Finishing

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benldwyer
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Finishing

Post by benldwyer » Mon Mar 05, 2018 2:02 pm

Hi Everyone,
I don't have any experience with finishing, the first couple of guitars I have built were finished by Gilet many years ago. Having resumed building I am now ready to finish a couple of guitars and would like to learn myself, so I have been doing a little research. I'm was interested in the non-toxic water based finishes but I noticed people stopped talking about them around 2012, is this the case? Are water based products still used? What other methods would people recommend other than french polish and true oil?
Appreciate any advice or links to good reading.
Cheers,
Ben

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Steve.Toscano
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Re: Finishing

Post by Steve.Toscano » Mon Mar 05, 2018 6:58 pm

For an easy to apply nitro finish ive had good success with both the Wurth and Mohawk rattle cans. Not exactly non toxic, still need the usual respirator protection. I do mine outside.
With some practise you can get a very professional finis with these.

Sorry i dont have any experience with water based finishes.

benldwyer
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Re: Finishing

Post by benldwyer » Mon Mar 05, 2018 9:38 pm

Thanks Steve, I will put these on my list to research.

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Mark McLean
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Re: Finishing

Post by Mark McLean » Tue Mar 06, 2018 6:05 am

Hi Ben
When you start a conversation about finishing it can go in so many different directions. I think the first thing that you need to think about is the look (and feel) that you are aiming for. And are you making these instruments for yourself (and loved ones), or for sale? If you want to make something that looks like it might have come from a factory you are going down the road of pore-filling followed by a sprayed lacquer or polyurethane finish which is then carefully leveled and buffed to get a smooth glossy finish. Bob Taylor said something like: "A long time ago, some guy figured out that if you keep spraying and sanding a guitar, you can make it really shiny. We need to exhume that guy and shoot him!" But in this day and age most guitar buyers think that an instrument should have a finish that looks like a pane of glass, and most guitar builders keep delivering that product. Of course, it is not really necessary, and it is probably acoustically bad. Other instrument makers and players don't have this fixation. When did you ever see a violin or a cello with a nitro finish? Personally, I actually like a guitar with a finish that doesn't get between you and the real wood. I think that a hand-applied oil or shellac finish with open pores, or minimal pore filling, is beautiful. Also easier, more repairable and more ecologically friendly. Recently I have settled on "Hard Wax Oil", which is probably similar to Tru-Oil. But, if I was trying to make a living selling my guitars I would go broke because that is not what the market wants. You will need to decide the route you want to follow. And if you want the professional look you can always out source the job, as you did before with Gerard.

There are lots of old threads on this forum which will help you with finishing questions (some of what I said above is a cut-and-paste from a bit of a rant in a discussion from 2009 on pore-filling with epoxy). There is some great expertise among the regular contributors here. Look back through the archives (especially for the early tutes by Allen McFarlen - a professional panel beater and spray painter turned ukelele builder extrordinare; whose finishes are the gold standard IMHO).
cheers
Mark

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Allen
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Re: Finishing

Post by Allen » Tue Mar 06, 2018 7:39 am

First up decide if you are wanting a pore filled finish, or an open one.

If pore filled then start your research on the type of pore filling that you want to go with. Note that this is a labour intensive process, and if you are wanting that mirror like finish this step is critical to get right before proceeding to applying the finish. This is where most builders fail, being far too impatient.

For the finish itself you then need to decide what is appropriate for your skill set, equipment and finally your shop conditions. Brush or wipe on is pretty easy, and you can build up a finish that can then be levelled with light sanding if required and buffed or waxed. Shellac can be brushed on to get a reasonable build. Lightly leveled and then application by a pad will give very good results. Time consuming but if you aren't making a living at it then it doesn't matter.

Spraying no matter what you are using as product or method from rattle cans to HVLP takes some skill. Probably the easiest for someone to learn is a nitro based product. Reasonably forgiving of less than perfect technique. They take many weeks if not months to harden and dry out for level sanding and buffing if that's your plan. The nature of lacquer is that it continues to gas off and shrink for it's life span of approximately 75 years.

2K finishes like polyurehtane and polyester take a great deal of skilll to apply and really are not for a first time user. Their advantages are very quick cure with high abrasion and chemical resistance.

As for water based finishes, people seem to think that they are non toxic, but this is a complete myth. What has been driving the move to water based products in not the toxicity of solvent based ones but the mandated reduction of VOC's. However the other additives especially in the high performance ones like automotive finishes are extremely toxic. I wouldn't touch them with a barge pole.
Allen R. McFarlen
https://www.brguitars.com
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Cairns, Australia

benldwyer
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Re: Finishing

Post by benldwyer » Tue Mar 06, 2018 10:25 am

Thank you both Mark and Allen for your thorough replies, I have read some of Allen's posts but I will go back and read them all, cheers.
I would like to sell a few instruments if I can down the track so I guess I'll take the hard route.. I have read about the colortone grain filler and this seems straight forward (if it works OK?), following this I think I might try a few different things ie. French polish, nitro cans (seem expensive), then buy a spray set up.
Thanks for the insight into water based, seems theres a lot of conflicting views out there.
Thanks again!
Ben

simso
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Re: Finishing

Post by simso » Tue Mar 06, 2018 11:02 am

I build electric guitar kits for a local music store, which they then do a building course from.

As no one really has the spray gear when building their first guitar we encourage them to use a rub on poly, the poly can make the wood look ala natural or with lots of coats and steel wool between give a mirror finish.

The beauty with the rub on, it does not leave streaks, scratches or anything, its newbie friendly

Thats my recommendation, that being said nitro/2 pack/acrylic/Ultra Violet/Enamel/shellac are all good but nitro is as per above comments, is the most forgiving

Steve
Steve
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Do your own repairs - http://www.mirwa.com.au/How_to_Series.html

benldwyer
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Re: Finishing

Post by benldwyer » Tue Mar 06, 2018 11:47 am

Cheers Steve, so I would guess that these rub on/brush on finishes are not as good as spray on, is that just because of the thickness of the finish, a time thing or inferior final aesthetics?

simso
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Re: Finishing

Post by simso » Tue Mar 06, 2018 1:06 pm

When you spray a coat of lacquer you are applying approx .1mm paint at a time, when you rub on you are applying .02 of a mm at a time, so 5 rub on coats equal around one spray on coat, 20 rub on coats = 3-4 normal coats which is whats generally applied to guitars.

3 spray on coats can be done in 30 minutes, 20 rub on coats are done in 20 days.

Painting however requires you to sand and buff the final finish, rub on does not.

Steve
Steve
Master of nothing,

Do your own repairs - http://www.mirwa.com.au/How_to_Series.html

benldwyer
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Re: Finishing

Post by benldwyer » Tue Mar 06, 2018 2:15 pm

Ahhh 20 days, that is a little excessive...
Thanks again Steve

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kiwigeo
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Re: Finishing

Post by kiwigeo » Tue Mar 06, 2018 3:32 pm

I like hard labour and doing things that people tell me I can't do.....so it's French Polish for me om all my builds.
Martin

yakka
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Re: Finishing

Post by yakka » Thu Mar 15, 2018 3:34 pm

hi there
i have used the hard shellac/acetone as described by Gilet/Gore in their Manuals and after a couple of goes have found it very quick and gives a great finish, i did not pore finish but it is all covered in depth in their books.
And no previous experience
regards
Chris

Crafty Fox
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Re: Finishing

Post by Crafty Fox » Fri Mar 23, 2018 11:28 pm

I've found the Stewart MacDonald book "Guitar Finishing Step-By-Step" to be very helpful.
Ken

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