Trillium 5500 Belly Band

[Reidster]

We are proud new owners of a Trillium 5500. Have been researching a bit on this site on how best to accomplish a full belly band removal and seam patch. We have the aluminum trim removed and cleaned around the two exposed halves - attached photos are before clean up. I am thinking about using Bondo Glass and trying my hand a laying a decent fill within the existing gap and then going back over with regular bondo filler to smooth out after sanding the initial bondo glass. The question right now (I am sure there will be many) is - do I have to grind away any of the gel coat or existing upper and lower halves to start this process, or can I go on to fill the gap? There are a few places where the old metal rivet holders have corroded and buckled out. Should I cut these out first and go in with a more aggressive patch? I have seen where some have aggressively removed a wide trough and refilled with either glass cloth/resin and/or Bondo short glass reinforced filler. I have mixed thoughts on removing all the good fiberglass just to replace it all again when all I want to do is fill a small gap.

[Island Claire]

I wondered the same thing before I removed fiberglass, but as mine was leaking, I wanted to make sure that there was no chance of moisture being sealed in, plus there was quite a bit of room between the front part and the plates, and I did not want to take the chance of leaving air pockets, so I removed and redid.

[David Tilston]

Claire, Do you have any pictures of what you did?

Reid, There are several approaches to this. Some have just filled the gap with Bondo, sanded and painted. This seems to work fine. My neighbour, who I learned almost everything I know about fibreglass from, felt that there would be a danger of cracks forming from such an abrupt transition. I think that the fibreglass bandage that is on the inside of the metal plates is sufficient to support the seam, and prevent any cracks, but I like the idea of a more ridged band around the perimeter of the trailer, so this is how I did it:
http://www.fiberglassrv.com/forums/f...ead-58763.html
http://www.fiberglassrv.com/forums/f...ead-59580.html

Removing the metal plates is optional. Once again, I just felt it would make a stronger perimeter to remove them.

[Jim Bennett]

I too think that a structural patch should be made, instead of just a surface fill. Where Trillium glassed the two halves of the shell together, it was done with just a thin layer. This layer was enough to hold the two halves together, but would allow way more flex that the shell itself, and no cracking on the surface would happen due to the separation in the halves, and the decorative band covered it up.

Actually, the band was not just decorative, as it and the clips riveted together held the to shells in line with each other, and does provide a bit of structure that way.

I chose to grind out the seem, remove the loose clips, add one layer of fiberglass cloth (as a backer for the holes/gaps created by the grinding, ad a few more layers of fiberglass matt, and then use the fibreglass reinforced Bondo filler. I am very confident the joint is now extrememely strong.

If just patching the joint without doing a full joint like I did, it would not do much to stop cracking in the filled joint, as the filler really has little area to bond to, and offer little strength to the joint.

Here is a link to what I did. If I was to do it again, I would do exactly the same thing, with maybe just a bit more care to not go onto the shoulder of the band profile, but that really did not cause me much grief. About 10 hours work total, and I figure just properly replacing the belly band strip would take at least half that time anyway.

http://www.fiberglassrv.com/forums/f...tml#post508078

[Island Claire]

Hi David, I have attached what pictures I have. Using the grinder I cut back like you did and then removed any lose plates. The rest I left and covered over. I had a look at what dleverton had done and then he gave me the "shaping" tool he had made. The cut out line was not used, just the rounded edge.

[Island Claire]

I did use some bondo, but I preferred the working time of the fiberglass. When it was all sanded we painted it orange. Hope this helps.

[Reidster]

Thanks a bunch for the feedback. I have resolved to grind down the bulging areas and remove at least the rust crusty metal bands that deserve to come out. I have heard there could be additional rust streaks if not removed. Also I believe the bulges would be hard to finish out smoothly if not removed or laid significantly down. The most important consideration I think has to do with structural integrity. Missing rusted bands mean less strength of the joint itself - so I will try my hand a laying in fiber and resin and finish off with glass filled bondo and see where we are at. I have some grinding to start with.
Thanks Dave, Jim and Claire for sharing your valuable lessons and techniques. I'll follow up with photos and I am sure more questions soon. Any other feedback and tips appreciated.