Seams - question for those who did their own bodywork

[Gumball]

So, as I wrote about on my bodywork thread, I had a few spots where there was gelcoat pockets between layers of fiberglass, causing me to remove a pretty good amount of material in those spots. I'm planning on filling the seams on the body tomorrow (the weather is supposed to be in the low 70s with minimal humidity) and wanted to get some feedback before I start piling on materials.

The largest of the four trouble spots is about 3/4" wide, 2" long, and less than 1/8" deep (actually .101 at the deepest point). Originally, I was thinking that I should fill these with fiberglass (a gooey mixture of chopped mat / flock and resin), then cover with HSRF, then finish off with Rage Gold. After pushing aside bodywork for a day of fun at the racetrack - and plenty of time to think about what I'm about to do, I'm now re-thinking that plan.

Given that these aren't anywhere as bad (meaning deep) as I originally thought, what do you all think about just using HSRF and Rage Gold? I'm concerned that if I also introduce the resin, that's just too many dissimilar materials in a relatively small void - potentially increasing the risk of printing or failure.

Thoughts?

http://i845.photobucket.com/albums/ab15/CCRsAC/Void1_zps3a8aa9ec.jpg (http://s845.photobucket.com/user/CCRsAC/media/Void1_zps3a8aa9ec.jpg.html)

http://i845.photobucket.com/albums/ab15/CCRsAC/Void2_zps5a23539e.jpg (http://s845.photobucket.com/user/CCRsAC/media/Void2_zps5a23539e.jpg.html)

[carbon fiber]

i'd go with the original plan myself, filling the void with mat glass/flock and resin and sanding it down, then continue with with the rage gold.

[skullandbones]

Hi Chris,

I like your second thought. I got a syringe and used resin to fill a few pin holes when I exposed the seams on my MKIII. There were very few but it wasn't a big deal (almost thought I was wasting my time). My seams were about the same as yours maybe a little less but I filled with body filler. After letting dry and sand, I did a second coat to start matching the curve on the two adjacent panels. I now have that primed and will be driving that way. Some drive with gel coat, I drive with primer. I figure I can do additional body work in small sessions as temp permits and re-prime. So it looks basically the same from session to session. If I were you, I would (KISS) and just do the HSRF if at all. I agree with you about the multiple components in the seam. There are chemical and some physical processes that can cause failure (moisture forming around a contaminant nucleus and then popping out).

My other suggestion is to make sure the surface is very clean and the glass is dried out. Trapped moisture is not good. I worked with the Gougean Method (West System) on racing sail boats like J24s. We found that our only failures came when we introduced foreign substances under the epoxy or did not properly dry out the hull before applying. The fiberglass doesn't know whether it is on a boat or a car (the same process). I live in AZ where we have a natural drying room so to speak. So moisture is not usually an issue here. BTW, I spoke with the guy who still owns the J24 I had not long ago and after fifteen years the surface is still without pop outs and cracks.

If you are using good quality filler and primer, you should be fine. Good luck, WEK.

[tcoon]

There are always air voids in the fiberglas and generally can be filled with rage, unless huge and causing structural weakness. Your seams look pretty normal. I would fill and sand. Lots of feathering onto the other parts of the panel. There will be a lot of pinholes and we filled this with metal glaze, much harder and less porous. As to the moisture issue, always clean bare Fiberglas with acetone as it dries instantly and leaves no residue.

[riptide motorsport]

Hsrf then body filler, you'll be fine.

[Jeff Kleiner]

HSRF is used when you have to grind gelcoat out of the layup along the mold parting lines. See the dark stripe? That's what has to come out.

http://i269.photobucket.com/albums/jj43/jkleiner/7c556d12-5329-4f0a-9acd-887399b69f17.jpg

If it gets into the deeper layers grinding a "V" or "U" to get it out and HSRF to add strength back are required. Yours must be a later Mk3 because I don't see any evidence of that in your photos. It appears that you have been able to expose the opaque glass simply by sanding off the parting line "boogers" and top gelcoat. If what you show is a worst case example and you don't have major voids that need to be filled you can go straight to Rage!

Cheers,
Jeff