Thread: Re-finishing Heron Deck

Howdy ...

If the existing coating is peeling you don't want to go over the top of it anywhere with epoxy.

If the existing coating continues to flake the epoxy will go with it. So bare wood.

The epoxy has some ability to fill hollows without adding powders. But sand the deck first and .... report back!

You can use a hot air gun and a sharpened triangular scraper or carbide scraper for the job if the build up is large or sand it off if the build up is not too big.

Some of the hollows or dents might reduce or disappear. Don't try to sand them out by the way ... you will just go through the top veneer.

Be VERY careful with the sander generally ... as soon as you get to bare wood keep away from that area in a disciplined way. Be aware that a bit of pressure on a corner of the boat or along an edge can go through the top veneer in a quarter second.

Generally if you watch like a hawk there is a little bit of a warning
1/ first warning ... the varnish or paint is gone from the surface
2/ second warning ... you can see slight black lines in the wood grain ... this is the dark coloured resorcinol glue that was used to glue the ply up.

a micro second later ... you will be through the veneer.

Big flat areas are not so risky but keep the sander moving and monitor the surface. Hooking the sander up to a vacuum cleaner gives you a clear view, takes care of your lungs and halves your sandpaper budget.

MIK

the coating is not that thick so I will use a Bosch random orbital sander to carefully sand it.

Can you apply a top coat directly over epoxy?

Two part polyurethanes (LPU's) and WR-LPU's (water based LPU), most single part polyurethanes (modified alkyd) and many enamels (alkyd) can be applied directly over moderately fresh epoxy coatings, with the LPU's actually getting some chemical "keying" if the epoxy is still fairly green. Acrylics (latex) should have a primer and to be on the safe side so should straight enamels.

If your epoxy coating is less then 24 hours old, dry but still slightly rubbery (test the remains of the mixing pot and you'll see what I mean), then you can go straight to top coats, just wash with denatured alcohol and tack cloth when dry. If the epoxy has cured (the remains in the mixing pot are brittle), then you have to clean the surface, abate (sand) the surface, then clean and tack before paint, just like a normal paint job.

Great info, thanks very much. I will probably go for 2 pack poly then. How many coats should I give it?

Originally Posted by mick0z

Great info, thanks very much. I will probably go for 2 pack poly then. How many coats should I give it?

Be wary of that stuff mate, and it'd pay you to have a read through here, search on my name if you have to.

I sprayed 2 pack poly onto Sixpence and it's lovely stuff - sprays easily, hard as the hobs of hang and dries quickly. However, it is amazingly toxic. I can't remember the exact advice I got on here (hence the suggestion to search), but I'll be giving my hull one more coat BRUSHED on, but only because it's already got 2 pack on it already. Future paintings on anything will be done with enamels and the like.

Basically, although you can use darned near anything safely if you try hard enough, with home boat building there comes a point where it's not worth the dangers. I've decided that 2 pack poly is in that category. Feel free to disagree (as I'm sure some will).

It's only a boat - 'tis better to drown thyself via thy own stupidity than to poison thyself trying to make it look pretty.

Richard

If you don't have good safety gear in good condition I would suggest giving spraying the polyurethane a miss.

Most polys have a specific "brushing" thinner available that gives more brushing time.

The water based polys are tricky in dry conditions such as Adelaide. Driest city in the dryest continent on earth. PAR gives some good advice about running a humidifier.

MIK

What about the durability of single packs enamels?