I need some Pointers for using Oil Base Varnish.

[Bill McCarthy]

There once was a time when I thought I knew what I was doing; that was before further education. Now I know more than I did then, so now I'm seeing more wrong with my methods. I've got a couple of questions but I'm not sure if I'm asking the right questions or all the questions I need to ask. I'm hoping you guys can help me out. I'm learning. This is a hobby, not professional.

I'm working with yellow pine because its cheap. I can see that my joinery skills need vast improvement; so I assume in those areas the finish will be better once the joints are better. I'm now also seeing where I need to pay closer attention when using the smoothing plane.

So the first question is about sanding. I read where its recommended to sand to 220 before applying the varnish. I've read that finer sanding inhibits adhesion. Is it worth the effort to sand beyond 220 to smooth the surface more, then go back and use 220 or am I just wasting my time?

Next question. I think its called a sag. Where two edges meet, I'm finding the varnish will build up along the adjacent edge to the one I'm working on, sorta like surface tension holding it in place. I do run the brush along the edge to pick up stuff that has overrun the edge. This happens after I set it aside to dry. Is there a way to avoid this?

I think I'm going to go back to this practice and I'm wondering if its a good idea. Between coats of varnish, I used to rub down with steel wool. My most recent attempt I didn't do this and I think I've spent to much time rubbing everything out in the end (after allowing enough time to fully cure). Is rubbing between coats a good strategy?

Is there a way to hang something, so that I can coat all the surfaces at the same time, and avoid the runs, drips, and sags that result from the vertical surface? At the moment, I coat one side, laying flat, let it dry, turn it over and do it again. This is taking twice as long to accomplish as opposed to being able to do all sides at once. Any tips in this area?

I'm using a brush. I tried wiping, but didn't care for it. I felt to much finish was wasted to the rag and didn't really like the process of applying it, so I went back to using a brush.

I'd appreciate any advice you guys can give me.
Thanks

[Wayne Lomman]

Here are a few comments. I'm going to address brush application because that's what you do. I do brush work on work sites but spray everything else for preference.

When sanding, the objective is to go only as fine as is necessary to remove visible sanding marks. With some timbers this can be 150 but mostly it is in the 180 to 240 range. Going finer is only required in limited circumstances. Going finer doesn't hurt adhesion but burnishing the surface does. This happen when the sandpaper is too worn or too much pressure is applied and your timber gets hot and shiny.

Sanding between coats is the right way to do it. You need to cut the nibs off at each stage otherwise they increase in size with each coat and are too hard to remove. I don't recommend steel wool though. It leaves bits behind etc. Use sandpaper in the 280-320 range.

With your brush work, you will always get material roll over the edge. This needs to be feathered out with your brush as it happens. Work on your routine technique to include this small extra task. You are probably already doing this. Also don't apply too much near the edge as it gets an extra coat when you do the adjacent side. In general, any edge less than 2mm radius will have this problem. It's one of the reasons why many commercial mouldings don't have sharp edges.

Setting up to apply coatings is always a task in itself. It depends on what is seen or not seen. You can lean items against the wall if opposite edges are not critical or turn the job wet onto nails tapped into an old bench for example. You could also try alternative coatings that cure quicker. Someone who lives in your country will have to help you with that. Cheers

[Robert LaPlaca]

Bill,

I typically sand to 220 and no finer for the raw wood.

I am am kind of curious as to what oil based varnish you are using? Some varnishes require the prior coat to be sanded for proper adhesion (Epifanes spar), others like Waterlox Original Sealer don’t require any such sanding, so the sanding between coats depend on the product being used. If necessary, would use sandpaper 320-400 to denib or deglaze between coats, not steel wool.

Best tip I have seen for applying oil based (marine spar) varnish was the use of one inch foam rollers to quickly apply the varnish, then using your very high quality natural bristle brush tip off the varnish the roller just layed down.

[Art Mann]

I am going to recommend something that sounds pretty goofy. To remove dust nibs, sand the surface with a brown paper bag rather than 320 or 400 grit. It works surprisingly well.

[Steve Schoene]

Art is not goofy on the brown bags, but generally this is best used on the final film surface. Between coats of varnish, 320 grit paper is more effective.

Some other points. A good china bristle, or bristle mixed with ox hair, brush is quite desirable. Keep it clean. See the sticky at the top. Kept clean, it will last for years and years.

Most oil based varnishes need a bit of thinning, perhaps 10%. in some early coats need even more thinning. Some manufacturers say not to thin, but thats for VOC regulations. Those don't apply for you using a few quarts or so.

Lots of light is desirable, paricularly raking angle light.

[Bill McCarthy]

Wow guys; thanks. So much good information, I'm not sure where to begin.


When sanding, the objective is to go only as fine as is necessary to remove visible sanding marks. With some timbers this can be 150 but mostly it is in the 180 to 240 range. Going finer is only required in limited circumstances. Going finer doesn't hurt adhesion but burnishing the surface does. This happen when the sandpaper is too worn or too much pressure is applied and your timber gets hot and shiny.

Sanding between coats is the right way to do it. You need to cut the nibs off at each stage otherwise they increase in size with each coat and are too hard to remove. I don't recommend steel wool though. It leaves bits behind etc. Use sandpaper in the 280-320 range.

With your brush work, you will always get material roll over the edge. This needs to be feathered out with your brush as it happens. Work on your routine technique to include this small extra task. You are probably already doing this. Also don't apply too much near the edge as it gets an extra coat when you do the adjacent side. In general, any edge less than 2mm radius will have this problem. It's one of the reasons why many commercial mouldings don't have sharp edges.

Cheers

Wayne, I've been trying to remove most of the marks with a smoothing plane. From there I was jumping to the 220 grit paper. Maybe I need to go to a larger grit and work my way up to 220, but coming off the plane I wasn't seeing many marks, but I could feel a difference between the planed surface then after the planned surface was sanded.

Most of the edges I'm having problems with are pretty much 90 degrees or 45 degrees, so they do have much less than a 2mm radius. I hadn't noticed that about the mouldings. When I go back to sanding between coats, I'll see what happens. Hopefully I can prevent a big build up over the entire course of finishing.


Bill,

I typically sand to 220 and no finer for the raw wood.

I am am kind of curious as to what oil based varnish you are using? Some varnishes require the prior coat to be sanded for proper adhesion (Epifanes spar), others like Waterlox Original Sealer don’t require any such sanding, so the sanding between coats depend on the product being used. If necessary, would use sandpaper 320-400 to denib or deglaze between coats, not steel wool.

Best tip I have seen for applying oil based (marine spar) varnish was the use of one inch foam rollers to quickly apply the varnish, then using your very high quality natural bristle brush tip off the varnish the roller just layed down.

Robert, the varnishes I have on hand right now are Cabot's Gloss Polyurethane and Richard's RichWood Marine Spar Varnish. The Richard's is what I'm currently rubbing out; its an alkyd varnish with no poly in it. You may be able to get it in NC, I'm not sure. The salesman told me they've partnered with Benjamin Moore stores to sell it in the southeast; its made in FL. Both say to sand between coats. The Cabot's says not to use a roller, whereas the Richard's can be brushed, rolled, or sprayed. I'm not equiped to spray and I've never tried rolling varnish. The last time I used the Waterlox Original, I used a cheap chip brush for each coat. I think I might have sanded between some but not all the coats. In that case I attributed the needed sanding to the brush I used, but thought that if it could go on with a rag a chip brush would work also. There was nowhere near the amount of sanding I'm needing to do now, compared to using the Waterlox. (Hmmm? Maybe that's a clue I need to pick up on because the recoat times are the same for all 3 products. Is the extra cost of Waterlox offset by the reduction in time required overall?)


Art is not goofy on the brown bags, but generally this is best used on the final film surface. Between coats of varnish, 320 grit paper is more effective.

Some other points. A good china bristle, or bristle mixed with ox hair, brush is quite desirable. Keep it clean. See the sticky at the top. Kept clean, it will last for years and years.

Most oil based varnishes need a bit of thinning, perhaps 10%. in some early coats need even more thinning. Some manufacturers say not to thin, but thats for VOC regulations. Those don't apply for you using a few quarts or so.

Lots of light is desirable, paricularly raking angle light.

Art/Steve, I'll have to give the paper a try (especially if I use the Waterlox).
Steve, I watched the video, thanks for telling me to do so. Its been sitting there and I never watched it before. Just before this go round, I read on Waterlox's site to use 2 rinses to clean the brush, I had never done that before. I always buy a new brush for the start of a project, because by the end, even after my cleaning (a couple of rises through the same thinner for each use) the brush wouldn't last. So I've bought good brushes but not the best ones. I'll have to get a new one and try the cleaning method shown in Scott's video.

In this particular project, in the first coat I did thin it somewhat, but not much; afterwards I use the varnish full strength. Next time I'll try thinning it again, a little more, and see what happens. I'm a little afraid if I thin it to much, it'll run causing the other problem I mentioned. Then there is the film thickness also. If I thin it, won't that require more coats and the associated drying time?

Maybe one of you guys can answer a question that I have as a result of Scott's video. Its about the brush and then "charging" the brush. I usually use an angled sash brush. Over the years, it seems to me that I can control the "edge" a little better, particularly if I'm painting and cutting in on a ceiling or a window. I just looked, only one of my current brushes has that chiseled shape to it. It appears as if the chiseled shape is important to applying the varnish; is this correct? I'll have to buy another brush and I might as well buy the correct kind.
Charging it with thinner. Somewhere, just recently I came across something that said to do that, so I tried it. Now it wasn't a chiseled brush and I loaded more varnish into the brush than Scott did, and I wiped the brush along the container's edge before I went to the work piece, so I'm guessing my procedure was all wrong. Anyway, it didn't work to well for me. It seemed that the thinner in the brush thinned the varnish even more than it was already. Is that supposed to happen? From watching the video, I gathered that I used to much varnish into the brush. I now assume one reason for charging the brush with the thinner is to prevent the brush from picking up to much varnish. Yes? How do you prevent the thinner in the brush from mixing with the varnish in the brush, thus thinning the varnish even more?

Oh yeah, I guess I'll need to pick up a small pan. I've been pouring the varnish from the can into a jar, then working from the jar. Pulling the brush along the edge of the jar on its way out. So it appears I was doing that wrong also. I am doing something right, I'm working by the window with the overhead light on. I did learn a long time ago to look at the varnish from an angle.

One last thing. The way I've been sanding this stuff right now. I'm starting with 400 grit, then 600, then 800. From there to 00 steel wool, then end with 0000 steel wool. Is that acceptable or should I be doing something different?

Thanks for all the info guys, it really helps.

[Wayne Lomman]

Charging the brush with thinner first is not the way to go. Sorry guys but this advice is leading people up the garden path. It just causes exactly the problem Bill has encountered. Charge the brush with the varnish you are using. You want to apply varnish, not thinner. There is no need to wet the whole brush right from the start. That will happen as the job progresses.

The best brushes have long, fine and flexible bristles. What they are made of varies but with the type of product you are using, the performance is more important than what the brush is made of.

Your paint pot needs to be a fair bit wider than your brush. The best ones are an empty paint can with a handle that has a scallop cut out of each side so that you have plenty of room to fit your brush in and out without getting anywhere near your handle hand. Never more than half fill it.

Always tap your brush against the inside of the can rather than wipe across the edge. Drips are still gone but your brush stays more evenly loaded. You also don't get runs down the outside of your can.
Cheers