Brass scupper tubes question

[riptide]

Im in the process of replacing the brass scupper tubes on my 77 23 sceptre.The old ones were not to bad and the wood blocks are a little wet but no rot.
Has anyone gone from 1"tubes to 1 1/4" dia tubes? I have some 1 1/4od 316 stainless tubing laying around I was thinking of using.
I know alot of you guys sealed them up and went thru the transom but mine worked fine and see no reason to change them except to increase the size to drain faster.
Just wondering if anyone went 1 1/4" and how they work and if its worth it? Thanks

[FLexpat]

That is pretty much what I am planning for my 23. I have some 1-1/4" 316 stainless tube, 0.030" wall, that I'm going to use. I plan on annealing the edges with a torch so I can flare them easily and I am also thinking about passivating the stainless in nitric acid before I put them in - not yet sure if that is necessary or smart though... gotta do some more homework.

[flyingfrizzle]

I would think the ss would work well if you could flare it. The brass flares ez with the right tool but the ss would not do well with that same tool. If you do something similar to what flex is saying it may work but hard as 316L is you may have a time getting the flare right.

[bigeasy1]

I thought about going to larger brass tubes when I replaced the originals on my Tsunami,but I was a little scared off by having to enlarge the tube exit hole on the hull where its got that wedge to help suck out the water.
I ended up leaving it the way it was.
I was new to this kind of stuff when I did the resto,but looking back,I wish I had,because the 1" brass tubes are no where near large enough to drain the deck fast enough.

Not sure on flaring the stainless,but if you go with brass,it helps a lot to anneal the brass with a torch before you flare them.Heat the tube red and just let it cool.Flares a lot easier,with no cracks at the edge of the flare. They can split sometimes if you flare them raw.

[Old'sCool]

Are you guys using o-rings under the flared flange on the brass tubes?? I had replaced these on my Whaler years ago and bought the tube and a bag of o-rings.I'll mail o-rings if anybody needs them. I think it's intended to "cushion" more than seal.

[FLexpat]

Thanks OC - PM sent. The 1-1/4" tubes have 156% of the flow area of the 1" tubes. I got 0.030" wall thickness from McMaster Carr since it was as thin as I could get - I don't think I can flare the 0.045" stuff; 0.030" will be challenging enough anyways. I think Moeller does not make the 1-1/4" brass tubes long enough for the scuppers. McMaster has 1-1/4 brass tube but I'm not sure if it is a marine alloy so I decided to add some 316 stainless to a recent buy and try it - maybe several times before I get it right. I'm not rushed for time since I haven't even finished the transom yet, much less started the decks.

[riptide]

Flexpat you are right they do not make the 1 1/4 brass tubes long enough. 3 7/8" is the longest I can find them which is an odd size. You can get 1" up to 8" long. I made my own flaring tool and did a test flare on .049 ss tubing it worked but took alot of muscle on the wrenches.You have to remove any burr inside and outside before you flare or the tubing can split.

[Bushwacker]

Originally Posted by FLexpat

. . . McMaster has 1-1/4 brass tube but I'm not sure if it is a marine alloy so I decided to add some 316 stainless to a recent buy and try it - maybe several times before I get it right. . .

If you ever get any leaks and the wood block gets wet around a stainless tube, you'll have the perfect conditions for crevice corrosion, due to moisture + lack of oxygen. The stainless might not be much better than brass in that situation!

[FLexpat]

Originally Posted by Bushwacker

If you ever get any leaks and the wood block gets wet around a stainless tube, you'll have the perfect conditions for crevice corrosion, due to moisture + lack of oxygen. The stainless might not be much better than brass in that situation!

I suspected so - thats why I was looking at passivating the stainless. After checking into it more, that is a PITA for this small of a job and nitric isn't cheap with hazmat shipping. Plan B is looking like using a fiberglass tube through the (soon to be replaced) block and a stainless tube inside of that. Redundancy works for me. Makes more work too - I don't want to finish too fast and have to start enjoying the boat. Should be easier to do since the cap is off for the transom recore.

[Old'sCool]

Seems like I bought 2' or so of the brass tube from McMaster years ago....anyway, I have the 1 1/4" ID O-Rings if anyone needs them let me know.