water borne lacquer waiting time plus an interesting site

[rob newell]

Hi all

I asked a question about water borne lacquer on the 'sand thru' thread and got some really helpful replies and was also led to several useful threads on the forum. There is some variation in opinion on the length of time one should wait after applying all the finish and doing the final level sand and buff. Some say 5 days (as suggested by the manufacturers - GF) is fine, while others go as long as a month! Does anyone have a sense of how long is long enough and how long is too long? When I did my first water borne finish (GF high performance topcoat), I did wait a month and it was not good. Such hard work to buff that it was hard to control and not buff through the finish. Be very interesting to hear you opinions.

Also, I came across the following site, which I don't think I have seen mentioned on any forums. It is nearly 3 hours on waterborne finishing and is free (and very detailed):

http://lichtyguitars.com/2016/05/02/app ... -ukuleles/

Thanks in advance for your help.

Rob

[Brian Evans]

I think it differs based on how the finish cures. If it's pre-catalyzed and has a definite chemical curing process, you can start to sand and buff after that has completed because the finish should at that point be stable. If it is a drying finish (which I think GF Top Coat is) then it changes and hardens more gradually over time. All water-borne finishes are not the same, I don't think it's fair to group them under a ubiquitous heading. I find it actually very complicated to follow, the manufacturers often are almost misleading about their products to make them appeal to everyone.

[Barry Daniels]

... When I did my first water borne finish (GF high performance topcoat), I did wait a month and it was not good. Such hard work to buff that it was hard to control and not buff through the finish. Be very interesting to hear you opinions.

Rob

That quote makes me think there is a problem with your buffing technique. No matter how hard a finish gets you should be able to buff it a month latter or a year latter. Can you tell us what tools and materials you are using and how you buff the finish?

[Barry Daniels]

I find it actually very complicated to follow, the manufacturers often are almost misleading about their products to make them appeal to everyone.

So true. Also, practically everyone else who uses the finish will have a much higher tolerance for some shrinkage after buffing or probably won't even level or buff the finish after the last coat. Guitar makers are a special case and recommendations from the finish manufacturer should be taken with a big grain of salt.

It's best to do some experimentation to determine how long to let a finish cure unless you are using a common guitar finish like nitro lacquer.

[rob newell]

... When I did my first water borne finish (GF high performance topcoat), I did wait a month and it was not good. Such hard work to buff that it was hard to control and not buff through the finish. Be very interesting to hear you opinions.

Rob

That quote makes me think there is a problem with your buffing technique. No matter how hard a finish gets you should be able to buff it a month latter or a year latter. Can you tell us what tools and materials you are using and how you buff the finish?

Hi Barry

Could be. As I said, it is the first time I did waterborne. I used progressive grades of Maguires auto finishes, rubbing on and buffing off by hand with microfibre cloths

[Barry Daniels]

I've used a lot of Meguiars over the years but mostly with a buffing machine. But it will work by hand if you are careful. The problem with hand application is if you dwell in one point too long you create a depression and possible burn through.

One thing you said that raised an alarm with me is using progressive grades. That is not really needed. I use M-105 which can take a surface flat sanded with 1000 grit sandpaper up to a full gloss. There is never a need for more than about 2 types of compound, and it is possible to get away with one if chosen carefully. Also, using a foam pad will keep things more level than a microfiber cloth.

[rob newell]

Hi Barry

That is helpful, and maybe nails the burn through problem right there. The GF seemed to take forever to get to a shine and I have read it is a lot harder than solvent based finishes - I certainly seemed to have to work small areas for a while to get it to a high gloss. What you say about not using different grades is interesting, too. Incidentally, I have used Maguirs as a hand buffing compound on wipe on poly and tru oil finishes with absolutely no problem, and achieved a high gloss on both with little effort. I have not heard about the foam pad in hand buffing. Is this similar to a foam pad one might use under sandpaper?

Thanks very much, by the way.

[Barry Daniels]

No, the foam pad is similar to the ones used on rotary or random orbital power buffing machines. Look at an auto detail supplier for hand polishing foam pads. They have pads of various density/hardness. Hard foam is for coarse compounds whereas the soft pads are used for finishing polish/swirl remover.

One new product is microfiber pads for polishing machines. This is microfiber with a stiff foam backing. They are considered a replacement for the coarser hard foam pads. But this could also work as a hand polisher.

I would recommend looking into a power tool to do your buffing. It will not only save time but will also give you a much better polish. I am a fan of the small detail polishers that use a 3" diameter pad. It works well on a guitar sized object. I use Chicago pneumatic polishers but recently recommend the Griots Garage 3" electric polisher to a fellow MIMFer and he has given it a good review.

[rob newell]

Thanks again, Barry - I think I'm going to go with the electric polisher, although we don't hve the brand you mention in the UK. One thing, I see from stores that there are different types of pad - basically 'dimple' or flat. do you have a recommendation? You can tell I'm new to this - previously did all finishing by hand. Cheers

[Barry Daniels]

Dimple or what we call waffle pads are designed to keep cooler. Probably either kind will work well. The important thing is how soft or firm the pad is. It is best to go with a major brand as the cheaper import pads will often fall apart quickly.

Look for a polisher that is DA instead of rotary. DA stands for dual action which actually means it is a random orbital type.

[rob newell]

Thanks for all your help, Barry. I'm on it. Cheers

[Bob Gramann]

Barry, is there a functional difference between one of those rotary polishers and a variable speed orbital sander? Will a polishing pad on the sander work as well?

[Barry Daniels]

I used to use a polishing pad on an electric drill and also a random orbital sander. All will work.

The deal with a rotary polisher is that it is easy to leave swirl marks especially if you are using an aggressive compound. The DA polishers don't work as fast but they are the most forgiving. They cannot leave swirl marks due to the movement of the pads. And the movement is the same as a random orbital sander. The only difference among these is the size of the orbit. Some DA polishers have an aggressive orbit of 15 mm, whereas the one I have has an orbit of 8mm. This makes it a bit slower but more forgiving.

[Bob Gramann]

Thank you. I had tried the sander with a lambs wool pad and wasn’t pleased at all with the results (or with the splatter). I went back to hand polishing. But, I’m always looking for a better way. And, I still got swirl marks with the random orbital—8 mm sounds about right. Every time I’ve gotten out that sander, usually just to sand, I’ve learned why I don’t use it much.

[Barry Daniels]

Lambswool is very aggressive and messy. Foam pads are much less aggressive and messy. (Definition of Aggressive is heavy and coarse polishing, sort of like 60 grit sandpaper versus 150 grit.)

Another big difference between a random orbital sander (ROS) and the typical dual action (DA) polisher is the size of the motor. I have a DA from Harbor Freight, which is a surprisingly decent tool. And the motor on this machine is very hefty (5.7 amps) versus my Bosch ROS which is rated at 2.3 amps. Using a ROS on a guitar is doable, but I can speak from experience that anything larger (like a headboard on a king size bed) will take hours to polish with a ROS.

Splatter is sort of a factor of the type of polish you use and your technique. The speed of the machine can be turned down to minimize it. Some types of polish tend to make the situation worse. Also, the amount of polish you use can be limited.

There are a vast number of automotive detailing products available. I have been researching the topic for several years and still consider myself a newbie.

[Bob Gramann]

Sounds like I’ll have to research the DA polisher. Getting a better shine than I can by hand would be worth a little investment. (I haven’t been able to bring myself to get a large buffing wheel. I know that I will be one of the folks to throw a guitar if Imuse one of those.) I have had such bad luck with Harbor Freight power tools that I won’t start there. Thank you for the information.

[Barry Daniels]

I think the Griots Garage mini polisher would be ideal for guitar sized objects.

https://www.griotsgarage.com/product/3+inch+random+orbital.do?sortby=ourPicks&refType=&from=fn

The car sized buffers that have a 5 or 6" diameter plate would be too big and heavy for guitars.

[Bob Gramann]

Thanks. I’ll get one before I get to that stage on the next guitar.

[Gordon Bellerose]

I have never used solvent based finishes, so I have no basis for comparison.
As a water base user, I have a bit of experience to draw on.

When I first started using water based lacquer, I sprayed too heavy, getting a lot of runs and droops.
When I sanded, I often got sand throughs also. Especially on the edges.

I first tried a couple of different products, before Bob Gramann advised me to try Target EM-6000. I used that for a half dozen guitars with decent results.
I then landed on Britetone. It is sold here in Canada by Wood Essence, from Saskatoon.
I really like this product. It sprays beautifully, and builds quickly, so less coats are required. I'm down from 10 or 12, to about 8.

I have never wet sanded in between coats. Dry sand only with 400 or 600 grit.
Curing times are between 3 - 5 days until wet sanding and buffing. My climate is very dry, so your cure time may vary.

I used foam polishing pads on a drill for buffing for the first 8 or 10 guitars. I now use a buffing wheel system.
I have not had a guitar thrown across the room Bob.

[Bob Gramann]

Gordon, you’re probably not as clumsy as I am. If there’s a way to drop a guitar, I’ve probably done it.