Flash Cards for the Roberto-Venn course of study
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Fraction to Decimal Equivalent
1” = 1.000”
3/4“ = 0.750”
1/2” = 0.500”
1/4” = 0.250”
3/16” = 0.187”
1/8” = 0.125”
1/16” = 0.062”
1/32” = 0.031”
1/64” = 0.015”
Solvents
Naphtha = removes goo & buffing compound waxes – will not damage finishes.
Acetone = softens plastics for better adhesion – will damage finishes, used as cleaning agent for spray equipment. Can clean up unwanted CA (superglue). Will damage lacquer finishes almost immediately. Can be used to strip lacquer.
Retarder (Butyl Cellosolve) = used to slow down lacquer drying time in hot weather. Will damage lacquer finishes. Reduces solvent popping and blushing.
Paint Thinner (Mineral Spirits) = thins oil based paints.
Alcohol – damages varnish & shellac & can be used to strip those finishes. Used to clean up uncured epoxy or to thin epoxy. Can damage violin finish
Glues
PVA (polyvinyl acetate) – Elmer’s, dries transparent. Used in some neck joins, long shelf life.
Aliphatic Resin – Titebond, yellow glue, higher quality of white glue with color added. Most widely used glue in guitar building. Light to moderate clamping. Can be softened with water or heat to separate joint. Shelf life of 6 – 8 months.
Hide Glue – made from animals. Used in bowed instruments. 24 hour cure time. Disassembly with hot knife or shocking joint. Used in repairing acoustic tops due the hard semitransparent glue line.
Resorcinol Resin – 2 parts (resin + powered hardener). 8 hr clamp time. Used in PRS & Gibson style neck joints. Generates heat & noxious fumes while curing.
Polyurethane Glue – used in laminations, does not contain water will not make wood move. Used in gluing veneers or fingerboards to necks, works well with oily hard to glue woods. 20-40 minute open time.
Glues(continued)
Epoxy – 2 part (resin + hardener). 2 types. Quick set – sets in 5 minutes, dries in a few hours. Slow set – sets in a few hours, dries overnight and is strongest of the 2 types. Mixed with saw dust for inlay and sands well. Solvent resistant so is permanent (not to be used for neck joints). Great for filling holes, repairing headstocks & gap filling. Can only be cleaned up before it sets with alcohol or lacquer thinner. Uncured epoxy is toxic to skin.
Cyanoacrylate Glue – aka super glue or CA. clear dries in seconds by absorbing atmospheric moisture. Accelerant (can be used to shorten curing time to 1 sec) but can cause the glue to foam which leaves a white look. CA is common in repair work but also works well in fretting, placing nut & inlay work. Shelf life 3-4 months.
Contact Cement – Spray Adhesive – available in brush-on or spray. Not to be used in structural situations but can be used to attach pick guards. Used in tool & jig making. Applied to both surfaces, allowed to dry and then joined. Sets in 1-2 minutes and can be released with Naphtha.
Weather
Temp – measured with thermometer in F or C degrees.
Humidity – moisture in air. Absolute – actual amount of moisture air can hold at a given temperature. Measured in grains. Relative – ratio of actual moisture in air to what air can hold at a given temperature.
Dew Point – temp at which water vapor in air will condense from the air.
Barometric pressure – weight of the air.
If pressure goes up weather should improve.
If pressure goes down then weather gets worse - warns of deteriorating conditions.
For below assume absolute remains the same.
If Temp goes up then RH goes down .
If Temp goes down then RH goes up .
If temp @ 90º & Dew Point @ 82º the RH is high.
If temp @ 90º & Dew Point @ 40º the RH is low.
if temp @ 85º & Dew Point @ 79ºthe RH is high.
Wood takes on moisture mostly through end grain.
Gibson / 24-5/8” / 24.625
Martin short / 24.9” / 24.900
PRS / 25” / 25.000
Martin long / 25-11/32” / 25.400
Fender / 25-1/2” / 25.500
Nylon / 26” / 26.000
Bass / 34” / 34.000
Bass 5&6 / 35” / 35.000
String tension increases as the scale length is increased. Increasing total string length also increases the string tension. Shortening scale length decreased the string tension.
5 String Bass / 1-7/8” / 2-3/4”
Jazz Bass / 1-1/2” / 2-1/2”
Fender Electric / 1-5/8” / 2-1/4”
Dread, Jumbo,Gibson/Martin,
Electric (not fender), / 1-11/16” / 2-1/4”
OM , 000,
(fingerstyle steel) / 1-3/4” / 2-5/16”
P Bass / 1-3/4” / 2-1/2”
12 String / 1-7/8” / 2-3/8”
Nylon classical / 1-3/4”
Theory
Pitch – relative frequency of a note
Frequency – measured in vibrations (cycles per second – Hertz)
Vibrating String – a vibrating string’s pitch is determined mainly by length, tautness, material
To raise pitch tighten string or shorten string length.
To lower pitch loosen string or lengthen string.
Frets – aka stops – used to shorten or lengthen string
Temperment – musical values given to each step of a musical scale
Equal Temperament – 12 equal semi-tones to the octave
Scale length – selected length of scale for purposes of calculating fret spacing
Scale length = distance from nut to 12th fret x 2
Compensation – small increment added to scale length with corrects of the difference between the theoretical fret calculations and the physical factors that affect actual pitch. Allows string to produce a more accurate pitch when fretted. Typically made at saddle or bridge, but some systems also use nut.
Theory …. continued
String length – actual distance between nut & saddle.
Scale length + Compensation = String Length.
Guitar Intonation – adjusting compensation to improve pitch accuracy & pitch relationships.
Sharp (#) – pitch higher than desired
Flat (b) – pitch lower than desired.
Strength of wood is greatest when the direction of force is applied parallel to the grain; vertical grained (quartersawn) wood yields a higher strength-to-weight ratio, as compared to flat grain. Strength in grain is parallel to the grain.
Conifer (Evergreen) (softwood) has pine cones. Typically used for soundboards & bracing because of the excellent strength to weight ratio.
Deciduous (hardwood) loses leaves every winter.
Wood is measured in Board Feet. One board foot is 12” long by 12” wide by 1” thick. To determine the number of board feet in a piece of wood use:
Length x width x thickness
144 = board feet
Soundhole DiametersNylon classical / 3-3/8
Classical steel string / 3-1/2
OM, 000 / 3-7/8
Dread, Jumbo / 4”
Acoustic soundboard thickness is .125”
Acoustic tops have a radius of 50’. Soundboard braces have a radius of 30’ except for the transverse brace which has a radius of 50’. This combination pre-tensions the soundboard.
Acoustic bottom plates have a radius of 15’. This arch in the back provides strength to the box and also reflects the directional sound waves back into the box which will decrease treble.
Back & Sides
Indian Rosewood – warm clear tone.Pore fill req.
Honduras mahogany – warm - best value for building. Lively sound, good clear warm tone but not as warm as rosewood. Pore fill required
Myrtle – good clarity, similar to koa in tone. Easy to bend and finish. No pore filling required.
Koa – medium - good clarity, not as warm as mahogany. Chosen for it’s beauty. Pore filler required.
Bubinga – punchy, clear tone, beautiful appearance. Pore fill required.
Walnut – medium - good clarity, not as warm as mahogany. Chosen for it’s beauty. Pore filler required.
Maple – bright. No pore filling required.
Soundboard
Sitka spruce – most commonly used soundboard wood. Clear, bright tone, very stiff. More headroom than cedar.
Western Red Cedar – more sensitive and slightly warmer tone than spruces. Less stiff. Used on smaller body shapes or for finger style.
Using spruce instead of cedar for a soundboard will enhance the treble response.
Bass frequencies have long wavelengths & are non-directional. Longer wavelengths = lower frequencies.
Treble frequencies have shorter wavelengths & are directional. Shorter wavelengths = higher frequencies.
The stiffer the wood the smaller the vibrations. Smaller vibrations produce shorter wavelengths, shorter wavelengths = higher frequencies thus more treble response.
Less stiff wood produces larger vibrations.
Larger vibrations produce longer wavelengths thus more bass response.
A thicker back plate and/or thicker bracing and/or more braces will produce more treble.
A thinner back plate and/or thinner bracing and/or few braces will produce more bass.
A smaller sound hole makes it harder for directional frequencies (treble) to get out of the box.
Larger volume boxes produce more bass response.
The heavier something is the slower the attack but the better the sustain.
Fret Sizes
Medium .040 x .080
Medium tall - .095 x .050
Jumbo- .105 x.040
Dunlop 6100 - .110 x .055
Pore filler can be thinned with naphtha.
Pore filler should be wiped off in a 45º motion to the grain.
Pore filler required / Pore filler Not ReqAsh / Alder
Bubinga / Bolivian Rosewood
Koa / Maple
Indian Rosewood / Myrtle
Mahogany
Walnut
Woods found in North America are:
maple, ash, alder, spruce, cedar, myrtle & walnut.
RV electric fret boards have a compound radius of 12’ and 16’. A compound radius is considered part of a cone.
RV acoustics fret boards have a radius of 12’ and are considered part of a cylinder.
Necks
Minimum amount of wood under truss rod slot
6 string - .125
12 string - .187
Final thickness of headstock - .593
Truss Rods
Up-bow and forward bow are the same.
Truss rods used at RV are double action.
One Way Truss Rods
Loosening a one way truss rod will add more neck relief. To loosen a one way truss rod you must turn the nut counter-clockwise.
Tightening a one way truss rod will decrease neck relief. To tighten a one way truss rod you must turn the nut clockwise.
Electric Set Up
Set-up Order
1. Neck
2. Saddle
3. Nut
- Neck Relief
Hold string down at 1st & 16th frets (body joint for acoustics). Measure at 7th fret – expect to vary from .004 to .015”. Fender & Gibson set at factory to .012”. Adjust truss rod to achieve.
- String height at bridge. Capo @1st fret. Measure at 17th fret. 3/32 to 1/8th.
- String action at nut. File nut groves for .020” clearance –fret top to string bottom.
- Intonation – tune to pitch on strobe.
Then check each string at 12th fret on strobe.
- If fretted note is sharp lengthen string by moving compensation back at saddle.
- If fretted note is flat, shorten string by pushing compensation forward at saddle. - Pickup height – hold at last fret
Pickup / Bass side / Treble side
Neck / 4/32 / 3/32
Bridge / 3/32 / 2/32
Acoustic Set Up
Set-up Order
1. Neck
2. Saddle
3. Nut
- Neck Relief
Hold string down at 1stbody joint. Gap at 7th fret should be same as high e diameter. Adjust truss rod to achieve.
Style / Bass / TrebleFingerstyle (low) / 3/32” / 2/32”
Moderate / 3.5/32” / 2.5/32”
Flatpicking (high) / 4/32” / 3/32”
Nylon (classical) / 5/32” / 4/32”
2.String height at bridge. Capo @1st fret. Measure from fret top to string bottom @ 12th fret. Determine difference from actual at 12th fret to chart below. Double difference & sand slightly less than this amount from saddle bottom.
3. String action at nut. File nut groves for .020” clearance –measured fret top to string bottom.
The following will affect the amount of compensation required to correct intonation:
Action
String tension
String material
String gauge
Raising the action will require more compensation at the saddle. Lowering the action will require less compensation at the saddle.
Humidifying a dried out acoustic will raise the action as the bridge rises, which will require more compensation at the saddle.
A wound G string does not require more compensation than an unwound G string. The windings only add mass.
Normally the inclination on a steel string guitar between the low E and the high e is 1/8”.
Electronics
Passive electronics remove something from the original pickup signal.(exp. - vol & tone pots)
Active electronics modify the original signal from the pickup.
Passive Pickups are high impedance and are generally noisy depending on the amount of resistance.
Higher gauss rated coils shut down the amount of string vibration.
Most Active Pickups are low impedance.
Low gauss ratings of coils used in active pickups allow the string more vibration range.
Impedance is the resistance to the flow of AC. Inpassive pickups this is variable with frequency.
An Active Pickup has less resistance in the coils
High-pass filterspass high frequencies well but attenuates frequencies lower than the filter's cutoff frequency. A low-pass filter passes low-frequencysignals but attenuates signals with frequencies higher than the cutoff frequency.
Tools
A joiner is used to 1st to mill rough lumber into useable pieces. The tool best to make one face of a board parallel to the other is a planer.
Routing on the outer perimeter of a work piece, moving the router in a counter-clockwise direction is called Conventional cutting. Moving in a clockwise direction is climb cutting.
Inspection
Step by Step Method of Evaluation Condition
1)Condition of top
- Rotation, Belly, Cracks, Brace Problems
2)Bridge
- Adherence, Profile, Pin Wear, Slot
3)Saddle
- Fit, Profile, Radius, Intonation
4)Neck Angle
5)Neck Relief
6)Fret Condition
- Profile, Width, Crown, Pitting
7)Nut
- Fit, Action, String Spacing
8)Soundness of Structure
9)Problems with Humidity
Actions
FingerstyleLow / Moderate
Medium / Flat Pick
High
Bass –
Low E / 3/32 / 3.5/32” or 7/64” / 4/32
Treble – High e / 2/32 / 2.5/32” or 5/64” / 3/32
Relief / 0-.010”
(3-8 realistic) / .005 -.012”
(10 realistic) / .010-.015”
( realistic)
String Gauge / Light or Med
(Beginner Extra Lite) / Medium / Typically Med is used
*Neck angle is measured with straight edge on top of frets to bridge, should be flat on bridge.