shore
New Member
No... I did not mean to suggest or imply that that you need to remove the 100 screws. The way that I understood your construction, the 100 screws were used to laminate the 2 sheets together, correct? All of them are fine. Both sheets will expand or contract at exacty the same rate. There will be no additional (horizontal) forces exerted on the screws holding them together at all.
The sum total of the changes that I would have made would be to make the 6 holes where the platform sits on the braces at the back a little larger. That would be it.
You don't get the same extreme temperature swings in Florida that you would in Chicago or Maine. You might never have a problem. Tobnpr's parts were black, so they absorb more heat more quickly from the sun than white parts would. At 1/16" per 40 degrees per foot, you will see just a little over 3/32" of movement at the 20" mark, and right around an 1/8" at the 2" mark. If you get 20 degree nights in the winter and 100 degree days in the summer, that is an 80 degree swing that will cause 3/16" to 1/4" of dimensional change every 20" to 24". Further north, it is not uncommon to see sub zero in the winter and 100+ in the summer making for even more movement. The 3/4" thickness dimension change will be minimal and the combined strength of the 100 screws holding the pieces together should be sufficient to prevent any problems there.
Finally, I apologize if I offended you. I am an amateur woodworker and I have already learned a few lessons the hard way. Movement is no joke, and the forces created by it can be extreme. I stated before that I thought your platform came out really nice. I like it. I was not suggesting that you needed to start over. I was simply suggesting oversizing the 6 holes at the top attachment points of the braces to prevent them from becoming levers and amplifying the forces applied at the top of them to the bottom mounts. You could accomplish the same thing by oversizing the holes where it attaches at the front edge. Whichever is easiest. My only concern is that if everything is assembled tight, even 1/16" of movement will put something under stress. Tobnpr's pics just illustrated that fact that the forces became strong enough to cause the part to self destruct. It is pretty easy to tell that the part shrank and applied all of the force to the outside of the screw holes. The weakest part gave in. His part was also only 1/2" thick. If it was 3/4" thick, it may have been strong enough to bend the screws or rip them out of the fiberglass altogether.
I'll refrain from further comment on this thread. I was just trying to be helpful. :huh:
Michael
Edit... I previously missed where you mentioned that the holes on the fiberglass side were oversized. That alleviates my concerns. You have the necessary room for movement accounted for back there. If you say that there are only 2 that are not, and that they are easy to get to, then my advice would be to do so. I would still consider enlarging the other 6 holes at the top of the braces though because the expansion and contraction may cause a little spreading out or pulling together force between the braces. Better safe than sorry.
You're not offending me at all.We learn from lessons.I got all wide-eyed when I read this the other day and took off to the storage lot to see how things survived.We had a week of 20's and constant 100 when it was put together...lol, Not to mention I assembled my deck in an A/C'd garage(that was nice) but mounted it to the boat in upper 90's.
I can certianly run the screws out of the deck at those side mounts and just over drill the mounts a bit more.I actually wanted to use bolts/washers on those originally.They are up against the rubrail and you would hardly notice them flush on the topside.