jaycee Posted November 20, 2006 Report Share Posted November 20, 2006 On my plans for a 12 string it recommends 2-3 mm thick sides ( = 0.098 inch which is 2.5mm) whats the thinnest that you guys reccommend Quote Link to comment Share on other sites More sharing options...
fryovanni Posted November 20, 2006 Report Share Posted November 20, 2006 On my plans for a 12 string it recommends 2-3 mm thick sides ( = 0.098 inch which is 2.5mm) whats the thinnest that you guys reccommend Depends a lot on the wood. My rule of thumb is to thickness sand it till I feel the flex I want. On dense woods that tends to be closer to .075" on less dense woods closer to .090". There is a drastic change in the flexability between .10" and the point it starts to give. I take it down about .003" per. pass until it gives. I would not go thinner than .07" as a general rule with any wood. Peace,Rich Quote Link to comment Share on other sites More sharing options...
Acousticraft Posted November 20, 2006 Report Share Posted November 20, 2006 I think 2.5mm is certainly easier to bend than 3mm especially if it has a tight curve for a cutaway. I dont think I would go any thinner than 2.5 as the guitar looses to much stiffness. Quote Link to comment Share on other sites More sharing options...
fryovanni Posted November 21, 2006 Report Share Posted November 21, 2006 I dont think I would go any thinner than 2.5 as the guitar looses to much stiffness. Is that just a total guess on your part? Peace,Rich Quote Link to comment Share on other sites More sharing options...
Mattia Posted November 21, 2006 Report Share Posted November 21, 2006 2.5mm? Hell no. Too thick. I shoot for between 2.2 (about .085") and 2.0mm (about 0.80) for regular sides, down to even 1.8-1.9mm (.070"-.075") for tighter bends, or for denser woods (say Cocobolo, Ebony). Backs are a little thicker, maybe 2.5mm normally, down to 2.2mm for (again) dense woods. The stiffness you get out of a side comes from its shape far more than its thickness, and I add side bracing to the weaker (flat) areas anyway. 1.8 to 2.0mm is about standard for a classical guitar, and those sides are plenty stiff enough. Quote Link to comment Share on other sites More sharing options...
jaycee Posted November 21, 2006 Author Report Share Posted November 21, 2006 OK thanks guys. So I will decide the thickness on the sides when I know what wood I am using Quote Link to comment Share on other sites More sharing options...
GoodWood Posted November 23, 2006 Report Share Posted November 23, 2006 How do you convert between thicknesses. My thickness gauge is standard hundredths? So thickness for tops is recomended say 7/16 s, but it says around 3.5 on the dial? How do you convert? Thanks Quote Link to comment Share on other sites More sharing options...
fryovanni Posted November 23, 2006 Report Share Posted November 23, 2006 How do you convert between thicknesses. My thickness gauge is standard hundredths? So thickness for tops is recomended say 7/16 s, but it says around 3.5 on the dial? How do you convert? Thanks I don't exactly understand your readings. Your thickness gauge measures in fractions of an inch(1/8"=.125"), or decimal units of an inch(.125"=1/8"). Or are you reading MM units in decimal units to the hundredth of a MM? If you need to convert decimal units mm to inches. Do a search for unit converters. If you need to convert fractional units of an inch to decimal just divide (1/8"=1 divided by 8=.125). Hope that helps Quote Link to comment Share on other sites More sharing options...
GoodWood Posted November 23, 2006 Report Share Posted November 23, 2006 Ok, they thicknessed my tops too thick I think. Said he was real close but after an hour of sanding 150 grit and scraping its not much closer to 1/8". If your thickness sanding with the machine, what is the best thickness for them to shoot for for Spuce tops, and Mahogany sides? I imagine Rosewood is really tough to sand and scrape to final. I'm thinking about a small orbital sander at this point. Learning curves, grrrrrrrrrrr Quote Link to comment Share on other sites More sharing options...
fryovanni Posted November 23, 2006 Report Share Posted November 23, 2006 Ok, they thicknessed my tops too thick I think. Said he was real close but after an hour of sanding 150 grit and scraping its not much closer to 1/8". If your thickness sanding with the machine, what is the best thickness for them to shoot for for Spuce tops, and Mahogany sides? I imagine Rosewood is really tough to sand and scrape to final. I'm thinking about a small orbital sander at this point. Learning curves, grrrrrrrrrrr The soundboard thickness will vary depending on how stiff it is and the size/design of guitar. I use some pretty stiff Alaskan Sitka. I generally wind up between .095" and .085" depending on the guitar. I would recommend you either use a well tuned plane, or have it done with a thickness sander. You will likely not have good relults with a hand held sander. This is a critical part of building acoustics don't accept anything less than a very well done job. Most of the time unjoined soundboards or backs are left thicker when you buy them to allow for easier joining and final adjusting. Good luck with it. Peace,Rich Quote Link to comment Share on other sites More sharing options...
Mattia Posted November 23, 2006 Report Share Posted November 23, 2006 Ok, they thicknessed my tops too thick I think. Said he was real close but after an hour of sanding 150 grit and scraping its not much closer to 1/8". If your thickness sanding with the machine, what is the best thickness for them to shoot for for Spuce tops, and Mahogany sides? I imagine Rosewood is really tough to sand and scrape to final. I'm thinking about a small orbital sander at this point. Learning curves, grrrrrrrrrrr The soundboard thickness will vary depending on how stiff it is and the size/design of guitar. I use some pretty stiff Alaskan Sitka. I generally wind up between .095" and .085" depending on the guitar. I would recommend you either use a well tuned plane, or have it done with a thickness sander. You will likely not have good relults with a hand held sander. This is a critical part of building acoustics don't accept anything less than a very well done job. Most of the time unjoined soundboards or backs are left thicker when you buy them to allow for easier joining and final adjusting. Good luck with it. Peace,Rich Agreed. Also, hand-planing well-quartered spruce is a joy to do, IMO, and it's not that hard to tune up a handplane to do the job. Quote Link to comment Share on other sites More sharing options...
GoodWood Posted November 23, 2006 Report Share Posted November 23, 2006 (edited) I decided against hand planing and went with thickness sanding for simplicity sake. Im using lower end Carpathian Spruce. The rings are wider at the ends (about 12 per inch) than at the center (about 20 per inch) I think I want 1/8" thickness, and then handsand and scrape it a bit to final and get the first one done. That was supposed to be done, but comparing to a 1/8 inch drill bit, its still too thick. I will try handplaning in the future for sure. I dont want to mess around with my first tops (and sides ) though. I jsut need a number to tell the sanding guy, as this number he used didnt work. Cumliano reccoments 1/8 inch for beginners. Then you sand and scrape it alittle, as now I know you just smooth it out. To reiterate: Should I just have them thickness to 1/8 inch on 120 grit, and then scrape it down smooth in a few swipes? We left it a bit fat, and handsanding, scraping is not moving it. Thanks Edited November 23, 2006 by GoodWood Quote Link to comment Share on other sites More sharing options...
fryovanni Posted November 24, 2006 Report Share Posted November 24, 2006 I decided against hand planing and went with thickness sanding for simplicity sake. Im using lower end Carpathian Spruce. The rings are wider at the ends (about 12 per inch) than at the center (about 20 per inch) I think I want 1/8" thickness, and then handsand and scrape it a bit to final and get the first one done. That was supposed to be done, but comparing to a 1/8 inch drill bit, its still too thick. I will try handplaning in the future for sure. I dont want to mess around with my first tops (and sides ) though. I jsut need a number to tell the sanding guy, as this number he used didnt work. Cumliano reccoments 1/8 inch for beginners. Then you sand and scrape it alittle, as now I know you just smooth it out. To reiterate: Should I just have them thickness to 1/8 inch on 120 grit, and then scrape it down smooth in a few swipes? We left it a bit fat, and handsanding, scraping is not moving it. Thanks I am not sure how far along you are, but I would suggest this. With acoustics you need to build with a high degree of accuracy. Tuning tools, making jigs, and the use of good measuring tools is a must. You can build an acoustic going a little heavy on the components(to play it safe because you can't control the build). It goes againgst the most basic concepts in building acoustics. Which is to build light and efficient. Down the road these things will become appearant. Taking the time to make the tools and jigs you need now. Will also make the building much more rewarding. Peace,Rich Quote Link to comment Share on other sites More sharing options...
GoodWood Posted November 24, 2006 Report Share Posted November 24, 2006 Oh I know, every time I turn the page, its another $100.00 bucks!! $#@@@!! Im just working through the basic knowlege here, because I didnt have it when I thicknessed my tops, which ended up too thick, going by the book, Kinkeads measurements I think. I have bad hypothyroidism, and I have very limited energy to work each day. This top wore me out. I just didnt understand how to read the dial gauge properly, now I understand it, thanks. Quote Link to comment Share on other sites More sharing options...
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