So I’ve decided to try a gloss coat with Marine Varnish on a HWS I recently finished for a client. I got a nice gloss coat with sanded epoxy, but I want to add a little more protection and am getting the feeling the varnish will give me what I want. I will be spraying the varnish with a gun and compressor.
The question I have, for anyone who has done this before, is; What grit paper would you suggest I use on the epoxy, so as to bind the varnish well? After the initial coat I’m clear on what to do, but I’ve never sprayed varnish on epoxy before.
TioPelon
Varnish over cured Varnish is a mechanical bond requiring 180 or 220. It’s the same for Epoxy. 180 if the finish is built up, 220 if its just a penetration or seal coat.
Now that I think about it I'm using a 2 part epoxy(thin) that is designed to prime wood for epoxy lams or varnish(1 or 2 part). Your epoxy gloss coat might need an extended cure time and a wash with something to remove blush, maybe even 120g to topcoat a 2 part poly varnish.
I'd check the epoxy and the varnish manufactures website.
I'm using Epifanes 1 part brushed. My gucci spraygun is reserved for laquer.
I would not sand to ruff. Unless you build up a lot of varnish 180 scratches will print thru in time. let the epoxy cure and no ruffer than 220 . 320 is evan better. the varnish will stick just fine. 3 - 4 coats buffed out looks pretty good on a board.
The epoxy is fully cured (been 7 weeks or so). I’ll go with a 240 grit to prep the epoxy and rinse it well with water then apply the varnish. Going to do at least 4 coats… sanding between with 320 and buffed out final coat. Sound good?
What varnish do you plan to use? like most products some are much better then others. I spent the better part of 20 years doing Yacht restoration and refinishing. if you are using a traditional marine varnish do not try to buff out the last coat. varnish is very tender and slow to full cure. You will only blush the top coat if you attempt to buff it . For a deeper richer finish apply more very thin coats.
Ahhh… this is very helpful. Thanks. I live in Costa Rica and the product selection is very sparse. I’m using a local brand (Sur) Marine Varnish or Barnice Marino as they say. I’ve got the proper thinner and will be spraying it on, so making the layers thin shouldn’t be too difficult. I’ll take your advice and not touch the last coat. Thanks Artz.
I'm curious about the benefits of spraying varnish. How is that better than brushing it on the board? In my limited experience with marine spar varnish I have noticed that is seems to spread out pretty nicely as long as the temperature isn't too cold.
Just out of interest, are you going to share the process of varnishing the board? (Or do I need to hassle you via PM? :)
Ok, here's what I did.
I started by getting a quart sized can of Pettitt Z*Spar 1015 Captain's Varnish, and a quart of Pettitt sanding sealer. I also read up a little bit about varnishing by combing through a forum for called The WoodenBoat Forum. Here are some of main things that I learned from posters on that sight:
It is a good idea for beginners to use a foam brush to apply the varnish. This is because it is hard to put the varnish on too thick with a foam brush. The general rule is to apply lots of thin coats. If you over do it you get pooling and drips. If that happens then you will have to sand everything down and start over again. The best way is to apply a thin coat, sand lightly, and apply another, and another, and another....
The temperature and humidity have a big affect on the viscosity of the varnish. If it is cold and damp the varnish becomes very thick, and harder to apply. If it is too hot the opposite happens, and it just runs all over the place.
Be careful when varnishing outside because dew will mess up your finish. Varnishing outside is also a bad idea because it generally takes about 2 to 3 hours for the varnish to become dry to the touch. In the meantime, any bug or bit of dust that lands on the surface is going to stick.
Before applying varnish make sure that you sand thoroughly. Any small scratches will become magnified after the varnish is applied. The best way is to start with rough sand paper and work you way down through every grit level until you get to 330 grit. After 330 I went to 600 grit, and then steel wool. Steel wool is great. It really polishes the surface up nicely. The sanding sealer is just that -- a sealer coat. After applying it, you sand the whole board down again so that it looks like you didn't do anything. I actually put two coats of sanding sealer on my board. The concept of the sanding sealer is that it will fill all the nooks and crannies in between the grains.
I used a $0.60 three inch wide foam brush to apply the sealer. Afterwards I just threw it away. I think it is probably better for the environment to do that than to use a bunch of lacquer thinner to clean an expensive brush.
Before applying the finish make sure the surface is clean. Tack cloths work will. Another option is to use a dry Swiffer dusting pad.
Applying the varnish is pretty straight forward. Just brush it on all over. You don't need to worry about bush strokes being visible. It will all meld together into a nice shiny sheet. You want to mount your board so you have access to the under side of the rails. This is because there are always drips. I found that it is important to wait around a few minutes after brushing on a coat. When you see a drip just brush over it. If you miss it and it dries, then you will have to sand it out, and all the previous coats that you lovingly applied will be gone.
The can said that you have to wait 24 hours before applying another coat. I found that it is good to wait even longer. I had a little drip on my fin, that didn't dry completely. When I rubbed it with sand paper the whole thing peeled off like rubber cement, and I was back to bare wood.
I ended up applying four or five coats to each side. That's a minimum of eight to ten days of varnishing. I actually stretched it out to three weeks. It doesn't take very long to apply each coat.
My garage smells like the inside of a boat now. I kind of like the smell of varnish. You should definitely wear a respirator while applying wet varnish though. I ended up using about 3/4 of the can. That leaves me will some extra in case I need to repair any dings.
After putting on the last coat of varnish it is good to let it sit for a few days to completely cure. That is what I am doing right now. The surface of the board is nice and hard. I'm pleased with the results so far.
Hmmmm… I’ve always just assumed that spraying was the way to go. I use my sprayer for some of the furniture I make, but maybe its more out of convenience… gets in the nooks and crannies. I’ve certainly finished pieces with a brush and gotten exellent results.
Since this is to be more or less an experiment, I’m going to try it both ways. I have a board I built for my wife which I wanted to finish in Marine Varnish… I’ll use a brush on that one and the sprayer on the other… see how it goes.