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[kitcrazy]

hi i need to bend my safety valve cover to fit next to the steam pipe on my boiler never done any pipe bending before whats the best way to do this?also need to make something up for the pipe work that goes from the gas tank to the burner because the pipe i got with it wont fit in the boat .do you have to have this made in a shop or do you make the pipe work up yourself?thanks guys

[gondolier88]

As a plumber and engineer I always bend my own- however it does take practice. You need to have the right equipment and a feel for what the limits of the material are. Linked with this you need to know what you are bending- the difference between half hard thin-wall copper and annealed thick-walled brass for example is amazing. You also need to know the outside diameter of the pipe.

The equipment you'll need is - a mini pipe bender- usually bends from 6-10mm used by air conditioning engineers. I think you can also get imperial equivalents. For smaller diameter pipes you can use either mini pipe springs- springs slip over the pipe in smaller diameters and inside on larger sizes. I prefer to use my hands- I know what i'm doing and have had plenty of practice- you will need thick walled tube- trying to bend thin walled tubes any more than a little bit will result in collapse or rippling at best.
The thick walled tube will also need to be annealed- heating upto a cherry red for a minute or so and quenching in water- bear in mind that you can easily bend/deform or even melt tube if you go too far or inadeqately support the pipe- also if you have a prebent tube that you are re-annealing don't quench it- just let it cool down normally as it can cause deformation from differential contraction.

Experimenting with different annealing temperatures can produce different characteristics- for example heating to just before red hot produces a nice material strength/plasticity ratio. Also don't expect any copper or copper alloy that you annealed to stay that way- the thinner the material the quicker it 'work hardens' and this will also occur as soon as you have bent the pipe.

Your other (more expensive option) is just to use fittings to make any change of direction, however bending pipe is a satisfying and useful skill to posess and I hope you give it a go.

Here's a couple of examples of my handiwork- all hand bent.

Greg

[kitcrazy]

very nice  thanks for the advice i will get a pipe bender and give it ago:-))

[Underpressure]

Practice makes....well, improvements.

Go and buy some 1/8th copper tube from your local model shop and anneal it. Then bend it! Try to keep all the bends smooth and don't try for very tight 90 degree corners, first because they usually kink or ripple and second because you get a better flow of liquid (and steam is a liquid) round a more open bend. Once you are happy with what you are doing, move on to your safety valve pipe.

You can get pipe bending springs which go on the outside of the pipe and help prevent kinks and such, I have never owned any mainly because I'm tight and have always managed using fingers and thumbs.

Provided you don't have little piles of 1/8th pipe with knots tied in them everywhere, use some to bend up the correct shaped gas feed pipe. You may need help silver soldering the cones on either end, but if you can track down a model engineering society in your area, one of their members will make it looks very simple indeed (which it is, with the right kit).

Hope that helps.

Neil

I am repeating a little on what's already been written, but that's only because I'm too lazy to retype it all 

[boatmadman]

I was in a similar position as you, kitcrazy, I found a set of pipebenders like these:

http://www.tooled-up.com/Product.asp?PID=8066

but was put off by the price. I tried springs with no success, hand bending gave me curves with kinks and ripples, so I bit the bullet and bought the benders.

With a bit of practise, you will find these easy to use and give good results.

Ian

[HS93 (RIP)]

the pipe that comes with the cheddar plant has been annealed and can be bent very easy it needs an S bend, you can do it around your thumb,if it starts hardening just re anneal it.

peter

[kitcrazy]

thanks guys for the advice sorry for all the silly questions 

[tobyker]

or you can anneal the pipe (longe rthan it needs to be), soft solder one end closed, fill the pipe with fine sand or salt well rammed down, seal the open end, bend the pipe, cut the ends off as needed, let the salt/sand out, and use it.

[Brooks]

Torry Krutzke, well known in the US for his coal conversions of Accuraft engines, wrote the following:

"I regularly bend the thin wall tubing, 1/8 OD X .097 ID to a 7/32 radius using the tubing bender below. It is machined out of brass.

Lay the tubing on a hard table overhanging the edge with the bender over it. Lift the overhanging portion while rolling the bender away from the edge as you hold it down tight over the tube. PERFECT BEND EVERYTIME. You will need to aneal the tubing to get the best bend.

The advantage to the thin walled tubing is that it has a MUCH GREATER cross sectional area, and is a lot less restrictive to the flow of the steam. The Accucraft and thick walled tubing tends to inhibit flow considerably. I also replace the stock superheater line with a pipe having .105 ID.

Torry"

His bender, which I have used sucessfully, here:
http://www.pikespeaklocoworks.com/tubebend.jpg

Once you get the idea, you could make benders for any diameter tubing, I imagine. I have had no luck with the spring style benders.

Hope this helps

[wideawake]

or you can anneal the pipe (longe rthan it needs to be), soft solder one end closed, fill the pipe with fine sand or salt well rammed down, seal the open end, bend the pipe, cut the ends off as needed, let the salt/sand out, and use it.

.....or get yourself a bit of Cerrobend or similar.   It's a metal with melting point just below boiling water.    Melt some, pour it into tube, allow to cool, bend, then put bent tube into boiling water and the filler runs out.    Like sand or salt, it stops the tube collapsing.

HTH

Guy