Official Luthiers Forum!

The "bias" against FP in the Steel string guitar field is something I hear about but haven't ever run into. As a matter of fact I have had a number of people comment on how glad they are to see people using it. I don't charge extra for French polish and have had people excited about this. Most companyies charge extra and to get it for no extra charge is a bonus. I have run into people with Bias against oil finish, polyester finish, even nitro, but never FP. Mind you I don't build for blue grass players

Rich I've brushed ktm and sprayed it, I prefer spraying. The only way I've brushed it on without getting bubbles is to thin it and put it on thin & I mean THIN. I use a cheap $99 harbor freight hvlp turbine sprayer & with my limited experience spraying get a manageable finish that I can usually wet sand flat with 800 grit. It dries so fast out of the gun that I get by with a particle mask.

I also love a tru oil finish as a matter of fact I tru oil the back of all my necks. Dale38655.0828009259

You can spray nitro outside even when it's quite cold, I even do it in the winter. My "spray booth" is outside my garage, and my guitars hang from the roof in there next to land mowers, skis and snow blowers until all spraying is done.

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Rian Gitar og Mandolin

[QUOTE=jwsamuel]How cold of temperatures can you spray in?[/QUOTE]

I've spayed laquer by -20? outside and then brought the work and the
lacquer in. It was for repairs, mostly very small surfaces and oversprays. No
problem at all, I let the laquer cure for a few weeks, wet-sanded, buffed and
that was that. I think what matters most is that the lacquer and the work be
at the at the same temp. , above 60? preferably.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

[QUOTE=laurent] I would add that the plastic bag, as soon as it is manufactured, is landfill material.[/QUOTE]

Reminds me of when I was living in Nova Scotia and they started a "blue Bag" program for re cycling. Then someone pointed out that the blue Bags wer't re cyclyble or bio degradable

[QUOTE=arvey] [QUOTE=laurent] I would add that the plastic bag, as soon as it is manufactured, is landfill material.[/QUOTE]

Reminds me of when I was living in Nova Scotia and they started a "blue Bag" program for re cycling. Then someone pointed out that the blue Bags wer't re cyclyble or bio degradable [/QUOTE]

They are recyclable. Here is an interesting link comparing paper and plastic. link

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Don Atwood
Arlington, VA

Thanks for the tip Dale, I applied a couple of coats tonight thinning it down and it seems to have worked much better. I agree, spray is the right way to go but need to build some ventalation in my workshop and no time right now.

Another tip is to warm up the KTM as well as the surface the KTM will flow much better and forms fewer bubbles. Maybe with both thinning and warming it will work well.

[QUOTE=jwsamuel]

How cold of temperatures can you spray in?

Jim [/QUOTE]

I haven't tried to spray when it was real cold, probably about -10 C at coldest. I have had to thin a bit more to get the viscosity (sp?) right but not problems other than that. One advantage is that the air is really clean, no bugs in the winter! Like I said, I don't take them in until they gas off a bit which means they will be hanging in the garage (with not temperature of humidity control) for a couple of weeks. I know some people like to bing them inside as soon as possible, I haven't really seen a good reason to do so.   

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Rian Gitar og Mandolin

[QUOTE=laurent] I
am still afraid to amalganate oil in the finish. /QUOTE]

No need for fear. Extra virgin olive oil or walnut oil is much lighter viscosity than the shellac, and will always rise to the surface when shellac is FP applied. after many, many pieces of furnisher and 18 guitars I can safely say It will not get trapped in the shellac

Another thing to consider here is that when lightly ragged on shellac could bridge on you, leaving a consealed micro-air pockets that will later collapse and become a recess. When padded with some elbow grease, as in French polishing, the shellac will become one continious film with no chance of bridging. This bridging affect is the reason shellac on its own is not a good chooice for a pore filler.MichaelP38656.3902777778

[QUOTE=rich altieri] We always hear of good results with KTM-9. I have not been as successful with it so here is my questions.

I brush it on right out of the can and have tried flowing it on with heavy coats, have tried putting on thinner coats and always problems with air bubbles not flowing out. If you apply even a little on the heavy side it runs ever so slightly.

I sand in between coats with 400 grit to keep knocking down the bubbles and runs, and then next coat - same result.

I have sprayed it and that does work better but would prefer to brush if I could due to shop conditions.

So for you guys with all the success - are you brushing it on, and if so - how the heck do you do it without the bubbles and runs?

BTW - if you do spray this stuff, heed the advise of all of those comments before me. Just get some overspray on your wrist and hands and you will understand how thick this stuff really is an how it could clog those pores in your lungs for a long long time.[/QUOTE]

I have some that disagree with me here but this has been my experience.

Foam brushes run a risk of introduction of air bubbles due to the cells in the foam. This, bubbles in the can or to much pressure during your stoke are the likly reasons for bubbles.

If I brush on any lacquer finish I always use high end China bristle brushes. They are expensive, about $20 each but worth it. I use 4 for a guitar to allow drying time after cleaning the brush. They also requiire a bit of prep to eliminate loose hairs. Poly brushes will create big issues with flow. China bristle brushes allow the lacquer to flow evenly.

The process is not at all like painting. It requires a very deft touch and a properly loaded brush. Learning to flow on and off the piece with out drips and the proper stroke weight on the brush, which is not much by the way. You want the finish to flow out of the brush at a very even rate. To do this takes some practice. Any attempt to back brush will cause problems. The over lap on strokes should be minimal and prior to the previous strokes film starting to skim, which is only a few seconds after being laid down.

In Tradition and Technology under the finishing chapter there is a brief but good description of brushing lacquer, the same technique would be used with KTM9.

Getting the proper load on the brush and the proper lay down technique is the key to no drip. Even then it is hard not to drip a little at the edges. So I do the top, wipe up any drips, allow to set, then side, wipe up any drips and allow to set, back, wipe up drips then allow to set then the other side. That way I can wipe up drips as I go.

MichaelP38656.4441435185

I will second what Michael says about brushing KTM-9. The trick seems to be in the brush-stroke. I found that if I try to "paint" the stuff on I get all sorts of problems - bubbles, runs, etc. If you kind of drag the brush across the surface and pay attention to the amount of overlap between strokes, you can get a real nice fininsh. You can use a foam brush if you are careful, but I would get a nice bristle brush like he says.

The biggest plus for me is the ability to apply the finish in the house. My shop is in my garage so there is no way to avoid having a lot of dust flying around. I use the guest bath as my finishing room - much cleaner than the garage.

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53% of all statistics are made up on the spot
http://driftwoodguitars.blogspot.com/

[QUOTE=MichaelP] This bridging affect is the reason shellac on its own is
not a good chooice for a pore filler. [/QUOTE]

Thanks for the tips Michael, I use the StewMac water-based grain filler to fill
the pores, sand it and then apply the shellac. I know that traditional FP
classical guitar makers use pumice and shellac as a grain filler, is that what
you use? It seems a harder technique to master than even FP, what do you
recommend as a pore-filling technique?

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

[QUOTE=laurent] [QUOTE=MichaelP] This bridging affect is the reason shellac on its own is
not a good chooice for a pore filler. [/QUOTE]

Thanks for the tips Michael, I use the StewMac water-based grain filler to fill
the pores, sand it and then apply the shellac. I know that traditional FP
classical guitar makers use pumice and shellac as a grain filler, is that what
you use? It seems a harder technique to master than even FP, what do you
recommend as a pore-filling technique?[/QUOTE]

I use to use pumice on FP but now I use Zpoxy Finishinig Resin on almost every thing. I highly recommend it. With some there is consern over shellac adhering well to epoxy. the trouble is with epoxy adhering to shellac. If you use an epoxy filler do not wet the boards with shellac to examin the wood color prior to filling. If you do be sure to sand back to wood everywhere. You do not want shellac under the epoxy. Other than that it is the simplest fill you can do.

The key to pumice filling is not to use hardly any shellac. That is where most make their mistake. Just a very little residual in the inner pad is all you need. Just enough to be a binder for the fibers that the pumice drags into the pores. As the Milburns say in their tutorial, "the best thing that can happen while pumice filling is that you misplace your shellac till your through filling" MichaelP38657.4813078704

[QUOTE=WayneC] I will second what Michael says about brushing KTM-9. The trick seems to be in the brush-stroke. I found that if I try to "paint" the stuff on I get all sorts of problems - bubbles, runs, etc. If you kind of drag the brush across the surface and pay attention to the amount of overlap between strokes, you can get a real nice fininsh. You can use a foam brush if you are careful, but I would get a nice bristle brush like he says.

The biggest plus for me is the ability to apply the finish in the house. My shop is in my garage so there is no way to avoid having a lot of dust flying around. I use the guest bath as my finishing room - much cleaner than the garage.[/QUOTE]

Wayne I know what you mean when you said drag, however to me drag implies a bit of friction or down pressure.

A better term to explain the stroke,I think, would be float the brush across the surface. The brush contact is just to release the media on to the surface.

The bristles should almost be suspended by the surface tension of the finish as it flows out of the brush. To do this requires almost no pressure applied to the brush bristles. To do this the handle of the brush will always lead the stroke in a pulling motion.

Don. The Orriginal Blue bags they were using in Nova Scotia were not Recyclible or biodegradable, I don't know why not but they wer'nt, That what caused the big huff. They quicly changed to ones that were. At the same time, Halifax Nova Scotia does have the best Recycling/Composting program in North america. With something like 90% of the wast diverted from Land fills it is amazing.

I have a question about the steel string guitar being French polished. Is it prone to flatpick scratch easily in case there's no pickguard? Thanks.

[QUOTE=ParamesB] I have a question about the steel string guitar being French polished. Is it prone to flatpick scratch easily in case there's no pickguard? Thanks. [/QUOTE]

Yes you will get pick scratches, Case scratches? not sure why. But even so that is the beauty of French polish. you can easily repair scratches and other finsh damage.

I think this may be one of the reasons why French polish is not widely accepted on steel string at least by the flatpickers but it shouldn't do anything wrong for the fingerstylers.

How do you guys see the trend of FP on steel string? Has it been increasingly asked for by fingerstylers or other non-flatpickers?

Thank you.    

More and more players that really know the how the guitar works are asking me about my hybrid lacquer-French polish option . The back, sides, and neck KTM9 or nitro and top French polished.

I find that player who know and understand French polish finishes don't have issues with the fact the it is a bit softer. It is so easy to recondition and probably sonically the best finish.

[QUOTE=ParamesB] I have a question about the steel string guitar being
French polished. Is it prone to flatpick scratch easily in case there's no
pickguard? Thanks. [/QUOTE]

I just finished work on a 1928 Martin 0-18K, not sure if FP, but definitely
finished with shellac. One side was smashed and the guitar suffered I
would say recent abuse by a nervous flatpicker. I do not see much
difference with lacquer in terms of endurance, nice thumb mark on the
neck at the 1st fret and yes, some pick marks around the rosette plus a
couple of nice deep scratches on the back, but nothing worse than most
'70 Martins for instance. All the blemishes diseapeared with some shellac
rubbing and buffing, I left the thumb mark though, it belongs there. This
guitar has nicely survived almost 80 years with its shellac finish mostly in
very good shape, that is except the side that I just rebuild and shellac-ed
(supposedly the guy put his foot through there…).

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/