Varnish anomalies

[tranmkp]

I used to have bad form when I varnished - always a clean brush that I dipped into the interlux schooner - worked very well for the most part - Now I pour my varnish in dixie cups and I have had issues - I might thin the varnish with 216 or 33 but only a little - Ill have 10 pieces of trim, the first 5 come out perfect -(hi gloss) while the rest come out satin and are not quite set overnight on the serface -

The ONLY thing I can think of is the dixie cup - they are standard cups, they might have wax, I am thinking that the solvants are breaking them down -

make any sense?

[rasorinc]

I only use clear(transparent) plastic cups whan using epoxy or varnish and have had no problems. I would bet that it is the cup your using.

[Landlubber]

Yep, for sure. Wax is certainly not what you want floating on your shiny new surface.

[mark775]

Do you like yogurt? Buy the kind with the plastic lid. You knew dixie cups were the problem.

[alan white]

Years ago when I was in the restaurant equipment business, I got some small clear plastic containers as part of a whole restaurant purchase. There were thousands of them. To this day, I still haven't used them all up.
I strongly suggest to anyone who does epoxy or paints, get some of these. Ask a restaurant owner where he gets his supplies and go there and buy some. Get the ones that are about four inches around by 1 1/2 inches deep, or even 2 1/2 or so deep.
Must have been the wax. Wax (beeswax) is used in polyurethane finishes(used for floors, etc.) to get the satin finish, I believe. There's enough solvent in the varnish alone, without adding more to thin it, so simply change your containers. You may be able to go over what you've already done, depending on the wood used.

[tranmkp]

well, I went real lab coat on the recoats. Clean clear plastic cups - (would have used pyrex if I had it) New foam brushes (good ones) and a 5% thin with correct thinner with Schooner - results were fantastic. I did about 20 piece. Only 1 anomaly, a ling strip (8') came out beautiful, except for 2 small arbitrary satin anomalies.

Did the same as above only with Polyurethane - two large hatch boards and a window frame - frame came out perfect - last piece done - hatch boards came out very satin - the more the area was brushed the more it was satin - first board the flow was perfect - just satin. Now I am wondering if its some kind of contamination...although each piece has cured for a week and is wiped down dry.

[alan white]

Originally Posted by tranmkp

well, I went real lab coat on the recoats. Clean clear plastic cups - (would have used pyrex if I had it) New foam brushes (good ones) and a 5% thin with correct thinner with Schooner - results were fantastic. I did about 20 piece. Only 1 anomaly, a ling strip (8') came out beautiful, except for 2 small arbitrary satin anomalies.

Did the same as above only with Polyurethane - two large hatch boards and a window frame - frame came out perfect - last piece done - hatch boards came out very satin - the more the area was brushed the more it was satin - first board the flow was perfect - just satin. Now I am wondering if its some kind of contamination...although each piece has cured for a week and is wiped down dry.

You could wipe down all varnish surfaces with acetone. If you're wiping or cleaning with paint thinner you might have some problems if you brush varnish within a certain period of time. You need a fast evaporating solvent when prepping. Otherwise some unevaporated residues can get trapped under the finish.
Of course, polyurethasne is far less fussy than varnish. Sounds like you've got the varnish licked. The poly can actually be rolled (after thinning about 10%), then tipped. I used to do a birch door in about three minutes that way.

[tranmkp]

right the varnish is far easier IMO - poly (goldspar) seems to set very quuickly, unbelievable that you can do a door. I would think the time it took to roll it out and the last tip is would be too tacky. Ive been wiping with 216 - fast thinner - acetone is quicker for sure - Ill try that next. may even try to roll.

[Boston]

ya I go with varnish
poly seems to suck the dust right out of the air
where as varnish never does
I also always wipe down my work with whatever solvent Ive got handy
works to kinda even out the finish for some reason

[tranmkp]

started using foam brushes all new - problems seems to have gone away - on another issue all the finished trim that has been installed as I torque down the screws into the pieces I can see that the varnish is slightly stripped away where the screw torques into the teak. I suspect that this migh be a spot where the varnish will start to fail over time - should I just do a spot touch up over the screw heads with a bit of overlap on the teak?

[alan white]

It makes sense to screw in the screws before the last few coats, but sometimes it's not possible. Longer drying time would have hardened up the varnish in the countersinks.
As it is, you're thinking is correct. You need to seal the skin around the screws. If possible, apply two coats over the screws, maybe using an eye-dropper. Obviously, you don't want to sand in between, just apply within a few hours to get a chemical bond. I've had luck setting the screws in wet varnish (a drop into each hole) and then wiping the excess away afterwards.
Foam brushes do a great job if used correctly. Thinner has tripled and quadrupled in price in recent years so anything that will reduce the need for it is worthwhile to try.
Even the cheap (10 cents apiece) ones I've bought at Wal Mart can do a good job. the secret to good varnishing has more to do with prep and dust control, along with becoming familiar with how varnish flows on different surfaces.