Replies

1. 
   hammer1 | Apr 14, 2005 04:24am | #1

   Deft is a modified nitrocellulose lacquer, not a true lacquer. It has additives to facilitate brushing. It's not as clear as a spray lacquer. With any lacquer, you don't want to over do it with many coats. It can become a separate entity and may craze and lift. If you want professional level finishes, get professional coatings, not off the shelf hardware store products.

   Beat it to fit / Paint it to match

2. 
   goldhiller | Apr 14, 2005 05:28am | #2

   Well, I'm gonna differ with Hammer a bit, I guess.

   If it's the Deft Clear Wood Finish that you're referring to and considering using....then yes....you are correct about some of the advantages.  That's the Deft product that is a nitrocellulose and yes, it dries slower because it has a type of retarder in it that allows for slow evaporation and so brush application becomes possible.

    

     It's an okay product for alot of stuff even though it isn't the nitro with the highest degree of clarity on the market.  But the retarders it contains can be very helpful to the novice who doesn't have alot of experience or knowledge under their belt about adding and using lacquer retarders for varyng conditions...... especially if application is being done in higher temps and drier conditions.....or both.  We all start at ground zero and Deft nitro isn't a bad choice for the novice to use. 

   I've thinned the canned product with lac thinner for spraying purposes with no ill effects ever, despite what the directions on the can say.  Just bear in mind that the ratio of solids in nitros are already pretty low and so if you thin the material, you'll have to apply a couple more coats to build sufficient finish thickness for your purposes. Same holds true for the stuff that comes in the aerosol can ready to spray.  It's the final mils left on the surface after the solvent evaporates that counts in this regard.

   As far as building too many mils.........when shooting stringed instruments and the like, we shoot 16 coats of high quality crystal clear nitro.  No ill effects yet.  But you have to shoot about four coats and then give several days rest before proceeding with additional applications.  Then wait a minimum of two weeks for final rubout.

    

    

    

    

    

    

     

    

    

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   Knowledge is power, but only if applied in a timely fashion.
3. 
   DougF | Apr 14, 2005 05:06pm | #3

   I too disagree with Hammer.  Deft is a true lacquer although not what I would consider good furniture grade.  It is easy to use and flows nicely on horizontal surfaces.  Each successive coat will meld with the previous coats to to provide a consolidated top coat.  Because of the additional retarders in Deft, you need to be careful about sagging and running on vertical surfaces.  You can achieve somewhat the same results in regular nitro lacquer by adding retarders.  Retarders can be purchased as such or my adding thinner, acetone or MEK.  Each of these act as a retarder but at different rates by volume.  You can combine these to achieve the balance that fits your application technique - brush or spray - humidity and temperature.  Retarders and thinners do not affect the quality of the finish only the build thickness.  The thinners simply flash off once the lacquer is applied.  More thinner/retarders, more product is needed to reach your desired finish layer.  BTH, Deft is not necessarily cheaper than other high-quality lacquers.  I would not recommend using the satin finish: use the gloss and rub out the final coat to achieve the desired affect. 

   Doug

1. 
   Tao | Apr 14, 2005 07:15pm | #4

   Doug, I think you've got your terminology a little twisted.  Acetone, MEK and lacquer thinners are not retarders, they are thinners.  Retarders slow the drying rate of finishes.  Typical retarders are various glycol ethers and heavy, slow drying alcohols like methoxypropanol.

   A lot of finish problems arise from using inapproriate thinners.  I've found it best to use cheap lacquer thinner for cleanup, but to use the thinner recommended by the manufacturer when reducing lacquers and other finishes.

   As a purely personal side note, while I agree that Deft is technically a lacquer (reversible), if confronted with the choice of using only Deft or oil based poly, I'd probably quit finishing altogether.

   Michael R

1. 
   DougF | Apr 14, 2005 07:32pm | #5

   Michael, I've been taught to use/blend various "thinners" when I need to slow down the flash-off.  Perhaps the difference is the solvent flash-off rate and the drying rate for the material.   But, it wouldn't be the first time I've been wrong :)

   Doug  

1. 
   Tao | Apr 14, 2005 07:56pm | #6

   Well, adding thinners of any kind will probably slow the flash off time simply because there is more solvent to evaporate, requiring more time. The same result can be obtained with a lot less thinning by selecting an appropriate retarder. As you probably know, some are made to extend flash off time, some to slow overall drying time.

   I don't like to overthin because it leads to other problems like curtains and runs. Too fast a thinner like acetone can promote blushing.  I try to spray my finishes as close to package consistency as my equipment and the weather will allow, and an addition of 3% retarder can give the same effect as 15%  thinner.

   I'll occasionally tinker, too, but I've found out the hard way that what I was taught in the past isn't always optimal.

   Michael R

1. 
   DougF | Apr 14, 2005 08:02pm | #7

   Thanks for the lesson.  Learning is aan every-day excercise.

   DOug

2. 
   kandrewk | Apr 16, 2005 04:51am | #8

   Thanks to everyone for the comments and ideas on spraying and on deft.
   I find it very helpful to hear everyones ideas.
   Thanks again.

3. 
   nikkiwood | Apr 16, 2005 06:32am | #9

   Re: lacquer thinnersI've heard that all lacquer thinners are not created equal. Some (i.e. the more expensive ones) are supposed to be "hotter" (stronger), and are more effective thinning agents when spraying. Anybody able to shed some light on all this?"I would never die for my beliefs because I might be wrong."
   -- Bertrand Russell

4. 
   Tao | Apr 16, 2005 06:45am | #10

   Lacquer thinners are a mixture of solvents tailored to dissolve specific resins, and to give a specific drying curve.  They are formulated to give a fast flash-off without blushing, but to stay liquid long enough to level out, and to keep the film "open" enough to prevent solvent pop.  The stronger solvents are expensive, so they are diluted with weaker solvents whenever appropriate.

   What i have found over the years is that cheap lacquer thinner is fine for cleanup, but that it is generally best to use the specific thinner that a manufacturer makes for their own products.  A lot of the time you can get away with using generic thinners, but on the other hand I have traced a lot of finish problems back to using the wrong thinner (orange peel, cloudiness, solvent pop, etc.).  Since you seldom need more than 10% thinner, it seems like a foolish economy to try to get away with a cheaper product.

   Michael R