Deck Lid Help

[Canuck]

I plan on using 3/4 fir plywood for my struts
i would like to know the smallest thickness to handle the cuve
i need to lay out the walls for cabinets.. and finding out i need all the extra room i can get
I will double on the outsides
What is the thickness of struts you feel comfortable with ??

[bobhenry]

Strut indicates to me you are running side to side but you mention a curve. Since most tear hatches are flat side to side I am assuming you are running 4 ribs from hinge to floor. Without knowing how tight the galley hatch curve is I would say 2 1/2 to 3 inches thick and I would use multiple plys glued together not just one.

[Canuck]

Thx Jimmy
My terms are probably not correct.. could be Spars ??
I will be running them up and down.. not side to side
The teardrop is about 52" side to side and i will need approx 5..(i Think) with the outsides doubled up
with 3/4 fir ply.. will 2 - 2 1/2 " be strong enough
i can add a spar if need

[Ira]

Boy, the language being used here is real confusing.

The spars run from the left wall to the right wall. Is this what you're talking about? And what do you mean by deck?

[Canuck]

Think i'm talking about the galley lid / door
I guees it would be called the door that opens in the back to your kitchen area cabinets
I dont have a lot of room and would like to know the smaleest thickness i could use to build my ribs / spars.. sorry i am not sure what the correct term is

[Ira]

Okay--the dreaded HATCH.

Since you're running them vertically and not side to side, you're not going to have to worry about springback that much when you attach the skin--the tendency for the skin to want to bend back to straight position, and distorting the hatch.

So your 3/4" is fine for those vertical ribs, but on the end ones, a lot of us who go side to side and have separate hatch ends, we go 1 1/2" thick on these ends to eliminate the springback.

But I don't know if you have to go that thick running all of your ribs the way you are. Couldn't hurt, but someone else can better answer.

[Miriam C.]

Canuck, My hatch ribs are 1" thick. They seem to be fine. I could have put the cross braces different and it would have been better but I wanted the glue surface.

[Canuck]

Thank You
I was hoping to double up the sides and top / Bottom
I will be using 3/4 ply
If i cut these 2" thick.. would they be strong enough
Again.. Thank You for all the help

I'm going to put pics on photobucket with my progress

[Miriam C.]

2 inches is fine.

[Canuck]

Thank You

[Micro469]

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Who is [/url]????????

[Canuck]

laffin
sorry bout that
i was trying to post a picture
all in good time i guess

[Sam I am]

Canuck, your choice of skinning material will greatly affect springback. I used 1/8" Baltic birch ply on my tear. This wood is so flexible that it literally falls around the curve of the hatch by its own weight! When glued and screwed to the spars and ribs it exerts virtually no "unbending" force, making springback a non-issue. I added a second layer of 1/8" over the first to get a 1/4" thickness. My hatch has no vertical ribs except the outside edges, which were cut free from the tear sides after the hatch was skinned.. This method saves a lot of weight and work! You can check my photos to see how it works.
Sam

[Canuck]

My sides are 1/4 oak ply
I was hoping to make the top skin plywood also... but as of yet i am having a tough time locating oversize sheets of ply

[madjack]

...just to add my 2cents worth...we use vertical spars(ribs), cut out of 3/4 ply and they are 2"s thick..........