Shellac Issues

[Bugsysiegals]

I'm really struggling to apply shellac and could use some experience/wisdom. 

I'm using a 2lb cut of shellac and applying it with lint free stain rags.  They're thin triangle shape pieces which I've continued to fold over and over again until they're small thicker triangles which are probably 3" wide.  I dip the soft folded over edge of the triangle into the shellac and then apply it by rubbing it from one side to the other and then back again to ensure full coverage.  I repeat the previous step as I move up a row slightly overlapping the previous wet edge.  I can see excess shellac and streaking for which I've tried going over the rows again to blend them and going the opposite direction both of which only makes it worse meanwhile it's all tacky.  I've also tried squeezing out the triangle before applying but it's still streaking.

I've seen some guys balling up cheesecloth, wrapping the stain rag around it, squirting the shellac onto the cheesecloth rather than the exterior cloth, and then using the pad to wipe on the shellac ... is this a better method which might resolve my excess/streaking issues?

How do I remove all the blotchy shellac so I can start over again?  Per another thread, I'm using mineral spirits and a 120 Ruby sanding disc, no vacuum suction, to knock it down but it's a slow process as I have to scrape the disc with a razor blade every few minutes, and it's taking quite a while to make progress.  In addition, my basement smells like a charcoal grill cookout ... is this safe to use in the basement?

Here's a picture of the top after sanding, I wish I had a before picture, it was terrible ...
View attachment 4

Here's the rest of the cabinet, not sanded, not as bad as the top was, but still streaked and not uniform ...
View attachment 1View attachment 2 View attachment 3

 

[semenza]

To remove it I'd skip the mineral spirits and just sand it off with vacuum.

Also ..... why mineral spirits when alcohol is the solvent?  (I didn't read the other topic.)

Seth

 

[Bugsysiegals]

I’d read mineral spirits acts as a lubricant in removing the old shellac, definitely scrapes off the sanding disc easier, whereas alcohol will melt the shellac creating a gooey mess which doesn’t help it come off.

 

[semenza]

Have you tried dry sanding?

Which sander are you using?

Seth

 

[Bugsysiegals]

Yes I tried dry sanding and within 1 minute the sandpaper has many residue spots on it which create a barrier between the sand paper and wood preventing further sanding. They’re difficult to remove even with razor blade. The mineral spirits has allowed them to scrape off much easier.

I’m using ETS 150/3.

 

[Lincoln]

There's a good video about applying shellac on youtube, by 'Guys Woodshop'. Only about five mins long, but covers a lot of ground. Your problem might be that you're going back over the shellac after you've applied it. Been a while since I've used it, but I remember that I applied two very thin coats, then lightly hand sanded 400g. Then more thin coats. Definitely no machine sanding once I started applying the shellac.

 

[Stone Message]

Shellac - French Polish

If you get to a stage where the layers have been corrupted then take a cloth, soaked in methylated spirit or alcohol and wipe off the excess until you are back to an even stage. Allow the spirit to evaporate and dry.

Then, when applying fresh polish use a tiny spot of linseed oil to lubricate the application pad (rubber). Build up thin layers to achieve a deep and attractive shine.

Peter

 

[Bugsysiegals]

Thanks for all the info guys, I will give it another go.

FWIW - I sanded again but with 220 and DNA but it’s still blotchy. If I can get it to apply without streaks perhaps I can try to build the light areas and blend them back together.

 

[mrFinpgh]

I've never had luck power sanding shellac - it always does exactly what you describe.

Do you have a card scraper?  Or even a utility knife blade?  Scraping is going to get you a lot closer to where you want to go than sanding will.  Fortunately, the way french polish works makes it really easy to repair. 

It sounds like you have too much shellac going down in one shot, and it's creating lap marks. You can use the razor blade or scraper and level it out pretty quickly.

The whole thing with shellac is to build up that film thickness with extremely thin coats.  I'd recommend cutting your shellac to a 1lb cut and try just using a folded up shop towel as a pad.  I've had a lot of success using a shop towel folded into a small rectangle and then just lightly padding the shellac on. 

Much like brushing waterborne lacquer, you don't want to go back over the same area more than maybe once per coat.  It sets up too quickly and this is both a challenge and a benefit of the finish. If you time it right, you can apply finish almost continuously to build up a body.

Garrett Hack has a video on youtube about applying shellac.  Patrice Lejeune is also an expert on the process.

If you want to go deeper, watch some of the guitar makers do their french polishing. I've read a couple ebooks on french polishing from classical guitar builders, and Richard Jones has one, too. Lately, that's been my finish of choice and it is really satisfying/fun once you get the hang of it.  It's easy on cabinets.. harder on small parts.

Last thing - if you can get ahold of it, everclear is a much friendlier solvent than any of the DNA you can buy at the store. In PA it's hard to buy, so I use bioflame, which is a very pure ethanol with a bitterant added so I don't drink it.  [wink]