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MicHughV · 11-01-2021, 17:05

there is a big salvage yard in Ft. Lauderdale...Sailorman....they must have 100's.....and 100's more s/s bimini tubes salvaged from various boats....odds are pretty good you'll find something to fit for your needs.....plus the canvas....
odds are you can likely buy the entire bimini, frames and all for less than buying the tubes yourself, bending them, sewing the canvas, etc...
most of the salvaged tubes will likely also come with the various end fittings, eyes, straps, etc...

sguerrero1971 · 12-01-2021, 06:07

Thanks all for your input, based on what you all have said I'll take the pieces to a shop and have the arc put in them. I had that as my backup plan if I couldn't find a simple way to do it myself.

SG

jen1722terry · 12-01-2021, 09:30

Sailrite may sell you the tubing bent to your specs. We've done this a few times and they were reasoable and helped us get the specs just right.

singlespeed · 12-01-2021, 09:31

I have bent 7/8" stainless tubing by plugging one end, filling and packing completely with dry washed sand and capping the remaining open end. It will be heavy. I found two power poles with a six inch gap. I marked the soil where the fixed end rests and pulled the other end, marking where I stopped pulling. Telephone poles have a rather large radius, yielding a soft curve. Repeat for each section. It is important to make sure there are no voids in the sand, as that spot will be prone to kinking, hence the clean dry sand. Prior to draining out the sand, compare the pieces for conformity. I first used this process, years ago, to straighten a surf bent Hobie14 mast. It took four men to lift the sand filled mast and a vehicle to pull the mast straight, the telephone poles showed no sign of damage.

MicHughV · 12-01-2021, 10:14

Some many years ago, I built a steel boat. The time came when I had to bend the metal bars that supported the deck, so that the deck would have some camber. Those bars were 1/4" thick x 2.25" wide and had to be bent in the 2.25" plane.
I constructed my own hydraulic press to do this...
It was a beefy structure, consisting of two arms with a 15 ton jack in the middle.
I had to induce a "slight" bend about every 2" along this metal beam to form a "curve"
It was brutal work...I was not sure I was going to succeed. After placing the deck beam thru' my press several times, I could barely notice a curve. It practically took all day to bend one deck beam.
After this experience, I also had to bend the s/s tubing that made up my bow and stern pulpit.
Having learned my lesson with the deck beams, I took the s/s tubing to a metal fabrication shop. They did a very nice job. There was no way in hell I could have replicated what they did.

I cannot even imagine trying to do any type of bending of this type, while at anchor.

**George DuBose** · 12-01-2021, 10:24

I would build a jig with a half sheet of plywood and a series of wooden blocks fixed to the plywood to form a bit more curve then I need to accommodate spring back.

Then fix wooden block with notches at each end to accommodate all four pieces of pipe.

Then use a ratchet band or two to pull the ends around the two end blocks and a third block centered below the curve youi want. Gradually tighten the bands with third block pulling the ends down and towards the center.

Just a DIY idea. I am sure the best solution is to let a pro do it.

Maybe Midas Muffler could help you???

Martkimwat · 12-01-2021, 11:08

My local friendly Stainless steel fabricator has a manual hydraulic bender for small curves like that. For larger radius curves, he uses the dry sand packed in the tube method and bends it around a 22" diameter tyre on the bench. for even gentler curves, ie the 'roofline' curve he uses the same technique but gently inches the curve in little nudges around the tyre. He would never advocate trying to bend such a small diameter by any other means than with a hydraulic bender, either manual or powered. Even he gets larger diameter tube bent by specialists who have power benders. he can manage up to 1 1/2" tube on his manual bender.

boatpoker · 12-01-2021, 11:56

Quote:

Originally Posted by sguerrero1971

If you wanted to put a 2 - 3 inch arc in an eight foot piece of 1" stainless tubing without the benefit of a tube roller or a pipe bender, how would you suggest doing it? It has to be repeatable, I need 4 sections.

A bonus is if you can come up with a way to do it while at anchor, and just using basic hand tools.

My idea so far is to take a piece of lumber cutting the arch into it and then use clamps to slowly pull the tube to the arc in the wood. Possibly use some heat to help it relax into the shape I want.

Any help would be appreciated.

No problem, I did exactly as you described with no heat, no problem
1" ss, 5" arch on this 12' X 13' bimini over our cockpit.
The short one near the stern was a little harder but the 9' -12' ones were easy.
Five of them took me about an hour.

Cheechako · 12-01-2021, 12:13

A mandrel or packed sand is only needed for tight bends. Evidently the OP only wants a shallow arc in 8 ft of length. The only thing making that arc difficult is making it repeatable and uniform.... otherwise a big tree or tank would work.

OP:I can visualize a plywood sheet, with various pegs or block screwed into it to accomplish this.

hafa · 12-01-2021, 16:26

Although the OP has specific DIY needs, ours are a bit different, as there are no shops to do this here and the nearest salvage yard is 10,000 miles away. All that said, how about something like this Klutch 16-Ton Air/Hydraulic Pipe Bender - 3in. Capacity?

Hoodsail · 12-01-2021, 16:36

I bought a tube bender and 7/8” SS from west marine who was surprisingly competitive in pricing. Cut to length with my Dremel, filled each tube with sand and made four bends...came to realize that even with sand if you are too aggressive and dont move the bender along to make a gradual curve the tubing will kink, it did...figured that out then realized the bend can be accurate but now are the ends in the same plane!!! Just to complicate, I also wanted to mount it completely on the cockpit railings, that is not the case for majority of biminis out there. It works, keeps both sun/rain off the helm, but looks a bit hinky. Smart move in having tubing bent by pros...altho if ever in CT, I have my bender am more than happy to lend it out...but I get to watch...

Reefmagnet · 12-01-2021, 17:04

I've got a TIG welder and my solution is to buy polished bends and use them if I need anything >= 45 degrees. If welding isn't an option, you can buy socket style bimini fittings, but this can get expensive.

When using sand, you need to block the ends of the tube once the sand is packed in otherwise it will have a tendency to displace and promote kinking.

wingssail · 12-01-2021, 17:40

I bent my 1" stainless steel dodger bows meself. The radius is about 1 foot.

I built a DYI tube bender out of plywood (three pieces, two outside plates and the circular inside section that I bent around.) I used a section of 2x4to force the bend.

I GOT KINKS!

But they were small and I used the bows anyhow. It's been 30 years and they've been good.

Cheechako · 12-01-2021, 18:40

Quote:

Originally Posted by hafa

Although the OP has specific DIY needs, ours are a bit different, as there are no shops to do this here and the nearest salvage yard is 10,000 miles away. All that said, how about something like this Klutch 16-Ton Air/Hydraulic Pipe Bender - 3in. Capacity?

What you really need for a minimal but long arc is a roller. A bender is usually used for tighter bends. it's potentially possible that with that bender, you could incrementally bend a minor amount, move a half foot or so, bend again, etc etc. etc. But a bit dicey.
As I mentioned earlier on, calculating a 3" high arc in 8 ft width means you need about a 32 FOOT bend radius!