I’m in the process of a Tenderly build and finishing the frames is driving me crazy. I’m looking for a high gloss, very smooth finish which I thought would be a snap, but it’s not going so well. First, I tried coating the frames with them sitting vertically using clamps as shown in the instruction manual, but this resulted in runs and sags – very unsightly. I sanded just about all of it off and tried with the frames lying horizontally – more voids. I’ve coated them and tried to sand with increasingly fine sanding pads, and that results in a smooth but not shiny surface. Can anyone give me a hint here?
You’re not supposed to get a high gloss finish with just epoxy. You need to add paint or varnish after you’ve gotten the epoxy smooth and fair. Epoxy is just too thick to easily get glossy and you need to add paint or varnish to protect it from UV degradation, anyway.
Runs and sags are caused by applying too much epoxy at once. Use thinner coats, even if it takes more of them. Lots of very thin coats are better than a few thick ones, as far as smoothness and needing to sand is concerned. Applying epoxy flat instead of vertically when you can is also a good thing, though it can double the time if you want to coat both sides.
Don’t sand beyond #220 paper. The surface will be dull, which is good. You need a small bit of roughness to make the paint or varnish stick.
But be sure the surface is fair before you stop. Unfair surfaces can be uniformly dull but still have a depressions or high spots. There’s no visible pits or holes, but there’s a waviness that will become very obvious once you get to a gloss finish.
To fair a surface, you need to fill the valleys and bring down the hills. The easiest way to do this is with a sanding longboard. You can buy them or make your own from scrap wood. They ride over the entire surface instead of concentrating on one area and they average out the variations.
Before it’s fair, you’ll probably have sanded enough epoxy off that you need to apply more. Try to apply it only in the valleys and not the hills, let it cure and sand again. You’ll save on epoxy that way.
Once it’s fair and sanded to #220, it’s ready to be painted or varnished. That’s the layer that will be glossy. With the stable, hard smooth layer of fair cured epoxy, getting a high quality Finish will be easier.
Check the shop tips for hints from CLC on how to do all this.
That makes perfect sense, Laszlo! I was sanding with increasingly fine paper up to 220, but your suggestion sounds like just the secret I was missing.
I’m reading the shop tips now – it’s like I was trying to read a book in the dark and now there’s a reading light! Thanks for directing me there!
Glad to help.My favorite varnish is Interlux Schooner sold by CLC. You’ll find it on the Finishing Supplies page. Instructions are on the Shop Tips page.
I’ve ordered a longboard and accompanying sandpaper. I also found Interlux Schooner on amazon at about half the price of CLC. Do you apply the varnish with a fine bristle brush or a sponge brush?