Thread: using hard, shellac

Originally Posted by Babylon5

I've probably been looking at the hard shellac in the wrong way. Maybe the method I should be doing is brushing on the main coats to build up the shellac thickness on the boxes. Then to leave it till crosslinked/hardened and instead of trying to get a polish using sandpaper etc and wax, should I be french polishing with a pad/rubber to achieve a gloss finish. Does this sound about right?

Is the "3 weeks" for crosslinking needed when the daytime temperature is constantly above 30c? Or is the 3 weeks a fairly conservative time frame taking into account winter temperatures of places such as victoria and tasmania?

Will a french polish/hard shellac finish stay glossy or will it eventually dull over time like wax? I'm wanting to reproduce a shiny finish similar to lacquer but don't want to use a wax finish to achieve the gloss level.

Shane.

Shane, I found this thread by going to the musical instrument forum and in the( search this forum box ) I type in shellac. The one you want to go to is, Any hard shellac advice, by cps music. In it Neil the creator of hard shellac recommends a brushing method and a place to get high quality brushes. I tried it out this morning using a china bristle brush, ( that`s all I had in the shop ) which I beat the tip of the brush on the corner of the workbench to soften. I then applied it as he instructed with great results from a crappy brush. I plan to aquire the brushes he recommends and start brushing the finish from now on. I held the brush at an almost 90 degree angle to the surface after wringing the excess shellac from the brush against the lip of the jar, and I mean all the excess. When it stopped dripping off the brush I started on the workpiece just kissing the surface with the bristles. The thing I like about this product is it goes on well no matter how it`s applied Mike

Well my patience ran out today and I decided that a week was nearly long enough for the hard shellac to cure. With the really hot weather in Brisbane lately, I was sure the shellac would have cured well and truly enough to sand and try to polish.

And it had, I attempted to try and sand out some ridge marks left by using the brush. Took a bit but had semi success. After sanding and thus causing the finish to change from a nice gloss to a dull satin finish, I tried to recover the shine by using micro mesh and polish. Limited success, the finish ended up with a bit more shine but nothing like the full gloss look before I had sanded.

Next effort was to try padding/rubbing on more shellac. I thought it went on well but upon checking it just before, there are alot of ridges caused by padding it on. Even though I tried to use a small amount of shellac and some oil, I was unsuccessful in getting a totally smooth finish.

Tommorow is another day and another chance to fix things. I can do either of two things or I may just try both to see which is more effective. First is to try spraying the hard shellac. I have a wagner HVLP spay kit that I used for lacquer. Second is to try diluting the hard shellac mix down to a very weak solution and try to pad it on with using a little more parrafin oil this time.

Any suggestions on which might be a better idea?

Shane.

Ps. I took your advice mike and I read up on the other hard shellac threads. I noticed that back in 2007 Neil mentioned to not use Hard Shellac with talc. He suggested using the other shellac just not Hard Shellac to use with the talc to grain fill. Is that still applied with the new formula?

Shane, It sounds like your between a rock and a hard place. I believe I saw a post where it said not to use talc with the new formula, as for the shellac not coming to a full gloss, it sounds like it`s still not hard enough. Normal shellac softens after wet sanding with oil, I`m not sure if thats the case with hard shellac, if it is you might have to wait a couple days after sanding before polishing. Don`t know what kind of polish your using, I plan to get some of U-Beaut`s EEE just to make sure I`m using something compatable with the hard shellac. It could be your getting too much finish on the piece, spraying will eliminate the ridges but go easy, it`s not hard to dump too much finish on the surface. I set my gun to where I can see the shellac flash off as I`m spraying, I`m misting on several light coats usually 3 or 4 each spraying session working my way around the guitar and changing the direction I`m spraying with each coat. I wait 4hrs between each session. One thing I started doing a while back was to sand my finishes dry, no wet sanding, because I was always getting water in screw holes and such and lifting the lacquer and I`m doing the same thing with the hard shellac. I start with 3M Free Cut sandpaper, 800 grit from ( it`s gold colored in all grits ) and wrap it around sanding blocks I cut out of styrofoam ( I`m using 1inch thick stuff I had left over from insulating my crawl space ) and sand just enough to remove the grittyness left from spraying, then go to Abralon sanding discs ( by Mirka ), 1000, 2000, 4000 grits. You should be getting a good gloss by the time you get to 4000 and need minimal polishing at that point. If you think you`ve got a lot of finish on the piece already you might want to sand it back a bit before spraying. Good Luck! Mike

Originally Posted by Heartstrings

Shane, It sounds like your between a rock and a hard place. I believe I saw a post where it said not to use talc with the new formula, as for the shellac not coming to a full gloss, it sounds like it`s still not hard enough. Normal shellac softens after wet sanding with oil, I`m not sure if thats the case with hard shellac, if it is you might have to wait a couple days after sanding before polishing. Don`t know what kind of polish your using, I plan to get some of U-Beaut`s EEE just to make sure I`m using something compatable with the hard shellac. It could be your getting too much finish on the piece, spraying will eliminate the ridges but go easy, it`s not hard to dump too much finish on the surface. I set my gun to where I can see the shellac flash off as I`m spraying, I`m misting on several light coats usually 3 or 4 each spraying session working my way around the guitar and changing the direction I`m spraying with each coat. I wait 4hrs between each session. One thing I started doing a while back was to sand my finishes dry, no wet sanding, because I was always getting water in screw holes and such and lifting the lacquer and I`m doing the same thing with the hard shellac. I start with 3M Free Cut sandpaper, 800 grit from ( it`s gold colored in all grits ) and wrap it around sanding blocks I cut out of styrofoam ( I`m using 1inch thick stuff I had left over from insulating my crawl space ) and sand just enough to remove the grittyness left from spraying, then go to Abralon sanding discs ( by Mirka ), 1000, 2000, 4000 grits. You should be getting a good gloss by the time you get to 4000 and need minimal polishing at that point. If you think you`ve got a lot of finish on the piece already you might want to sand it back a bit before spraying. Good Luck! Mike

I have a swansdown mop that I use to apply EEE but didn't use either today. That would be a quick way to tell if the shellac has fully cured. The amount of friction generated by the mop I assume would quickly take all the uncured shellac from the surface.

It was so frustrating starting the day with the shellac finished boxes looking nice and glossy. I only had to remove the high ridges and other brush strokes and it just went all downhill from there. I'm pretty sure the shellac has cured dry enough as sanding back took more time than when I previously sanded back another piece that had only dried for a day or two.

I'll try and post a picture or two in the next couple of days. Until then I'll keep that famous quote, "Rome wasn't built in a day". It is all a learning process.

Shane.

Shane, Thought of a couple more things I should add about my sanding methods. One good thing about sanding dry is you can tell if the finish is cured enough right away, if the paper starts to gum up, it`s not hard enough. The Mirka Abralon disc`s have a foam back so if you want to use oil you can, just squirt some into the face of the disc and it will distribute itself on to the surface as you sand. I use the discs on my orbital sander for larger surfaces using a light touch, but I have to cut them down to 5inches in dia., because they only come in 6 and 3inch dia. I`ve used the Micro mesh before but thought they clogged too easily and had to wet sand only with them. Dry sanding you can see what`s going, if you start going through the finsh you can stop before doing even more damage. Since it`s been really hot at your location you might want to contact U-Beaut and see if it`s safe to add a retarder to the shellac before spraying. I`ve used it when spraying in hot wheather here in Ohio with regular shellac and it helped give a smoother finish. Hope some of this pays off for you Mike

Update...

Went looking for n-butanol for the shellac retarder. No luck after trying 5 different paint/ automotive shops. Some had heard of it and one place looked further into it and appears that n-butanol is a raw chemical. In the end I settled for buying a general retarder after they looked up the MSDS and it showed the retarder contained butyl acetate.

Tried to spray the boxes but finish wasn't as glossy/shiny as padding the hard shellac. Gave up with spraying the hard shellac.

I checked out this guys website fp banner frames page and tried to follow his instructions for glazing. Using the rubber I was able to get a nice glossy finish. I've attached some photos. The boxes still need some more sessions of hard shellac but was nice to see things going right for a change.

Shane.

Hi Shane,

The Millburn tutorial is the one most luthiers point people to as it is quite comprehensive. Youve probably worked it out by now but the final stage of any session is a polishing step. A vitually dry pad, rubbing really hard and fast, leaves a great finish.

Nice work BTW!

I've still got the ever so slightest of marks from where the rubber was wiping across the surface.

Has anyone had success using the tripoli powder to polish the surface? Is so has it retained the gloss instead of making the surface a satin finish look?

Quote from ubeaut website...

Use over French Polish for a brilliant blemish free sheen.

Dust the polished surface with the TRIPOLI POWDER and with a clean soft rag firmly rub the powder over the work until the desired effect is achieved. Clean off with a clean rag and if desired go over the whole surface with our Polish Reviver to help protect it from heat & water marks, etc. and to remove any residual traces of the TRIPOLI POWDER.

Can also be applied with a soft rag that has been moistened with paraffin oil or water to help lubricate the surface of the polish and make the work go easier.

Does anyone know a business that sells the tripoli powder on the north side of Brisbane? My current supplier is out of stock at the moment.

Regards,
Shane.

here ya go, TRIPOLI POWDER every time I have bought by mail its been at my postbox within a couple of days.

Ive used car polish (Meguiars #7) and Brasso for polishing with success.

Originally Posted by Sebastiaan56

here ya go, TRIPOLI POWDER every time I have bought by mail its been at my postbox within a couple of days.

Ive used car polish (Meguiars #7) and Brasso for polishing with success.

Thanks for the reply. Yes I was going to order directly from Ubeaut. But I was after the powder to use today or tommorow. Looks like I may have to end up getting it delivered by mail.

Shane.