Search found 195 matches

by Craig Bumgarner
Thu Jun 01, 2017 4:53 am
Forum: Instrument Builders Forum
Topic: Picking a Drum Sander
Replies: 18
Views: 22709

Re: Picking a Drum Sander

My homebuilt works well. I used this web page as a guide: http://www.krtwood.com/ww/sander2/index.html The only substantial change I made is to use spiral velcro and velcro sand paper instead of the slot and wedge concept in the article. It was pretty easy to build, certainly easier than coming up w...
by Craig Bumgarner
Tue May 23, 2017 6:49 am
Forum: Instrument Builders Forum
Topic: Forum Software Update
Replies: 14
Views: 20598

Re: Forum Software Update

I got rid of the drop down (up?) menus by logging out, logging in and then forcing a new load of the page with the shift key and clicking the reload icon (Chrome). I think the shift key works that way in other browsers, Mozilla for sure. Clearing history would do the same thing, but gets rid of a lo...
by Craig Bumgarner
Fri May 05, 2017 10:11 pm
Forum: Instrument Builders Forum
Topic: Modal Tuning in Denver
Replies: 8
Views: 10302

Re: Modal Tuning in Denver

Trevor Gore wrote:.... It's pretty clear that there is a lot of demand though, which augers well for more classes in the future.
I'd probably go to your class most anywhere in the US 48 states, so please put me on your list of those interested if you have such a thing. Thanks!
by Craig Bumgarner
Wed May 03, 2017 5:45 am
Forum: Instrument Builders Forum
Topic: Modal Tuning in Denver
Replies: 8
Views: 10302

Re: Modal Tuning in Denver

Man, how did I miss that was happening? Dang it!
by Craig Bumgarner
Mon Apr 03, 2017 11:19 pm
Forum: Instrument Builders Forum
Topic: Advice on fixing edge chips in top and back
Replies: 6
Views: 8203

Re: Advice on fixing edge chips in top and back

... then fill with clear CA.

Or, drop fill with nitro, multiple times. Nitro is very clear.
by Craig Bumgarner
Mon Apr 03, 2017 10:32 pm
Forum: Instrument Builders Forum
Topic: Advice on fixing edge chips in top and back
Replies: 6
Views: 8203

Re: Advice on fixing edge chips in top and back

Beautiful mandolin. A burst is a good idea, certainly in character for this one. If you are committed to a clear finish, you can at least try to blend pieces into the chips. Hopefully you have some of the same wood left (I save my cutoffs until the instrument is done and gone for just this kind of t...
by Craig Bumgarner
Tue Mar 28, 2017 12:00 am
Forum: Instrument Builders Forum
Topic: Adjusting sound
Replies: 38
Views: 33615

Re: Adjusting sound

FWIIW, I use the default settings on the settings page. On the main display, I use No Smoothing on the smoothing options in the lower left corner and Peak Hold in the lower right. I have not utilized the many custom options because 1) FFT seems to work fine with the defaults and 2) I'm lazy. Don't l...
by Craig Bumgarner
Sat Mar 25, 2017 1:07 am
Forum: Instrument Builders Forum
Topic: Jigs - Are they worth it?
Replies: 11
Views: 14917

Re: Jigs - Are they worth it?

Some jigs are very worthwhile, others no so much. I'm sure we all have a collection of jigs we once used, but no longer because somehow the task is better done without the jig. No way to know how it is going to fall out most of the time, so jigs get made and some are used, others are not. Patterns f...
by Craig Bumgarner
Thu Mar 16, 2017 12:44 am
Forum: Instrument Builders Forum
Topic: Adjusting sound
Replies: 38
Views: 33615

Re: Adjusting sound

....it's a buzz that sounds like a fret problem that is heard on top two strings whether open or fretted, there is no fret issue as I have already looked into this replacing both saddle and nut with plenty of clearance. If the problem exists on the open B and E strings and every fret all the way up...
by Craig Bumgarner
Wed Mar 15, 2017 11:31 pm
Forum: Instrument Builders Forum
Topic: Adjusting sound
Replies: 38
Views: 33615

Re: Adjusting sound

I'm not real good at looking at other builders Frequency Response Curves (FRC) because there is a fair amount of information picked in recording the curves that helps interpret. A couple things though. The big peak at 94hz seems too low to be T(1,1)2. More likely T(1,1)1, the air resonance. Are you ...
by Craig Bumgarner
Wed Mar 15, 2017 12:34 am
Forum: Instrument Builders Forum
Topic: Adjusting sound
Replies: 38
Views: 33615

Re: Adjusting sound

I used Visual Analyzer at first but switched to the FFT app by Andrew Smith a couple years. It is about $10. As far as I know, it works only on Apple iOS, iPhone and iPad. VA is kind of quirky to set up and use. FFT by Andrew Smith requires minimal set up, very intuitive to use, saves files for futu...
by Craig Bumgarner
Tue Mar 14, 2017 1:09 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Implications of back resonance lower than top
Replies: 2
Views: 5673

Re: Implications of back resonance lower than top

Thanks for the insights Trevor, will read up on 2.3-11.
by Craig Bumgarner
Sat Mar 11, 2017 1:12 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Implications of back resonance lower than top
Replies: 2
Views: 5673

Implications of back resonance lower than top

I keep running into Selmer style guitars with soft backs with low monopole peak resonance (T(1,1)3. So low, they are below the top monopole peak, T(1,1)2. I don't think it is intended other than it makes the guitars lighter and light weigh is revered though the reasoning is not scientific that I kno...
by Craig Bumgarner
Thu Mar 09, 2017 1:33 am
Forum: Instrument Builders Forum
Topic: vacuum pumps
Replies: 17
Views: 17708

Re: vacuum pumps

Have a look at Veneer Supplies in Maryland, USA. They sell pumps, vacuum bags, etc. and have some DIY kits / plans. I bought the vacuum bag I use for laminating backs there, has worked well for 15 backs so far. It might be a stretch for you to buy out of country and I'm sure can find what you need l...
by Craig Bumgarner
Wed Feb 22, 2017 12:11 am
Forum: Instrument Builders Forum
Topic: Maple and Spruce archtop
Replies: 22
Views: 27056

Re: Maple and Spruce archtop

Very nice Rod! I too like that satin finish, would you mind saying what you use?
by Craig Bumgarner
Thu Feb 16, 2017 8:17 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Boom
Replies: 6
Views: 9319

Re: Boom

Okay, I see what you are saying. Yeah, the added area of the sound port raises the air resonance. But, to me as a player, the larger the sound hole area, the more of that air resonance I hear. Whether it is 90hz, 100hz or 120hz, it is still very bassy. I've done sound ports and abandoned them for th...
by Craig Bumgarner
Thu Feb 16, 2017 1:45 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Boom
Replies: 6
Views: 9319

Re: Boom

Unless I misunderstand you, I think I need to go the other way. My experience is sound ports accentuate the lower register to the player, I'm trying to reduce it.
by Craig Bumgarner
Wed Feb 15, 2017 3:13 am
Forum: Instrument Builders Forum
Topic: A different side of life in the workshop
Replies: 16
Views: 16685

Re: A different side of life in the workshop

I don't have much to add but would agree with waiting it out. Contacting the buyer directly and putting cards on the table is worth doing. Sounds like buyer is just strapped at the moment. Work out payment plan, set goals, make reasonable commitments. He's probably just as worried about all this as ...
by Craig Bumgarner
Wed Feb 15, 2017 1:21 am
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Boom
Replies: 6
Views: 9319

Re: Boom

Thanks Trevor! The bigger the sound hole, the more the boom characteristic is heard. I've progressively closed off sound holes with a bit of top wood and a clamp several times and the result is dramatic. If the hole approaches being completely closed off, the sound gets thin and weak. As expected, t...
by Craig Bumgarner
Tue Feb 14, 2017 1:03 pm
Forum: Contemporary Acoustic Guitar Design and Build - Trevor Gore
Topic: Boom
Replies: 6
Views: 9319

Boom

My guitars have been getting louder but along with that has come a boomy sound I'd like to reduce. I build Selmer style, ladder braced. The smaller sound hole option of the petite bouche helps but still some boominess. Air resonance is typically 90-110 us. Peak monopole 230-240hz. Reading the Book, ...
by Craig Bumgarner
Sat Feb 04, 2017 6:26 am
Forum: Instrument Builders Forum
Topic: Deepest Somerset
Replies: 11
Views: 10494

Re: Deepest Somerset

Nice work Dave! The rosette looks very interesting and nicely done. Care to post a straight on shot of it?
by Craig Bumgarner
Thu Jan 26, 2017 1:56 am
Forum: Instrument Builders Forum
Topic: Macaferri soundhole
Replies: 15
Views: 14323

Re: Macaferri soundhole

My experience with deflection of tops with back is it will be pretty much the same with the back off or back on. Sometimes the top stiffens up a little after the back goes on and the bindings are installed, so if it is a petite bouche where it is hard to do anything about it after the box is togethe...
by Craig Bumgarner
Tue Jan 24, 2017 9:10 am
Forum: Instrument Builders Forum
Topic: Macaferri soundhole
Replies: 15
Views: 14323

Re: Macaferri soundhole

Ross, Most good gypsy guitars, at least the ones I like have a T(1,1)2 down around 220-235hz. Higher than that is an indication they are too tight. Deflection is probably only .10-.11mm, so the SM is down around 16 which combined with the high T(1,1)2 will make for an under powered tinny sound. I go...
by Craig Bumgarner
Fri Jan 20, 2017 2:45 am
Forum: Instrument Builders Forum
Topic: Removable Back
Replies: 10
Views: 9673

Re: Removable Back

I've played around with this idea for some time and the closest I have gotten to it is to tape the back on. I do this like taping bindings in place, but use enough pieces to completely close off the joint so that hopefully it is air tight. This does not seem to fully duplicate the glued up back, but...
by Craig Bumgarner
Fri Jan 20, 2017 1:52 am
Forum: Instrument Builders Forum
Topic: Macaferri soundhole
Replies: 15
Views: 14323

Re: Macaferri soundhole

Dave, top thickness will vary depending the builder and how many braces the gypsy guitar has. This can be as few as two ladder braces only (!!) or as many as five ladder braces plus little support braces in the bridge, head block and sound hole areas. Fewer braces, thicker tops. I've seen tops as th...