Very Cool Parts

Visit our community sponsor

Thanks Thanks:  0
Likes Likes:  0
Results 1 to 8 of 8

Thread: Warning about Body Seams

  1. #1
    Member AGH's Avatar
    Join Date
    Feb 2013
    Location
    Paso Robles, CA
    Posts
    31
    Post Thanks / Like

    Warning about Body Seams

    Finally got around to installing my front end. Dressing the seams I ran into several significant air pockets as well as many large pockets of the soft clay like stuff that is apparently used in the construction process.

    This material was just under the Gel Coat and in some spots was pretty deep. Photos show the worst area about an inch around and 3/16" deep.

    The main body seams were not nearly this bad although I did run into a few small pockets and quite a bit around the hood latch areas.

    If this stuff is not removed it will eventually "print" though your nice new paint job.

    Can all be remedied by re-glassing the ground out areas but an issue that shouldn't exist and will be hidden unless you look for it.

    Be very interested in any info on what this material is and how it is misused in the assembly process causing this issue.

    Aaron
    GTM #403
    aghcars.com
    "C5 and C6 Donor Build" thread
    Attached Images Attached Images

  2. #2
    Senior Member 68GT500MAN's Avatar
    Join Date
    Feb 2011
    Location
    Fresno, CA
    Posts
    1,808
    Post Thanks / Like
    This has been around for years in most of the bodies, especially the MKI and MKII roadsters. The easiest remedy is to grind out the seams and then fill with the product from West Marine made for vinylester. Mot trying to excuse anything, just letting you know about a solution that has been around for a long time.
    Doug
    Built FFR5196 MKII in 2003, 427w
    Building FFR0058HR, Edlebrock 347-AOD

  3. #3
    Member AGH's Avatar
    Join Date
    Feb 2013
    Location
    Paso Robles, CA
    Posts
    31
    Post Thanks / Like
    Thanks Doug,

    I'm well aware of the solution which I discovered while building my MKII. I personally like the Vinylester based 3M Marine repair filler.

    Issue for me here is the was way worse than anything I have personally seen or read about on the forum. The soft areas were so large and deep that once ground out I would not be comfortable just filling. The proper fix is to use glass first!

    Haven't seen much said about the seams on the GTM Forum and I would hate to have a builder find out about this after the car was painted.

    Aaron

  4. #4
    Member AGH's Avatar
    Join Date
    Feb 2013
    Location
    Paso Robles, CA
    Posts
    31
    Post Thanks / Like
    Going back to my original post I would like to clarify my question. I'm very curious how that soft material gets right under a thin layer of Gel Coat. It feels like clay but is it some kind of filler that wasn't properly catalyzed? I ask because normally Gel Coat is applied to the mold and backed up with Glass. How does this stuff get between the Gel Coat and the Glass layers? Seems maybe it is something that is supposed to harden??

    Aaron

  5. #5
    Junior Member
    Join Date
    Oct 2013
    Posts
    4
    Post Thanks / Like
    It's probably clay, commonly used to correct mold imperfections. Normally, it gets applied to the mold to smooth things out, then gelcoat and FG are applied. In your case, it appears that it may have been added after the initial gelcoat has been applied, which would be contrary to normal use.

  6. #6
    Senior Member mikespms's Avatar
    Join Date
    Apr 2011
    Location
    North Miami,FL
    Posts
    145
    Post Thanks / Like
    Hi Aaron,

    IT is like deja vu all over again! Your guess is as good as mine I had a few spots like that I found in the area around the the engine hatch opening corners with very thick gel coat that had spider cracks and had thin spots around the windshield openings with air voids. Do yourself a favor and grind all the seams down to the glass and reglass them,the rear hatch opening,windshield opening,hood corners and wheel well openings will require work. After you get your glass work done block it out with 80 grit and spray it with duratec polyester surfacing primer it is like the gel coat used to seal the corvette factory panels and it fills all the pinholes and is easy to sand.
    Mike

  7. #7
    Member AGH's Avatar
    Join Date
    Feb 2013
    Location
    Paso Robles, CA
    Posts
    31
    Post Thanks / Like
    Here is a little more info.

    In 2011 I built a MK4 not a MK2. Reading the forums at the time I assumed the "seams" needed to be ground because of all the posts regarding earlier models. I ground the seams and was confused because they didn't appear to be "seams". I did not encounter any of this clay on the MK4. I called FF at the time and asked about this, I was told that on the MK4 these are not "seams" but only the lines where the molds part. FF told me that you should NOT need to grind these down as in earlier models.

    A year ago when I started the bodywork on the GTM I was still skeptical and started lightly grinding the seams. This is the first time I encountered the clay and as I commented found small pockets. Just this past week I got into to front end and ran into these large clay areas. I've already got it all ground ground out and on the way to a solid repair.

    My concern is for all the other builders out there who may just sand these lines down as FF told me to do. If you do it would appear as a nice hard surface ready to paint only to have these unstable areas just below the surface.

    Aaron

  8. #8
    Senior Member
    Join Date
    Feb 2011
    Posts
    119
    Post Thanks / Like
    Yep. Found the same thing in my gen 1 GTM. I didn't know if it was a mold release agent or unhardened gelcoat, but there was a lot of it and it was relatively deep (~3/16") in a couple places.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Brown County Customs

Visit our community sponsor