finish bah humbug

[arie]

Originally Posted by WaddyT

The last verdict I saw on PolyWhey was that it was pretty soft. Not saying it's bad, but that it didn't solve the hardness problem some are looking for.

imo you gotta go with the floor finish. not all of their products are the same. ime it's 2X harder then the furniture stuff.

when you talk to polywhey they'll recommend the furniture version or their luthier's stuff but various internet posts say that it's too soft for instruments. no proof that i've seen yet but you know how the internet is.

the floor finish on the other hand, is quite hard. i actually came across it while rehabbing the vintage oak floor in our condo. it was $80 a gallon. while not the overwhelming scientific proof some people require these days, i compared it to the furniture finish side by side on a piece of scrap pine. after one week my thumbnail went in on the furniture side but not on the floor finish side.

almost a year later the high traffic areas of our condo show very little wear from shoes, furniture dollies, dragging chairs and tables and boxes and stuff around, and a cat with sharp claws.

they also sell tinting to mix in directly into the finish which requires a good deal of power stirring btw. the dye is super-aggressive and they supply a syringe to dose it with.

[WaddyT]

Interesting comments. Can you control the thickness? That would be my concern, keeping it thin.

[pb+j]

Just thinking about it I suspect that in a floor finish, transparency is a lower priority than it would be in a furniture finish. But in general it seems like floor finishes would have a lot going for them

I'd like a finish that doesn't involve sanding a ridiculously high proportion the finish away.

That new shellac stuff reminds me of "qualisol," which is no longer available. You could pad that stuff on and rub it like French Polish and it formed a nice gloss and was hard and durable. I used it on an electic guitar and was very impressed, but I'm guessing it was too toxic.

[jeff crisp]

Originally Posted by pb+j

Just thinking about it I suspect that in a floor finish, transparency is a lower priority than it would be in a furniture finish. But in general it seems like floor finishes would have a lot going for them

Its true that in this day and age with health and safety being more of a concern that transparency may suffer when compared to past products. Often more and more solids are being added to gain durability that was usually in the past offset with harder products. These products often contained high or higher levels of isocyanates that are either now banned or are being fazed out. However all sorts products used in finishing right across the board are suffering from this same issue. Just like when it comes to coating anything, with floors there are all sorts of options and in general transparency would not be on the top of my list of concerns. It is however one reason why I have never been a fan of satin.

[QUOTE] I'd like a finish that doesn't involve sanding a ridiculously high proportion the finish away.[QUOTE/]

This can largely be controlled by the viscosity you choose to use your product at (how much you thin it) and the method and skill with which you apply it. One thing I like about a hard product or at least a product that hardens quickly is the ease of cutbacks in terms of tearing (often from the dust pimples in the coat trapped under the sandpaper you are using).

In 2008, the year before I started making real guitars I was making cigarbox styled guitars and coating them with what I was familiar with. I was using a Cabot's flooring product that is a modified (alkyd resin) oil based polyurethane. I liked it's golden color (reminded me of shellac) and while not as durable as some solvent based products I often used it did come close for hardness. I was thinning this product with 50% turps and wiping on about 16 coats (pore filling would have reduced that number). Lightly cutting back between all but the first couple of coats with 2000 grit. I would have barely removed much more than the dust pimples on each coat but due to the way I was applying it , it would have been considerably thinner than 3 coats on a floor. Some floors and guitars look like they have been dipped in plastic, not a look I particularly like.

I found this site helpful at the time. He uses the term satin ( I was taught this referred to the amount of matting agent in it not the level of sheen) which as I have already said I'm not fond of because I don't like what matting agents do to the color or transparency. I generally prefer full glosses that aren't a high gloss/and build (french polish, I was taught is a full gloss, just not a high gloss (at least in comparison to some plastics out there), it has no matting agent).

http://liutaiomottola.com/PrevPubs/W...ingVarnish.htm

Here are some shots of boxes I made. You'll have to hunt to find a reflection but they are there and its all I have.
https://www.flickr.com/photos/799108...n/photostream/
https://www.flickr.com/photos/799108...n/photostream/
https://www.flickr.com/photos/799108...n/photostream/
https://www.flickr.com/photos/799108...n/photostream/

[pb+j]

I've used tru-oil, which I believe is a wiping varnish despite the name (flexners book suggests that's the case) and it's easy to apply and can be buffed to a nice gloss.

The aesthetics of guitar finishing are interesting. The ideal is the pore-filled, perfectly leveled, mirror glaze look. It's a good look and it's hard to pull off on a small scale. But lots of cheap guitars with polyester finishes manage that look. I had a mexico made fender bass with a poly finish that was like a coat of bulletproof lexan. It was remarkably thick too. Felt like playing a bar-top.

I have a travel guitar with a Sapele neck, and the neck is not pore-filled. It has stain and some kind of thin moderate gloss finish, but the pores are completley unfilled. No doubt a cost cutting measure, but I find I kind of like the aesthetics of it. I suppose their could be a guitar finish aesthetic that was less focused forcing the surface of wood to look like a mirror.

[LouieAtienza]

The whole key is the prep work. The smoother the wood is prepped beforehand (pore filling and sanding) the less coats you need to achieve a good finish with little leveling needed. If you use the finish itself to pore fill you can expect many coats and many hours cutting back down. The exception would be some of the heavy electrostatic polyester finishes that are put on.

Also the traditional satin finish actually started as a gloss finish which was rubbed down with 4-0 steel wool and wax, AFTER the finished was leveled off and rubbed out. The modern satin finishes do it with something like talc, which also adds body to the finish. Also some modern finishes do require a minimum film thickness to achieve a high gloss as that thickness provides the "depth" associated with a high-gloss finish.

And yes, most rubbed oil finishes sold today are actually hand rubbed varnishes. I used to use MinWax Tung Oil to refinish pool cues with success. I was able to build a nice coat that rubbed out to a very high gloss, with the warm amber look of the varnish.

Again, get your wood surfaces as smooth as possible with the pores filled BEFORE laying your finish down, including pre-raising the wood grain, so that you have minimal work smoothing the finish layers.

[pb+j]

I left this guitar for a week and when I came back i sanded the back down to level. i think I like the KTM9 a little more than I did. But I don't love it.

I also got a new brush in the mail, a Davinci nylon bristle flat wash, and it does an excellent job, no bubbles. Brushing with this stuff is possible, but a pain--I just can't get the brush stokes to level out, and if I thin it, it runs to much. There must be a sweet spot I'm not finding. But the brush marks sand out pretty readily. Wish I could avoid brushing. It's economical and easy on the local environment though, and it seems to sand up well..

Really dislike the KTM on the neck, for some reason. It seems "plasticy." I've tried toning it but I still don't like it. Maybe when it's buffed out.

[Ned Milburn]

Originally Posted by pb+j

I left this guitar for a week and when I came back i sanded the back down to level. i think I like the KTM9 a little more than I did. But I don't love it.

I also got a new brush in the mail, a Davinci nylon bristle flat wash, and it does an excellent job, no bubbles. Brushing with this stuff is possible, but a pain--I just can't get the brush stokes to level out, and if I thin it, it runs to much. There must be a sweet spot I'm not finding. But the brush marks sand out pretty readily. Wish I could avoid brushing. It's economical and easy on the local environment though, and it seems to sand up well..

Really dislike the KTM on the neck, for some reason. It seems "plasticy." I've tried toning it but I still don't like it. Maybe when it's buffed out.

If you are brushing and it is running too much, you likely are loading the brush with too much finish.

I have used Target water based em6000 and em7000 with fine results. They keys to success with this finish include using a synthetic bristle brush and keeping it CLEAN, because the water based finish tends to dry in between the bristles and leave bristle-shaped lengths that come out in the wet finish next application if not washed/rinsed thoroughly. Also, I tried both watering it down and the retarder at maximum recommended dosage, and the retarder gives better results. Using no retarder is not recommended with water based brush-on, because it gets tacky/gummy pretty quickly - the retarder helps the self levelling process.

Build up a few coats, then let dry for a few days (4 days), then sand, then repeat. Anywhere from 3 to 6 sessions of this process should give satisfactory results, if the base was prepared well. (I used pumice-stone and shellac for pore filling, since my primary finish is French Polish and I am comfortable with pumice-stone filling, but any standard type of pore filling will be fine.)