Gelcoat vs Dura Tec

[Wayne W.]

Re: Gelcoat vs Dura Tec

Wayne,

Now you really have me scared. Are you one of the folks that agree with the statement that an old A/C hood should be thrown away, or that a section should be cut out and repaired ?

As to the statement that " fresh fiberglass should be applied and than treated with those products to make sure it doesn't come back ."........ I don't know that I ever had the problem before. As soon as I bought the car I began stripping the paint from it , and only learned of the problem later on , from reading the experiences of others. I than thought that by applying Gel coat one would solve the possible situation . If I read you right, you are saying that if the problem exist , even the gel coat won't stop it ! Is there any way to tell if I do, or will have a problem from looking at a bare hood ?

Jim

Jim,

I got the impression that your hood was showing the problem already. Now, from your last post, maybe it isn't. If that's the case, I am not sure why we are even discussing the fact. Just prime it with good stuff, epoxy, gel, polyester, and get on with it. If its not there already, take care to seal the underside and try to keep the oil from underneath in the future.

What I am saying is that if it is already there, the surface needs to be ground out (not cut out) and glass laid in. This is the only way to break the syphon. Otherwise it will keep coming back.

[Jim S.]

Re: Gelcoat vs Dura Tec

Hi Wayne,

Thanks for the responses and sorry for the giving the wrong impression.

As I said earlier ,I stripped the paint off years ago ,long before I knew of the potential problem. Had I known then what I know now ,I would have looked more closely at the paint on the hood before I stripped it .

As far as I can see from looking at the bare glass hood, I have no such oil problem so far. The gel coat, or other possible products , was just to make sure I didn't develop one in the future. I assumed that there was no way of telling if or when the years of oil leakage might poke through. Am I wrong ?

If there is a way to determine if it could be a problem ahead of time , or something else I can do before painting, while it is still in the " bare glass" stage , I would sure appreciate the further imput !

Thanks ,

Jim

[Wayne W.]

Re: Gelcoat vs Dura Tec

You would know from the oil spots on the fiberglass.

[Chuck S.]

Re: Gelcoat vs Dura Tec

You would know from the oil spots on the fiberglass.

As Wayne said.

Oil shows up on the dark gray or black fiberglass as a darker spot. In the case of AC seal leakage it would probably be a narrow band or oval of darkness across the passenger side of the hood right about where the belt pulleys are located.

If you don't have a dark spot on the top surface, and you don't have a dark spot on the bottom surface, don't worry about it...the AC seal never leaked. You may consider having the compressor rebuilt if it's been off the car and been kicked around the garage for awhile.

If your painter says Duratec doesn't have the problems with the wax buildup after spraying, then Duratec is probably similar to the gelcoat used for boats which uses an alcohol based inhibitor. The wax coating on the Eckler's gelcoat keeps air/oxygen away from the gelcoat while it's curing; the alcohol based inhibitor does a similar task.

Personally, if the car doesn't have fresh repairs or reproduction panels, I wouldn't bother with either gelcoat or Duratec...use epoxy primer on a good clean, prepped fiberglass substate and you'll be set. Less money for you; less work for your painter.

[Jim S.]

Re: Gelcoat vs Dura Tec

As Wayne said.

Oil shows up on the dark gray or black fiberglass as a darker spot. In the case of AC seal leakage it would probably be a narrow band or oval of darkness across the passenger side of the hood right about where the belt pulleys are located.

If you don't have a dark spot on the top surface, and you don't have a dark spot on the bottom surface, don't worry about it...the AC seal never leaked. You may consider having the compressor rebuilt if it's been off the car and been kicked around the garage for awhile.

If your painter says Duratec doesn't have the problems with the wax buildup after spraying, then Duratec is probably similar to the gelcoat used for boats which uses an alcohol based inhibitor. The wax coating on the Eckler's gelcoat keeps air/oxygen away from the gelcoat while it's curing; the alcohol based inhibitor does a similar task.

Personally, if the car doesn't have fresh repairs or reproduction panels, I wouldn't bother with either gelcoat or Duratec...use epoxy primer on a good clean, prepped fiberglass substate and you'll be set. Less money for you; less work for your painter.

Thanks Chuck ,

I will look closely for those tell-tale signs . Unfotunately I did have to replace the rear lower quater pannel and the exhaust pannel on the Car as well , so for all of those reasons I am going to bite the bullet and gel or dura coat it !

Jim

[Scott S.]

Re: Gelcoat vs Dura Tec

Thanks Chuck ,

I will look closely for those tell-tale signs . Unfotunately I did have to replace the rear lower quater pannel and the exhaust pannel on the Car as well , so for all of those reasons I am going to bite the bullet and gel or dura coat it !

Jim

Hi Jim,

We found oil spots on the hood of my Dad's '67. The car had been in storage for a long time, and I don't remember seeing bubbling of the paint on the hood, but there was a big oil spot in the fiberglass when the paint was stripped.

We tried cleaning it with various solvents. It would go away for an hour or two, then come right back. I found some Threads on the subject here in the NCRS archives, and this one had an idea that seemed to work: https://www.forums.ncrs.org/showthre...+hood&uid=9146

Summary: Put a heat-lamp on the oil spot. The oil will rise to the surface. Wipe it off with laquer thinner. Repeat the process until the oil spot doesn't return.

To prevent the problem from happening again, there is an A/C compressor shield that bolts onto your A6 compressor. Ecklers used to sell them, for around $40, but I just checked, and it shows that it has been discontinued: http://www.ecklers.com/product.asp?p...dept%5Fid=1230.
It shouldn't be too difficult to make your own. I bought one a few months ago, if you need more pictures, just let me know.

It should be easy to remove for judging purposes, but prevent the compressor from throwing oil on the underside of the hood while driving.

[Scott S.]

Re: Gelcoat vs Dura Tec

It happens and its not that rare of an occurrence. I have seen and dealt with it many times. Jim, just spraying gel coat or any one of the other polyester primers will not solve the problem in most cases. The surface needs to be removed and repaired with fresh fiberglass, then sealed with those products to make sure it doesn't come back.

What I am saying is that if it is already there, the surface needs to be ground out (not cut out) and glass laid in. This is the only way to break the syphon. Otherwise it will keep coming back.

Hi Wayne,

Can you explain what you mean by "ground out" vs. cutting out? I was thinking we had solved the problem, and the oil spot has not returned after the heat-lamp treatment, but this is my first and only experience with this problem.

Should we be taking more steps to address this situation before primer and paint? It sounds like we should, but I'm not sure what you mean when you say the surface needs to be ground out. How far down should the surface be ground out? Just far enough to allow for a new layer of fiberglass to be laid down and then sanded smooth/flush with the rest of the hood? What keeps the any remaining oil in the fiberglass (assuming there is some left) below where the surface is ground out from coming up through the new layer of fiberglass again?

Thanks very much,

Scott

[Wayne W.]

Re: Gelcoat vs Dura Tec

The heat laps and drawing the oil out may work, but I just don't trust it totally. Unfortunately the panel is very thin and you cant grind off very much, but I take it as far as I dare, until it is very thin and then lay glass over the area. This creates a barrier that resist any further penetration. That along with gel or other good sealing products will usually do the job.

[Jim S.]

Re: Gelcoat vs Dura Tec

Hi Jim,

We found oil spots on the hood of my Dad's '67. The car had been in storage for a long time, and I don't remember seeing bubbling of the paint on the hood, but there was a big oil spot in the fiberglass when the paint was stripped.

We tried cleaning it with various solvents. It would go away for an hour or two, then come right back. I found some Threads on the subject here in the NCRS archives, and this one had an idea that seemed to work: https://www.forums.ncrs.org/showthre...+hood&uid=9146

Summary: Put a heat-lamp on the oil spot. The oil will rise to the surface. Wipe it off with laquer thinner. Repeat the process until the oil spot doesn't return.

To prevent the problem from happening again, there is an A/C compressor shield that bolts onto your A6 compressor. Ecklers used to sell them, for around $40, but I just checked, and it shows that it has been discontinued: http://www.ecklers.com/product.asp?p...dept%5Fid=1230.
It shouldn't be too difficult to make your own. I bought one a few months ago, if you need more pictures, just let me know.

It should be easy to remove for judging purposes, but prevent the compressor from throwing oil on the underside of the hood while driving.

Thanks Wayne

I will look close;y and repair as needed.


Thanks Scott,

I must have missed that one when searching. It seems to me that that idea is a good way to find out if I have any oil in the hood , even if I dont see any evidence of it now !

JIm