# Help me choose my topcoat...



## RobH (Apr 25, 2007)

I am building a set of bookshelves for a contractor that I go to church with. I am ready to start on the first staining run (the carcases, fixed shelves, and backs). I usually use polyurethane in these cases. Usually the finishe turns up with some undesirable stuff in it (bugs, dust, etc.). For my own stuff this does not bother me that much. For someone else this really bugs me.

I have not totally dismissed the use of polyurethane, I am just trying to decide exactly what to do. I am also thinking that I could use shellac or a quick drying finish that Jeff Jewitt wrote about (Quick Drying Finish). This is basically a fast drying varnish thinned 50/50 with Naphtha. I have used all of these finishes before and the quick drying finish from Jeff really does dry like gangbusters.

I just need some help thinking this out. Pluses for polyurethane are that is what I have used the most. Pluses for the other two are easy application (I will wipe either shellac or the thinned varnish).

Help me out here,


----------



## oscorner (Aug 7, 2006)

Rob do you have a deticated room for finishing? Is there a way you can isolate this piece (with a make shift curtain of visqueen) to reduce the amount of dust, bugs, etc.? I have had times, even with shellac that dust will get in to the mix. I just sand with 600 grit, wipe down with a damp clothe to remove all the dust and respray. You can finish with your normal polyurethane, then sand and wipe down and finish with shellac or other quick drying finish. Hopefully this will alleviate most of your trouble.


----------



## Dorje (Jun 17, 2007)

I like the idea of the Jewitt fast dry finish - (thanks for the tip! - I printed the article). There are those pieces that you just don't want to take days and days on to finish.

I typically save the poly for the heavy use items, such as the kitchen table. For a bookcase - why do you need the protection the poly would give? And, if you're worried about what might settle in the poly film finish, then then a wipe on application is called for! I vote for giving the fast finish a shot - they're bookcases!


----------



## TomFran (Jun 19, 2007)

Personally, unless you have a suitable place to spray a mineral based product, I would stick with lacquer since it dries quickly. That is important for (2) reasons.

Lessens the problem of overspray sticking to everything in the vicinity.
Less time for dust nibs / bugs / etc. getting in your newly sprayed finish.

Go to Lowes and buy a can of Deft (lacquer). This sprays well and is a pretty good finish. It is also much easier to rub out the finish with steel wool, and if you ever have to repair the finish, it is better for that as well.

Or, you could go to a paint store and buy a can of precatalized lacquer (Campbell) and that will work well too. IMHO

I have had excellent results spraying lacquer, and I don't have a booth. I have had to spray my large projects in my backyard. Lacquer doesn't hold up as well for table tops exposed to moisture, but for bookcases or other projects where people are going to be putting wet items on it, it works fine.


----------



## doyoulikegumwood (Jun 21, 2007)

i agree with tom the best finish fo this would be a lacquer it dris fast most in less then hour ready for a second coat in 15 min i meen for something that isnt going to have heavey use its great i even use it on heavy use items i just put on more layers


----------



## WaywardHoosier (May 9, 2007)

I too have been trying to improve my finishing techniques. I am hesitant to spray lacquer because I do not know how how much air pressure to use and what the ratio of lacquer to mineral spirit (thinning agent guess?) should be.

Also, typically how many coats is a good rule of thumb?

Or are we talking about spray cans here? I tend to over think things sometimes.


----------



## Karson (May 9, 2006)

Thinner for Lacquer is Lacquer thinner. Not mineral Spirits. Also use it to clean brushes and spray equipment.

I'd go the lacquer route.


----------



## TomFran (Jun 19, 2007)

"Lacquer doesn't hold up as well for table tops exposed to moisture, but for bookcases or other projects where people are going to be putting wet items on it, it works fine." - TomFran quote above

I just noticed a typo on my previous post. It should read "where people are *NOT* going to be putting wet items on it…"

As to the amount of pressure to spray lacquer, I usually spray it at around 40lbs.

The number of coats will depend on how much you thin your lacquer, but for me, (3) coats is usually just right. You can use your lacquer for your sealer coat and then lightly sand it with 280 grit or finer to smooth it before the next coat. The nice thing about lacquer is that you can complete your finishing in one day. Whereas, with varnish, you should let it sit overnight before applying the next coat.

In all honesty, finishing is just as much an art as the woodwork itself. Some people can build beautiful projects and end up with a lacklustre result because they don't have their finishing techniques down. A couple of good books on the subject are essential for all serious woodworkers. They are:

Understanding Wood Finishing by Bob Flexner
Finishing by Jeff Jewitt


----------



## WaywardHoosier (May 9, 2007)

Tom,

Thank you for the detailed information. I have read an article from Jeff Jewit and have checked out his website of the finishing products that he promotes. I will also check out Bob Flexner's information as well.

I have never used an air compressor, lacquer, or shellac. But I think I need to start to get that "Furniture store finish" look that will make my projects look more professional and not "craftsy".

I agree finishing is an art.


----------



## Radish (Apr 11, 2007)

*Ultima Spray Lacquer* (waterborne, poly-based). Target Coatings (order online) or through Jeff Jewitt's Homestead Finishing website (at last order you have to fax in). I have a home shop and used to use MC Campbell Magnalac. Terrible odor, dangerous lacquer thinner based (explosive). I am totally won over to this stuff. You might find it best to spray as much of the case as flat parts and then do the final assembly (mask off the glue joints first with green 3M tape). Target also has pre-cat and varnish offerings, all waterborne. Soap and water gun clean up (don't use solvents or you'll end up picking balls of white crud out of your gun). You might check to see if they sell a gun cleaner where you buy yours. I got a product called "The Challenger" at a local independent paint store that works great. Spraying light, 20 minutes dry out of dust, one hour recoat.

If you finish in the flat you can lightly use a card scraper (Veritas sells an Ultra thin card scraper you can bow with one hand and put a gentle hook on just for finishes) to knock off the nibs, scuff sand with 320 grit between coats and shoot 3 coats in a day without blowing up the neighborhood and without the hideous aroma (that draws bugs like rotting fruit) of Magnalac or Deft. This stuff burns into the next coat like shellac or lacquer. I even shoot this stuff in my funky garage workshop, which is none too clean, although I sweep it up about an hour before spraying. General Finishes has a good (and cheaper) waterborne that rated well in Fine Woodworking's recent test if saving a few buck is important. It just isn't as heat resistant, but unless you client is storing heated hex nuts (their test material) in his bookshelf, that shouldn't be an issue.

As far as rubout, look for Mirka Abrasives Abralon pads. They let you rubout to 4000 grit dry with a Random Orbital sander. I use them on my jewelry boxes, posted on this site.

Take a look at a blog entry of mine for links and info
http://lumberjocks.com/topics/549

Or you could just use wipe on BLO/Mineral spirits/Thinned varnish and do an "in the wood" finish or Doug Stowe swears by Deft Danish oil on his boxes.


----------



## Radish (Apr 11, 2007)

Oh. And always do tests on a test board first with any new finish or process before applying to your piece. And TomFran's literature choices are highly recommended!


----------



## TomFran (Jun 19, 2007)

Doug, 
Thanks for the tip on this water-based topcoat. I am very interested in finding a suitable replacement for lacquer based products, but I have a few questions for you.


What about the grain raising tendency of water based products?


Do you not have to wet the wood and sand off the raised fibers before you can use a water based topcoat?


Do you think that the finish is comparable to the lacquer based as to the beauty of the finish?

The grain raising problem creates another step in finishing, doesn't it?


----------



## Radish (Apr 11, 2007)

I use Zinsser Sealcoat de-waxed shellac to seal the wood after P220 grit prep, then rub that with a red or gray non-woven adhesive pad. Just be sure to avoid steel wool as you will get rust flecks that don't go away. Follow with the waterborne. No grain raising.

Beauty wise, it's no question at least the equivalent of solvent based lacquer. It is water-white finish, but the shellac sealcoat does warm it a little. Over darker woods, I mix a *little* amber additive (I add a drop or two of Jewitt's Trans-Tint per pint measure) which warms it to Nitrocellulose tint. On maple it is simply glorious without additional tinting, preserving the creamy tints of tiger maple etc., while providing the chatoyance (color reversal dependent on visual angle) that one experiences with figured woods. And it doesn't tend to yellow over time like solvent based Nitrocellulose. I could not be happier with the change from standard lacquer, plus I am allowed to bring it in the house to cure, something none of the other residents will allow here at the Bordner house (especially Magnalac which off-gases with a smell of toxic nuclear bananas for at least a week). Stuff smells like standard Latex paint as it cures.


----------



## TomFran (Jun 19, 2007)

Doug,

Do you use an HVLP system with a conversion gun or a turbine?
Do you spray your shellac?
Does this have to be sprayed with an HVLP system? (I don't have one - mine is a regular compressor)

I have never sprayed a water based topcoat. I was wondering if it sprays any different than solvent based.


----------



## Radish (Apr 11, 2007)

Tom, 
I have a conversion gun. I usually don't spray shellac, but rather pad it on the flat pieces with the glue areas taped off with blue or green 3M tape. I tried spraying one, didn't find it to be so satisfying (more mess, more explosive risk, creeps up the sides of box interiors, padding seems suitably fast due to the fast drying time. Six boards for boxes can be done sequentially and by the time you finish the last in series the first is ready for next coat. You can get three padded on coats in about an hour.
I think you can use any type of gun, but HVLP has less waste and overspray. Highland Hardware has a ShopFox gun under $50 bucks, or the PC gun at Lowe's (actually DeVilblis) is reasonable.


----------



## woodspar (Mar 6, 2007)

This is great - I did not know anything about lacquer. Thanks all, TomFran, Douglas, esp.


----------



## TomFran (Jun 19, 2007)

Doug,

Did you buy the small touch-up HVLP gun or the full sized one?

I thought I saw a conversion gun at Lowes, but it was a full sized one priced at $100.

I guess it would be nice to have both sizes, but probably start with the full size one which will do projects of all ranges.

I'm definitely going to try to transition toward the water borne products, because if it's a comparable product, the advantages far outweigh the disadvantages for all the reasons you mentioned.


----------



## Radish (Apr 11, 2007)

I got a gravity-fed PC, but I got mine at a local dealer, bundled in with the 18ga brad nailer and a pancake compressor. probably got a deal, and it's been a few years. I think the ShopFox at Highland Hardware will be cheapest


----------



## doyoulikegumwood (Jun 21, 2007)

shalac and varnish are extremly messy to sprey all i use for spreying when i started out was my porter cable pancake and a cheap set of gravity feed hvlp guns i bought at northern tool for like 50 bucks and got great results cuz i hand rub almost everything i do and i mostly use lacquer dont know if it helps but almost all store bought funiture is finished in lacquer


----------



## TomFran (Jun 19, 2007)

"almost all store bought funiture is finished in lacquer" - doyoulikegumwood,

That is absolutely true. In fact, here is a quote from Bob Flexner's book, *Understanding Wood Finishing*:

*"The highest quality and most expensive furniture produced by the furniture industry is usually finished with a rubbed nitrocellulose lacquer."*

The smell is atrocious and the hazards of its use are substantial, but as for the results that can be had with the product, I think this quote says a lot.


----------



## doyoulikegumwood (Jun 21, 2007)

lol tom thats the book that got me hooked on using lacquer its just about the only finish i use any more


----------



## TomFran (Jun 19, 2007)

For small projects, a can of *Deft* with it's improved spray nozzle, works very well. I find that it is a nice way to finish a small job without the hassle of using my spray system (cleanup of gun, etc.). I finished this project in about (2) hours in this way.


----------



## Radish (Apr 11, 2007)

I'll keep plugging for the waterbornes. Part of the afterthought about the industry use is that the furniture factories are set up to spray CAB lacquer and Nitrocelluse, with dedicated rooms, explosive-proof fans and the ability to effectively handle the environmentally toxic by-products that come from it's use.

Neil Lemans, The Furnitologist here (web site Furnitology Productions) has made it a point to not feature use of solvent based lacquer on his projects because he intentionally focuses his e-blog to the neighborhood cabinetmaker, who likely doesn't have the facilities to safely spray solvent lacquers. Waterbornes have come along way, many meet KCMA standards (I may have the acronym wrong - but it's the Kitchen Cabinet Makers industry standards group). If it's tough enough for kitchen furnishings, with the need to handle hot, wet, food-stain situations, then it's likely to meet the needs of most of us. Just my two cents.

As for the rubout, nothing beats the silky feel of rubbed out lacquer. See my comments about Mirka Abralon pads, which are used by the auto-finishing world, and work great for wet or *dry* rubout with a RO sander, all the way to P4000 grit. They are the bomb.


----------



## RobH (Apr 25, 2007)

Thanks all for the great discussion. I am about 85% sure I will use a wipe-on polyurethane. At first I was going to purchase a conversion gun ans spray a solvent based lacquer. Then I started thinking about the mess, the cleanup, and most of all the neighbors. Plus, I am not sure that my first spray job should be a pay job that I am in a hurry to finish anyway.

Since I am so familiar with wiping poly I think I will keep it with the KISS theory and stay with what I know.

Thanks for all the discussion,
Rob Hix


----------



## doyoulikegumwood (Jun 21, 2007)

rob i have to agree with you if this is a commision job and youve never sprayed befor stick with what you know. and try out the spraying on some projects that are going into your own home or things your not pressed for time on youll need a learning curve when you start out spraying


----------

