Gel coat to hardenner ratio.

[davidpbo]

Hmmm unfortunately I have only just become aware of the need to wash before sanding. Also when laying new layers on top of cured resin I have been using finer sandpaper to provide the key. Keeping a hose on the job is not an option. Boat in dry barn used for storage. I will have to wet and wipe copiously.

 

[gjgm]

Hmmm unfortunately I have only just become aware of the need to wash before sanding. Also when laying new layers on top of cured resin I have been using finer sandpaper to provide the key. Keeping a hose on the job is not an option. Boat in dry barn used for storage. I will have to wet and wipe copiously.

You should do the cloth lay-ups while the previous layer is tacky, or at least unset. IF you leave it (say 12-24 hours,)you need to wash and sand as mentioned to get a true bond.
I cant say I have ever had to go to the lengths mentioned. Different epoxy gives off differing amount of blush/waxiness. I wipe down with a scotch pad and some diluted floor cleaner to remove the wax, and then rinse with a cloth and fresh water. Then you can sand.You are not making a major structural joint here, so dont worry too much.
West Systems have some good free guides on the web if you can find them. All you are trying to do is remove the waxiness which would obviously prevent a good bond and sand to make a key for the fresh epoxy. Simple stuff, really.
I've just used about 5litres of epoxy this way and believe me, this stuff sticks! Top tip.. get rid of every drip you can spot with acetone while it is still wet.

 

[davidpbo]

Surely the water should not bead up if the wax has been removed?

 

[oldsaltoz]

Surely the water should not bead up if the wax has been removed?

You are right, I have edited my post, thank you for pointing this out.

Good luck and fair winds.

Note to self, read what you type before submitting a post.