cracked fiberglass shell

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chin_k
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cracked fiberglass shell

Post by chin_k »

I did not take a close look all around the exterior when I was looking to buy it, but I noticed it when I got it home. :oops:

The area in front of the generator seems to have a few cracks near the corner of the cutout. They are not that long, about 2 or 3 inch long, about half a dozen cracks. When I remove the gen cover, I noticed that the shell does not seem to be flush again the plywood. The shell is about maybe 1/4 inch thick??? There is a gap of maybe 1/2 between the shell and the rest of the rigid body. When I press hard on the shell, it will get closer to the plywood. I feel something like silicon behind the shell on the inside (maybe the previous owner tried to fix it before?) but I am not sure. I was not able to feel the cracks from the inside, but I did not do any water test.

So my questions are, how big of an issue is this? Should I need to keep an eye on it to make sure the cracks won't get worst, or I need to get the Chinook to bodyship to get the fiberglass repaired before the rain come?
2000 Concourse dinette, on 1999 6.8L Ford E350 Triton V-10 Chassis
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kdarling
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Re: cracked fiberglass shell

Post by kdarling »

Photos, please.
1994 Concourse dinette, Ford 7.5L (460 V8)
chin_k
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Re: cracked fiberglass shell

Post by chin_k »

I figured it is difficult to described without photo. I will try to get some when I got home tonight. Halloween night, so it is going to be busy. Boo!
2000 Concourse dinette, on 1999 6.8L Ford E350 Triton V-10 Chassis
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Blue~Go
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Re: cracked fiberglass shell

Post by Blue~Go »

Photos will be helpful, but I think I have a basic idea.

Cracks around corners, or where there is little material are relatively common in fiberglass shells. Basically there is stress or flexing in the shell (from driving in our case) which causes it. The cracks can either be just in the gelcoat (shiny outer layer), or in the actual fiberglass. Much more likely on corners, or in areas with small sections (two openings near each other, etc.).

Either way it can be repaired.

Most of the openings on my Concourse have 1/2" plywood "rims" stuck to the inside edge. Well, mostly stuck to. They were applied with just a basic polyester resin/glob and many were loosening. I think the main reason they exist is so that whatever fasteners are holding the door/hatch/etc. in place have something to grab.

I haven't looked over the generator opening closely, but I am very familiar with the water heater, electrical hatch, and lower refrigerator vent openings. The refrigerator one might be very similar. I did some fiberglass/reinforcing around mine when I took my refrigerator out because I had seen photos of other Chinooks with cracks radiating from the upper/forward corner. There was lots of room for improvement. (What I mean by that is that making it stronger was pretty low hanging fruit because the original way was not that strong.)

Anyway, if you post some photos, we can have a look and perhaps suggest some options.
1999 Concourse
chin_k
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Re: cracked fiberglass shell

Post by chin_k »

Actually, it is the frig cutout, not the generator. See photo
Attachments
you can see the gap between the shell/plywood and the partition
you can see the gap between the shell/plywood and the partition
this is what the outside is like.  I probably want to ask about the clear coat repair later
this is what the outside is like. I probably want to ask about the clear coat repair later
2000 Concourse dinette, on 1999 6.8L Ford E350 Triton V-10 Chassis
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Blue~Go
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Re: cracked fiberglass shell

Post by Blue~Go »

I've seen that on quite a few Chinooks. I'll explain why I think it happened there.

See the strip of plywood just to the left of the opening in the first photo? See how it ends in a certain place? And how that corresponds with the crack?

Well, there are two main "bulkheads" (sort of like bearing walls in a house, but in a fiberglass boat sort of way) in the Chinook. The one between the sink and the shower, and the one between the stove and the refrigerator. That little strip of plywood is fiberglassed to the hull (wall), and then the bulkhead is attached to that. So there is some pressure there, especially when driving. Then there's a cutout (fridge vent) right next to it. Now bounce down a few dozen roads, and .... crack-a-roo. It makes sort of a stress riser, IMO.

When I saw how that was put together (I had the fridge, stove, and all those walls out for a remodel), I added some structure below that fiberglass strip (at least that's the simple description). I also reinforced that "square" around the opening.

Now, that crack may only be in the gelcoat, because the gelcoat is brittler and less reinforced than the actual fiberglass skin. So it often cracks first. And gelcoat can be repaired. But then too, it can crack again if the same reason is still there. And the fiberglass itself may be cracked (although it's likely fine).

It's sort of a pisser that it happens to be in one of the areas that also has painted stripes :x Natch :roll:

Anyway, if you want to DIY a fix, we can discuss further. Or even if you want a pro to do it, I always like to know the basics before I talk to them, if possible. Maybe you do too. There is a range from "do nothing" to "stop it from moving any further," to "strengthen but leave the cosmetics alone," to "strengthen and fix the cosmetics."
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reddingnative
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Re: cracked fiberglass shell

Post by reddingnative »

I've got same issue where my furnace vent plate attaches. All 6 holes have cracks around them and there is no support behind the fiberglass. Was thinking I could make an oversized piece of something, seal and attach that and then attach the vent plate to that.
Chinook Concourse Manufactured 6/1996
1995 Ford E350 Chassis, 7.5L 460
dougm
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Re: cracked fiberglass shell

Post by dougm »

Im curious, what shape is the wooden wall in front of the fridge at the bottom?
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Blue~Go
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Re: cracked fiberglass shell

Post by Blue~Go »

dougm wrote:Im curious, what shape is the wooden wall in front of the fridge at the bottom?
I'm not sure what you're asking exactly (?). My '99 didn't really have a wooden wall in front of the fridge at the bottom. There was the "floor" of the fridge compartment (1/2" plywood), and then extending down from that was a face frame of sorts (1/2" MDF plus 3/4" x 3/4" stapled corner boards on the inside) in the shape of a rectangle, and a raised panel oak door that pretty much opened the whole area (to a shallow storage compartment inboard of the generator compartment enclosure).
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dougm
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Re: cracked fiberglass shell

Post by dougm »

Im talking about the area where the oak door is.
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