Problems with applying shellac

[msweig]

I have been trying to pad on shellac (about a 1.5lb cut) onto a tabletop, and I'm getting some ridges (it kinda reminds me of brush marks).  I'm assuming that they are coming from the edges of the pad.  Any suggestions on how to get this to not happen?  I'm assuming my technique is off, and the shellac is drying before it flows out and levels.  

The pad I've been using is a ball of old t-shirt material with one layer tightly wrapped around the ball so there are no creases, etc.  Squirt some alcohol on the pad so that the inner ball is pretty wet, then add some of the shellac and apply to the tabletop.  Then the motion is the whole landing and take off maneuver.  

Any suggestions? I've thought of maybe trying to brush a layer on (might be a thicker coat so has more time to flow out), but not sure how well that will work. 

Thanks in advance.

Mark

[Willyou]

Spray it on. I have always had that problem trying to brush or pad shellac. Some can do it. I can't.

[jteneyck]

I can do small panels pretty well using the process you described, but I almost always spray shellac.  It's just so much easier to get good results.  If that's not an option then you could try Behkol instead of DNA if that's what you are using,  It evaporates more slowly than DNA.  I think turpentine added to shellac also slows down the evaporation rate but I haven't tried it.  And then there's true French polishing where linseed oil is part of the ground coats (I think).  Research, and persevere.  

John

[Rob Young]

I can do small panels pretty well using the process you described, but I almost always spray shellac.  It's just so much easier to get good results.  If that's not an option then you could try Behkol instead of DNA if that's what you are using,  It evaporates more slowly than DNA.  I think turpentine added to shellac also slows down the evaporation rate but I haven't tried it.  And then there's true French polishing where linseed oil is part of the ground coats (I think).  Research, and persevere.  

John

Yes, turpentine will act as a retarder for shellac. Don't need much, I think I was using a teaspoon-ish amount per quart of 1.5# when spraying (notebook isn't here). I did get real turpentine, not the substitute stuff so read the label. When brushing/padding I'm usually at the bench in the basement so haven't found it necessary to use a retarder.

For small areas say up to chessboard size I have had good luck using a Taklon bristle brush. You can get 1" to 2" wide brushes from the art supply store for small money. They work great. Other shapes might be necessary for contoured and carved stuff. Got this tip originally from Don Williams.

[rwe2156]

You're basically French polishing - not for newbies.

I good quality oil type brush will do a pretty good job. Maybe 1:1 on the shellac.

Large areas +1 on spraying.

What's great about shellac is you can "erase" it and start over!!

[msweig]

Ok, I have a spraying setup, but at this point I don't want to pull it out and deal with it. But I will keep that in mind for the future.

I brushed on 2-3 coats to get more buildup. Then scraped, followed by wet sanding with mineral spirits to get it more level/remove brush marks. Not perfect, but much better. Unfortunately I think I went through the shellac at one spot in the middle. Luckily, I don't think I got through the BLO below that. So need to brush on one or two more coats, sand again, and should be done.

[Willyou]

Now that you have the surface sanded and scraped to level and the brush marks are removed, I strongly encourage you to pull out your spray equipment and give it a try for your final coats. Yes. It can be a bit of a hassle assembling everything and then cleaning it up when you are done. However, all of this is not as labor intensive as all of the sanding and scraping and, in the end, the results will be better. if needed, find a large piece of cardboard to practice on before do your final work. Also, i have always used alcohol to clean up but I have read that an ammonia solution works great for cleaning up shellac from spray equipment.

[Rob Young]

Now that you have the surface sanded and scraped to level and the brush marks are removed, I strongly encourage you to pull out your spray equipment and give it a try for your final coats. Yes. It can be a bit of a hassle assembling everything and then cleaning it up when you are done. However, all of this is not as labor intensive as all of the sanding and scraping and, in the end, the results will be better. if needed, find a large piece of cardboard to practice on before do your final work. Also, i have always used alcohol to clean up but I have read that an ammonia solution works great for cleaning up shellac from spray equipment.

Yes, household sudsy ammonia will clean out shellac from a gun. Cheap stuff is fine. I fill my cup about 1/2 with sudsy ammonia, 1/2 with water and spray it through. After that I rinse with a bit of water. Pressurized cup so I have to spray it through. Also works well for water borne finishes.

[Cooler]

Foam brushes will last about 15 minutes with shellac.  After that they become limp.

But for small jobs I have gotten good results with a foam brush. 

Note:  I only normally use SealCoat, but also some pre-mix.  The SealCoat is generally the first coat to be followed by poly.