[Karl Borum – Borum Acoustics]

I’m about to join the club- my cheap microphone I bought a year ago doesn’t work with my laptop so I just ordered the UMIK-1 Omni-Directional USB mic in Giuliano’s book. In the meantime, I’ve run REW with my PC microphone, so not posting anything until I get the UMIK.

It looks like my peaks are all lower in frequency that the lower limit in the charts: I’m interpreting that as “braces not stiff enough”/ too much scalloping. We’ll see if a good, calibrated, USB microphone changes the capture.

[Karl Borum – Borum Acoustics]

For the sake of future generations, I buy my celluloid binding from Rothco and Frost in the UK. Good product, reasonable cost, and shipping cost has been comparable to STANDARD US shipping.

Search: 61 results found for “celluloid binding” – Rothko and Frost

rothkoandfrost.com

Search: 39 results found for "celluloid binding"

Rothko and Frost

[Karl Borum – Borum Acoustics]

Hey Dalton!
Have you found a better alternative than canopy glue for your ABS binding yet? I’ve had a similar issue finding an adhesive for celluloid binding repair that won’t attack NC lacquer.

Karl Borum (GAL)
Saint Charles MO

[Karl Borum – Borum Acoustics]

“…I am wondering where that extra length came from? Is that from the string travel (intonation adjustment) on the tuneomatic bridge piece?”

The intonation at the bridge is related to the stiffness of steel strings, and the differing degree of string stretch when fretted. String stretch is also why, when you check intonation at the 12th fret, you FRET the note as opposed to plucking the harmonic.

[Karl Borum – Borum Acoustics]

I’m brought back to this thread, searching for more discussion on bridge materials in terms of weight and stiffness. Just read a paper by Trevor Gore* which has a brief mention of bridge woods, relating to mass (weight). In it, he identifies three woods that rated well, balancing stiffness, density and hardness: padauk (Pterocarpus sp.), walnut (Juglans nigra) and Tasmanian blackwood
(Acacia melanoxylon). These have not been particularly easy to find in a standard bridge blank sized chunk.

I may end up cutting my own billets from Black Walnut I harvested and cut into boards, 15 years ago. Anyone else focusing on bridge weight and material? A heavy bridge is a sure way to limit top mobility, and vise versa.

*161st Meeting
Acoustical Society of America
Seattle, Washington
23 – 27 May 2011
Session 3aMU: Musical Acoustics
3aMU4. Wood for Guitars

https://aipp.silverchair-cdn.com/aipp/content_public/journal/poma/12/1/10.1121_1.3610500/4/pma.v12.i1.035001_1.online.pdf

[Karl Borum – Borum Acoustics]

I have been using water based filler over sealer: sealer/ black filler/ sealer/ lacquer. I may just give that a test, (but with WB lacquer) but I would love to seal my purfling lines with epoxy. My last build was a nightmare with tiny “invisible” gaps that I couldn’t see until lacquer. I could barely see them afterward with a visor + loop. I would like to seal those almost invisible gaps before top coating (I know gaps shouldn’t be there in the first place, just coming clean……).

[Karl Borum – Borum Acoustics]

The EM-6000 WB topcoat and EM1000 sealer finally arrived; let the testing begin….

I’ve made a number of test panels for black grain filler under EM-6000 top coat and over Silver Tip Epoxy grain filler (including Michael Bashkin’s suggestion). I am going to update this thread with the results as the panels are completed. Materials are listed in the order applied.

The black filler, when done properly, accentuates the natural effect of dark shadow in the bottom of the grain, so there must be grain deep enough to accept the black filler, while the surface wood must be sealed such that dye from black filler will not discolor it. I had a killer method for nitro, but I’m moving away from nitro, hence the method testing.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Panel #1 A and B (rejected; process not recommended) Honduran Mahogany:

1/2 the panel was grain raised with water then 320 sanded, the other half was not (A and B)

<b style=”background-color: var(–bb-content-background-color); font-family: inherit; font-size: inherit; letter-spacing: 0px;”>EMTECH EM1000 WB Universal Sanding Sealer

Silver Tip Grain Fill

Light scuff with red Scotch Bright

Rockler Wunderfill water-based Black Grain Filler

Final level sand with 320 on hard block

No top coat (yet)

RESULTS: The water-based sealer raised the grain, on both A side and B side, surprising given B side was grain raised. After the final “level sand” the surface was lumpy looking and uneven. A more rigorous flat sanding removed the black filler, down to a flat surface without grain.

Flat sanding the EM1000 sealer before epoxy would have likely sanded through the sealer due to the raised grain, I would rather not chase raised grain, so I reject this process. Another panel (#4) will have epoxy base with black filler directly over epoxy, then sealer. The #4 test case is drying and will be evaluated later.

Panel 1 might have been acceptable with 2 coats of sanding sealer with a flat sand in between but would have likely filled the grain to the point that the black grain filler was moot- that is, there would be insufficient grain depth to hold the black filler. The sanding sealer appears to fill grain very well, albeit it does raise the grain (damm it).

[Karl Borum – Borum Acoustics]

I just wrote Jescar about EVO gold. They said they still have some limited stock available for sale. I would give them a call as the website may not show availability.

I used SM gold on my last build with no regrets, they have a variety of sizes. Maybe SM wire is Jescar???

[Karl Borum – Borum Acoustics]

I’ve gone through ½ a lifetime of sharpening tools and methods. Here is the one I landed on for Luthiery and fine wood work, YMMV :

· 9×12 Granite Surface Plate B grade +/- .0001 (Grizzly IIRC- surprisingly affordable $39)

· Veritas Mk II honing guide (wish I would have bought the “Deluxe” cauz it includes narrow bladeholder which I added later) $79.

· DC Combination Diamond Plate 300- 1000 2 ¾ x 8” : $120

· 3M Wet or Dry various (use 1000 and 1200 most when sharpening)

· Leather strop with green and white (just a piece of leather)

· Cheap Glass Cleaner in spray bottle

9″ x 12″ x 2″ Granite Surface Plate, No Ledge – Grizzly Industrial

Veritas Mk.II Standard Honing Guide – Lee Valley Tools

8″ Double Sided Diamond Benchstone – MPOWER Tools

For Re-grinding an edge: Drill Press Sharpener Ultimate Starter Kit with Sharpener, Jig, & Flat — Taylor Toolworks $89: I can grind a shaving edge on a chisel in under 3 minutes- plane blades need a little second operation due to the width. For carpentry or coarse work, the two part process alone is sufficient and provides a shaving edge.

Honing Methods:

Pretty simple really- I flatten with diamond or paper on the surface plate, then hone with the MkII (it has a micro bevel feature too). After honing with MkII I polish with Wet or Dry 1000 + 1200 followed by light strop. Strops have a hanging hole and hang on a nail behind my bench.

I can touch up an edge with strop or touch up on paper, by hand, in 30 seconds. The glass cleaner works very well to adhere paper to surface plate and to lubricate the diamond stones, and its not harsh or toxic in this application, its minimally soapy and smells good too.

The TayTool fixture works with the drill press. Chuck up your disk, align your tool on the holder and push it into the disk (one hones, one is leather and polishes). Its crazy I know but it works so well. I can even strop an edge if the disk is chucked up in the drill press.

I also use that granite plate for a variety of flat sanding and measurement stuff. I use the surface plate for fretting a FB off the neck. Add a dial indicator and DI stand and you’ll be set for another magnitude of useful measuring configurations.

Everyone has a method that works for them, and fits their budget. It took me years and many stones to settle on this. Best wishes on finding yours….

grizzly.com

9" x 12" x 2" Granite Surface Plate, No Ledge - Grizzly Industrial

G9649 9" x 12" x 2" Granite Surface Plate Great for taking accurate measurements from. The G9649 Granite Plate is for those needing precision measurements from a common surface base. This tool room-grade "B" plate has a bilateral accuracy of … Continue reading

[Karl Borum – Borum Acoustics]

BUMP

$48 on sale, Internatinal Violin

Econo Digital Hide Glue Pot, Electric, 1 pint capacity (internationalviolin.com)

I currently use a Phillips thermostatic controlled baby bottle warmer

https://a.co/d/5kSRUMr

internationalviolin.com

Econo Digital Hide Glue Pot, Electric, 1 pint capacity

Econo Digital Hide Glue Pot, Electric, 1 pint capacity

[Karl Borum – Borum Acoustics]

Jeff Jewitt does it and so does Tom Bills. My thoughts are that shellac would be better than poly as it is easier to remove/ sand off if a glue repair on the inside is required. I don’t do it because of the repair/ glue concern.

I once sealed the top side of a 3/4″ thk plywood work bench that was mounted over 1×2 “cleats” attached to the wall. The non=supported corner of the plywood top had a 3×3 leg attached. A day after applying poly to the top, that 3/4″ plywood curled up like a potato chip on the unbound edge, lifting the leg off the floor a good 3″. A woodworking buddy told me that’s what happens when you seal only one side of ply board. I trust that doesn’t apply to guitar tops, backs and sides, but it’s an interesting phenomena.

[Karl Borum – Borum Acoustics]

R.M. Mottola: Building the Steel String Acoustic Guitar Paperback – October 20, 2021, is a very good book that covers almost every aspect of guitar building. It’s much more modern and applicable than Cumpianio’s book and it focuses on Steel String guitars. There are other methods of work besides the ones Mottola describes but this book is extremely thorough, 512 pages. Many bonuses in the book, including templates and links to calculators. Even a guitar design tool that plots your design as you enter the parameters (see links).<div>

https://a.co/d/5xFuxSM <—- amazon link to book

The “G” Thang Acoustic Guitar Design Tool (liutaiomottola.com) –> link to design tool

Building the Steel String Acoustic Guitar – Online Annex (liutaiomottola.com)–> more

I would suggest pulling the trigger on Nicoletti’s <b style=”background-color: var(–bb-content-background-color); font-family: inherit; font-size: inherit; letter-spacing: 0px;”>Mastering the sound of the acoustic guitar. It’s also a very good book. Information in the book can be applied even if you don’t want to do analysis. Cheaper tahan amazon with StewMax…

I break out this one fairly regularly; Erlewine: <b style=”font-family: inherit; font-size: inherit; letter-spacing: 0px; background-color: var(–bb-content-background-color);”>Guitar Finishing Step-By-Step.

</div>

a.co

Building the Steel String Acoustic Guitar: Mottola, R.M.: 9781734125610: Amazon.com: Books

Building the Steel String Acoustic Guitar [Mottola, R.M.] on Amazon.com. *FREE* shipping on qualifying offers. Building the Steel String Acoustic Guitar

[Karl Borum – Borum Acoustics]

Giuliano Nicoletti’s 2023 book, Mastering the Sound of the Acoustic Guitar, gives a general bridge weight recommendation of “not to exceed 20-25 grams….while the bridge plate should weight around 4-8 grams” (p.87). A VERY good book BTW…

That certainly is a LOT of weight to remove. IS it an oversize bridge? Compare all dimensions of the new bridge with other bridges and see where you could remove material and still maintain the appearance/ critical geometry. I might start by taking wood off the top-tail end-radius of the belly, Maintaining the footprint, and blending the radiused edge into the top of the bridge. A drum sander could remove material by moving the top-to-wing radius on both ends inward toward the center while retaining the rigidity of the “wings”. Have you considered making your own bridges, it’s pretty satisfying.

[Karl Borum – Borum Acoustics]

WTF does the “squid” mean when you click the LIKE button? Hope it isn’t derogatory….

[Karl Borum – Borum Acoustics]

Outstanding Excell SS, thanks,

Your Mother

[Karl Borum – Borum Acoustics]

Interesting, how certain are you that it is a carbon strip?

On that subject, how would one test the material to confirm its carbon fiber?

[Karl Borum – Borum Acoustics]

Another option from amazon.com; lighted, adjustable, comfortable, 3 levels of mag, and sub $15 bucks. I have one on my shelf for reserve.

https://www.amazon.com/gp/product/B08J2V8M8Y/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1

[Karl Borum – Borum Acoustics]

I had a similar issue where the frets wouldn’t seat in the FB extension. The cause was that the FB extension was not completely glued down in places and that was absorbing the force from the hammer. I found that out when the shadow of a piece of tape on the FB was illuminated by a work light, the tape’s shadow “amplified” the FB’s movement. I could not see the FB move, even with magnification but the shadow from the tape moved when I pressed the FB down. Re-glued the extension and the fret slots were so chewed up by then, I used the fret crimper to widen the tang. That may not be your issue at all but something I would check, with a long piece of tape sticking up from the offending fret area and casting a long shadow.

[Karl Borum – Borum Acoustics]

OK, that is fine, thank you Ian.

[Karl Borum – Borum Acoustics]

Thanks Michael. I just watched your Epoxy Pore Filling demo today, what timing…

[Karl Borum – Borum Acoustics]

I route thinner material for acoustic builds so I dont have much to add except to map out the grain direction before you start, chalk works good for that. Also, a fulcrum/ starting pin can be useful to stabilize your work piece. Here is a video from Woodpeckers that illustrates the use of a fulcrum point. Many router table inserts provide a threaded hole for that purpose: https://youtu.be/1g9IjIj1tdM

youtu.be

- YouTube

Enjoy the videos and music you love, upload original content, and share it all with friends, family, and the world on YouTube.

[Karl Borum – Borum Acoustics]

This is a remarkable video explaining kickback using high speed photography about how compression bits help prevent kickback and tearout: ithttps://youtu.be/titM-kmfu-g?feature=shared

[Karl Borum – Borum Acoustics]

Saw this tool on my Instagram feed (from February 23 2023) today, and it lead me here…. Thanks for sharing Doug….

[Karl Borum – Borum Acoustics]

OMG I bought one and it’s a total piece of $shit, made in China, thin cheap aluminum pot with a plastic handle, like on a cheap Dollar Tree toy, and not UL approved (or any other safety approval). I won’t even plug it in!

How do I delete my post about it in this thread?

[Karl Borum – Borum Acoustics]

Thats fair enough and I agree, its aimed at beginners (as I consider myself one). His website does have several advanced calculators and tools.

[Karl Borum – Borum Acoustics]

The sell the actual jig now. I’ve bought a lot of machinist type tools from TayTool.com and they have a great selection of scales, rulers and straight edges too.

[Karl Borum – Borum Acoustics]

What does it mean, this “squid”? If a US Marine said it, it would mean a member of the Navy….