Finishes

[Karl Card]

I have been playing around with poly spray made by Deft. I love the clarity of it but someone once told me (noone on this forum) that poly was much tougher than lacquer. Maybe it is, but it does not work like lacquer for me. For example I used to take my pen blanks and dip them in deft lacquer, let them dry a couple of hours then dip again, wait 2 hours then dip the 3rd time. Let it dry for a day, use 0000 steel wool to even it out 100 percent then use EEE cut n paste polish on it to make it shine like glass. Well when I do this with deft "defthane" it just messes up the poly real bad. Makes it dull, it is smoth but very dull and I cant get the shiny back.
If someone can shed some light on this as to am I doing something that shouldnt be done with poly or what the ????? But looks like I am going back to just good ole deft lacquer until at least I get my spray booth and spray guns setup.

One last thing I did notice with defthane is that even after days of drying I could take my finger nail and put an indent in the finish, with deft alcquer I could not do this.

[Michael James]

Karl, Im not a huge fan of poly but it has it's place, I suppose. But you can't treat it like lacquer or shellac to build up your finish. I think if you have a good finish going and use it for your top coat you'll be ok. I wrecked a couple of pieces a month or so ago...forgetting what I had learned a long time ago about spraying that stuff. I spent more time getting it off the wood to re do them than it took to turn and prep for finish. MY .02
I'm sure there are those who have developed techniques to make it work, but for me, wipe on is all Im doing with that stuff.....for now.
Good luck!

[Ken Fitzgerald]

This is my opinion based on my personal experience and interpretations of those experiences....and may be very wrong....but it is what it is....

Shellac and lacquer are evaporative finishes. When you add a 2nd layer of the same finish to the existing layer...it dissolves with and becomes one layer. In other words with shellac and lacquer additional layers just make the existing layer thicker.

Polys on the other hand, each layer forms a separate layer. I would think it is much more important to allow each layer to dry completely before adding an additional layer. JMHO.

I use Deft brushing lacquer and shellac a lot on my turnings.

I am FINALLY getting a finish on a cherry pedestal table I started long ago. I am using Deft brushing lacquer. On pens I often use a light coat of BLO frictioned, then 2 light coats of dewaxed shellac frictioned (used as a sealer) and then friction 2 or 3 coats of Deft. Then, I may immediately buff it out. When it comes off the mandrel it's finished.

On the cherry pedestal table, the largest turning I've done to date, I tried initially to use shellac and ran into some problems. I elected to use satin Deft brushing lacquer instead. I ran into similar problems but finally figured out how to correct and circumvent them and am progressing nicely.

Good luck with your finishing!

[Thom Sturgill]

Ken is right about Shellac and Lacquer. The solvents cause the finish to disolve into the previous layer, no matter how old. Poly REQUIRES sanding between coats as it does not otherwise bond. that is one reason lacquer is considered the most repairable finish. Since shellac uses alcohol as its solvent, it is more susceptible to environmental damage.

[Jeff Nicol]

What I have noticed over the years is that poly likes to be put on as thin as possible and let dry, then that coat must be roughed up with 220-320 grit and remove all the dust. Then apply another coat and build it up using the same steps. If you try to put on one heavy coat and then try to sand it back or polish it to soon the top is dry but the deeper you go the tackier it is. So if you are trying to dip like with lacquer or shellac it does not perform the same. The wipe on poly is much thinner and acts like an oil finish and will probably work allright, but still maintain the drying and sanding lightly in between coats as it needs something to grab on to unlike the lacquer and shellac as metioned already.

The milky state that you are getting is most likely caused by moisture being trapped in the wood or the coats are too thick and the base is not cured enough for the next coat and the off gassing is then between layers and that is not good.

Another good dipping finish is the Tung oil finishes that are on the market, they act like poly in some ways as they are a polymerizing finishes that are not like true pure tung oil. A friend of mine uses it for all of his duck and goose calls and they come out beautiful.

Enough rambling, try some different things on some test pieces to find the best process for each finish and keep a diary of what works best for you.

Have a great day,

Jeff

[Karl Card]

See everyone on here maes perfect sense to me. I also prefer the deft brush on lacquer or spray also but anyway deft lacquer. It really bothers me to say this but at least I know it to be the truth, but the same guy who told me walnut oil is for walnut etc is the same guy who told me poly is better and tougher than lacquer. I guess I just really dont understand his actions.

But anyway thanks for the info and I just basically needed some reassurance that what I was thinking was the gospel. I also use a little amber shelac if I have a piece of wood that needs just a little bit of color to it and that works out really nice too.

Thanks.