Often when you’re taking care of cars there is a must form tubes with bends, depressions or other shapes within them. You could be focusing on carbon steel oval tube, intercooler plumbing, a cylindrical airbox, as well as heater or turbo oil drain plumbing. So how do you form these bent pieces of tube?
In case you are making something similar to an exhaust or intercooler plumbing, buying pre-formed bends and then joining these is the simplest way to visit.
The bends – best are mandrel bends where the internal diameter remains constant – can be bought in steel, stainless steel or aluminium. An exhaust should utilize the steel or stainless bends, while intercooler plumbing can use the three forms of metal.
Joining of the bends may be carried out by welding – MIG, TIG or gas welding in the matter of the two steels, or TIG with regards to the aluminium bends.
If you don’t have a welder, tape the bends together after placing ‘witness marks’ (the place you have tried a marker to run a line across the pipe and across the join, showing how the bits align) and after that go ahead and take assembly to a welder.
Mandrel bends can be found in a selection of angles (eg 15, 45, 90 180 degrees) and diameters from about 1.5 inch to 4 inches.
When creating plumbing utilizing these bends, make sure that you:
Work with a friction saw using a large diameter blade to cut the bends to length. Don’t use a hacksaw – it really is almost impossible to produce a cut that is sufficiently straight it may be easily matched to another bend.
Try not to cut the bends anywhere except where they may be straight – cutting around the bend itself will disclose a wall thickness thinner compared to unbent tube (as the wall is stretched) so the weld is very likely to intrude and the join will probably be weaker than if this were made where the tube is straight.
If you use mild steel bends to create intercooler plumbing, the final result might be blasted, undercoated and then powder-coated to get a durable and professional final result. Stainless or aluminium may be polished.
The benefit here is that you could have the bend the particular required angle, rather than being limited to the angles by which preformed bends can be found. The downside is the fact except if you have an extremely expensive mandrel bender sitting in your house workshop, the bends will have a college degree of crush and you may incorporate some wastage before getting a bend you’re completely happy with.
Generally speaking it’s not worth trying to make your own personal bends in large diameter tube. A steel oval tube which uses a hydraulic jack and curved tooling is ideal for heavy-wall pipe and will give poor bends in thin-wall tube. (However, in an emergency you may be able to pull off sand-filling the thin-wall tube – see later.)
However, small diameter tube may be successfully bent with a hand bender such as this one. It comes with dies to accommodate 3/8 inch, ½ inch, 9/16 inch, 5/8 inch, ¾ inch and 7/8 inch (most tube sizes are imperial).
Listed here is a bit of 5/8 inch diameter steel tube bent with a hand bender such as that shown above. It is really an oil drain pipe for the turbo.
If you wish to gain some clearance, it is possible to ‘ovalise’ round tube – even when you use a preformed bend.
The secret is always to fill the tube with a coarse sand before starting to reshape it. The coarse sand has lots of voids involving the grains that can progressively close-as the tube is squashed. The inclusion of the sand resists the modification in shape, giving the tube more support therefore preventing deformation inside the wrong directions.
This 2.5-inch mandrel bend was utilized as being a turbo dump pipe – it’s shown here after being ovalised. It was ovalised for a couple of reasons – firstly, the oval shape matched the exhaust dexopky14 in the turbo, and secondly, the oval shape required to continue across the tube to offer clearance for the alternator and steering tie rod (shown within its worse position of maximum suspension droop and full right-hand lock).
The bend was loaded with coarse river sand. Note that if you intend heating the tube (eg with an oxy) the sand should be absolutely dry. Here the sand is shown within a cast iron baking tray drying out across a wood stove.
After being filled up with sand, the ends from the tube were capped with aluminium foil and tape. Unlike first thoughts, the end caps aren’t under lots of pressure – the sand doesn’t flow along the pipe that easily.
The sand-filled pipe was then placed into a hydraulic press. Two hefty pieces of flat timber were placed above and below the pipe, having a steel plate placed under the press’s ram. A clamp was applied to quit the arms from the bend spreading because the ovalisation occurred. In this case the job was completed with no tube being heated.
The pipe will attempt to create a figure-8 cross-sectional shape as it is being compressed; the outer edges could be pressed separately (as they are occurring here) to decrease their height as required. Note the usage of the timber block – this deforms a bit and spreads the stress. Consumption of a metal plate straight in the tube will have a tendency to dent the tube.
Make sure that you look into the sand level in the pressing process – as being the grains are crushed together, the amount can drop.
In case you have a desire for clearance at just one spot, you can place a depression in the wall in the tube. As was described above, ideal results occur when the tube is first filled up with sand.
This stainless steel gas pipe needed a dent placed into its wall to deliver adequate clearance into a starter motor solenoid. The dent was put into the tube (ex truck exhaust tube) as step one after the tube was cut to length.
Remember that this process gave a far neater result than using a ball-pein hammer and forming the depression by traditional panel beating techniques.