View Full Version : How to cut 1/2" thick Naval brass

08-06-2011, 06:53 PM
I have had this 4'X8' sheet of what is apparently salt water corrosion resistant Naval brass(or bronze) for years. This could be aluminum bronze. I am sure it is salt water corrosion resistant stuff. Came out of a Navy yard auction years ago. The guy who bid on it thought he was buying a pile of sheet metal,and this 1/2" sheet was inside the pile.

It has a beautiful golden color to it,and it is tough to cut.

I made a cannon out of a 5" bar of the same gold colored brass(or bronze).

Do I have to invest over $300.00 in a Milwaukee metal cutting circular saw and blade to cut it,or would a cheaper saw of similar amperage and RPM be suitable? After I get the brass sawn up,I'd have no further use for it,so I hate to spend a lot on it.

I'd obviously have to put suitable guards over the open side of the blade.

This sheet weighs about 800#. All I need to do is get it cut into more manageable size pieces so I can get it onto my Roll In bandsaw,where I have HSS tipped blades.

Any suggestions? Years ago I bought a good saber saw to try to cut it,but after quite a while,I only made it about 9",and stopped,afraid I'd ruin the new saw.

08-06-2011, 06:59 PM
A HF sawsall and a good quality metal cutting blade.

08-06-2011, 07:44 PM
Find someone with a plasma torch that is rated for 1/2 inch or more. A plasma torch will cut anything that conducts electricity. It is as easy to use as drawing with a magic marker. You can clamp a straightedge on the plate and make any size of squares or strips you want. It is a way better option than a circular saw.

Dr Stan
08-06-2011, 08:45 PM
Find someone with a plasma torch that is rated for 1/2 inch or more. A plasma torch will cut anything that conducts electricity. It is as easy to use as drawing with a magic marker. You can clamp a straightedge on the plate and make any size of squares or strips you want. It is a way better option than a circular saw.

Exactly what I'd recommend.

08-06-2011, 08:46 PM
Sell it and buy what you really need.

08-06-2011, 08:51 PM
Moving it to and from will be the killer. How about a water jet?

08-06-2011, 09:31 PM
If I sold it,I'd only get scrap value,and pay full price for what I bought!!

Normally,I just saw up what I need,but this plate is way too heavy to get up onto a saw,if I had one with a huge ball bearing table.

Probably,I'll get a Milwaukee metal saw and saw it into manageable pieces using a clamped on fence to stay in the same kerf if multiple passes are needed.

There is an Arcet store not too far away. I might ask what they'd charge to plasma cut it. I think there will be some damage to the material near the cut,though,and probably fumes to stay away from,too. The brass is out of doors.

I just hate to buy an expensive saw that I'll only use once.

Just Bob Again
08-06-2011, 09:36 PM
Zero rake on the blade. 800 pounds is worth probably over 2 grand as scrap. Red brass spot prices are up around $3/pound. Unless you can actually use most of it, sell or trade and get what you can use.

08-06-2011, 09:39 PM
There will likely be a BIG difference in cutting aluminum bonze and naval brass. Aluminum bronze is designed to resist wear in bearing applications. Naval brass is more to resist corrosion. Aluminum bronze is a very light gold color, Naval bronze is darker gold color.

I've cut 1/4 " engravers brass with a hand held skill saw and a wood cutting carbide blade. Worked nice, and it threw chips every where. If it is aluminum bronze you probably won't want to make much out of it anyway. Me, ifI neededto cut I would just use a skill saw and full protection. Most it would cost you is a blade. A lot of the secondary scrap resellers I;ve dealt with in the past use a skill say for the same thing. Proceed with caution.Cut 1/2 way through and flip if your nervous about it.

FYI, scrap value may suprise you. I have not checked in a while but was about $1.70 lb about 6 months ago. For 1200-1500 bucks you probably could get what you want.

08-06-2011, 09:46 PM
I have the metal cutting saw from Northern Tool and for $130.00 I'm really impressed, when I bought it I also got a spare blade which I still haven't used. The only thing you have to watch for is the random escaping chip they are really hot, the saw has a chip catcher built in but some escape. They say that it has a capacity of 1/4" but I've cut 3/4" steel just don't push to hard.

08-06-2011, 09:47 PM
I am pretty sure that it is Manganese bronze by now. It is a darker gold color.

The junk dealers have been after me to sell it,but,of course,at scrap value as the metal has no certification to prove exactly what it is.

08-06-2011, 09:48 PM
I brought some scrap to the yard yesterday and got $1.90 for yellow brass. I meant to ask for a price sheet but forgot. FWIW, my 25lbs of brass fetched 4x more money than my 120lbs of steel.

08-06-2011, 09:57 PM
If I was to try to cut it with a saw. Would use a worm drive saw . We used to cut 2 inch thick aluminum all day long with a worm drive Skill saw. Never tried brass though.

08-06-2011, 10:10 PM
This stuff looks like the same stuff I made a couple of cannons from. It was very tough,like turning stainless steel. Pretty sure by now it is manganese bronze.

I could just take my cheap orange B&D with a carbide blade and see if it will cut in a promising way before I buy something more expensive. With a fence clamped onto the plate,successive shallow cuts could be taken.

08-06-2011, 11:06 PM
Don't be too surprised if even carbide doesn't touch it. It depends on the hardness. If it was rolled to dimension and not annealed it could harder than the hobs of hell. I have a big chunk of bronze here two inches thick. I was trying to cut off a piece in my bandsaw using a good Lennox bimetal blade and the blade just skidded on it. It wouldn't cut at all. I finally succeeded in cutting it with my shaper and a cutoff style blade. Even then I managed to do a couple of soft crashes that broke the blade each time.

If you sell it you should get top dollar for scrap in that condition.

08-07-2011, 01:31 AM
Its going to take more than a plasma cutter rated for 1/2" to cut it. Probably something in the 3/4 to 1" range (60-70amps.) Brass is somewhat like copper and pretty tough to cut. I once tried to have a 1/4" brass piece cut on a 40 amp machine that should have been able to do up to 1/2". Hardly touched it. And what little did cut looked terrible.

Mike Burch
08-07-2011, 01:38 AM
Naval brass is still a brass, so it will dezincify in salt water, albeit rather more slowly than "ordinary" brass. Its most common use on boats is for the prop shaft tube.
Managanese bronze is, as I expect you know, not a bronze at all. It has zinc rather than tin as the alloying material, so it's really a brass. Although it is the commonest material used for boat props, after several years in the water is can eventually dezincify.
It can also be a real bitch to machine, as you have already discovered.
If you were feeling wealthy, you could always send a small piece to be analysed.

John Stevenson
08-07-2011, 06:15 AM
Ask yourself "What am I going to make out of the few bits I'm going to cut off after a lot of effort and cost "?

Then as others have said ask what it's worth and sell it.

You posted this exact same thread in January 2010 so in at least 18 months you haven't had a need for it but it's now gone up in price.

Added to this you still don't have a clue what you have, in the last post you thought you had aluminium bronze, now you are reaching for manganese bronze.

Or you could keep it as a conversational piece and post again in another 18 months, this time it could be nickel bronze?

Weston Bye
08-07-2011, 07:31 AM
Just get on with it. Hack a hunk off however you can, hacksaw, skilsaw, hammer and chisel, anvil and hardie, whatever. Then machine something - anything - out of it just to see how it machines. If it machines to your satisfaction you may learn something. Then decide how to render it into managable pieces.

08-07-2011, 08:30 AM
For what it's worth,I bought a good saber saw,and did cut about 9" into it with the same blade,so it will cut. Just was going too slow to be practical.

The dark gold color as opposed to the lighter gold color mentioned by another poster makes me pretty sure its manganese bronze,Sir John. Does look the same golden color as the cannon,which I was able to machine out of 5" bar stock.
If all you have to offer is sarcasm,John,keep it to yourself,and get back to putting servos on rotary tables. Posting a question here does give the jerks a chance to make out like I am stupid,doesn't it?

I think I can tell the difference between nickel and other stuff. I've had to prove that I do blacksmithing work. Need proof that I have worked this tough alloy? See new cannon thread.

If all else fails,I can get it plasma cut and bandsaw off the affected areas. I am not about to give this plate away for 1/3 the value to the junkers.

I don't actually need the brass,but I could make tools to sell from it,and sell pieces to others.

08-07-2011, 10:39 AM
Evan,I made the cannon with HSS tools,and bored it with a HSS drill.

I am sure the brass was meant to be used. Why would anyone make stuff that could not be cut,even with carbide? How would they make use of it?

The 9" cut I did put into the brass plate was also just a HSS cutter.

08-07-2011, 11:08 AM
You might see if there's anyone in your area that could cast it into usable shapes for you, for a % of the stock. Let them deal with cutting it up.

08-07-2011, 11:30 AM
FWIW, you can buy circular saw blades for cutting non-ferrous metal. I used one in my circular saw to rip about an inch of width off a 4' aluminum stair tread. It worked very well, but tiny aluminum chips went everywhere. I don't know how it would work on whatever you have, but the blade was $18.99 so it wouldn't be an expensive experiment...assuming you already have a saw.

I got this one:
There are lots of others, of course.

08-07-2011, 01:38 PM
I am thinking about purchasing a used Milwaukee metal cutting circular. It has a fully guarded blade. There is no opening on the front of the blade housing like there normally is on regular Skil type wood saws. They also make metal cutting blades.

SGW,that cheap blade looks a lot like the more expensive Milwaukee blade. The Milwaukee has cerment teeth.

08-07-2011, 03:50 PM
I've cut tons of metal with skill saws,everything from 2-1/2"Aluminum to 1/2 Steel.I've even accidentaly cutoff 1-1/2 x 1/4 steel angle with a common carbide woodworking blade.It's perfectly doable.

I would not run the saw at anything less than full depth however.Doing so insures the least number of teeth in the cut(less HP required)and more of the cutting forces are directed into the saws base rather than against your arm.Making multiplr shallow passes is asking for trouble IMHO.

08-07-2011, 04:14 PM
Sounds like a plan,Wierdscience.

08-07-2011, 08:48 PM
I am in with Weirdscience, use a skill saw and a cheap big box store carbide woodworking blade. Wear ear and eye protection and get er done.

08-07-2011, 11:15 PM
I am sure the brass was meant to be used. Why would anyone make stuff that could not be cut,even with carbide? How would they make use of it?

Because you are expected to treat it. You can generally buy materials in full hard conditions and that becomes your problem. Hard brasses and bronzes are notoriously difficult to cut. Some kinds are virtually unmachinable just as some alloys of steel can be.

Right now what you have is a very large and nearly impossible to handle sheet of money. It has very good value and can be used to buy quite a lot of similar material that is positively identified.

08-07-2011, 11:32 PM
Oh,I LIKE those big sheets of money!!

08-08-2011, 04:53 AM

For what it's worth,I bought a good saber saw,and did cut about 9" into it with the same blade,so it will cut. Just was going too slow to be practical.

So why haven't you done a 90Deg. cut and tried to turn it?

Value? worth what you can get on the day/hour. Cost more in checking than it's worth if your planning to retire on a sale. Are you sure it's not Gold? Why not get it analised so you know exactly what it is?

Regards Ian.

08-08-2011, 08:28 AM
Being a copper/tin/zinc alloy I would lop off a small piece and try annealing it.If it will anneal great,if not then maybe off to the scrap.

John Stevenson
08-08-2011, 08:37 AM
You need one of these.


:) :D

08-08-2011, 08:57 AM
Wierdscience: I have already cut a 9" cut into the brass plate with a saber saw,so it is established that it will saw,and is about the same toughness,and the same color as the cannon. I just need to use a more effective saw. Something stronger than Sir John has drawn just above! I think he covered just about everything except welding a blade cover over the exposed front side of the blade.

Circlip: The 9" cut put too much strain on the saber saw as it was. I think a good,strong Milwaukee(or equivalent) circular saw with a proper blade will not take very long to cut the material up. The time element doesn't matter as I am retired. My back trouble matters!

I may hire a helper I have to saw the plate up,anyway. I'd rather do that than be given a fraction of what the plate is worth,then pay full price for new material,plus shipping on the heavy stuff. I have full safety gear,and will make sure the job is doable before letting the helper do it. I'm expecting the circular saw route to be easy enough that I just do it myself. At the moment I am having a LOT of trouble with my right knee,coming from my sacrum. Also waiting for cooler weather,and ordering a proper saw and blade.

08-08-2011, 12:00 PM
You need one of these.

The saw in the thread that prompted that cartoon was recalled because the blade guard wouldn't close reliably which often resulted in the cord being cut.