titanium tubing | DeeperBlue.com Forums
  Guest viewing is limited
  • Welcome to the DeeperBlue.com Forums, the largest online community dedicated to Freediving, Scuba Diving and Spearfishing. To gain full access to the DeeperBlue.com Forums you must register for a free account. As a registered member you will be able to:

    • Join over 44,280+ fellow diving enthusiasts from around the world on this forum
    • Participate in and browse from over 516,210+ posts.
    • Communicate privately with other divers from around the world.
    • Post your own photos or view from 7,441+ user submitted images.
    • All this and much more...

    You can gain access to all this absolutely free when you register for an account, so sign up today!

titanium tubing

Thread Status: Hello , There was no answer in this thread for more than 60 days.
It can take a long time to get an up-to-date response or contact with relevant users.

ajwaverider

New Member
Jan 3, 2004
422
30
0
45
I came across some Ti tubing it's 1.250x.030 wall thinkness. I was thinking of making a barrel with it but not sure if it's strong enough. Anybody got any imput?
 

icarus pacific

Human-in-training
Nov 7, 2001
2,880
212
0
61
I have a couple of hybrids that use titanium pipe for the barrels and it's sweet stuff, but you better have real sharp tooling to work on it. The pipe derives it's strength from the tubular shape and less from the thickness in a situation like this, but you get over with the inherent stiffness of the titanium, so jump on it. :cool:

If you have a bunch of it, send some over this way.
 

ajwaverider

New Member
Jan 3, 2004
422
30
0
45
I bought it from a guy for $2.50 a foot for 20 feet.He has plenty the only prob is that He lives in Canada and it takes about 8 days
to get it .
 

efattah

Well-Known Member
Mar 2, 2001
3,294
487
173
Can you please send me this guy's contact info (for the tubing)?


Eric Fattah
BC, Canada
 

GilbertG.

New Member
Jul 28, 2004
113
23
0
Hold on, hold on guys. Don't be so quick to jump. Exercise some caution here. I don't want to seem like a party pooper but hear me out first since this is right up my alley. It would be terrible to hear of someone getting hurt.

Whether or not this material is strong enough depends on the type of titanium, the length of the barrel you intend to make, and the amount of power you intend to use.

I would say the tubing is plenty strong for anything up to a 45 inch barrel with 1 or 2 bands. But I would hesitate to make a gun much longer with more power. Realize that the wall is pretty thin, 0.030 inch. I wouldn't be saying anything if the wall was 0.05 or thicker. I ran some quick calcs and the geometric properties are only as good as the aluminum tubing on my Beuchat Mundial. And that bugger is really designed for one or two bands. Thin walled tubing under high compressive load may experience an instability failure known as buckling. It gets worse if the applied load (power bands) are not in line with the centerline of the tubing, which would cause it to bend. It gets even worse with longer tubing. Scariest of all is that buckling will occur quite suddenly, without much warning.

Also realize that there are all kinds of titanium allloys, some of which are very strong, more than twice the strength of aluminum and rivaling the strength of steels, and some only as strong as some types of heat treated aluminum. AJ, can you tell us what kind of titanium it is? If you're not sure what kind of titanium it is then its all speculation.

You could always test out a sample piece. Rig up a come-along (ratcheting mechanism) to a 500 pound fishing scale and hook it into the ends of the tube. Ratchet the sucker tight and keep going until you reach the amount of load you want the gun to be able to hold plus a little extra. If it doesn't buckle on itself at that load than all is good and you have enough confidence to build the gun of your design.

One other option, I'll buy some off of you, send it out to me and I'll do the testing for everyone else to see.

Gil:)
 

icarus pacific

Human-in-training
Nov 7, 2001
2,880
212
0
61
Very true Gilbert. What needs to be considered also is that the tubing should be filled with a solid dowel that will serve to keep the tube from filling with water, allow for holes to be drilled and tapped and to further add to the stiffness of the tube.

I agree that this wall thickness would be a stretch for much more than 50" and two 9/16" bands.
 

Ted Budion

Menace from the South
Aug 24, 2004
189
26
118
65
No so fast guys. Titanium barrels for spearguns aren't new. 20 something years ago, John and Bill Ernst had some spearguns with titanium barrels. They had 1" overall diameter. But, they were heavier than aluminium. If you're looking for lightness and flex-resistance, carbon fiber is the way to go.

Ted
 

efattah

Well-Known Member
Mar 2, 2001
3,294
487
173
The weakest titanium is grade 2 (commercially pure), which is slightly weaker than low-grade steel. However, grade 2 titanium is also more corrosion resistant than the common allows such as grade 5 (6Al-4V) etc...

I'm not interested in the tubing to make gun anyway.

Eric Fattah
BC, Canada
 

icarus pacific

Human-in-training
Nov 7, 2001
2,880
212
0
61
rofl

Carbon fiber is great stuff Ted, until you ding it on a rock and break a few of the strands. That point becomes a localized weak spot in the laminate that depends on the continuity of it's fiber(s) for strength. A few of us were talking about this last year and it's probably still available through the search function.

I've seen carbon fiber tubes, in an aerospace application, being subjected to the compression loading that would be imparted by the gun's bands, and the place(s) were there were faults in the laminations due to abuse, let go in a rather impressive fashion.

The letting go when there's a 5/16" shaft is sure to be even more impressive...

Hey Def, were you the guy that had the hookup on the triangular shaped, UHMW material that Merlo is using, from some industrial supply place like MacMaster? Lob me a PM.
 

ajwaverider

New Member
Jan 3, 2004
422
30
0
45
I'm not sure what grade I think he said grade 1 but not sure.
It's made by timet codeweld tubing . I though of another way to test it and I'll let you all know tomorrow how it turns out .Sven!
What would you use to fill the barrel and not weight it down?I looked on ebay and I could find only a piece of 1"x 40 " or so for $40 dollars so at $2.50 a foot I figered i'd give it a try .
 

icarus pacific

Human-in-training
Nov 7, 2001
2,880
212
0
61
I fill mine with Delrin that I turn down to fit the barrels tight. I let the tubes heat up a bit and put the rod in the freezer and then slam 'em in, like pressing in pistion pins. One I put the Delrin in at the points that I needed attachment points and filled the rest with 8lb foam. Both haven't leaked and weigh about the same in spite of one being 45" and 52"

You could probably use wood as well and pour epoxy over the ends to seal them up.
 

GilbertG.

New Member
Jul 28, 2004
113
23
0
AJ, Take some good pictures man. Can't wait to see um. By the way, don't forget the safety glasses and the flak jacket. Some titanium shrapnel might just come flying your way.:D

Like Sven said, its pretty impressive when the S%[email protected] starts to fly. Thats what I love about testing...
 

Alison

Offline
Mar 6, 2004
1,898
204
0
Originally posted by efattah
I'm not interested in the tubing to make gun anyway.

Eric Fattah
BC, Canada

Eric I have it from a reliable source that a 94 metre snorkel just isnt practical ;)
 

Ted Budion

Menace from the South
Aug 24, 2004
189
26
118
65
To Icarus Pacific

As for the carbon fiber barrels, I agree they may be too delicate. The problem you mentioned happened with earlier fin blades and barrels.

Also, I'm not an advocate for carbon fiber barrels in my particular use, which is medium to long guns (75 to 130cm) with heavy Tahitian shaft (7mm diam.) and strong 19mm diam. bands. In such rigs, eventhough the carbon fiber barrel won't flex, the recoil is massive. I prefer heavier and thicker aluminium barrels. The compensate the extra weight and have a balanced rig, those barrels either have more internal air volume (my case and a factory feature in my guns) or have some extra floatation, like a EVA sheeting a buddy of mine covered his barrels with.

The carbon fiber barreled guns made in European are devised to be used with light shafts (6 and 6,5mm diam.) so recoil isn't much of an issue. As for South African made euro-type rigs, I can't comment because I haven't used one myself. OTOH, I recall reading that Rob Allen's carbon fiber barrels are of heavier gauge when compared to european models, to absorb recoil.

Ted
Rio
 

ajwaverider

New Member
Jan 3, 2004
422
30
0
45
Originally posted by efattah
...

I'm not interested in the tubing to make gun anyway.

Eric Fattah
BC, Canada


Snorkel!I was wondering what else you would use it for .

This is the way I tested the tubing. I used the jack from my car and a bathroom scale.I took the longest piece I have which is 67"
and put it between the header of my garage door and the jack,the jack is placed on top of the scale and then I started cranking it up.The scale only goes to 300#,which it reached and
went around to about 130#.Because of the design of the jack I couldn't keep the pressure going in a straight line.I used some 10# mono ran from end to end around the sides of the pipe to
measure the deflection. I know it sounds pretty crude but I was suprised at the results anyway .The deflection was less than 3/16 and I checked it over for any bulges or loss of straightness and found it was the same as when I started. I think it wil be fine for what size gun I want to build.
 
  • Like
Reactions: GALADION

icarus pacific

Human-in-training
Nov 7, 2001
2,880
212
0
61
anyone what??

The deflection seems a bit much over such a short span, but filling the tube with delrin or wood will pretty much bring that down to nothing, so it seems that you're good to go.
 
DeeperBlue.com - The Worlds Largest Community Dedicated To Freediving, Scuba Diving and Spearfishing

ABOUT US

ISSN 1469-865X | Copyright © 1996 - 2021 deeperblue.net limited.

DeeperBlue.com is the World's Largest Community dedicated to Freediving, Scuba Diving, Spearfishing and Diving Travel.

We've been dedicated to bringing you the freshest news, features and discussions from around the underwater world since 1996.

ADVERT