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danielj

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Reply with quote  #1 
Hi all. Thought I would share my experience so far with this material. I was talking with Lars (raincitymusic) recently, and mentioned that i planned on making a jawari bridge for my hansa veena, to replace the guitarish original bridge. I said I was planning on using delrin, as I had used it sucessfully for guitar nuts. he recommended that i use corian instead.

I ordered some 4x4x.5 in. samples from corian.com for about 2.50 a piece. They come in many colors including a natural bone. The corian machined down to size very nicely, tho regarding the .5 in. thickness I slices down by hand with a mitre boxsaw and that took some time.

The material works and feels very much like bone while shaping the jawari and it sounds very good. Of course, I don't know about how it will wear on a sitar with all that string pulling, but i bet it would work just fine.

blessings Dan
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rex@sitar.co.za

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Reply with quote  #2 
Hello

Do you know why corian was suggested over delrin?

I have a delrin bridge on my sitar and will never go back. The qualily of the tone is indistinguishable from bone or antler and it's mainenance free. I did my first and last jawari on the bridge two years ago and have never needed to touch it since. I've never played a corian bridge.
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Lars

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Reply with quote  #3 
I suggested Corian for Dan as it's easier to work with and not toxic if heated like Delrin. Also it has a density that's closer to natural materials. I've had a few Delrin bridges but never liked them although the self lubricating properties are desirable but I find it to dense and don't like the sound. Have had all types of stuff through here, Delrin, Urethane, Corian, etc. Could just be a matter of personal taste though, this is just my own experience.
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trippy monkey

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Reply with quote  #4 
Do all you 'over-the-pond' people call the 'plastic' bridges delrin???
The terms synthetic & plastic is common in India, certainly Varanasi anyway!!
Is Delrin a particular style of synthetic?

I have a synthetic bridge on that old dark brown Munda I sent back from Varanasi, this year. It has a great mid tone. I would recommend it to any veggie/vegan sitarist out there!!! :wink:

Nick
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Sitarfixer

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Reply with quote  #5 
I've worked with Corian in the past as well. A kitchen cabinet shop had sink cutouts from corian countertops piled up in a dumpster - thousands of them ! ! ! I stocked up with bone, egg shell, off white, Bahama beige, marbled cream and others. I found the stuff a little brittle to work with. I would suggest watching the operations carefully. When you've got a bridge, nut or what ever finally cut and shaped to satisfaction, you'll be most pleased. I made a sarod bridge out of Corian years ago and remembered it was too heavy as compared to deer horn. That added weight killed the sound. For Sitar, Sur-Bahar, Tanpura, Rudra Veena, etc., there shouldn't be a problem. The wide range of color choices is also a huge bonus. I'm totally sold on Delrin, especially with the mock marrow feature added but Corian will work very well also. Have fun with the Hansa Veena and the new bridge.
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Hamletsghost

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Reply with quote  #6 
I have written of the joys of Delrin in the past - Per Trippy's question - Delrin is a Name Brand of substance developed by Dupont in the 50's as a bearing - machine tool guide - wear surface replacement that is NON TOXIC ( sorry Lars check the MSDS ) repeat - it does put off a smell that is unpleasant when melted but is non toxic. I have written on the glories of this material before but I will have to search out the old string in the next couple days but sufice to say it wears like iron. I do agree with it being personal preferance, I have heard and played at least 30 sitars in Chicago fitted with delrin including MANY vintage monsters of the finest houses and with only one or 2 exceptions they have all stayed delrin because of the beauty of sound and toughness of material. On my personal sitars the jawari on my main axe - The Karasek Rose - the delrin jawari needed only a MINIMUM touch up after 3 years of banging away. and the sound gets better all the time.
I have had minimal reports or experience with corian and am eagerly awaiting the results of your use of it - Good luck and please keep us updated.

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danielj

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Reply with quote  #7 
Well, it seems we have differing opinions on the merits of delrin for bridges...thats to be expected. Im sure diff. materials make for different sound signatures, and I imagine that the material for the base of the bridge affects the sound sig as well.


I use diamond files to shape jawari and i really like the way corian works; just like bone. However, Tony is right about corian being a bit brittle. I cut my starter string slot with a .010 razor saw; i needed to move one of them over about 1/32 and part of my second cut chipped off...not a problem as it was for a thicker string and I just melded the two cuts into one slot. I can see that care would need to be taken when cutting all those fancy borders designs on a sitar bridge.

corian has a much more glass like tap tone than does delrin; perhaps that will results in stronger high freq harmonics..just a guess.

my next bridge project will be for a solid body indian slide guitar. the bridges will sit atop little hollow boxes, where the jawari material will be the top of the box. I plan on fixing piezo transducers directly to the underside of the jawari. So if i make two jawari, one out of delrin and one out of corian- should be able to experience the diff sound sigs of each will keep you posted Dan
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Lars

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Reply with quote  #8 
I should have been more specific but typing on an iphone is tedious. Delrin can be toxic when heated over 230 degrees, so if you're using any power tools to rough cut everything it can be an issue with isocyanate gasses, etc and it contains formaldehyde and can pose an inhalation hazard according to MSDS listings which I did check again so not sure about your info Brian but it's no big deal really as it's a matter of personal experience which will always vary among all of us. Someone posted on the forum about this also if I remember in detail quite awhile ago. I played around with Corian adhesive/liquid Corian about 6 months ago, was trying to find a way to mold my favorite bridge and so made molds, etc. and it ALMOST worked. The problem is it's not stable when curing to the degree necessary (air bubbles) to get an exact match so it just isn't possible. Also quite toxic in that form until it cures too but it sure would have been great as they turned out with the same density as Baruns bridge material which he calls 'bulletproof fiberglass'. Whatever that is..... but imagine being able to duplicate your favorite bridge 'forever'....

Nick they use all kinds of materials, Rikhi Ram was using a hard Urethane last time I saw one. Also very dense with loss of some sound but long lasting. Have seen a lot of mystery materials, God only knows what, melted down milk bottle plastic? But if it sounds good, who cares?

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Hamletsghost

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Reply with quote  #9 
YES I DO AGREE SOUND IS THE PROOF OF ANY SYNTHETIC MATERIAL (or natural materials for that matter.
But we do need to be aware of the TRUTH of the TOXICITY and other characteristics of ANY material we will be working with.
Lars the reason for my above statement was because I worked in heavy industry for many years and have encountered Delrin in a number of applications. I also have used MSDS sheets for not only benign substances like Delrin & Corian but some pretty NASTY and extremely hazardous stuff as well (maybe THAT'S my pppppproblem :roll: )
Lars please re-read the MSDS below on temperature facts - not a slam on you for sure - Just check the temp facts etc. so we can be properly informed to hazards.
OK CLASS -
HERE IS THE TRUTH about Delrin AND Corian
Below are excerpts from the Material Safety Data Sheets REQUIRED by the Government on all materials covered by OSHA.
You will see that Delrin does indeed contain Formaldehyde LESS THAN .005 % THAT'S - 5 THOUSANDTHS and the only danger to respiration other than using a respirator like ANY material for dust, is when you heat Delrin above 230 degrees centigrade that's 446 degrees farenheit Your tool would indeed have to be spinning very fast to heat it BEYOND it's MELTING POINT. You would have to REALLY TRY to melt it as Delrin is even used for the bodies of DISPOSABLE LIGHTERS. (Note - Corian DUST is even more combustible than Delrin - and releases MORE toxic gasses when burning - but you still have to try and screw up - A LOT of dust from many substances will ignite with an open flame - CONCLUSION - DON't HAVE AN OPEN FLAME WHEN MAKING DUST - DUH :roll: )
Delrin is an EXTREAMLY SAFE material when used properly even being used in the food industry as well as wear parts for Mercedes & BMW's as well as many other applications. Properties and Characteristics
The chemical composition, regular molecularstructure
and high degree of crystallinity result in a
unique combination of outstanding characteristics
of Delrin® acetal resins not found in metals or most
other plastics:
• High mechanical strength and rigidity
Toughness and high resistance to repeated
impacts

• Long-term fatigue endurance :!:
• Excellent resistance to moisture, gasoline,
solvents, and many other neutral chemicals
• Excellent dimensional stability
• Good resilience and resistance to creep
• Natural lubricity
• Wide end-use temperature range
• Good electrical insulating characteristics

But again it is the sound that's KING Delrin really does sound good when used for Jawari and Tony's forrays into simulating marrow give it an even richer sound. Heck if I played halfway descent I'd give you a sound sample from 3 of my sitars that are fitted with Delrin - just don't feel like embarasing myself just yet ops: .
AND JUST TO BE FAIR I ALSO INCLUDED THE MSDS ON CORIAN - You will see just as with Delrin - This substance releases small ammounts of toxic gasses EVEN when Machining - so your risk might be slightly higher than with Delrin because you have to melt Delrin to get toxic gasses.
AS WITH ANY SUBSTANCE YOU WORK WITH - USE PERSONAL PROTECTIVE EQUIPMENT - WEAR A RESPIRATOR - GOGGLES - ETC ETC - KOW WHAT YOUR WORKING WITH.
Heck wear a respirator when working COW BONE -
You don't want MAD COW DISEASE.
Why hasn't anyone carved a hunk of Mamoth Ivory to see how it works :?:
How about sawing that mother of toilet seat trim :?:
Oh and a final BTW - you will see below the exact quote for Corian:
DuPont recommends using the exposure limits for polymethyl methacrylate
I wonder what that is? :mrgreen:

OK HERE'S THE TRUTH FOR THOSE THAT WANT TO DO THE RESEARCH.
FROM DUPONT:
MANUFACTURER/DISTRIBUTOR
DUPONT ENGINEERING POLYMERS
1007 MARKET STREET
WILMINGTON, DE 19898
PHONE NUMBERS
Product Information : 1-(800)441-7515
Transport Emergency : 1-(800)424-9300
Medical Emergency : 1-(800)441-3637
----------------------------------------------------------------------
COMPOSITION/INFORMATION ON INGREDIENTS
----------------------------------------------------------------------
Components
Material CAS Number %
ACETAL POLYMER >97
STABILIZER <3
FORMALDEHYDE 50-00-0 <0.005
Components (Remarks)
Material is not known to contain Toxic Chemicals under Section 313
of Title III of the Superfund Amendments and Reauthorization Act
of 1986 and 40 CFR part 372.
DEL003 DuPont Page 2
Material Safety Data Sheet
----------------------------------------------------------------------
HAZARDS IDENTIFICATION
----------------------------------------------------------------------
Potential Health Effects
ADDITIONAL HEALTH EFFECTS
Read the specific datasheet for product to be used before using
this resin, as well as the Delrin Molding Guide.
ACETAL POLYMER
There are no known effects from exposure to the Delrin polymer
itself. If overheated, the polymer releases formaldehyde which
may cause skin, eye, and respiratory irritation and allergic
reactions.
Significant skin permeation and systemic toxicity after contact
appears unlikely. There are inconclusive or unverified reports of
human sensitization.
Carcinogenicity Information
The following components are listed by IARC, NTP, OSHA or ACGIH as
carcinogens.
Material IARC NTP OSHA ACGIH
FORMALDEHYDE 2A X X A2
----------------------------------------------------------------------
FIRST AID MEASURES
----------------------------------------------------------------------
First Aid
INHALATION
No specific intervention is indicated as the compound is not
likely to be hazardous by inhalation. Consult a physician if
necessary. If exposed to fumes from overheating or combustion,
move to fresh air. Consult a physician if symptoms persist.
SKIN CONTACT
The compound is not likely to be hazardous by skin contact, but
cleansing the skin after use is advisable. If molten polymer gets
on skin, cool rapidly with cold water. Do not attempt to peel
polymer from skin. Obtain medical treatment for thermal burn.
EYE CONTACT
In case of contact, immediately flush eyes with plenty of water
for at least 15 minutes. Call a physician.
INGESTION
No specific intervention is indicated as compound is not likely to
be hazardous by ingestion. Consult a physician if necessary.

Engineering Controls
Use sufficient ventilation to keep employee exposure below
recommended limits.
Personal Protective Equipment
EYE/FACE PROTECTION
Wear safety glasses. Wear coverall chemical splash goggles and
face shield when possibility exists for eye and face contact due
to splashing or spraying of molten material.

RESPIRATORS
When temperatures exceed 230 degrees C (446 F) and ventilation is
inadequate to maintain concentrations below exposure limits, use a
positive pressure air supplied respirator. Air purifying
respirators may not provide adequate protection.

PROTECTIVE CLOTHING
If there is potential contact with hot/molten material, wear heat
resistant clothing and footwear.

DEL003 DuPont Page 5
Material Safety Data Sheet
----------------------------------------------------------------------
PHYSICAL AND CHEMICAL PROPERTIES
----------------------------------------------------------------------
Physical Data
Melting Point : 175-183 C (347-361 F)
Solubility in Water : Insoluble
Odor : Slight formaldehyde
Color : Off-White.
Form : Pellets
Specific Gravity : 1.40-1.44
----------------------------------------------------------------------
STABILITY AND REACTIVITY
----------------------------------------------------------------------
Chemical Stability
Stable at normal temperatures and storage conditions.
Conditions to Avoid
Maintain polymer melt temperatures below 230 C (446 F) . Avoid
prolonged exposure at or above the recommended processing
temperatures.

*******************************************************************************
CORIAN® MATERIAL SAFETY DATA SHEET (MSDS)
CHEMICAL PRODUCT/COMPANY IDENTIFICATION
Material Identification
Corian® is a registered trademark of DuPont.
Company Identification
MANUFACTURER/DISTRIBUTOR
DuPont
1007 Market Street
Wilmington, DE 19898
PHONE NUMBERS
Product Information: 1-800-441-7515
Transport Emergency: 1-800-424-9300 (CHEMTREC)
Medical Emergency: 1-800-441-3637
COMPOSITION/INFORMATION ON INGREDIENTS
Components
Material CAS Number %
Corian® solid surface material 100
Exposure limits may be applicable for the following:
Methyl Methacrylate <1
Butyl Acrylate <1
Components (Remarks)
Material is not known to contain toxic chemicals under Section 313 of Title III of the Superfund Amendments and
Reauthorization Act of 1986 and 40 CFR part 372.
HAZARDS IDENTIFICATION
Potential Health Effects
Corian® solid surface material is not hazardous as shipped. However, operations such as sawing, routing, drilling and sanding can generate dust. High concentrations of dust can irritate eyes, nose and respiratory passages and cause coughing and sneezing. Since there are no exposure limits established for dust from Corian® solid surface material,
DuPont recommends using the exposure limits for polymethyl methacrylate. (See details in the Exposure
Controls/Personal Protection section of this technical bulletin.)
Corian® solid surface material does not off-gas at room temperature. At higher temperatures, small amounts of methyl methacrylate and butyl acrylate can be released, the amounts of which are dependent upon temperature, time and
other variables.

Methyl methacrylate and butyl acrylate vapors can irritate eyes, skin, nose and throat and can cause allergic skin rashes.Overexposure to vapors of methyl methacrylate can cause headache, nausea, weakness and lung irritation with cough,
discomfort and shortness of breath. Individuals with preexisting diseases of the lungs or skin may have increased susceptibility to the effects of overexposure to methyl methacrylate or butyl acrylate.

Carcinogenicity Information
None of the components present in this material at concentrations equal to or greater than 0.1% are listed by IARC,
NTP, OSHA or ACGIH as a carcinogen.
FIRST AID MEASURES
First Aid
INHALATION
No specific intervention is indicated as the compound is not likely to be hazardous by inhalation.
However, if large amounts of dust are inhaled, or if exposed to fumes from overheating or combustion, remove to
fresh air. Consult a physician if breathing is difficult or if symptoms persist.
SKIN CONTACT
The compound is not likely to be hazardous by skin contact but cleansing the skin after use is advisable.
EYE CONTACT
In case of contact, immediately flush eyes with plenty of water for at least 15 minutes. Call a physician.
INGESTION
No specific intervention is indicated as compound is not likely to be hazardous by ingestion.
Consult a physician if necessary.
FIRE FIGHTING MEASURES
Flammable Properties
Corian® solid surface material can be combusted only with difficulty.
Hazardous gases/vapors produced in a fire are carbon monoxide, methyl methacrylate, butyl acrylate and aldehydes.
Extinguishing Media
Water, dry chemical, CO2, foam
Fire Fighting Instructions
Keep personnel removed and upwind of fire. Wear self-contained breathing apparatus.
ACCIDENTAL RELEASE MEASURES
Safeguards (Personnel)
NOTE: Review “Fire Fighting Measures” and “Handling (Personnel)” sections before proceeding with cleanup.
Use appropriate “Personal Protective Equipment” during cleanup.
Spill Cleanup
Recover undamaged and minimally contaminated material for reuse and reclamation.
HANDLING AND STORAGE
Handling (Personnel)
Avoid breathing dust.
Avoid breathing fumes generated during heating. Temperatures reached while thermoforming Corian® solid surface material are high enough to release some methyl methacrylate or butyl acrylate. Machining operations during fabrication, such as sawing, sanding or routing, create friction and may result in temperatures high enough to release small amounts of methyl methacrylate or butyl acrylate at the cutting tool surface.
EXPOSURE CONTROLS/PERSONAL PROTECTION
Engineering Controls
Use ventilation that is adequate to keep employee exposure to airborne concentrations below recommended limits.
Provide for appropriate exhaust ventilation and dust collection at machinery.
Personal Protective Equipment
EYE/FACE PROTECTION
Wear safety glasses during operations such as sawing, sanding, drilling or routing.
RESPIRATORS
During grinding, sanding or sawing operations, if airborne particulate concentrations are expected to exceed
permissible exposure limits, use a half-face, NIOSH-approved, air-purifying respirator with type N100 filter.
Respirators should be selected based on the form and concentration of the contaminant in air and in accordance
with OSHA Respiratory Protection Standard CFR 1910.134.
PROTECTIVE CLOTHING
Wear leather or cotton gloves when handling large pieces and during operations such as sawing, routing or drilling.

OK FRIENDS NOW YOU KNOW THE TRUTH ABOUT DELRIN CORIAN AND MACHINING ANY MATERIAL FROM A SAFETY STANDPOINT - NOW GO MAKE SOME BRIDGES & LET US KNOW HOW THEY SOUND
Your Friend
Hamletsghost 8)

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Lars

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Reply with quote  #10 
Wow Brian, Ok then....I see you feel strongly about Delrin and faux marrow and all and I'm happy for you! If it feels right then DO IT but I still stand by my opinion and stick with what my little amount of experience has given me and be happy with it and leave the last word to you. 8)
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Hamletsghost

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Reply with quote  #11 
NO NO MY FRIEND - YOU MISUNDERSTAND
This was NOT to say Delrin OR Corian was the end all be all substance for Jawari - This was to get out the proper info on both substances and more a tutorial reminder to WEAR YOUR PROTECTIVE GEAR when working with any substance and KNOW what your working with. I do believe you when you say Corian gives a good and pleasing sound just as Delrin does (with or without the simulated marrow ). With your many years and vast experience I am sure You and Scott have tried MANY subtances - and we trust you implicitly.
I Just wanted proper info out there when you're thowing out statements like "Delrin can be toxic when heated etc "
( I think Power tools would be hard pressed to get Delrin over 446f don't you? - The heat factor is why it's recommended for machine tool guide bearings - remains stable even at extremely HIGH speeds and heat transfer - 1st hand that)
This type of statement might frighten some away - This is why I printed BOTH MSDS'S so that our friends on the Forum can make a truely informed decision and to emphasise - DO YOUR RESEARCH no matter what you're working with - be it Jawari Bone substitutes - French Polish (talk about some TOXIC Goo ) Urethane - Polymers - Dust from Ebony ( REALLY BAD that) etc etc etc -
KNOW THE HAZARDS B-4 You start working with ANYTHING.

Your Friendly
Hamletsghost 8)

PS: Isn't it interresting Dupont makes both substances we are experimenting with

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