I looked at the Duramix website after following another thread. I am in the process of putting a sheet of 12-guage diamond plate down in the bed of my 72 El Camino. Could I use Duramix adhesive to attach it, the then use the fowable sealant around the edges? I would like it in there permanently and know that welding is not a good alternative. I am also not eager to bolt it down and encourage rust in the bolt holes. I have refinshed and sealed the bed itself.

I have never thought of such a project but it sound like you have a good plan. The thing is you will want to paint all surfaces if they are not. Then grind away the paint where the adhesive will be. Then put a strip of adhesive where you plan on bonding it and spreading it out OVER ALL bare metal. Then put a nice strip down the center of that area and lay the sheet down in the bed. Put some bricks or something down to hold it in place but don't SMASH it down, you want a little layer of adhesive. Then you can put a good urethane sealer on the seam around the sheet. You can apply this by masking the little seam with tape. Apply the sealer then press it down with your finger into the seam. Unmask it and you are done. Some times a little smoothing is nessisary and can be done by putting wax and grease remover on your finger and smoothing it out.
As you mentioned, there are "flowable" seam sealers that could also be used. They are at times a little hard to work with because the flow too much. That is why I said to just use "regular" urethane seam sealer.

------------------
1965 Buick Gran Sport Convertible
1965 Buick Skylark H/T
"Fan of most anything that moves human beings"

RobtW, Duramix is not a toy, that baby is gonna be permanent. Follow MartinSrs directions and you'll be good. I'd slightly roughen the surface of the bed and the diamond plate where the glue will be to give a good "tooth" to hang on to.Also, get the "Large Panel Adhesive" it will give you a bit longer working time.
I use Duramix for everything. Holes in radiator tubes. Concrete statuary. Aluminum side boards on a steel frame utility trailer. BMW motorcycle tranmission case, the list goes on.
Good stuff,,Good luck

I saw a truck that the owners would put alum. diamond plate on the bed with window adhesive. Seemed to work for them because they would move it from one to another when miles got high.