Often when you’re focusing on cars you will have a should form tubes with bends, depressions or another shapes within them. You may well be working on corrugated steel pipe, intercooler plumbing, a cylindrical airbox, as well as heater or turbo oil drain plumbing. 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 after which joining these is the simplest way to travel.
The bends – best are mandrel bends where the internal diameter remains constant – can be found in steel, steel or aluminium. An exhaust should use the steel or stainless bends, while intercooler plumbing can make use of some of the three types of metal.
Joining of your bends might be completed by welding – MIG, TIG or gas welding in the case of both steels, or TIG with regards to the aluminium bends.
When you don’t have got a welder, tape the bends together after placing ‘witness marks’ (in which you have used a marker to operate a line along the pipe and all over the join, showing how the bits line up) and then go ahead and take assembly to your welder.
Mandrel bends can be bought in a selection of angles (eg 15, 45, 90 180 degrees) and diameters from about 1.5 inch to 4 inches.
When making plumbing with such bends, make sure that you:
Utilize a friction saw by using a large diameter blade to slice the bends to length. Don’t use a hacksaw – it is extremely difficult to generate a cut which is sufficiently straight it may be easily matched to a different one bend.
Do not cut the bends anywhere except where these are straight – cutting around the bend itself will reveal a wall thickness thinner compared to the unbent tube (since the wall has become stretched) so the weld is very likely to intrude and also the join will likely be weaker than whether it were made where tube is straight.
If you work with mild steel bends to create intercooler plumbing, the last result may be blasted, undercoated and after that powder-coated for any durable and professional final result. Stainless or aluminium might be polished.
The benefit here is you can create the bend the particular required angle, rather than being restricted to the angles through which preformed bends can be purchased. The downside is the fact unless you have an incredibly expensive mandrel bender sitting at home workshop, the bends can have a college degree of crush and you might get some wastage before you get a bend you’re completely content with.
Generally it’s not truly worth trying to create your very own bends in large diameter tube. A steel oval tube which utilizes a hydraulic jack and curved tooling is designed for heavy-wall pipe and may give poor bends in thin-wall tube. (However, in an emergency you might be able to pull off sand-filling the thin-wall tube – see later.)
However, small diameter tube can be successfully bent using a hand bender like this one. It includes dies to suit 3/8 inch, ½ inch, 9/16 inch, 5/8 inch, ¾ inch and 7/8 inch (most tube sizes are imperial).
Here is a part of 5/8 inch diameter steel tube bent by using a hand bender that way shown above. It is really an oil drain pipe to get a turbo.
If you have to gain some clearance, it really is possible to ‘ovalise’ round tube – even whenever using a preformed bend.
The secret is always to fill the tube by using a coarse sand before you start to reshape it. The coarse sand is loaded with lots of voids in between the grains that will progressively close-up as the tube is squashed. The presence of the sand resists the alteration fit, giving the tube more support and so preventing deformation inside the wrong directions.
This 2.5-inch mandrel bend was applied as being a turbo dump pipe – it’s shown here after being ovalised. It had been ovalised for just two reasons – firstly, the oval shape matched the exhaust dexopky14 of the turbo, and secondly, the oval shape required to continue along the tube to offer clearance towards the alternator and steering tie rod (shown in its worse position of maximum suspension droop and full right-hand lock).
The bend was initially filled with coarse river sand. Be aware that if you plan heating the tube (eg with an oxy) the sand needs to be absolutely dry. Here the sand is shown in a cast iron baking tray drying out more than a wood stove.
After being full of sand, the ends of your tube were capped with aluminium foil and tape. In contrast to first thoughts, the end caps aren’t under plenty of pressure – the sand doesn’t flow along the pipe that easily.
The sand-filled pipe was then put into a hydraulic press. Two hefty components of flat timber were placed above and below the pipe, with a steel plate placed underneath the press’s ram. A clamp was utilized to prevent the arms of your bend spreading as being the ovalisation occurred. In such a case the job was done with no tube being heated.
The pipe will attempt to make a figure-8 cross-sectional shape since it is being compressed; the outer edges could be pressed separately (as is occurring here) to lessen their height as required. Note the application of the timber block – this deforms a little bit and spreads the stress. Consumption of a metal plate straight in the tube will tend to dent the tube.
Ensure you check the sand level during the pressing process – since the grains are crushed together, the level can drop.
For those who have a requirement for clearance at just one spot, you can put a depression from the wall of the tube. As was described above, best results occur in the event the tube is first filled up with sand.
This corrugated stainless steel pipe needed a dent put into its wall to provide adequate clearance to a starter motor solenoid. The dent was positioned in the tube (ex truck exhaust tube) as step one once the tube was cut to length.
Remember that this process gave a far neater result than by using a ball-pein hammer and forming the depression by traditional panel beating techniques.