52 replies to this topic

[Rick]

I have come upon some full hard brass, tin plated. Would that be objected to in your organization? For chassis use.

[tonyp]

In my opinion it would not be legal. We already went through this with the silver brass pieces Chicagoland made several years ago. One other thing the tech inspector would have to check and no way to be sure it is actually brass under plating and not bronze which would be much better than brass in certain designs.

[Samiam]

Just punch out some vintage re-pop stuff with it. Pans, drop arms, etc. 

[Bryan Warmack]

We went through a similar thing out here at BPR when I came across some nickel plated phosphor bronze sheet that was almost like spring steel. The phosphor bronze is much more orange in color than brass and not legal.

 

Maybe you could grind off the plating, Rick, as it might be very thin and a 320 grit 3" sanding disc with a high speed grinder might do the job...

[Rick]

Yes, Brian, the plating is very thin, prob .0002, It took most of it off on the Backatcha piece on one side by tumbling the pieces. You can see the brass on the edges where the laser cut it and this shop is ISO certified so every bit of material has the certs to back it up...

[idare2bdul]

Sigh, where are the hard fought conflicts of old. Fortunately dead and buried. The funny part for me is that back in the days of our misspent youth we built because you couldn't buy a competitive chassis or motor over the counter. Now we have to protect our retro chassis from the fast cheap products that are readily available. There is also the assumption(probably valid) that is ok to have home built chassis legal( even if built by local pro's) but that motor building would be bad for the sport. I guess there were always more chassis builders than motor builders and todays cheap sealed motors make a pretty good argument for their use.

Still it might be fun to have an ARCO rules race possibly using D cans.

[Samiam]

I see this thread has drifted  to the age old debate of  " Built vs Sealed "  motors. But I'll take the bait.

 

I will race in Mike's ARCO race.. But let me warn you. I'll be sporting this 'ole 16-D:

http://slotblog.net/...-well-champion/

 

Or one just like it.

[Rick]

It has not drifted, it was just ignored. But the doubt was instilled, maybe he's trying to sneak bronze in. It is tin plated BRASS, full hard. The full hard was the important part! ...............

[Samiam]

Rick,

How thick is this FHB ( Full hard brass) ?

 

I would think the parts can be bottom sanded rather easily. This would make it very plain to the inspector what it is.

[Cheater]

It has not drifted, it was just ignored.

No, the question is not being ignored. With five members on the IRRA BoD, there is often a lot of discussion so instantaneous answers are not always possible.

[Noose]

And one is trying to get away from a hurricane.

[Matt Sheldon]

It has not drifted, it was just ignored. But the doubt was instilled, maybe he's trying to sneak bronze in. It is tin plated BRASS, full hard. The full hard was the important part!...

First, I give props to Rick for asking. 99% would have just used the brass as it is just brass to most of us.
 
There is a chassis kit that used what Rick is inquiring about, but not sure if they are still being offered. I have one and it was part of my materials that I submitted to the lab when I wanted to understand the properties a little better.
 
The terms "hard brass" and "full hard brass" are being used loosely here. By what I have seen Rick post on Facebook and here I would say that if the technology was around during the era it should be legal because it is not "hard brass." It is simply hardened by the coating and not the molecular build up of the brass. While completely different process, it is similar to hard anodizing to where it increases surface resistance which translates to the psi numbers. Not sure if what he has falls into a beta classification category.
 
in general the hardness comes from the ratio between the brass and zinc. The higher percentage of zinc, the harder the brass. Beta brasses are typically the hardest with Rockwell ratings of H04 and H06 if you are really looking for true full hard brass. Another method of hardening brass that would in my opinion be completely legal is through annealing. This is an easy process that can double the psi and tensile rating of almost any malleable material. Now that being said there is hard brass that also consists of bronze and that is where the "ooohhhh scary" concern is. Like many things how will the average person be able to tell just what the hell is being used.
 
Why would I offer this info up? There has been a lot of hoopla over something that at least for those involved have not been tested yet. It is a one and done bend in an accident and it has no memory. It acts like a stainless material with a hard shell and soft center. The reason of concern with bending it at a 90 and the coating is that typically the coating will not conform when stretched while making the bend and cracks. As Rick has shown there are ways around it. Additionally the real question is if there is a benefit to using hard brass? Sure it is more durable, but you reduce the ability to straighten it out mid-race. Hard or not, it still bends (keep your mind out of the gutter).
 
I would assume the time to look at all this and what it does to the future of materials used is what the BoD is looking at.

[MSwiss]

By what I have seen Rick post on Facebook and here I would say that if the technology was around during the era it should be legal because it is not "hard brass".

The technology being around back in the day has nothing to do with IRRA^® deeming something legal or illegal.

I'm glad Rick brought this up.

The IRRA^® has been due to tighten up the rules involving plating brass and allowing nickel silver brass.

[Bill from NH]

"Full Hard Brass" chassis parts in the '70s were neither plated nor coated with something.else.  Are you using the term "hard brass" today to describe a product such as "printers brass"? Not too common, but it's still around.

[Rick]

The plating has nothing to do with the hardness, it is tin. Think of solder. The brass under the plating is full hard. This was a special order of material probably because of its electrical qualities for the function intended. My laser dood, told me he has some left over. Simple as that. But would be a plus for chassis function because of being full hard.

 

Here is a pic of the backatcha that tumbling removed all the plating. I guess I could just extend tumbling process and remove it all and end the discussion, but thought the thin coating would stay good looking and easy to solder to.

 

 

[Matt Sheldon]

My misunderstanding as on a Facebook post I though you stated it had a hard coating.
 
So it more than likely has 50-55% zinc. As long as there is no bronze I guess I do not see the issue.
 
If we are allowed to paint the chassis, coatings should not be a concern.

[Greg VanPeenen]

You never know that stuff may have already been used. With the tin plating removed you would never know the difference. Better buy a hardness tester fast. LMAO. Its brass not silver nickel brass.

 

GVP.

[MSwiss]

GVP,

 

Why are you assuming we will need a hardness tester or have ruled against Rick's piece?

The question is whether we would allow plating or coating.

The above back piece, while the picture isn't great, on my phone, if it's yellow brass, it would be legal.

[Matt Sheldon]

Hardness tester will simply show the hardness, not the material buildup. Many ways to achieve a psi or hardness number through various processes. Being held to a hardness number would be pretty ridiculous as the same 260 material for instance can have as many as 8 different ratings as I have found.

[Greg VanPeenen]

Ridiculous is the word I was looking for. Matt.

 

Making rules you can't enforce is crazy. Just like zapping the motors no way to police it. When Mosetti use hard brass in his retro kit there was no issue. Tumble the tin off and there should be no issue. Correct Mike.

 

But what if we plated Silver nickle Brass with yellow Brass. Now there is an idea. I just happen to know a guy who ran plating shops all his life.

 

 

GVP.

[Noose]

The question is about plating or coating. Sheesh

[MSwiss]

GVP,
Where do you see either a no zapping, or there is a hardness limit to the brass we allow, in the rules?

Of course, if Rick tumbled off whatever metal his chassis pc. is coated with, and a yellow brass piece remains, it is legal.

[MSwiss]

The question is about plating or coating. Sheesh

Joe,
I think we are supposed to be answering the questions, as if we were on that closed FB page, also. Lol

[Greg VanPeenen]

That's the simple answer I was looking for. Plating off it's legal. Plating on chassis parts not legal. Do I have it correct.

 

Thank you.

 

Regards,

GVP 

[tonyp]

As long as it's yellow brass with no plating, tining, painting etc it would be legal.