Official Luthiers Forum!

If Royal Lac works on top of regular shellac, is there a good reason why I should spend the extra money and order Seal Lac when I order Royal Lac, or should I just go ahead and use the shellac flakes I already have as a sealer under the Royal Lac? They are dewaxed blond from Vijay.

I would ask Vijay.

I looked on Vijay's website and in the FAQs he says that regular shellac works fine as a sealer prior to Royal Lac. The reason he recommends Seal Lac is that he claims Seal Lac works as a pore filler. I am using some very porous Honduran Mahogany back and sides and I had been planning on trying Aqua Coat filler first, since I don't want to deal with epoxy. If I fill first, then there is no reason not to use dewaxed shellac as the sealer before the Royal Lac. If Vijay thinks Seal Lac can pore fill very porous wood, then I might try it instead of the Aqua Coat. I emailed him.

This was my question to Vijay:

Hi Vijay, You claim it is better to use Seal Lac as opposed to regular dewaxed shellac as a sealer before Royal Lac because the Seal Lac acts as a pore filler. I am using very porous Honduran mahogany for a guitar back and sides and was thinking of using Aqua Coat filler first. Will Seal Lac fill very porous wood?
> > > > > Thanks, Wendy

Here is his very informative reply, which he has given me permission to post here:

Seal-Lac is a pore filler and a sealer. However, it will not easily fill open pores that Mahogany exhibits. It will, if many coats are applied, but this may not be time and cost effective. Therefore in your case, it is best for you to fill with Aqua Coat or even epoxy, level sand, apply 3-4 coats of Seal-Lac or shellac, level sand to leave a very thin layer on the surface and lastly apply Royal-Lac. I would suggest that you view Robert O'Brien's video on my website showing application of Seal-Lac and Royal-Lac.
Here is some information about polymers and how they work:
Thinking very simply, pore filling is achieved by embedding solids into the pores. Pore fillers have high solids content to do just that. Seal-Lac is also high solids content but not as high as other pore fillers. Hence it will not be as effective on open pored woods like Mahogany, Rosewood etc.. On the other hand, Seal-Lac which is shellac based, is an excellent sealer and foundation for Royal-Lac or any other solvent based finish to meld with. The adhesive qualities of shellac are by far the best than any other man made resin. Hence the thin layer of Seal-Lac or shellac is advisable before final finishing with a solvent based finish like Royal-Lac.
Finishes are of two types; Thermoplastic and Thermoset. Thermoplastic finishes are those that can be redissolved in their respective solvents after application and complete cure. Thermoset on the other hand are finishes that cannot be re dissolved into their respective solvents after complete cure. Examples of thermoplastic finishes are shellac and NC lacquer. Mostly all other finishes like Royal-Lac, Polyurethane, Urethane, pre/post cat lacquer are thermoset finishes. Here are some facts about the two:
1) Thermoplastic:
Advantages
Quick-drying
Easy to repair
Excellent depth and clarity
No problem with recoat ability and adhesion





Disadvantages
Poor chemical resistance
Poor heat resistance
Poor mar resistance
Not durable

2) Thermoset:
Advantages
Relatively good chemical resistance
Quick-drying
Meets KCMA (Kitchen Cabinet Manufacturers Association) specifications





Disadvantages
shelf life stability is about 6-months
May need sanding between coats for better adhesion
Not as easy to repair

As you can see, the two exhibit different qualities that are desirable by most users but unfortunately you can't have it all!!

Royal-Lac has been able to bridge the two to an extent; where you get the great looks that only shellac can provide by enhancing the personality of the wood and the excellent durability that synthetic finishes will provide. But since it is a thermoset finish, repairing is not as easy as shellac. Why? Because once it has cured, it cannot be redissolved and hence when a coat is applied, it sits on the existing coat and does not meld in. But there are ways to circumvent this problem as you would know.

To sum it up and going back to my suggestions that a layer of Seal-Lac or shellac is advisable, it can be seen that since Seal-Lac or shellac have the ability to redissolve and have excellent adhesion qualities, it is good to have a thin layer so that when Royal-Lac is applied on top of this layer, it melds with it to form a single layer.

If you have any other questions, please ask anytime. Regards,
Vijay

Trevor,

According the the manufacturer of Royal Lac, there are no plasticizers. The string chemical bond between the ingredients make sit unnecessary.

I just wanted to do a quick "adder" to this 5 years old thread.

I had contributed my experience 5 years ago on a guitar I had used Seal Lac and Royal Lac to finish. At that time it was a new product

The finish failed on the guitar on which I used it. I sanded the finish off the guitar in the fall of 2019 and had it refinished with Lacquer (Barry Daniels did the work for me since I was too busy to do it. Thanks Barry.) I talked to Vijay last fall and he reported that several finishes had failed and that all had the common issue of wet level sanding with water. He now recommends that no water be used with the product.

I contacted Robbie about this and he reported that he had previously learned of this issue and changed his finishing video to eliminate the use of water for the level sanding. (I had used his video 5 years ago for the level sanding process.)

I thought it was worth this posting as a warning in case this thread was being read and used by someone.

Wow! Thanks for posting the update. I hope everyone gets a chance to see it!

I used Royal Lac as FP for the first time a little over a year ago. I really liked it. While I was getting the feel for the differences in FP with this instead of regular shellac, I got a little heavy handed and had some texture to level sand out. I had never sanded an FP finish before. I'm 99% sure I only lubricated with oil when I sanded (only a very small amount of sanding was done) but I may have used some water. What did the finish look like when it started to fail? I still have one of those two guitars in my possession so I'd like to keep an eye on it.

_________________
Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

I didn't realize that the Seal-Lac still had the melting properties of shellac, interesting.

I did my last guitar in Royal just using the FP method. No sanding except to hit any mistakes, cat hairs, whatever, and then go on. I use it with walnut oil to make it easier for the mouse to glide on and off. I was very pleased with the results. I didn't even do a final polish on it, just cut the RL back with alcohol and glazed.

I do have to wonder though it the problems with wet sanding was becasue it was not let to dry enough? I mean once water evaporates it's gone right?

You can apply for a special license to buy the high octane stuff in VA. I used to live in Staunton and I was able to get the license to buy the good everclear pretty easily. Then you go to your local ABC and order it through them. Just a thought!

I had some e-mail discussions with Vijay a few years ago about Royal-Lac. He made it clear to me that Seal-Lac has none of the special proprietary additives that Royal-Lac has. Seal-Lac is just plain old dewaxed shellac flakes, dissolved in denatured alcohol. So, you can use it the way you would use any dissolved, dewaxed shellac, and if you want to use your own mix of dewaxed shellac instead of Seal-Lac, it will probably be fine (assuming there is nothing wrong with the shellac in the first place).

When sanding shellac finishes, I either use oil or go dry anyway, so I have avoided the water problem.

I liked French Polishing with Royal-Lac. As I have mentioned before, it felt a little gummier than regular shellac, but that was manageable. If I use it again, I think I will pad it (per Vijay's videos) rather than, strictly speaking, trying to French Polish it. But that is mostly about me and wanting to get more of the stuff on quicker.

If you do, I'd really like to hear about it. I had zero luck padding it on. It was such a horrific mess I ended up spraying over it. But I've never fp'd before either, so...

I have heard about that, thanks. I might look into it.

A source for high proof ethyl and denatured alcohol. Pricey though....https://www.laballey.com/. Don't know if they ship to VA.

I just bought a bunch of both denatured and 200 proof ethanol from Lab Alley, and got it shipped no problem. And I live in the People's Republic of California.

My closest Everclear state is Kentucky, just FYI. Maybe some of you go there on occasion. If you do, find a decent sized liquor store and stock up. That's what I do.

Ed (Bond. Ed Bond.)--

If I come back to shellac finishes, the thing I really want to experiment with, other than padding on Royal-Lac, is the azeotropic mixture of shellac, alcohol and acetone outlined in the Gore/Gilet Build book, and apparently made known to us all via Brian Burns and some chemist friend of his. That is reported to be a great way to get everything about a shellac finish (including pore filling with pumice) to happen faster and with less work. I can see myself liking that process for getting the pores filled and getting a good finish built up, doing some level sanding as needed, then switching to Royal-Lac for the final coats.

We'll see. I'm also experimenting with the whole Silvertip pore fill, Enduro Var finish method. Different topic, but it is why I'm not immediately doing any shellac finishing.

Last gloss guitar I did myself, after probably 10 years or more farming out, I used West epoxy. And I found it incredibly easy. I found myself wondering why I used to find it so difficult...

Also, I should really finish reading the rest of those books instead of just picking up the bits I needed to know...

This strikes me as odd since the claim was made in one of the videos on Royal Lac's site that the cured finish is impervious to water. I wonder if the warning of wet sanding with water would still apply to a Royal Lac film that was cured for 35 days as documented in the "Proving" video?

_________________
Stay with the happy people.
--Reynolds Large

I as well thought the issue was wet sanding to level in between days of applying new coats of finish, not at the end of curing. I have used it since it first came out, original and precat and have not had any failures. I wet sand after it cures but dry sand during application.

Precat Royal Lac

_________________
http://www.Harvestmoonguitars.com

I think John has the right approach: only dry sand during application, and then let it fully cure, and then you can wet sand if you want.

Because wet level sanding with water is such a familiar step for nitro application, I think we may (mistakenly, it turns out, in retrospect) assume it is safe for other finish materials. Then we have problems, because these other materials have a negative reaction to the presence of that much water before the finish has fully cured. Enduro Var is best dry sanded during application, too.

Ive finished 4 guitars and a mandolin with Royal Lac. I sprayed the first three and got finish crazing after about 6 months. After corresponding with Vijay it was apparent that I had applied it wrong (too fast and too heavy). The last two I French Polished, Aqua Coat filler, Seal Lac then RL FP. I put the Seal Lac and initial RL coats on using Robbie O'Brien's fly on/off method then move to FP. I FP by thinning the RL with Everclear and use a bit of Walnut oil if the muneca is not sliding easily. Muneca is cotton T shirt material around gauze with a rubber band to hold it together. Any sanding I do is dry with P320 although the only sanding needed is when starting with the first coats. I did buff lightly after the RL cured for a few weeks although I probably won't bother anymore since it's not necessary.

Here's a little size 5 with a redwood top. Just after the FP, no buffing.

_________________
Steve Smith
"Music is what feelings sound like"

You make an interesting point for those coming from nitro applications. Prior to using Royal Lac my experience has been with water based lacquers and shellac. Em6000 and even more so EM9000 needs a wet coat thickness applied with a pretty tight tolerances. For me right around 3 mils. Plain Shellac also has a tendency to craze if applied too thick to quickly. I do not spray it. I sprayed nitro from a rattle can once. My experience is it matters a lot less how it goes on, if you let it cure long enough and level and buff it looks good. The post-cat Royal Lac is formulated to spray. I am still very careful with my wet coat thickness. (I still use around three mils). I apply no more than 4-5 coats a day an at least 1.5 hours in between.

_________________
http://www.Harvestmoonguitars.com