Mountain Buzz banner

1 - 20 of 29 Posts

·
Registered
Joined
·
1,085 Posts
Discussion Starter #1
I have an NRS Top Cat cataraft frame, & I love it, but I recently purchased a welded steel frame made of conduit that is larger but even lighter. Afrer another post in this forum recently referred to NRS frames as heavy, and it got me thinking. As a weight conscience rafter, would I save that much weight by going with a welded aluminum frame over a fitting aluminum frame?
 

·
Registered
Joined
·
3,344 Posts
Yes, a welded aluminum frame of the same dimensions as the NRS would be lighter. Think about the weight of all those LoPros you lose. I like my NRS because I can take it apart for winter storage and fly-in trips, and to adjust for different coolers & set-ups. But it's not a super lightweight frame for sure.
 

·
Registered
Joined
·
1,085 Posts
Discussion Starter #3
yeah, I'm with you. I love the versatility and modular design of the NRS. I just never thought of them as particularly heavy.

I must admit, I never thought the low pro fittings would make such a big difference. and I am now surprised at just how heavy my aluminum frame is.
 

·
Registered
Joined
·
166 Posts
I have heard on several occasions that on welded frames, going aluminum does not save much weight because you have to go to a bigger pipe to get equivalent strength as steel.

I don't know from experience how accurate that is, and I'm sure it varies from builder to builder. Maybe someone else can comment on that.

The new NRS lo-pros are significantly lighter, so that helps, but they are still heavy frames once you piece everything together.
 

·
Registered
Joined
·
4,607 Posts
The LoPro's are HEAVY! Yes, it will be heavier than a welded frame, heavier than a speedrail frame. That said, our raft frame has mostly LoPro's in the main structural connections, then I have some speedrail for a few crossbars (and 2nd rail of double rail) that can't go anywhere even if the setscrews loosen. The new LoPro's look to be super light, I think those are going to be an improvement for NRS.

The layout of stock NRS frames also often means an extra cross bar for the seat bracket that other frames don't necessarily have.
 

·
Registered
Joined
·
4,607 Posts
How much of a concern is rust on a galvy frame? I haven't seen much (maybe not any) on a close friend's galvy frame.
Oh, I was picturing the cat frames that I've seen which aren't galvanized. If you are looking at galvanized, search "games with frames", chip's old thread about building frames with fencing. It is very informative.
 

·
Registered
Joined
·
166 Posts
Oh, I was picturing the cat frames that I've seen which aren't galvanized. If you are looking at galvanized, search "games with frames", chip's old thread about building frames with fencing. It is very informative.
He said "conduit" so I was automatically thinking galvanized. Maybe there is some conduit that is not galvy, I don't know.

That is an interesting thread, thanks!

In my very limited experience and opinion, aluminum gets an overly positive rap compared to galvy. Aluminum is lighter but weaker, so you need more of it. A person building a custom aluminum frame needs to be a real aluminum expert. Aluminum done wrong has great potential to break after years of stress and use. There's also the awful black shit that rubs off on everything it touches.

I still like aluminum, and my NRS frame is mostly aluminum. I just think there are pros and cons to each to consider, along with the price tags.
 

·
Registered
Joined
·
4,607 Posts
He said "conduit" so I was automatically thinking galvanized. Maybe there is some conduit that is not galvy, I don't know.
This is a great case study in Buzz thread divergence. He says conduit, you say steel, I respond to steel with rust. It is like the whisper game, lol!
 

·
Registered
Joined
·
2,261 Posts
My NRS cat frame is heavy at the yolks, that is for sure. Its a beast to carry alone. Makes a difference with my 14 foot cat. That said, I would not worry about a slightly heavier frame on a raft. If you are getting close to the weight limits of a modern raft its not likely the frame's fault.
 

·
Registered
Joined
·
3,344 Posts
Getting rid of the yokes & lower bars with the switch from cat to raft has made a big difference in my frame weight. Plus the 50 million straps are gone....hallelujah!

My rafting buddy has several 10+ year old Recretec frames (cat & raft). They are aluminum, and are made with mostly square tubing. They break down nicely, and are the lightest frames I've ever come across.
 

·
Registered
Joined
·
2,191 Posts
I have an NRS Top Cat cataraft frame, & I love it, but I recently purchased a welded steel frame made of conduit that is larger but even lighter. Afrer another post in this forum recently referred to NRS frames as heavy, and it got me thinking. As a weight conscience rafter, would I save that much weight by going with a welded aluminum frame over a fitting aluminum frame?
It depends if the frame is designed and manufactured with the goal of being light weight.

Nrs pipe is sized to support a huge weight suspended across up to 84" span. Which means If your frame is 60" wide with nrs pipe, or you are not supporting a 300qt cooler, it's overdesigned.

Round tube is not as good as rectangular tube in supporting weight in this axis. Welds are a lot lighter than lo pros.

The advantage is much more pronounced in a cat frame as the frame provides all structure to the craft, there is more material as well as a third dimension.
 

·
Registered
Joined
·
2,191 Posts
It depends if the frame is designed and manufactured with the goal of being light weight.

Nrs pipe is sized to support a huge weight suspended across up to 84" span. Which means If your frame is 60" wide with nrs pipe, or you are not supporting a 300qt cooler, it's overdesigned.

Round tube is not as good as rectangular tube in supporting weight in this axis. Welds are a lot lighter than lo pros.

The advantage is much more pronounced in a cat frame as the frame provides all structure to the craft, there is more material as well as a third dimension.
Similarly a welded steel frame can be lightweight also if designed properly, or a tank if built with what is easily available or without attention to the mechanical properties of the materials
 

·
Registered
Joined
·
138 Posts
Avatard,
I have been thinking a bunch about this lately, and maybe this needs a new thread, but...I've been putting together my first legit personal raft this year, and I built a frame out of aluminum pipe and speed-rail fittings. It's effective, burly and heavy.

But, I can't help but thinking every time I move it that I could weld and bend up a steel frame that would be just as strong, and lighter (as well as at least somewhat more elegant in form and function)
I don't care about adjustability on the frame so much, as I can get that dialed in with the current one and make to those measurements...
I have experience in steel tube work, and I am curious what materials folks use to make nice, strong, steel frames.

I've seen conduit stuff, and I'm not to into it, as conduit is flimsy in weight-strength ratio, and I value my zinc-free lungs. I am not worried about rust, at all, as I could keep the steel finished easily...
Round tubing would be preferable....So maybe 1", or 1 1/4', 16 gauge?
 

·
Registered
Joined
·
2,191 Posts
No idea re materials. You probably want to make a good notching jig as well as some sort of stable level platform for setting up the frame. And bending thin wall pipe is not easy.

Then that leaves you with a need to powder coat.

A big but possibly rewarding project. Me, I'll just get a friend to help lift.
 

·
Registered
Joined
·
1,085 Posts
Discussion Starter #19
Get a speed boat. You'll find friends you never knew you had
I found that same thing with my cat. Everyone wants to go with me or use it, but no one wants to help me get cancellations. :?

Thanks for all of the help everyone
 

·
Registered
Joined
·
427 Posts
NRS frames are some of the heaviest on the market. I transitioned from an NRS to a welded aluminum frame and it completely transformed the boat. However, I sold the welded frame because I wanted to go back to a modular design. I estimate the old NRS weighed about 75 lbs while the welded aluminum probably weighed about 45 lbs. The 1'' IPS schedule 40 aluminum speedrail frame I built weighs about 55 lbs. Not as light as the welded frame, but certainly lighter than the NRS. Once I started using speedrail I have not gone back to NRS for anything...
 
1 - 20 of 29 Posts
Top