[PSUBS-MAILIST] buoyancy

Wed Apr 15 16:24:03 EDT 2020

 Rick, my feeling is heat will make it worse.  I would try it with sand and no heat.Hank
    On Wednesday, April 15, 2020, 1:54:11 PM MDT, Rick Patton via Personal_Submersibles <personal_submersibles at psubs.org> wrote:  

 Thanks for the offer Alec and I may just do that if the sand thing doesn't pan out! Heat bending aluminum tube or pipe is an art and easy to screw up if you haven't done much of it as there are no tell tale signs unlike stainless or steel on when it is ready to bend. tube being much less forgiving than sked 40 pipe. The reason I asked you if you used a rose bud is because it is much more efficient in heating a larger area than a regular burning tip. I'll try and document this if it turns out and share it with you guys. Rick
On Wed, Apr 15, 2020 at 8:44 AM Douglas Suhr via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Quite a few years ago (when I was still a kid) I remember endeavoring to bend a curve into a piece of aluminum tubing. Dad had mentioned to me the idea of filling the tube with sand (something he had heard from someone down the line) and so I did just that: loaded the tube with as much sand as I could ram in there, capped it off and then heated the aluminum up with a torch. I had bolted a solid rubber cart wheel horizontally onto the workbench as a jig. The sand didn't help at all and this experiment failed miserably! As Alec suggests, there must be something more to this sand business. I finally resorted to investing in a conduit bender with the radius I was looking for and that did alright (but of course this was just thin-walled aluminum). 
Last year Alec made me a couple of (very strong) stainless steel bumper bars for Snoopy's bow (think: SportSub) and he curved those things beautifully! ~ Doug  
On Wed, Apr 15, 2020 at 2:27 PM Alec Smyth via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Same as you, around the CT. If you need me to bend you a piece, just let me know. It’s much cheaper to ship a bit of bent tube than a bending machine!

Sent from my iPhone

On Apr 15, 2020, at 2:09 PM, Rick Patton via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Good to know as a plan B. What radius were you bending to?
On Wed, Apr 15, 2020 at 7:57 AM Alec Smyth via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Ah, I did the same at one time on Shackleton - 1” SS tubing with Swagelok fittings. The bending machine did it fine and I used the standard rollers.
Sent from my iPhone

On Apr 15, 2020, at 1:48 PM, Rick Patton via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

I up sized the MBT vent tubing on my 350 to 1" and so I need to have it wrap around the con until it gets below the external exhaust valve and the con is 24" dia. I have the sand and the tubing already so I'll let everyone know how it comes out.Those tube rollers are nice but you need a dye for ever size tube you want to roll which can get expensive unless you only roll one size all the time. Rick
On Wed, Apr 15, 2020 at 1:47 AM Alec Smyth via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Ouch, I forgot you were in Hawaii. I actually can't recall what sort of jig I used because that little experiment was quite a few years ago. What I've been using in recent times is this:
https://www.harborfreight.com/automotive/auto-body-trim/metalwork-tools/tubing-roller-99736.html 
I've been very happy with it, but it's not for small diameter work. What is it you're trying to make?  

On Wed, Apr 15, 2020 at 1:49 AM Rick Patton via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Did you use a rose bud and was your jig something welded to the table like flat bar or steel tabs tacked to the table close together? that was what i was thinking of doing. I hate to send it to the East coast from Hawaii if I don't have to.
On Tue, Apr 14, 2020 at 5:49 PM Alec Smyth via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

It dimpled just like it had without sand. Its a well known technique, but there must be something more to it beyond than filling the pipe with sand and blocking the ends. 
:)
On Tue, Apr 14, 2020 at 11:28 PM Rick Patton via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Thanks Alec,What happened when you tried it and did you have a good jig to bend it around?
Rick
On Tue, Apr 14, 2020 at 5:13 PM Alec Smyth via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Hi Rick,
I've attempted the sand technique with no luck. I do have a couple of simple bending machines, but if its something difficult there's an outfit in Maryland that does nothing but bending. I've used their services many times, and can't recommend them more highly. 
https://www.josephkavanaghco.com/ 

Best,
Alec
On Tue, Apr 14, 2020 at 10:52 PM Rick Patton via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

A reach out to the K-350 gang. Do any of you happen to know the total payload weight (two people)  the boat is designed for with the MBT's and VBT flooded? Also, has anyone hot bent SS tubing with sand im it in a tight radius before with good results? I am going for a 25"/26" diameter.ThanksHope all are doing OK with this friggin virus going around.Rick

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