Fitting deck, fuel tank cover (PICS)

[picflight]

Hello,

I am sure some of you have come across situations where you are trying to mate two surfaces to sit flat against each other.

I am looking for ideas on how to effectively make a deck, pretty stiff 1" thick piece of plywood cored fiberglass, on to a 2" ledge.

Picture 1 is the deck turned upside down showing the surface that has to sit flush in the cavity shown in picture 2.
Notice the 1" high cavity with a 2" ledge all around. The middle area just floats in picture 2.

One corner is slightly raised and is not sitting flat. I am looking for ways on how to find where I have to grid to make it sit flat.

Picture 1

Picture 2

Base has following dimension, 2 " ledge.

 

[The_Chain]

Humm maybe a better explanation or pictures I'm having a hard time making sense of what you got there? Is it from a grady? Are you making a new deck plate? What's the end goal other then a flush deck? I think I'm missing something

 

[picflight]

Let me try again, sorry about the lack of clarity.

Deck is the floor of the boat, covers the fuel tank.
Also, the deck has a center console mounted on it, the depression is the area where the center console sits.

Took the cover (deck) off to do some repairs.

After repair on one corner it is not sitting flush, one corner is higher and I am unable to locate the pivot point to make it ride flush.

I hope this will make it more clear.

 

[DennisG01]

It's still a little unclear exactly what is/was happening... but I believe I at least understand that you made some altercations to something and now it isn't sitting flush (rocking) and you can't figure out where the "high" points are. If that part is correct, try a tube of lipstick. Smear it on the entire perimeter and then set the piece into place. Remove the piece and the lipstick will have transferred onto the piece at the high spots. You may get some contact transfer on other parts, but you really shouldn't have any trouble figuring it out since you should already know "about" where the high points are based on the rocking.

 

[The_Chain]

Yeah that's what I was going to suggest or something along those lines...worth a shot

 

[DennisG01]

I keep a tube of lipstick in my toolbox... I SWEAR it's for this purpose! :mrgreen:

 

[picflight]

Now because the cover is about 150 lbs, the rocking is not pronounced at all, just one corner is higher. The higher corner is just a few millimeters, enough to cause a slight flex.

I have thought of using engineer's blue, same purpose as lipstick but the lifting of the cover and removing it from the boat will wipe away the areas where I handle the cover and might not give an accurate reading.

I will try it nevertheless and also thinking of trying some of putty to figure out where it is making contact.

 

[gw204]

Figure out a way to lift the cover vertically.

Line the opening with a continuous strip of Play Doh. Cover that with wax paper. Set the cover down, lift off, find where all the Play Doh squished out.

 

[DennisG01]

Do you have a barn or a tree that you can use to lift it off? Even so, unless you have it 100% perfectly balanced, it's not going to come off evenly. But, with lipstick or playdoh (or something) you should be able to figure it out.

Another possibility - assuming the deck is still true, set the cover down on a "known" level surface and check the perimeter. This really shouldn't be too hard to figure out once you really dive into it.