Hi Mike; To answer your question first, in reality I am cost minded kind of guy. This is exactly why I did not contracted someone to do it for me. I have considered all of my options. Repairing the old frame would have added approximately 132 lbs of weight in order to return the frame to the original strength. Sandblasting is expensive. Welding onto previously rusted steel is not in my opinion a 100% fix. Moisture will cause rust in areas inaccessible with paint. Por 15 is expensive. In the end I would still have a frame that will rust. Here is the clue why I am not doing a overkill. I buy SS at $1.50/lbs.
Why in this world would I want to put out money for sandblasting repairing and painting where for almost same amount of repair time involved I can have a frame which will never rust without using a spoonful of paint. In addition a frame that has no parts welded to it in places where it just looked good to the person welding it originally. Having the equipment and facility to build a new one had a lot to do with my decision.
The floor is aluminum clad on both sides 1/2 Omega Panel. Floor is fastened with 1/4-20 SS flat head screws with frame being drilled and tapped. Screws were coated with blue removable Lock Tite. The frame contact area to aluminum clad ply was covered with .065" thick by 2" wide 3M Mastic tape
#3M Scotch 2228. Floor panels were joined with 1/16" wall aluminum H molding and sealed with 3M 5200 Marine adhesive. Edges of panels were trimmed with aluminum C molding and sealed with 5200. 1/2 panel ended up being 3/4" on edges. Cork flooring panels will be route red to accommodate the 1/16" H trim thickness in order not to telegraph through the cork floor covering.
Not all of us have the facility equipment or the knowledge to do what I am pursuing, but in my case it is the best choice. If you choose to do a new frame I can help you with details. Thanks, "Boatdoc"