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I spent some time on the phone with an expert on Mohawk's line of wood finishes.
The conversation was enlightening to say the least.

After years of spraying nitro, I found that the gospel according to LMII isn't a one size fits all finishing recipe. (duh)
I know there are a lot of us who follow that schedule, but when McFadden's went away, I continued to use the same schedule with each subsequent lacquer I tried. My finishes have always been fine. I've been religious about waiting, waiting, and more waiting before continuing to the next coat and doing all the right stuff with the leveling. I figure it takes about fifteen to twenty days to do a decent finish.

But today, I tried something authentic. I read the instructions from the Mohawk PDS.

Here are the instructions for getting a great finish with their product

Directions: DIRECTIONS: Mohawk Clear Gloss Instrument Lacquer is a high quality
nitrocellulose wood lacquer specially designed for musical instruments. Apply over E-Z Vinyl®
Sealer, M610-800 or Mohawk WW Clear Lacquer Sanding Sealer (M610-2500), with standard or
HVLP spray equipment. Four to five coats of topcoat are recommended. Apply in light, even
coats of no more than 3-4 wet mils. Scuff sand between coats with 320 grit stearated sandpaper.
Total film build of the entire system, including topcoats, should not exceed 4 dry mils. Excessive
build may lead to poor adhesion, cracking or cold check problems. May be applied at 1 hour
intervals. Allow to air dry 2-3 days then wet sand with P400A, P800A, P1000A, and P1200A Classic Instrument Lacquer Page 2 of 2
Revised 9/1/11 formula versions: 1.003
waterproof sandpaper using Wool-Lube™ Rubbing Lubricant, M720-13xx, cut 1:1 with water.
Rub with Poly-Buf™ Rubbing Compound, M890-003. If reduction is necessary, use Lacquer
Reducer 2255, M650-010.

That sounds A LOT easier than what I've been doing.

First thing I realized was that I was laying down the finish WAY too thin.
Sprayed via these guidelines today and it looks great.
I'll give it a few days, level it out and see how it looks.

Will probably still wait as long as possible before final buff, but hey if it is good enough for the manufacturer, maybe I should give it a go and see what happens.

Comments?

Dave

I've been using Mohawk for years. The longer you can let it dry the nicer it will buff out. You can buff it after a few days, but it will shrink back. I like to give it at least 3 weeks to dry if I can and will leave it for a month if I'm not in a rush.

Josh

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Josh House

Canadian Luthier Supply
http://www.canadianluthiersupply.com
https://www.facebook.com/canadianluthiersupply?ref=hl
House Guitars - Custom Built Acoustic Instruments.
http://www.houseguitars.com

Mohawk/Behlen instrument lacquer needs lots of curing time in my mind. I also wait 3 to 4 weeks after final coats before sanding and buffing. I dry sand with a RO sander and find that it works better to wait 24 hours between grits so spend about 5 or 6 days leveling before buffing. When you sand you expose less cured lacquer after the hard surface is cut through, so I think that it needs to harden between grits. I buff with course, medium, then fine compound and also wait over night before buffing with the fine compound, it seems to leave less wheel marks. The finish continues to harden for years and is easier to damage in the 1st months of playing. It think the same thing needs to be done with wet sanding though I only wet sand the last finest grit.

Fred

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Fred Tellier
http://www.fetellierguitars.com
Facebook page http://www.facebook.com/pages/FE-Tellier-Guitars/163451547003866

Ya.....lots of waiting but using Mohawk stuff has worked best for me so far. I will add that Phil at Mohawk told me you don't have to sand between coats...even if you wait overnight. I've never had any issues following that advice. Also, I use their Industrial Sanding Sealer for pore fill because I can spray it on. I spray a 50/50 sealer/reducer coat on raw wood. The next day I sand barely back to the wood and spray another reduced coat. After letting that sit 2 weeks I level that and it's ready for topcoats.

The classic instrument lacquer is reduced 25% with a 100/5 mixture of reducer/retarder. I'll get millions of tiny air bubbles trapped below the surface without the retarder. On the first day I spray 4 coats and spray the next 4 coat on the following day...without sanding anything. Phil also mentioned that as a method to greatly reduce total drying time and reduce fallback into the pores. Even so I'm waiting roughly 4 weeks to do the final leveling.

Recently I used only 6 coats on a guitar. Although I haven't leveled that guitar yet...it looks like 6 coats is plenty.

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I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

For those that are thinking about Cardinal lacquer, it is also 16% solids, like Mohawk. So it takes a few extra coats to get a 5 mill finish. I have been spraying 3 wet coats 1st day, drop fill and sand with 320 or 400, 3 wet coats 2nd day, drop fill (if necessary) sand with 400, 2 wet coats on back and one wet coat on top 3rd day. Drop fill and let dry for 2 weeks.

Chuck

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I can confirm you should wait at least a couple of weeks before sanding and buffing Mohawk instrument lacquer. I was pretty amazed how soft it was after a couple of weeks compared to McFaddens. I now give it three weeks and that seems to work well for me.

Since the thinners have changed over time and are now HAPS compliant, does this change the way we should be applying NCL? For example, the Sherwin Williams High Build Lacquer instructions are pretty specific regarding thinning. In fact no more that 5% thinner is recommended.

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Ken

That recommendation may have more to do with VOC levels and EPA compliance than anything else and not necessarily the coating itself.

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Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

I am about as sure as I can be, after talking to various people in the business, that it is because of what's mentioned above...I regularly thin SW products ~15% and have had no issues...it's what my system requires to get to the right viscosity to spray correctly and it flows out very nicely too boot...

I thought about that Howard and it seems reasonable. As Mike P stated, I have also thinned it so it would go through my HVLP Mini gun. But I wonder if it makes it softer or renders a longer cure time. In fact the product literature says just that. I also wonder if the old recommendations that are available from various sources apply to the formulations that are current for NCL.

I am now following the recommendations for the SW High Build to the "t" and I must admit that I have never done that before, in 30 years of building.

By the way, there are very few manufacturers of NCL according to Sherwin Williams Rep who told me that SW makes the product for several companies. Just provide the product to SW rep and they will give you it labeled as SW.

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Ken

Adding thinner will increase dry times a tad. In the end it will not have any effect on film strength when completely dry. It will mean you will need extra coats to get the proper film build, and that sort of negates using a high build doesn't it? If you need to add more than 10% thinner you may be better off with a standard formula if it will spray right out of the can.

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Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

I am a bit confused on the mohawk finishing schedule.

I have pore filled with z-poxy and I'm about to spray the vinyl sealer
And nitro coats. Should I be thinning any of these or spraying right from the can?
My plan was two coats vinyl sealer scuff and three coats lacquer a day three times then waiting three weeks to level and buff.

Thanks Todd,

I opened my can of vinyl sealer and turns out I bought white..... Uhhhh hahhahah
I have bulls eye shellac in a spray can would there be any issues using that for a seal coat?

I thin the lacquer a little be fore spraying. Probably a bit less than 10%.

When I originally started using Mohawk I was spraying around 4 coats a day over 3 days with a 220 sanding between spraying sessions. I found that after levelling and buffing I would occasionally buff through the finish along the edges. I now spray 5 coats a day on the back and sides and 12 or 13 total on the top, with a 220 sanding between spraying sessions. You may want to consider adding some extra coats to your schedule, or at least shooting a few extra coats on the edges. The number of coats you use will be partly determined by how much you thin your lacquer.

It is very disappointing to go through the whole finishing process only to burn through the finish during the final buffing. Then you have to respray part of the guitar and wait a few more weeks before trying again. Making up test boards helps.

Josh

_________________
Josh House

Canadian Luthier Supply
http://www.canadianluthiersupply.com
https://www.facebook.com/canadianluthiersupply?ref=hl
House Guitars - Custom Built Acoustic Instruments.
http://www.houseguitars.com

Todd, do you measure the film thickness as you go? Is there an affordable option for such a device?

BTW thanks for all the info a huge help.

The shellac i sprayed seems to have gone on ruff where I pore filled with z-poxy. the top looks great because it was raw wood and soaked in nicely. The rest is ruff like orange peel. I feel like if I try to level it it's going to sand thru. Should I spray some build coats of nitro and level after? Or am I doing something wrong in spraying the shellac?