 hours ago. I am not doing composites professionally but as a part of various hobbies. I have worked on many times more expensive boats than any normal late C3. Used polyester long time ago but then went to epoxy and have been much happier. I have also a habit of investigating new and better ways to do things but haven't yet seen any reason to use other resins than epoxy. Have also taken courses on experimental aircraft composites.

Well, I can see I am not welcome and will bother you no more.

 

Yes I didn´t realize there were other types of resin and I always used one type and never had a problem. I came on the forum and did some reading and tried the other type. I really don´t think it is the problem because the other parts I used it on have no problems. The front bumper and the top of the rear bumper. So if it was the problem it would happen to all the other pieces also.

I also questioned your experience because some times you get answers from guys on here that have never done any type of work like this. And they will argue with you about how you did something when they have never done it.


I am not being hostile towards you And if I came off like that I apologize.

I would also post picture but it wouldn´t help because it dosen´t show up in pictures.

 

Actually I don't have a problem with using polyester products...in fact if it is regular glass, that is the product I use. For smc repairs I use epoxy. I still use regular fillers over smc with zero problems.

I'm in school right now for my third year of autobody and in fact they teach that once polyesters cure, which is usually a couple hours, they are now inert and will not shrink or cure anymore, they are done.

However I did ask a question last week regarding ghosting before I saw this thread, which is exactly what this post is referring to. The teacher referred to ghosting usually coming from metal panels which were bonded on during replacement using epoxy bonding adhesive. If the epoxy is not fully cured, I'm talking about 90 percent, and then you put filler, primer, base and paint, the remaining 10 percent of epoxy will cure over heat cycles and a ghost line will show. They also mentioned that this remaining10 percent of curing is usually done with a heat lamp to a certain temperature, which was actually quite high...either that is done, or you have to wait an extremely long time for it to fully cure they said.

I can't offer any advice from personal experience, but this is what I was told by the instructor here at SAIT polytechnic, who teaches courses for GM . It sounds like this is the problem you might be having.

 

Thanks Stinger. I usually wait 3 to 6 months before I paint a car after doing the body work, so everything will be cured and shrunk by the time I paint the car. The rear bumper the part I am having the problems with was done about 4 weeks ago. The molded in front bumper was done last September. Well I am going to finish buffing out the car and use it this summer. You really can´t see the ghost lines unles pointed out. By September it will be fully cured and I will redo it.


Your car is coming out great.