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Cermet saw blades vs Plasma

JoeKultgen

Registered
While this isn't technically welding, striking an arc is only the back half of metal fabrication. Until you have the parts you need, cut to the right size and shape, the welder doesn't help you much. The project I'm planning involves cuts in 4mm mild steel sheet measured in feet rather than inches. While it might be possible to do it with abrasive disks I'm looking for a better way. The disks have their place and I'm sure to use up a stack of them but long straight cuts probably isn't the best place for them. I'd also like to keep my equipment investment as low as possible while still getting things done in a workmanlike manner and a reasonable time frame.

I'll be running off a diesel powered generator, possibly a welder/generator combination if I can find one in my price range, (or adjust my price range to cover what I need). I don't mind taking a chance on burning up a cheap inverter welder on unstable power. Even the cheapest plasma cutter will cost two or three times that much. So I've been looking at metal cutting circular saw blades. They seem to break down into carbide and cermet. For long cuts on sheet, cermet looks like the way to go.

Most of the YT video looks like sponsored advertising for Diablo. Interesting, but they don't have a retail presence on this side of the planet. Makita is big here and a couple others will ship internationally. $45 is about the limit where customs charges kick in so it will probably be Makita. Does anyone here have experience with their cermet tipped circular saw blade?
https://www.amazon.com/Makita-36-Teeth-General-Purpose-Cermet-Tipped/dp/B00080FEVC?psc=1&SubscriptionId=AKIAILSHYYTFIVPWUY6Q&tag=duckduckgo-d-20&linkCode=xm2&camp=2025&creative=165953&creativeASIN=B00080FEVC#HLCXComparisonWidget_feature_div
 

JoeKultgen

Registered
what about a sawsall…?
I'll probably get one of those as well for shorter curved cuts. Diablo makes cermet blades for them too. I need to split two 4x8 sheets diagonally and take several lengthwise cuts on a couple more. That will most likely work best using either a plasma cutter or circular saw with a guide bar.
 

cobbadog

Registered
I've not heard of these type of saw cutting blades so I do like learning new stuff. Only thing that I feel you might need to consider is what happens if you chip or loose a tooth / teeth, it then becomes a BBQ hot plate and you will need another.
If using plasma the consumables should be easy to find and buy, are cheap compared to the blade and with a guide can cut straight or curved lines on a radius. Some plasma units come with a built in compressor but these are dearer than the ones available where you have to have your own compressor to supply the air so this is an extra cost as well.
I guess the other thing to consider is at the end of the job if you use the blades to do your cutting you will have some worn out blades. With a plasma cutter you will still have a usuable tool to keep or re-sell to re-coupe some costs.
Thats my thoughts anyway. It will be interesting to keep reading other replies especially on the benefits of using these blades.
 

JoeKultgen

Registered
I've not heard of these type of saw cutting blades so I do like learning new stuff. Only thing that I feel you might need to consider is what happens if you chip or loose a tooth / teeth, it then becomes a BBQ hot plate and you will need another. If using plasma the consumables should be easy to find and buy, are cheap compared to the blade and with a guide can cut straight or curved lines on a radius. Some plasma units come with a built in compressor but these are dearer than the ones available where you have to have your own compressor to supply the air so this is an extra cost as well. I guess the other thing to consider is at the end of the job if you use the blades to do your cutting you will have some worn out blades. With a plasma cutter you will still have a usuable tool to keep or re-sell to re-coupe some costs. Thats my thoughts anyway. It will be interesting to keep reading other replies especially on the benefits of using these blades.
The big problem I have with plasma is that I won't be operating off of mains power. The motor on a circular saw is a lot more tolerant of power fluctuations than the electronics inside a plasma cutter. Some of the biggest advances in my lifetime have been in materials technology. When I left high school cermet was pure science fiction, right up there with transparent aluminum, (that is also a real thing now). In some of the YT vids they zip through steel so easy it looks like some kind of movie special effects.

Cermet is only a little more expensive than the best grade of tungsten carbide and supposedly gets two to three times as many cuts. Either of them is more economical on a per cut basis than abrasive disks. However the extra hardness of cermet makes them more brittle. I worked for a while at a place that did carbide saws and other tooling. Properly installed in a properly designed tool the inserts held up well, but a relatively small bump from the wrong direction would break them. A saw designed to cut concrete often wouldn't survive falling off a work table onto a concrete floor. From what I've seen and read so far cermet is the same only more so. While it *can* out perform carbide by a wide margin, an unskilled or careless operator can drastically shorten the blades service life. That's why I was curious about how it performed for real people rather than the videos saying, "This is great, if the manufacturer wasn't loaning it to me for free I might actually buy it".
 

cobbadog

Registered
Yep, technology caught up and passed me by decades ago. I see your point with the blades so the only way to find out is to maybe hire one and do some cutting of similar thickness and grade steel and then you can make your own informed decision.
Would I want to go back to a car that runs points and condensor and a carby, not by choice, I am quite content to run fuel injection off a computer and save on fuel but get the extra HP.
 

Bear67

Subscriber
Last Subscription Date
02/02/2020
Not my job, but I was on site where Cermet was used to do some field mods to a new fabrication in 10 and 8 ga. mild steel. .
My observations.
Don't cut without guide for saw. If you don't hold the blade straight on the cut, it will self destruct.
Be careful starting the cut or the edge of the plate will nick the blade. They used 4 blades where one should have done the cuts.
My personal opinion is the saw should be a slower rpm, but I really did not have a dog in the hunt, so I kept my trap shut.
Personally I would have made a quick shop drawing and had the steel supplier/fab shop who supplied the steel, shear the plate to the needed panels.

For 50 + years when planning a project, I have gotten a quote from my steel supplier/fabrication shop and found they could shear and produce parts cheaper than I could torch or plasma cut the same. I recently had a 5 x 10 sheet of 10 ga sheared into 6 pieces for about $42 and there was no weld prep. That does not apply if I want it off of a Plasma or Laser CAD table--that costs more.
(did I say that I lust after a Plasma CAD/CAM table, but for my personal use at this point in my life it is not realistic--ONLY to dream)
 

CharlieB

Registered
I have a variety of hand held tools in my shop for cutting steel.
More and more, for sheet steel, I use a Dewalt variable speed jigsaw with a metal cutting blade in it.
I find the jigsaw much more user friendly than grinders and circular blades., and the jigsaw blades are cheap.
The last sheet steel job I did was with 1/8" thick sheet. I started with a new blade, made about 20' of cuts, and the blade still had plenty of life left.
For long straight cuts, I follow the edge of masking tape, and the cuts are straight and smooth enough for welding with no further prep.
I also like that shop clean-up is a lot easier because the shop isn't covered with the black grinding residue that abrasive discs sling everywhere.
 

JoeKultgen

Registered
From what I've found so far, most of the YouTube vids are BS. (I'm shocked, SHOCKED, I tell you.)

Tube, angle, channel, and bar stock are best handled by cermet in a reduced speed chop saw. Under those conditions a good carbide blade works nearly as well and is quite a bit cheaper in the larger diameters and tooth counts.

A circular saw is better for sheet, but if you also want to do other cutting, the reduced speed models from Makita or Milwaukee are the best option.

To get the best blade life cutting sheet with a cermet blade in a normal circular saw, you need a guide bar. The sheet needs to be fully supported including the cut off. The depth has to be adjusted to barely break through the back side. Go easy on the feed, *very* easy at the start of the cut. If you can avoid binding, side loading, or shock loading the teeth, they're great. Break those rules, break the teeth. Each one that breaks makes it that much easier to break the next. Where you might take out a single tooth on a carbide blade and stop in time to get it repaired cermet will completely destruct. They can technically be sharpened or repaired but it's sort of a catch 22. Where they have the knowledge and technology to do the repair, labor charges are high enough to keep it from being practical. Places where labor is cheap enough to make a repair worth the time, they have no idea how to fix it.

Bottom line, I'll probably try some of the less expensive Diablo blades in a borrowed saw while I'm stateside. Once the project is started I'll need to have several cutting options available so a single broken blade doesn't shut me down.
 

Scotty 2

Registered
If your considering plasma, what about good old oxy cutting?
If your going to be doing a fair bit of cutting over the years I'd invest in a cold cutting saw. No clean up and pretty straight cuts. Near all the portable tool makers make one or several now-a-days.

Cold saws do have a much lower spindle speed. I personally would not put a circular metal cutting blade into a saw designed to cut wood. Horses for causes.
 
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JoeKultgen

Registered
If your considering plasma, what about good old oxy cutting?
If your going to be doing a fair bit of cutting over the years I'd invest in a cold cutting saw. No clean up and pretty straight cuts. Near all the portable tool makers make one or several now-a-days.

Cold saws do have a much lower spindle speed. I personally would not put a circular metal cutting blade into a saw designed to cut wood. Horses for causes.
I'm in the Philippines, I'll be stateside for a while and commence the project I have planned on my return. While not a major reason for the trip, one of the perks will be shopping for tools and other items that are not readily available here. The Philippines is... different. In many cases, older technology and especially the consumables to support it just isn't available.

The phone system is a good example. This place is literally the texting capital of the entire planet. Cell phone text messages cost almost nothing to send and nothing at all to receive. However, cell phones hit the market well before the entire country was hard wired for the older system. If you want to get a hard wire phone line installed the wait can be over two years in some places and in much of the country they'll treat you like you're retarded for even asking. As a result, every piece of older equipment that hooked up to a phone line is rare to non-existent. You can't go to a swap meet or public market and find a old, hard wired, phone cheap. There is no pool of old phones pulled from service. Likewise no fax machines, telex, modems, hard wired security systems. All these things exist, but in relatively small numbers with little and expensive after market support.

Pretty much everybody here that does any sort of DIY has a welder even if it's an old AC buzz box. Normal house mains are 220v. Angle grinders and chop saws are common. O-A is generally confined to industrial settings served by volume suppliers of welding gases. Smaller shops, even smaller scrap yards often will not have a torch simply because the gas is too expensive. For what it costs to lease the bottles you can pay some guy to take things apart with an angle grinder.

When I return from the states I'll have a checked baggage allowance of roughly 100 lbs. included on my ticket. I can add another 50 lb. checked bag for $65. A freight consolidator, who fills cargo containers with smaller pre-paid boxes isn't much cheaper and it could take three months to arrive and pick up some nasty import duties coming through customs. I can get a good used contractor grade circular saw at a reasonable price here from an importer of Japanese surplus. They use blades with a 20mm arbor. I need to check the tang on recip saw blades and what types are available before I go stateside. Most power tool consumables sold here are sized to Japanese standards. Welding electrodes are widely available and inexpensive. House brand 3.2mm 6011 or 7018 can be had almost everywhere for less than a dollar a pound. 2.4mm is harder to find and may cost three times as much. 4x8 sheets of 4mm mild steel are a little over $70 each at the only supplier I've checked so far. I'll need at least ten sheets and should be able to shop around for a better deal on a bulk buy. I'll be working outdoors so a real bad mutha of an angle grinder may be my best option. After I have the minimum to get started I'll add tools later as the budget permits.
 

CharlieB

Registered
I'll be working outdoors so a real bad mutha of an angle grinder may be my best option.

That'll get the job done. My real bad mutha is a Black & Decker Wildcat grinder that I keep a 9" diameter cut-off disc on. It's cut everything from sheet metal to train rails. Very versatile, and nearly indestructible. Starting up a metal shop on a budget? My first purchases would be a welder, and a Wildcat.
 
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zuhnc

Subscriber
Last Subscription Date
12/08/2019
I recently had the opportunity to cut a 3/4" steel round with a Diablo metal-cutting blade in my circular saw (12 amp Craftsman). Sliced through it like the proverbial hot knife through butter; I was impressed. Prior to that I used the same blade to cut about 200 linear feet of pole barn siding and cut up some 1/16" plate. I won't use cut-off wheels again to cut plate or sheet, unless absolutely necessary, or where I can't get the saw to fit. Cost isn't too much to experiment with. Goggles, gloves and a face shield are a must; lots of tiny chips. zuhnc
 
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