How Do I Apply PU Varnish

Hard to see in a picture. Certainly you are finishing wood with a coarse grain structure. The secret to rapidly produce good quality work with a brush and Polyurethane is to pile on the coats of paint...green on green. Dont worry about brush strokes or dust, just get the paint on and build film thickness. Once a good film thickness is achieved , sand flat... then finish coat with care. Normally there is no need to thin the buildup coats....only the fininsh quality topcoats.

Remember...the big advantage to spray application is that you rapidly and effortlessly build film thickness by going three times around during each shoot. With a brush the buildup coats will always be a bit cruder.

 

RX, you need to start with fresh or still good material The left over stuff you thinned, is probably partially cured and/or has been over brushed and/or is out gassing. I'll repeat, do not thin top coats, only the coats that go on raw wood are thinned. The only reason to thin is to decrease viscosity to spray. If you need to reduce viscosity while brushing, use a flow modifier like Penatrol or warm up the polyurethane.

Satan finish isn't as water proof as gloss. Use high gloss on every thing. If you want semi gloss or satin finishes use the them as the last two coats only.

Yes, it takes lots of coats, especially if it's sprayed. Over 10 is usual if you want a mirror finish, over 20 isn't uncommon, especially on course wood, where the grain needs to be filled with several coats and block back down.

 

The first picture is Philippine Mahogany, a relatively expensive wood. The second one is coconut lumber which was sanded smooth. The coco lumber is a crap wood but I like the contrasting characteristic of the wood so I tried on it.

I am using leftovers because I am still a student and just tinkering. I guess its time to throw them away. I am just learning from you guys. The fresh Satin finish is available only in gallons and I do not want to experiment on it yet and leave a fire hazards when I am away. I am only on holidays.

The expensive wood was given by the pros with a very light coat. Sort of a "commercial" finish as you can see the little holes are still there but enough to see the beauty of the wood. Not good enough but the question is, can I do better?

I guess when I become confident about it, I will start tackling on the expensive ones.

Thanks to you guys.