Carbide and Lye (Oven Cleaner) - Problems?

[Jacob Reverb]

Hey, all,

I've always used spray-on oven cleaner containing lye (sodium hydroxide) to remove pitch/gum from my saw blades, and it works darn well.

However yesterday I watched this video that came with my Freud router and they said NOT to use lye or oven cleaner on their router cutters, suggesting that the lye could harm the carbide. Instead, they said to soak router bits in kerosene to remove pitch.

I've never heard of lye harming carbide before, and although I once wondered whether lye might harm the brazed joints, I haven't seen any signs of that either...what gives?

[Mike Gott]

I have always been told never to use anything like oven cleaner on brazed carbide tiped blades and bits, I was told it could possibly damage something in the brazing that holds the carbide to the steel plate or shaft. The DeWalt site has addressed this exact issue and you'll find everything you may be asking at the link I pasted below:

http://www.dewalt.com/us/articles/article.asp?Site=woodworking&ID=353

Mike

[David G Baker]

My Dad and brother had a paint stripping business and most metals that were nonferrous would dissolve in the chemical stripper. The chemical was a lye/sodium hydroxide product. I never checked to see if it dissolved brazed items.

[glenn bradley]

I've never heard of lye harming carbide before,

There have been many magazine articles and forum discussion on the corrosive effects of oven cleaner. There have also, like you, been those that report using it for extended periods of time without launching a blade tooth. A mild citrus cleaner works well for me but there have been a couple of times I was tempted to reach for the Easy-Off. I just let 'em soak for 30 minutes instead.

[Josiah Bartlett]

It may attack the brazing, and it is probably a long term effect. I mainly don't use lye on saw blades because I don't want to have any flung into my eyes when I turn on the saw. Usually carbide blades have little nooks and crannies in the brazing that hold liquids pretty well.

[Cliff Rohrabacher]

It can attack the brazing setting the carbide loose.

[Ray Moser]

A friend has had good results using 'Simple Green' to remove pitch from saw blades. He says a brief soak and the stuff wipes right off and the product is supposedly more environmentaly friendly than those with lye. And not as tough on the skin.

[Howard Acheson]

Never, never, NEVER use oven cleaner on carbide tooling.

[John Gregory]

I too have used Simple Green with success. Effective and safe.


A friend has had good results using 'Simple Green' to remove pitch from saw blades. He says a brief soak and the stuff wipes right off and the product is supposedly more environmentaly friendly than those with lye. And not as tough on the skin.

[JohnT Fitzgerald]

There was a review of cleaners in one of my WW mags recently, I'll try to dig it up. I do remember them recommending Simple Green and 409. They also recommended not using oven cleaners.

[Jim Weisgram]

I used to use Simple Green (immerse and soak for a while). Their web site now advises against it that; it can damage the carbide. I guess if you use it right after sawing and before the pitch hardens it can be sprayed on and wiped off.

I'm now looking for a better alternative, so far it appears to be get a jug of CMT.

[Tom Walz]

As near as I can tell this all started with some of my research. In 1997 I was granted U.S. Patent Number 5,624,626. In it I explain how you can use a bath of 150 degree 15% sodium hydroxide as a medium for electric current to affect the surface of tungsten carbide. It is not the sodium hydroxide, it is the electric current.

We pretin millions and millions of tungsten carbide saw tips. (Pretinning is putting the braze alloy on the tip.) We deal with hundreds and hundreds of customers who make and repair saw blades and other tools. We have run our own tests. We have soaked pretinned saw tips in oven cleaner for a week and we have not seen any mass loss or any evidence of damage under microscopic examination.

What follows is something I did maybe a year ago on this topic. If you want more information go to www.carbideprocessors.com (http://www.carbideprocessors.com/) for information on carbide, braze alloy, saw blades.

Tom

Cleaning Saw Blades

Sawfiler Opinions


Victor Da silva
I came up with the tank cut in half & water heater element years ago, except I used an old galvanized pressure tank, which had thicker walls. I use Saw Kleen, distributed by J Tool Express, which, according to the manufacturer, works better when heated. Heating any solution will help soften the pitch & gum, making it easier to brush off.

That being said, I eventually moved up to an ultrasonic tank, which really works great. I still use the Saw Kleen and heat it to about 175 degrees. Brand new units can be costly, although they are a great investment. I searched E Bay for a few weeks until I found a unit that could handle 12" blades laid down or 14" stacked on an angle. I put my saw blades on a galvanized carriage bolt with washers in between and can fit several stacks in at the same time. Nasty old chain saw blades have the gunk brush right off and the hose takes care of the rest.

Bob Cook
You can buy sodium hydroxide/Lye at most janitorial supply houses in 50 # bags for around $2.00 a pound. A stiff wire hanger suspending each individual saw blade from a rod across the top of the open drum will allow you to soak more saw blades at a time without the weight when removing them. A good machine coolant concentrate in the rinse water will let you drip dry the blades without rusting.

Mr Neil Franklin, Marietta Saw
Removing residue on plastic and Corian-cutting blades. I use a very concentrated solution of NaOH (sodium hydroxide) to loosen it, and then wearing long rubber gloves, I scrub the blades with a stiff plastic bristle scrub brush. What doesn't break loose with that procedure, I'll hit with a wire wheel on a bench grinder.

Rob Rzasa, Equipment Ltd.
We have a very good machine that will clean all types of blades and tools. We offer an ultrasonic tool cleaner in two sizes, one for saws up to 16" and another unit for saws up to 26", both machines will clean in excess of 24 to 36 blades at a time in about 5 to 7 minutes.

The easiest thing to find is: Red Devil Lye. A 16oz bottle costs about $ 4.00, we used to get it at Lowes but not every store carries it. The last time we bought some, we got it at Home Depot.

David Farris
I just ordered a drum of powder from ZEP with product number 9878 and is called heavy duty vat stripper and it says that heating the mixture works best.

Stan, Aksarben Saw & Tool, Inc.
I too use a solution of sodium hydroxide, however maybe not strong enough. Then we wash with soap and water, clean the edges, and polish the plate.

R.S. Ponton, ICE
Cut a 52gal steel drum around its "belly" forming 2 half tanks. One is used as a cold water rinse tank and the other is used as a heated sodium hydroxide (NaOH) soak tank.

The NaOH soak tank is constructed as follows: Purchase a 220V hot water heater heating element at a hardware store. It must be the straight type, a not folded-over type. Mount
it into the side of the tank at the bottom.

Drill random holes in a length of pipe which is long and large enough to cover the exposed length of the heating element inside the tank. This pipe serves as a physical protection guard for the heating element when sawblades are immersed into the tank. Mount it inside the tank at the bottom covering the exposed heating element. Wire the 220V heating element through a standard wall mount light switch and connect to a 20Amp 110V outlet.

Fill the tank with water and add about 6lbs of NaOH. Exercise care because NaOH is a very strong organic solvent.

The heating element can be left on all day and it will not overheat. No regulating thermostat is necessary because the element is 220V but powered by 110V, it provides an ideal soak bath temperature. It is advisable to switch-off the heater at night and on weekends. The heating element typically lasts about 5-6 years before needing replacing.

After a 5 minute soak in the heated NaOH tank, gummed sawblade are quickly cleaned. The worst gummed sawblades might require a few light strokes with a plastic bristle brush.

Add water and NaOH as necessary to maintain a full tank and a saturated solution. Change the solution periodically as residue accumulates in the tank. The solution can be dumped down the drain because it is the equivalent of Drano(tm) and should contain no hazardous products.

A handy "carrier" for holding the sawblades being cleaned can be fabricated as follows: Bend a 24" length of 3/8" steel rod or "all-thread" into an "L" shape with the foot of the "L" about 4" long to serve as a handle. Weld the straight end vertically in the center of a steel plate about 1/4"T x 1-1/2"W x 6"L. This carrier provides a simple means of containing a stack of sawblades while immersing them into the soak tank, the rinse tank, etc.

Stan, Aksarben Saw

Our shop does not heat the mixture. I use heavy rubber tubs used for livestock, big enough to lay 18" blade in the bottom. (Local farm supply store) I made a rod for holding the blades out of 1/2" rod with a threaded end on one end and a small plate welded to the other end. (about 16" long) I made T handle that screws to the theaded end. As we stack the blades on the rod we space each blade with 2" washers made of plastic mud flaps (Local truckstop gives them to us free) This whole arrangment is stored in a lockable cabnet.

Ed Bissell
For information only you might want to be careful what you put down your drain. Several issues to consider;
1. What is it going to do about the working bacteria system of your septic tank.
2. Is your system large enough to handle the volume your going to put in.
3. Last but most important, anything you discharge from your shop is considered industrial waste and must be disposed of properly. Big EPA problem if not handled correctly.

TSP (Tri Sodium Phosphate)
Marty at Carbide saws, Inc. in High Point, NC sent Emily a sample of this with a great drawing just in case Emily didn’t know how to scrub saw blades. They mix 1 pound per five gallons and really like the results.

Our Tests

Dip Tanks
There are a variety of chemical preparations available. Oakite #3 is a product that was recommended to us. It is effective on oxides and scale as well as oil and grease. Oakite is in New Jersey at 908 464-6900.

Pretty well any strong caustic solution from a janitorial supply will work. The problem with caustics is the danger. Hot caustic can burn skin and eyes. Working with a dip tank can make the danger much worse.

Caustic is popular and effective so we tested Easy off oven cleaner in spray can as well as “Oven & Grill Cleaner” from our local janitorial supply house.

Citrus based
We have been hearing good things about these so we tested a couple.
Citrus – from Orange Fresh and
Orange Clean form Orange Clean

We also tested 409 as well as Simple Green and Brakleen

$ / oz.
Brake cleaner - spray can 0.33
Simple Green 0.24
Caustic - Spray cans 0.23
Orange Clean 0.15
409 0.12
Caustic - spray bottle 0.10
Citrus - spray bottle 0.09
Citrus - spray bottle 0.06

One stood out for being really horrible: Brakleen is far and away the most expensive. It is the worst cleaner, it causes cancer and it can explode.

This is a great product for getting in very tight spaces and dissolving greases and other packed crud. However this is not what we are doing with saw cleaning. We want to dissolve a thin layer of light materials on a flat surface.

We tested the sprays with a 2 second spray and 8 wipes. We tested the liquids by holding the towel over the top of the bottle and tipping it to soak a patch on the towel and then giving that 8 wipes.

The cheap oven and grill cleaner was far and away the best cleaner followed by the Easy Off then the orange cleaners (no real difference among them). The 409 and Simple Green were not as effective and Brakleen was the worst at cleaning.

Safety
Brakleen is Carcinogenic as well as having other problems. All the rest cause skin and eye irritation. It looks like the caustic might be worse than the citrus which might be worse than the 409 and Simple Green. All recommend gloves and goggles. Aprons are a good idea and some recommend them. Brakleen mentions a respirator (not just a mask) if there is a possibility that the exposure limits maybe exceeded.
Basically the stronger they clean the more likely they are to irritate skin. Skin has oil sort of like any other oil so this makes sense.

Advice:
1. For best cleaning use a strong caustic such as an oven and grill cleaner.
2. Avoid brand names. Most of the extra ingredients are to make it easier to spray. You also get butane as a propellant and spraying butane in a saw shop doesn’t sound like a good idea.
3. We know one very good shop that uses an orange cleaner and likes it because they don’t have to rinse it off. Caustic compounds can be a bit hard to rinse.
4. Buy concentrate and mix your own. You can drop your cost in half and you can get the mixture you wish.


Two Additional Cleaners

Ram Cleaner & Picoclean 123 orange
Because cleanliness is absolutely essential to successful tipping we have done a great deal of research into it. Whether you are brazing carbide or welding on Stellite® tips you need a clean surface. Any oil or grease can interfere with the join and cause tip loss.
Picoclean is a highly advanced version of the traditional caustic cleaners. Ram cleaner is heavily solvent based with some caustic cleaner.

Some customers are using straight caustic cleaners such as Lye, caustic soda or sodium Hydroxide. Others are using a solvent such as Acetone, alcohol or similar. These seem to be the two most popular approaches and either can be very effective.

No matter which way you go you will almost certainly get better results using a specially formulated cleaner.

Both these cleaners are more effective than just plain chemicals. These cleaners will clean more types of oils and dirts and clean them better. They are specially formulated to rinse cleaner. A specially formulated cleaner will also give much greater service life.

PICO 123 Orange
I had read some articles written by Picoclean personnel so I called them with the problem of cleaning saw blades. They asked us to send them some really dirty saw blades. They then developed a special formulation for saw blades, and similar tools.

This concentrate has a high pH, it is made by PICO with a reacted caustic base to inhibit its effect on base metals such as carbide. This is a heavy-duty, water-based cleaner and degreaser used to dissolve a wide variety of ink, paint and resin coatings, dirt, oil, carbon and grease from floors, equipment and other substrates. It is biodegradable and has a pleasant odor as well as being formulated with non-solvent cleaning additives, surfactants and wetting agents, which are non-flammable and non-carcinogenic. This cleaner replaces flammable, toxic, hazardous solvent based products historically used for this type of cleaning and it forms a stable, low foaming solution when diluted with tap water and is completely free rinsing. Product features and benefits: biodegradable, non-flammable, water dilutable, low volatile emissions, high detergency, petroleum solvent free

PICOCLEAN 123 ORANGE has a variety of uses so that you can use the product for maintenance as well as a production saw blade cleaner.

PICOCLEAN 123 ORANGE does have a strong pH so that precautions should be followed by all workers handling the product and involved with any cleaning processes. After cleaning blades should be rinsed, then a corrosion inhibitor applied to bare steel to prevent any rusting.

Application:
Use this cleaner concentrated or diluted up to 50 parts with hot or cold tap water to remove the ink, paint or resin coatings, dirt, oil, carbon and grease from floors and other substrates. Note: time, temperature, concentration and severity of cleaning should be considered for total effectiveness. Use it as well in steam cleaning, soak tank cleaning, manual type cleaning operations and industrial floor cleaning machines. We recommend that parts are rinsed with water after use and coated with rust inhibitor if desired.

Recommended dilutions:
Dilutions will vary depending on the application. Heated soak tanks will probably run 5-10% and spray bottle hand cleaning about 3-5%. Heavy duty cleaning for dip tanks and fast cleaning. Spray bottles and other light cleaning use it at 4% (25 parts water to 1 part concentrated cleaner.

Ram Cleaner
RAM cleaner is very versatile. It can be used as a mild spray for things such as cleaning furniture and windows, or a full strength cleaner to clean things such as concrete driveways, boats, motorcycles, pools, and lots of other things! All you have to do is adjust the strength to fit the type of cleaning job! For small jobs, all you need is a small amount of RAM on a damp cloth or sponge, and wipe. RAM can clean tough problems such as rust, road tar, degreasing car engines, glue, and soap buildup.

Ram cleaner is based on several very potent solvents with some caustic cleaner added as well. It comes highly recommended to us in spite of the cost. See cost comparisons at the end of the article.

Safety Comparisons
Both cleaners are designed with safety as major consideration. However pitch, tar, grease, oil and many other substances are chemically similar to people so cleaner that affects them will also affect people. Read and follow the MSDS and the label.

Cost Comparisons
Ram Cleaner concentrate retails at $40 a quart while the Picoclean 123 orange concentrate retails at $15/ gallon. A quart is the minimum from Ram and a gallon is the minimum from Picoclean. If you buy a 55 gallon drum of Ram cleaner the concentrate is $0.06 per ounce and $0.011 diluted for heavy use. A 55 gallon drum of Picoclean is $0.05 per ounce as a concentrate and $0.005 per once diluted for heavy cleaning. Ram Cleaner has a heavier discount schedule than Pico does.


Dilution for Heavy Cleaning
Ram recommends 5:1 and Pico recommends 10:1 This makes the Ram cleaner for heavy use $0.25 per ounce diluted ounce while the Pico cleaner is $0.012 per ounce for heavy use.

Other Options
There are a variety of chemical preparations available. Oakite #3 is a product that was recommended to us. It is effective on oxides and scale as well as oil and grease. Oakite is in New Jersey at 908 464-6900.

A clean saw plate is critical to effective brazing. There are people who report good results with just a “gum and go” method. In other words the plates are notched and used with no special cleaning. There are other people who feel that additional cleaning is needed. One of the simplest procedures is to use a room temperature dip tank.

The solution we found was a water based solution of :
Master BXX
(Sodium Hydroxide)
Distributed by Pacific Chemical

This caustic solution should work faster and maybe better if warm or hot. After soaking, the plates are dried and sandblasted where possible. It is important that the plates be used pretty close to immediately. If they are allowed to sit the grease and oil in shop air can redirty them.

Machinery’s Handbook, 22nd Edition
“In order to obtain a sound joint the surfaces in and adjacent to the joint must be free from dirt, oil and oxides or other foreign matter at the time of brazing. Cleaning may be achieved by chemical or mechanical means. Some of the mechanical means employed are filing, grinding, scratch brushing and machining. The chemical means include the use of Trisodium Phosphate, Carbon Tetrachloride, and Trichloroethylene for removing oils and greases.

Soldering Stainless Steel: Stainless steel is somewhat more difficult to solder than other common metals. This is true because of a tightly adhering oxide film on the surface of the metal and because of its low thermal conductivity. The surface of the stainless steel must be thoroughly cleaned. This can be done by abrasion or by clean white pickling with acid.

Muriatic (Hydrochloric) acid saturated with Zinc or combinations of this mixture and 25% additional Muriatic acid or 10% additional Acetic acid, or 10 to 20% additional water solution of Orthophosphoric acid may all be used as fluxes for soldering stainless steel.”

The Electroplater’s Handbook
This recommends a 50/50 mixture of Benzene and Carbon Tetrachloride. This removes mineral grease and is followed by a caustic solution to remove animal greases. A recommended solution is one pound of Sodium Hydroxide per 2 1/2 gallons of water used hot.

A good caustic cleaning solution with abrasive action is:
2 ounces sodium Hydroxide
10 ounces Sodium carbonate
2 ounces sodium triphosphate
1 ounce sodium silicate
1 gallon water”

Metal Finishing Guidebook & Directory
“Degrease with a vapor degreaser or clean in a solvent emulsion such as a detergent containing naphtha. Then use an acid pickle to prepare the metal.”

The Brazing Book, Handy & Harman
“The surface must be clean of oil, grease, rust, scale, oxides and just plain dirt. If they are on the surface they will form a barrier between the braze material and the base metal surface. Oil will repel the flux and leave bare spots that will oxidize during brazing causing voids. Other kinds of oil and grease can carbonize forming a carbon surface over which solder will not flow. Braze material will not bond to a rusty or otherwise oxidized surface.”

Henley’s Formulas for Home and Workshop by Gardner D. Hiscox, M.E.
“The parts to be joined must be free from oxide and thoroughly clean; this can be secured by filing, scouring, scraping or pickling with acids. The edges must fit exactly, and be heated to the melting point of the solder.”

From saw users on the Internet

I did an Internet search. Here are recommended cleaners in alphabetical order. All of these have people who strongly favor them. Many have people who oppose them. Some I would not use for health or safety reasons. All can be dangerous. For MSDS info check

409
Pro Pride Heavy Duty Cleaner Degreaser' from 'Smart and Final'
Ammonia
Arm & Hammer washing SODA
Black Maxx
Bladesnbits
Boeshield Bit and Blade cleaner
Borax
brake fluid
bug and tar removers for cars
Castrol degrease
Castrol Super Clean
citrus-based cleaner
CMT Formula 2050
Dawn dishwashing detergent
Dawn Power Dissolver
De-Solve it
Dish Soaps (For a Dishwasher)
Do All machinery cleaner
Empire Blade Saver
Fantastic
Fast Orange hand cleaner
Freud fresolv(?)
Fume Free Easy Off Oven Cleaner
Gasoline
Goo Gone
Goof off
Goop
Greased Lightning
Hand Soaps
Hand Washing Dish Soaps
Hot tap water and a nylon brush
Kerosene
Krud Cleaner from HD
LA's Awesome Original Cleaner and Degreaser (undiluted)
Lestoil
Lye - a half teaspoon of lye and a drop of detergent in a quart of water
M.E.K
Mean Green
methyl hydrate
Mild Detergents
mineral spirits, but will use Naptha, Acetone, Toluene or gasoline if that's all I have.
most degreasers or citrus cleaners
Mr. Clean
Naphtha
Oil Eater
Orange Glow
Oven cleaner works well too
OxySolv, from Woodworker's Supply
Purple power
Rocklers cleaning kit
Rolloff
Scrubbing bubbles bathroom cleaner
Simple Green
Simple Green Xtreme
Solvents
spray carburetor cleaner
Spray Nine
strong coffee for long term soaking
Sudsy ammonia
TSP or tri sodium phosphate
Varsol
Washing Soda
water - just soak the overnight in a pan of water then scrub with a soft bristle brush.
WD-40
Woodcraft Resin Remover
Zep Purple

Can cleaners hurt carbide?
First, there are thousands of grades of carbide so discussing the properties of carbide is like discussing the properties of wood. Therefore, I suppose, everybody is right.

Freud is an excellent organization with a fine reputation. If they say that caustic solutions damage their blades then I believe them. However that is not what my research has shown on other grades of carbide. It is not what my research has shown of Freud blades either. I think there may be a bit of an effect but too small to be of practical concern. See the SEM argument above.

I think maybe this whole caustic thing started with my research. I have two patents (5,624,626 and 6,322,871) where we use a caustic solution to change etch the surface of tungsten carbide and related materials so we can braze them. This gets changed on the Internet over and over.

However the caustic has little or no effect on the carbide by itself. When you run an electric current through the material, as in EDM or in electro etching, the caustic solution serves as a medium to carry the current and the current acts on the difference in electrical susceptibility of the tungsten carbide and the cobalt to remove material. In order to make any practical difference in the surface of the carbide you need an extremely strong caustic solution and a lot of current for a long time.

The whole point of our research was to develop saw tips that stayed sharper much longer than carbide. To do this we wanted materials that resisted chemical attack of any kind. (See Forintek ((University of British Columbia)) report) Our saw blades cut green cedar, MDF, OSB and everything else you can think of.

Chemical attack is one of twelve factors we assess in building superior saw blades. Email me for a complete list. We are working on getting it on the web. It is in my book Building Superior Brazed Tools.

The handbook of Physics and Chemistry shows Cobalt as being soluble only in acid only. Even then an acid attack will create an inert surface on the cobalt that will slow or prevent any further attack.

I do not know what braze alloy Freud uses. Common braze alloys are about half silver and about a quarter copper and zinc with maybe a little nickel or tin or manganese. (AWS Bag-3, 7, 22, 24, etc.) Chemical attack on copper or cobalt as a pure metal is different than a chemical attack on a metal alloy. Iron corrodes differently than steel which corrodes differently than stainless steel.

Much of this argument is similar to arguing about whether you can lose weight by getting your hair cut. You can but it is not practically important.

Again I do not know about Freud blades but most blades are not significantly affected by any commercial chemical cleaner. In our test we found that BBG grill cleaner from a janitorial supply store was cheapest and worked best. Simple Green was good.

Anyway, that’s what my research shows. If you are interested I have primary sources for this.

Can cleaners hurt braze alloy?
When we want to remove braze alloy we use a combination of acids such as 1/3 hydrochloric acid, 1/3 Sulfuric acid and1/3 water. This works but is horrible strong.

We have soaked braze alloy in oven cleaner for a week with no discenible damage to the braze alloy.

How Carbide Wears Out
Typically people think that carbide is worn away. There are other considerations that are often much more important.

Tungsten carbide is actually tungsten carbide grains cemented with a metal, usually cobalt.
A. You can have individual grains breaking or pulling out.
B. You can generate an electrical potential through rubbing that will accelerate this.
C. You can get a chemical leaching that will dissolve the binder and let the grains fall out.
D. As with any chemical reaction of this sort the acids create a salt that protects underlying binder until the salt is abraded away so grain size and binder chemistry are also important.
E. You can get welding between the carbide and the material being cut depending on the carbide grade and the material.
F. Heat from rubbing can affect carbide so a slicker grade can increase life. G. You can get macro-fracturing (breaks large enough to see) and micro-fracturing. With some grades a good hit can start a fracture (fracture propagation) that will sometimes run and sometimes not (fracture propagation). H. The binder is a metal so it can flex and fatigue.
I. If there is too much binder the part can deform.

Theoretical considerations
1. Macrofracture – big chunks break off or the whole part breaks
2. Microfracture – edge chipping
3. Crack Initiation – How hard it is to start a crack
4. Crack propagation =- how fast and how far the crack runs once started
5. Erosion – the binder leaches away and the carbide grains fall out
6. Electrochemical effect – erosion compounded by the differences in electrical resistivity between carbide and cobalt
7. Wear – the grains and the binder just plain wear down
8. Physical Adhesion – the grains get physically pulled out. Think of sharp edges of the grains getting pulled by wood fibers.
9. Chemical adhesion – think of the grains as getting glued to the material being cut such as MDF, fibreboard, etc.
10. Metal fatigue – The metal binder gets bent and fatigues like bending a piece of steel or other metal
11. Heat – adds to the whole thing especially as a saw goes in and out of a cut. The outside gets hotter faster than the inside. As the outside grows rapidly with the heat the inside doesn’t grow as fast and this creates stress that tends to cause flaking (spalling) on the outside.
12. Tribology – as the tip moves though the material it is an acid environment and the heat and friction of the cutting create a combination of forces.

Actual Practice
1. Straight wear – almost never found alone and typically not the most important reason.
2. Fracture of individual grains
3. Grains being torn out
4. An electrical effect through rubbing that will accelerating grain fall out.
5. Chemical leaching that will dissolve the binder and let the grains fall out.
6. Chemical leaching is affected by grain size
7. and binder chemistry
8. You can get welding between the carbide and the material being cut depending on the carbide grade and the material.
9. Heat from rubbing can affect carbide so a slicker grade can increase life.
10. You can get macro-fracturing (breaks large enough to see) and
11. micro-fracturing.
12. With some grades a good hit can start a fracture (fracture propagation) that will
13. sometimes run and
14. sometimes not (fracture propagation).
15. The binder is a metal so it can flex and
16. fatigue.
17. If there is too much binder the part can deform.

[Jim Weisgram]

A little more web searching found several people recommending washing soda (not baking soda) in warm water. Supposed to be very fast. I've *got* to get some (it's in the laundry section of a grocery store) and try it out.

[Tom Walz]

Washing soda MSDS

https://fscimage.fishersci.com/msds/21083.htm

[Bill White]

A little more web searching found several people recommending washing soda (not baking soda) in warm water. Supposed to be very fast. I've *got* to get some (it's in the laundry section of a grocery store) and try it out.


This stuff works, is not caustic, is bio, flush it down the drain, is cheap. What else do ya want?
Bill

[Charlie Plesums]

A friend has had good results using 'Simple Green' to remove pitch from saw blades. He says a brief soak and the stuff wipes right off and the product is supposedly more environmentaly friendly than those with lye. And not as tough on the skin.


I too have used Simple Green with success. Effective and safe.

I used Simple Green until I saw a response from the makers of Simple Green, posted on a forum (perhaps this one), that said to NOT soak saw blades in Simple Green.

I also saw something that said the FAA did not allow Simple Green to be used on airplanes, because if it seeped into a crack or joint, it could corrode the structure (not a good thing to do to airplanes).

I found it interesting that "Simple Green Extreme" had been approved by the FAA... apparently the "Extreme" version is less corrosive. After looking for a long time, I finally found the Extreme version available at Sams club in gallon jugs of concentrate. That is probably more than a lifetime supply, but it works good.

[Charles McCracken]

As near as I can tell this all started with some of my research. In 1997 I was granted U.S. Patent Number 5,624,626. I

Tom,

I assure you that my admonishments against using caustics predate your patent by a number of years and those from Freud in general by a number of decades. Being a manufacturer of carbide gives us a little knowledge about it. Here are some photos from our SEM showing the damage from 24 hours of soaking in a popular commercial cleaner (which will remain unnamed) that is less caustic than oven cleaner:

Before:
http://s91443592.onlinehome.us/BeforeMedium.jpg

After:
http://s91443592.onlinehome.us/AfterMedium.jpg

[Greg Funk]

Tom,

I assure you that my admonishments against using caustics predate your patent by a number of years and those from Freud in general by a number of decades. Being a manufacturer of carbide gives us a little knowledge about it. Here are some photos from our SEM showing the damage from 24 hours of soaking in a popular commercial cleaner (which will remain unnamed) that is less caustic than oven cleaner:

Charles,

Do you think there would be much of an effect if one used oven cleaner for 5 minutes? Basically spray it on and wipe it off followed by rinsing?

Greg

[Tom Walz]

Dear Mr. McCracken:

I am afraid that I owe you an apology. I didn’t read your information closely enough. Our whole focus has been on carbide developments in the last few years. We ran our test last year with oven cleaner and a modern grade of carbide with an alloy binder instead of straight cobalt. Finally, our tests were designed to give a practical answer to the home user or commercial saw shop.

As I understand your post we ran our tests several decades after yours on a more modern material using a different chemical and with a different objective. Hardly the same thing and I should have picked that up.

In any case I apologize again for not paying more attention.

Tom Walz

[Charles McCracken]

Charles,

Do you think there would be much of an effect if one used oven cleaner for 5 minutes? Basically spray it on and wipe it off followed by rinsing?

Greg

Greg,

All exposure is bad, it's just a matter of severity. I do not recommend exposure to oven cleaner using any method. Soak in a vented container of kerosene and scrub clean with a stiff nylon bristle brush.

[Charles McCracken]

Dear Mr. Waltz,

Evidently, I did not make myself clear enough for you. I did not mention a time frame for the test above, nor did I mention the composition of the carbide but I do appreciate the imaginative way you chose to fill those blanks for me. The test was performed in the last 18 months using a "modern" carbide. At least it was at that time but we are constantly developing new blends.

[Tom Walz]

Dear Mr. McCracken:

Let me apologize again, then. I really am not trying to fight. It has been my experience that these sorts of discussion usually boil down to differences of viewpoint and comparing viewpoints leads to an increase in knowledge for all.

I took the best data I could from the information you gave. If you could tell me where the paper is I would be happy to read it.

My research is the only research that I have ever seen where a caustic substance affected carbide. All the literature, starting with the CRC Handbook of Physics and Chemistry and continuing through the latest research at Forintek, show that acids effect tungsten carbide, not basic solutions.

Again I will apologize. In no way am I implying that you are incorrect. I just wish to reconcile the differences. I have had the pleasure of working with Freud R&D scientists and engineers over the years, and found them to be invariably intelligent, knowledgeable, unfailingly polite and almost always with a good sense of humor.

I will certainly amend my literature to include your statement. I am sure you are correct. De Walt also issues a similar caution and I will include them as well.

A great deal of what we see falls under the ‘haircut rule’. You can lose weight by getting your haircut but it is not a major factor. In my opinion, based on 27 years on the industrial side, and twenty years of my research and others research your reference is the only one I have ever seen to caustic solutions damaging carbide. Again I don’t mean to imply that you are wrong just that we are looking at things differently.

I am going to be running some experiments and, if you wish, I will run a second set of samples for Freud to analyze. I would also be happy to include Freud tips in the test as well, if you wish.

It would be really nice for woodworkers everywhere if there was some sort of definite answer to this question is.

Sincerely,

Tom Walz

[Jim Weisgram]

OK, based on the MSDS, use rubber gloves and safety glasses... I did get some and it did get the crud off very quickly. I had to scrub for a few seconds with a toothbrush.

Also since it is a water based chemical you should plan to to rinse well and then use something like WD-40 afterwards.