On topic because it's old car wood . I've done up two pieces of trim for the Jaguar MKIV, they look incredible, BUT, I've had hell getting rid of the air bubbles that seem to emenate from the brush itself. There are NO bubbles in the varnish. I bought very good brushes. But I still have air bubbles. A buddy suggested foam brushes, is this the trick?? Thanks, Cosmo
Foam brushes work pretty well but I would spray just to make sure. If you want to keep trying with the brush, remember: just like with the ladies, dip it in slowly, remove it smoothly, and gently draw it against the side of the container to clean it. With brush on urethane it doesn't take much activity to get some air in it and due to its viscosity, it doesn't float to the surface very quickly, if at all. Hope this helps.
Foam brushes are worse! Sometimes, they actually build up a "foam" on them...... If possible, spray..... Try several VERY light coats with fine steel wool in between coats..... Also, you may try thinning the (I ***ume clear) with what ever the "cutter" is... gotta go the wife is staring at me!
My guess is that you are slapping the brush on the side of the can to pull some material off the brush???? It puts the bubbles back in the can, which gets picked up by your brush. Varnish does not flow out quickly like paint. I dumped a little varnish in a smaller cup and let the brush soak if it starts to bubble, use your other brush. If you can try not to work directly out of the can. Work slowly, working from one end of the piece to the other, keeping each coat level. In the end it will take less time. I still don't miss boats....
I've had very good luck with Marine Spar Varnish. Use with a quality brush. Don't shake the varnish and if it needs stirring, use a clean wooden stick and go slow or you'll put bubbles in the varnish. I find it works well to put the open varnish can in a larger container of ice to bring the varnish temp down. That allows a longer flow-out period. The varnish can doesn't need to be buried in the ice, a third to a half of the way up will do it. Use care not to contaminate the varnish with water or ice. Work in the shade if you can. Let each coat dry 24 hours. Steel wool - with 4/0 - between coats and most importantly wrap a strong magnet in a clean lint-free cloth and pull the steel wool bits off the varnish. Wipe it down with another clean lint-free cloth and inspect for any little pieces of broken off steel wool. They can be hard to see, but they need to come out. If you're near a Marina you may be able to get some fine bronze wool. It doesn't seem to be as troublesome as steel wool, but if you're careful and clean it all off steel wool works fine. There are three coats on the roadsters oak bows and 12 years down the line they still look good. I don't think the spar varnish changes the color of the wood, but it brings the colors and grain out better than other things I've tried. Easier to get a good finish as well. Boats that have their brightwork - the shiny wood - done with spar varnish sit out in the sun, rain and wind when docked and the spar varnish is good for a little more than a year before it requires freshening. On a car that's not used every day, the spar varnish will last a long time.
It's what I'm using. Yup, best in the store, says storekeep. All that I've done, never HAD bubbles in the can. This I'll try. Inside the garage, doors shut. Done. Will do, used sandpaper on the first two, tack cloth between, worked very well, but dragging the bubbles out - oh boy This car fits that description, should last well. And as I said, the first two pieces look great, just that bubble problem... Thanks again, Cosmo
I've found the bubbles to be a problem with the first coats, but after using a fine sandpaper on the first coat, and re-applying, it has less. Then repeat process for 3rd coat and they are pretty much gone. Surface can be buffed if you really want it to be smooth. My theory on the bubbles on the earlier coats is that air is trapped in the pores of the wood. Each successive coat seals it up. Don't know if there is any merit to my theory, but it sounds good to me!
dont shake the varnish. stir it only., i dont know if this will help u but its the rule for varnish. try using a little paint thinner mixed in the varnish. this may help. also make suer the wood has been wiped down with a tack cloth and apply the varnish in one direction of brush stroke. dont go back and forth. hope this helps.
Fwiw, I used Man of War Spar Varnish. Available at Home Depot. If you have a Marina nearby and want to try a different brand of varnish, look for one called "Chilled Varnish". It may have a different brand name, but I think that is the brand name. It's designed to do the ice bucket trick, but the ice bit did well with the Man of War so who knows? Another fwiw, keeping catalyzed fibergl*** resin in a small can sitting in a bed of ice holds back the "kick" giving you a little more working time. Really helps on the hot days of summer.
You can signifigantly reduce the first coat to seal the pores in the wood. This may raise the grain,but it can be lightly sanded. The proper reducer will allow the top coats to flow out flat before it flashes off. I've had good luck with the cheap Offshore foam brushes,after the surface is covered,the trick is to VERY lightly drag the brush across the surface to break the bubbles.A foam roller will work for coating larger jobs,then stick your finger against the side of the roller to stop it from turning as you drag it across the panel,same as with a brush. When I'm using 2 part clear Polymer for coating panels,I use a Propane torch to get rid of the bubbles. Works excellent. Might not be a good idea with a solvent based product.
Ditto on the propane torch , lightly heat the varnish, the gas or bubbles will work to the top and pop. Plenty of ventilation and a fire bottle would help too.
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