Epoxy over Polyester

[Blue Heron]

Hi,
I'm new to the forum and have a question. I'm planning a rebuilding project on a 17' seasquirt center console. I've had this thing for over 10 years, but the transom and deck have gone soft. I've never been really happy with the layout, so I want to start over rather than just repair the soft spots. I'm thinking of this project as kind of a short cut to a home built.

I want to pull the console and inner liner out and start over from the bare hull. My intent is to lay up new foam core stringers, floors, and deck and then build foam core cooler, fish box, live wells, storage compartments, and forward and aft casting platforms.

My first question is this. Is there any major prep work needed to bond epoxy resin to the old polyester lay-up other than roughing it up for good mechanical keying? In other words, are there any chemical bond incompatibility issues I need to mitigate?

Thanks,
Dave

[gasdok007]

Make sure the existing glass is cleaned of contaminants,then key it with 80 grit or coarser. Epoxy will stick to existing polyester very well.New polyester won't adhere well to already cured stuff.

[glassman]

there is one other way a lot less sanding have your parts sand blasted lite a good blaster can blast heavy like 36 gt or as light as 180 gt cost but saves time also it will find all that is bad

[Blue Heron]

Thanks for the info, guys. I read somewhere that polyester resin is sometimes used with additives (wax, for instance) and I was conerned that bonding could be affected. If sanding to break the surface and provide mechanical bonding is all that's required, that keeps it simple. Other than the obvious downside to sanding a lot of fiberglass, that is.

Dave

[JR-Shine]

Originally Posted by Blue Heron

Thanks for the info, guys. I read somewhere that polyester resin is sometimes used with additives (wax, for instance) and I was conerned that bonding could be affected. If sanding to break the surface and provide mechanical bonding is all that's required, that keeps it simple. Other than the obvious downside to sanding a lot of fiberglass, that is.

Dave

wax can be from the fiberglass, or left over from the mold surface. You must get it off, and I would not rely only on sanding. If I were doing any work on FRP part (hull, deck, console, whatever) I would wipe the area down with a solvent (MEk or Acteone) then sand, then wipe it down again. It doesn’t take much wax or PVA to cause a bonding problem

Joel

[SamSam]

Originally Posted by Blue Heron

Hi,
I want to pull the console and inner liner out and start over from the bare hull. My intent is to lay up new foam core stringers, floors, and deck and then build foam core cooler, fish box, live wells, storage compartments, and forward and aft casting platforms.

Thanks,
Dave

If you disassemble the boat this much make sure the hull is well supported and in the correct shape before you start and remains so until enough strength is built back in so it keeps its original designed shape. Sam

[Blue Heron]

Originally Posted by SamSam

If you disassemble the boat this much make sure the hull is well supported and in the correct shape before you start and remains so until enough strength is built back in so it keeps its original designed shape. Sam

Thanks. A guy I work with did the same with his boat and already offered the same advice. I'm planning to do just that.
Dave