First time using Earlex 5000 HVLP-Shellac or Poly over transtint?

[Chris Atzinger]

Hi,

I am ready to finish a book rack project and want to use my Earlex 5000 for the first time.

The rack is made from curly maple. I intend to spray it with transtint diluted with DNA, to avoid raising the grain, while making the curly pop. My initial finishing choice was shellac (Zinsser, from Home Depot). Then I thought that spraying shellac over the transtint may cause the dye to run, since I used DNA to dilute the dye.

Should I use polyurethane instead? Will I need to thin it before spraying? is A 2mm needle okay or should I use a smaller one (i have a 1.5mm).

The project is going in the kitchen to hold cookbooks and some picture frames, so not a lot of daily abuse like a table.

Any help is appreciated!
Thanks!
Chris

[Scott Holmes]

Spraying shellac over TransTint dye can cause it to run. A couple of very light spray coats can lock it in place. Since you are new to spraying; there is no substitute for practicing on scrap.

Spraying varnish (poly is a type of varnish) is a whole new set of issues... varnish is slow drying and the overspray will get on anything within 15 feet of the spray location...then it will dry to a crusty mess. Shellac on the other hand, the mist will be dry before it gets to the tablesaw, so, when it lands on the saw it will be dust not something that will stick and be a pain to remove.

[Bob Wingard]

What he said ... don't try spraying varnish until you have lots of experience with your spray system. Unless you lay down some pretty wet coats of shellac, it shouldn't be a problem. If you make it wet enough to run or sag, it will probably take some color with it.

I hate to say it, but this is not the time to practice on a good project ... surely you have some leftovers & scraps to play with. Time shouldn't be an issue, the way DNA & shellac dry, you can do a few test pieces in an hour or so.

[Chris Atzinger]

Thanks for the input. I have screwed up enough projects to know that you test your finish on scrap first! I practiced with the transtint on some scrap today and was reasonably pleased. It did make me go back to the actual piece and ensure the surface prep was as good as I could possibly get it.

I'll practice with the shellac.

Should I thin out the shellac any or just use it straight from the can?

-Chris

[Curt Harms]

I haven't tried it but how about transtint in the shellac?

[Bob Wingard]

That will work ... but, again ... if your spray technique is not real good, you can wind up with a striped effect.

[Scott Holmes]

This would turn your seal coat into a toner coat. Toners should be applied BETWEEN clear coats. Without the initial barrier coat any mistakes or streaks would be very difficult to remove and or correct.

Spray a light coat or two of shellac at the 2# cut. No sanding until you have a few coats of your top coat applied.

[Howard Acheson]

Let me suggest that there is no better way to get down the road of spray finishing than buying Charron's Spray Finishing. Amazon will have it. It will tell you how to set up your equipment, what adjustment to use to control the spray, how to thin the products for best performance and, most importantly, how to "read" the spray and the applied finish to know what needs to be adjusted.

Finally, there is not substitute for actual practice on scrap. An not just a small piece of wood. In our shop, new finishers would learn and practice on cardboard boxes and then move to prototypes or shop boxes. It was a couple of weeks before they were allowed to spray anything real.

[Chris Atzinger]

I have Jeff Jewitt's Spray Finishing book which is a good introduction. I haven't watched the DVD that came with it yet, though. I have some scrap pieces that I have been practicing on. I quickly figured out that i need to double check everything before starting, as I had way too much fluid coming out the last time (forgot to adjust the set screw after cleaning).

Is it ok to use store bought zinsser shellac, or should I be making my own?

Thanks!
Chris

[Scott Holmes]

Zinsser seal coat is a 2# cut of dewaxed blonde shellac. Mixing your own is better, in my book, but I use the Zinsser too.

[Curt Harms]

This would turn your seal coat into a toner coat. Toners should be applied BETWEEN clear coats. Without the initial barrier coat any mistakes or streaks would be very difficult to remove and or correct.

Spray a light coat or two of shellac at the 2# cut. No sanding until you have a few coats of your top coat applied.

Thanks Scott. That makes sense.