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| Author: | Steve_E [ Mon Aug 06, 2012 10:23 am ] |
| Post subject: | Guitar Finishing course |
I'm spraying my final coats of Cardinal Nitro this week in preperation for the long wait for final leveling and buffing. Just like in building, I had no prior finishing experience, however when building, if I mess something up, I could always start over and make a new component (like the 2 necks I made on my first guitar). I understand the logistical difficulty of offering a training course for guitar finishing; need a completed guitar, the long wait times, etc., but I could sure use some help. Courses that would be beneficial: * proper pore-fill technique (both past and epoxy) * proper sanding/leveling technique * proper drop fill * proper coverage * proper final sand/level * proper buffing and different methods In other words - how to finish. I have watched quite a few on-line tuts, but there is nothing like being able to see, ask questions, and have experienced hands guide you through the process. Needless to say, I'm not thrilled with my latest effort and would love to get some insight on how some of you have addressed some of the above in your own experience. Steve |
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| Author: | Tai Fu [ Mon Aug 06, 2012 11:01 am ] |
| Post subject: | Re: Guitar Finishing course |
Robbie O Brien's video is pretty helpful for most of the steps in the process. You can borrow or buy his video courses if you need more than what LMI has for free... It's not difficult and the key is patience and not taking short cuts. I personally don't use epoxy though because its relatively hazardous, and very difficult to sand. For big grains I use a paste filler colored to match or contrast the wood (like swamp ash). Just keep trying, its not like pyrotechnics where a short cut could mean a trip to the emergency room or worse... |
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| Author: | Mattia Valente [ Tue Aug 07, 2012 8:00 am ] |
| Post subject: | Re: Guitar Finishing course |
Patience and making sure the guitar is PERFECT between steps - no scratches from previous grit, properly leveled where appropriate, and so on - are key. Like Tai Fu says, the Robbie O'Brien DVD is pretty comprehensive, although there's a lot available on YouTube that will help you out. I'll disagree strongly on the 'epoxy is difficult to sand' front, though. Z-Poxy finishing resin sands very easily and does not clog my papers much at all. As for 'proper' ways to do things, there are a lot of variations depending on shooting conditions, equipment, materials used and experience. My personal 'schedule' goes something like this: - Sand to 220 or 320 grit (with the grain), making sure all imperfections are gone. I use stiff cork blocks or chunks of eraser as sanding blocks. - Pore will with Z-Poxy (Todd Stock's YouTube videos are very comprehensive and all you should need) - Spray finish (how many coats, pressures, tip sizes, thinning depends on too many factors to list in a 'short' way), laying down just 'wet' coats for Nitro - Drop fill and level sand at the start of day 3 (after 6 coats), P800 wet-or-dry (lower if orange peel, but no less than P600). Basically shoot for a dull, matte surface, but don't worry if it's not totally perfect at this point. Don't sand through! - Drop fill again if needed. - Shoot 3 more coats (1 day) - Level sand (P1200 if it's level enough, otherwise P800. Should be perfectly smooth now. - Shoot 1-2 light final coats - Straight to power buffing I will say finishing remains by far my LEAST favorite part of building. Love the results, really don't like the process. But farming it out is not cost-effective for me (would double the cost of many of my instruments). |
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| Author: | Rod True [ Tue Aug 07, 2012 12:47 pm ] |
| Post subject: | Re: Guitar Finishing course |
After a quick google map check, I know it's a long way but you're about 2 hours from Santa Cruz where Addam Stark is. Maybe you could look him up (Facebook page info https://www.facebook.com/pages/Addam-St ... 28?sk=info ) and see if you could spend a day there learning a few things.... |
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| Author: | Steve_E [ Tue Aug 07, 2012 1:42 pm ] |
| Post subject: | Re: Guitar Finishing course |
Thanks for the replies everyone. I know it's mostly just experience and learning to get a "feel" for what is right. I'll post pictures of this build when it's done in a few weeks. Steve |
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| Author: | Otterhound [ Wed Aug 08, 2012 6:30 am ] |
| Post subject: | Re: Guitar Finishing course |
Steve_E wrote: Thanks for the replies everyone. I know it's mostly just experience and learning to get a "feel" for what is right. I'll post pictures of this build when it's done in a few weeks. Steve Please don't sand past 180 on the initial sanding ( raw wood ) as this is not necessary and is even detrimental to the mechanical bond with nitro processes . |
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| Author: | Barry Daniels [ Wed Aug 08, 2012 9:23 am ] |
| Post subject: | Re: Guitar Finishing course |
Otterhound wrote: Please don't sand past 180 on the initial sanding ( raw wood ) as this is not necessary and is even detrimental to the mechanical bond with nitro processes . I can't agree with that. I can see 180 grit sanding scratches under finish on many woods. 220 is better and sometimes even 320 is required. And a properly applied finish should have no problem bonding with a 220 or 320 grit sanded surface. |
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| Author: | B. Howard [ Wed Aug 08, 2012 3:33 pm ] |
| Post subject: | Re: Guitar Finishing course |
180 grit has been an industry standard for prep sanding white wood for finish since I started building cabinets 30 years ago. With their modern high solids coatings most manufacturers are now recommending to white out at 150 to avoid delaminations. The only finish I white out at 220 is for shellac because it has better grip and is thinner material. I prep everything else at 180 and see no sanding marks under my finishes. If you are seeing scratches under your finish at 180 then your technique may need improvement. Also I am considering doing some hands on French Polish workshops in the future and was wondering what if any interest folks might have in something like that. |
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| Author: | parrotheadmj [ Wed Aug 08, 2012 7:19 pm ] |
| Post subject: | Re: Guitar Finishing course |
I'm in for French Polish. Please coach me up on that. Marc |
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| Author: | Otterhound [ Wed Aug 08, 2012 7:40 pm ] |
| Post subject: | Re: Guitar Finishing course |
My info/instruction comes from Dale Bartholomew . He is retired from Martin and did run the finishing department there for a number of years . I consider him to be an authority and have seen him work . He knows nitro and finishing in general with it . |
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| Author: | Otterhound [ Wed Aug 08, 2012 7:43 pm ] |
| Post subject: | Re: Guitar Finishing course |
B. Howard wrote: 180 grit has been an industry standard for prep sanding white wood for finish since I started building cabinets 30 years ago. With their modern high solids coatings most manufacturers are now recommending to white out at 150 to avoid delaminations. The only finish I white out at 220 is for shellac because it has better grip and is thinner material. I prep everything else at 180 and see no sanding marks under my finishes. If you are seeing scratches under your finish at 180 then your technique may need improvement. Also I am considering doing some hands on French Polish workshops in the future and was wondering what if any interest folks might have in something like that. I am and am only 20 minutes from you , but you already knew that . |
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| Author: | Ben Pak [ Wed Aug 08, 2012 8:50 pm ] |
| Post subject: | Re: Guitar Finishing course |
Count me in on a french polish class. I'm only a couple hours away (well worth it). |
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| Author: | Robbie O'Brien [ Thu Aug 09, 2012 10:17 am ] |
| Post subject: | Re: Guitar Finishing course |
Finishing is just as difficult if not more difficult than actually building the guitar. I have put together some online courses on my website for both French polish and spraying lacquer. Perhaps you will find them useful. Happy Finishing! http://www.obrienguitars.com/courses/ |
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| Author: | Tai Fu [ Thu Aug 09, 2012 10:42 am ] |
| Post subject: | Re: Guitar Finishing course |
Robbie O'Brien wrote: Finishing is just as difficult if not more difficult than actually building the guitar. I have put together some online courses on my website for both French polish and spraying lacquer. Perhaps you will find them useful. Happy Finishing! http://www.obrienguitars.com/courses/ Finish repair is again more difficult than (re)finishing a guitar too. |
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| Author: | Clay S. [ Sat Aug 11, 2012 11:57 am ] |
| Post subject: | Re: Guitar Finishing course |
You will find a lot of different opinions on how fine to sand bare wood. It depends somewhat on the tools you use and the type (and brand) of sandpaper. Some random orbital sanders manage to leave "swirl" marks even at 180 grit. And some sandpapers are poorly graded and 180 grit will have a few 80 grits thrown in for not so good measure. I try to use a good quality sandpaper and take things to 180 cami grit. Sometimes I see areas I'm not happy with and hand sand to 220. Micron papers offer the advantage of having more uniformly sized particles and can give better results, but cost a fair bit more. They may be worth the extra expense when level sanding the finish. When buying sandpaper note whether it is cami or "P" grit. They use a different grading scale so you need to know how they compare when going from one system to the other. |
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| Author: | Mattia Valente [ Mon Aug 13, 2012 8:18 am ] |
| Post subject: | Re: Guitar Finishing course |
Clay S. wrote: You will find a lot of different opinions on how fine to sand bare wood. It depends somewhat on the tools you use and the type (and brand) of sandpaper. Some random orbital sanders manage to leave "swirl" marks even at 180 grit. And some sandpapers are poorly graded and 180 grit will have a few 80 grits thrown in for not so good measure. I try to use a good quality sandpaper and take things to 180 cami grit. Sometimes I see areas I'm not happy with and hand sand to 220. Micron papers offer the advantage of having more uniformly sized particles and can give better results, but cost a fair bit more. They may be worth the extra expense when level sanding the finish. When buying sandpaper note whether it is cami or "P" grit. They use a different grading scale so you need to know how they compare when going from one system to the other. CAMI and P/ISO grade 180 and 220 are the same thing. Does not apply to the full spectrum, though. |
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