Offshoreonly.com - IMO......Formula may have a safety isssue with the hull/deck bonding.

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- - IMO......Formula may have a safety isssue with the hull/deck bonding. (https://www.offshoreonly.com/forums/formula/246413-imo-formula-may-have-safety-isssue-hull-deck-bonding.html)

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Originally Posted by PhantomChaos (Post 3326534)

Where did you get those number Z5? The Plexus application specification example I showed had 6mm maximum to 1.2mm minumum (basically 1/4" max to a 3/64" minumum).

I converted the 1.2mm to inches. its .047 minimum(on your chart) in answer to Audiofn's question. same number you have for minimum (3/64)

I saw smaller gaps listed here
http://www.itwplexus.com/UserFiles/F...ves_1.2009.pdf

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Ratios.......are you talking about the working time/temp ratio? It talks about temperature, surface prep, estimated working times, product shelf life, clamping and control samples.

I was talking about a ration of how thick you had to apply it to get the final minimum thickness after it was clamped. for example. a 1/2 wide bead that is 1/2 inch hig compresses to "x". Plexus and/or Formula needed to know this to apply it.

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Interesting, but depending upon the temperature of the factory, I see Formula having a hard time putting sufficent Plexus on the area (one single bead doesn't seem suffice to me), then lower the deck on the hull, get all the hardware in and clamp it down (but not too much) before the Plexus is beyond the "working time".

If 425 is what Formula uses in the factory, according to the data sheet at 68 degrees, it has 60-70 minutes work time. Colder is longer. I have no idea how long it takes to run a bead around a 38 foot boat, lower the deck and tq the bolts. I would guess that an hour would be pushing it. Calibrated air guns that give "X" Tq would set the gap by their tightness, but I agree, it does seem like a lot to do in a short period of time. (course if they are doing it at 50*, they have 2 hours, and that seems doable)

I don't know what 1 bead will or won't do. I've only ever seen the pictures/video that I assume you have of Formula doing it. I would think that they and Plexus came up with the correct amount. Plexus uses Formula on their web site as a case study in how to use it, so I don't think Formula would advertise pictures to the world with the wrong amount being used.

I just realized that Plexus corporate offices in the states is about 10 min from my shop (Danvers, MA). Maybe I will stop in and see if I can get some info that concerns me about using the product resolved....

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Originally Posted by Zone 5 (Post 3326896)

I meant more specifically.....the 0.010..........waaaaaay too thin.

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Originally Posted by PhantomChaos (Post 3326931)

I meant more specifically.....the 0.010..........waaaaaay too thin.

I was going by the link that I found, which is a plexus link.

Couple of thoughts,if plexus only has a 60 minute work time that could explain why this problem is more common on 382's less common on 353's and so far no one has spoken up on a 292. I also thing it has to do with the length of the bow,but work time could be a factor.

I have been to two boat factories Pantera and Fountain the side of a hull before it is mated to a deck is not that strong.If it is important for the plexus to be even in thickness I do not see this happening.Reason being as I stated before the hull sides are very flexible before they are mated to the deck.The bolts will compress the plexus of course but will be unable to properly compress the Plexus for the entire 18 inches before the next bolt.

Is temperature because of work time of Plexus a factor?If so are boats made in the summer more prone to failure?

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Originally Posted by Expensive Date (Post 3327486)

Is temperature because of work time of Plexus a factor?If so are boats made in the summer more prone to failure?

I would sure think so. Look at the PDF that Nort posted which has work times. If its 80* in that building they have very little time.

Formula does not use the bolts & nuts to compress the joint. There is a set of assembly screws that are removed from the joint after the plex is cured. It looks like #6 or #8 screw holes that are used to draw together the joint. I think the 1/4 20's are installed after the joint is cured. I think with 4 guys, a 55 gal drum of plex, a crane and a air gun they would have plenty of work time. The deck would be pre fitted and a few inches above the hull. It probably would take 5 minutes to wrap the seam with plex, the deck would be lowered into position with a crane. Two or three guys would install the assembly screws and pull the joint together and its done. When it is cured the assembly screws are pulled, the bolts installed and then the rail. If anyone from Formula is following this tell me if this is not the case??

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Originally Posted by fossil fuel (Post 3327615)

If thats the case, then, I'd agree they could do that quickly. All the static pictures I have seen of them putting the Plexus on shows the deck right above the hull waiting to be dropped.

I didn't see any extra screw holes in your boat. Did I just miss them?

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Originally Posted by fossil fuel (Post 3327615)

Ok then why did it not hold,Was it just assembly error as Formula kinda agreed or something else?

They probabally install the thru bolts in the same holes as the assembly screw holes.

As far as temperture and shorter cure times, the summer built boats thought is very interesting. Unless Formula comes out and discloses all the info on the subject, its going to be hard to pinpoint the exact cause.

Thickness and temperture are probabally at the top of the list though. Dont know how the factory's climate is controlled?

Some build dates on known boats couldnt hurt.

LE