I'm guessing you meant 3m 5200, don't know of a 520 but anyway I would go with what Cal said but be advised once you use that 5200 it will NEVER come off, with out cutting it. Once dried no solvent will remove it so it's pretty permanent. It comes in white/black or Mahogany color. IF you ever want to remove the seat again I would use 3M 4200 but I think it only comes in white. I use 4200 for fittings and things I might want to remove again later without having to use a multi tool with a slicing blade to get it off. lol Just my 2 cents.
yes 5200 i got it online at walmart for $16.00 but white seemed like the only option. I am going to use it on the two wood rails the run along the hull to support the seats and on the very bottom of the two middle bench seat supports. all those items seem to have had a black adhesive on the joining parts when i took things apart. I was not going to do the actual bench board to the supports as those spots just had the screws and bolts connecting them.
thanks for checking in and the info
got down to the bare wood to do the adheasive. And I am putting on on my final coat of varnish. I think it is number 7 or 8 regardless that's my limit ( especially working outside doing this) and i am on my 3 gallon of varnish ( i think I did put on too thick of a coat as I applied them. IF there is ever a next time more ceps, more sanding, and thinner coats of varnish, i'm learning , lol
adding a little color splash to the outside. i think i put on 8 coats (outside finished) and i have one more to do on the inside. and i can start to put things back together.
But looks like a lot of rail for a while so it will have to wait