How to Remove Deformation in End of Aluminium Pipe?

Google "tube expander".

Something like this (not an endorsement)?

Thanks that might be the answer.

Maybe something like this would work...

https://www.ebay.com/itm/10pcs-Pipe-Flaring-Tool-Kit-Tube-Repair-Flare-Includes-Clamp-Spreader-Die-/142428560976

I was thinking of a hacksaw. Unless you cannot afford to lose the length.

Thanks. Can not cut any off.

A tool called a swedge will do what you want. Unfortunately, swedges are designed to expand pipe to a larger size. If you were to try to use one on your aluminum tubes, it might expand it more than is acceptable for you.

My suggestion would be to find or make a tapered shaft/rod that you can push into the open end. You might still risk enlarging the end, so you'd have to decide if that's OK.

Thanks. Tapered something could work. Thanks for reply.

I think you are on to something here. Here is a sketch of the KrisDel SwedgeRounder tool

.

Or was that LynDoor Industries?

RIDGID®10281 Model S Tube Expander Head, 5/8-3/4" O.D.

Global Industrial Sales.

You did not give the size.

Thanks for reply. Pipe is on a ruler in photo but maybe I should have measured it so as to be accurate.

Well, a tool called a rerounder is available, but I sort of doubt it will work here.

Shown is a Reed RCR1 - not an endorsement

Your image appears to be alum pipe sized the same as steel pipe - can you confirm?

Boiler tube expander might also work. Probably ruin the tool within a small number of uses, if you can acquire the appropriate size for your need.

Thanks for reply. That tool might do it but looks a bit expensive.

http://www.caldertech.com/product-category/re-rounding-tools/

Thanks SolarEagle.

I didn't realize the pipe was so small....here is a smaller cheaper version...

http://waterworkstoolcompany.com/ti-sales/product.php?id=79

Although truthfully I would probably just stick a large screw driver down the tube and bend it out with that....

Thanks. I tried a few efforts with re-bend with screwdriver type approch... but tubes are strong...and tricky... since I have quite a few tubes I will probable get some cheap pipe expander that I have seen on line. Thanks.

Remember: 1/2" Pipe and 1/2" Tube are NOT the same size.

Remember: Pipe and Tube are NOT the same anything.

thanks. It never occurred to me tube and pipe were different. Will google now.

just an update ... last night I was trying the unbend with screwdriver method and while my screwdriver left marks all over the aluminium I think that method might work better if instead of screwdriver I find right diameter steel tube with right wall thickness.

Yes you need to wrap the end of the screwdriver with tape, or insert in wooden dowel, or something to reduce galling in the softer metals....

I think steel rod with very slight taper may work a little bit better, and it oil can be tolerated use it to prevent any galling while spinning one piece against the other by hand. Never try to hold a tube or pipe by hand while spinning a taper force by machine, as injury can and will result.

If oil may not be used, apply glycerin, if allowed. Last resort, use water.

The taper that would work the best: 1%-5% outside diameter, such that at the distal end from insertion, the outside diameter is about 5-15 thousandths inch (0.127-0.381 mm) smaller than proper inside diameter of the work piece. Things are less likely to "stick" or "hang up", if there is at least some dimensional clearance. I would not expect perfectly round work from this, however. It depends on the quality of the finished work needed.

Having a rod such as this, and an outer mandrel (such as one of the tools suggested by others) that fit to the outside diameter of the work, you can easily limit expansion of the work beyond a reasonable tolerance.

Thanks everyone thats been replying. I have been looking around ebay and I think tube / pipe expander is the thing that may well do the job without costing me too much. Thanks all.

Go to a machine shop with those tubes, and have them chuck up in lathe on a straight portion (assuming the tubes are not generally bent), then use a standard Morse taper, to round out the end I.D.

I doubt even that will restore all the damage to the roundness on the ends.

How round do they need to be, and what extension along the length is required?

A Morse taper will only work on the very distal end of the piece.

Most of the suggestions so far involve techniques that will work but will also stretch the aluminium creating a larger diameter. I have never seen the type of tool that I am proposing but it should be easy to make. I suggest that you roll out the deformation. with the equivalent of a roll bender. Get a piece of metal that you can fix upright in a vice 100mm of 50mm x 6/8/10mm strip would be ideal. Drill and tap two M8 holes both about half way up, equidistant about the vertical center line and 16mm apart (enough clearance to turn hex bolt heads). Cut an 8mm x 15mm vertical slot on the center line with the bottom of the slot 10mm above the horizontal center of the tapped holes. Screw all the way in 2x 30mm x M8 bolts into the tapped holes so tha 20mm of thread is protruding from on side. Slide a 20mm length of 8/10mm bore steel tube over each bolt to create rollers. Fix an M8 x 30 bolt into the slot with an M8 nut and tighten to a slide fit. Slide a 15mm length of steel tube over the top bolt to create an adjustable third roller. Place the workpiece onto the top roller with the flat uppermost. Slide down until the work piece is nipped between the top roller on the inside and the other two rollers on the outside. Tighten the nut. Rotating the work piece by 360 degrees will roll out the flat without stretching the metal. Once set all the other work pieces can be corrected with out any resetting. Make sure that the outside of the roller tube is smooth as the aluminium will imprint any imperfections. The sizes suggested reflect what I keep in my workshop, imperial equivalents, shorter or longer bolts, whatever you have to hand would work just as well.

Thanks for taking time to lay that out. That would work I think and I since I have lots of bits of tube to unbend I might give it a go. Thanks for reply.

Are they aluminium? looks like brass, have a insert made to the diameter you need with a tapered end that you can knock in, should only cost a few £s or $s.

Bazzer

Thanks for reply Bazzer. I know for sure its aluminium. Photo was taken under a yellowish incandescent bulb ...so might look more yellow than in life. The tapered insert that gets knocked in is a good idea. Thanks.

Perhaps something like a shotgun barrel dent remover would work.

http://www.wideopenspaces.com/dented-shotgun-barrel-homemade-tool-will-fix/

I have had luck just tapping in a tapered drift punch.

You will stretch the pipe / tube to a larger diameter. You would need to try and see what you tolerances are. Any reworking will change dimensions because you have to take the material to the plastic state and that will cause a dimensional change. Reducing the diameter after the bend removal may be accomplished by drawing the pipe through a round die. ( A piece of metal with a hole of the correct diameter and a chamfer to allow easier drawing).

Good luck with your endeavor.

What is most important: the internal "circle", or, the external circumference?

Or both?

If the pipe end is too hard to correct the shape with a good pair of pliers (not a 'screwdriver' ha ha!), then you need to anneal it regardless of what other tool is used to restore the round shape. Otherwise it's liable to crack during or after your repairs.

I haven't worked with aluminum myself but the anneal process is to heat to 650-775 F (depending on the alloy) and allow it to cool slowly without quenching. This softens it so it can be worked without cracking it. There are some simple tricks for gauging the temperature - lampblack (soot), or soot from a candle flame, or marks from a Sharpie, will burn off at around the right temperature so you don't overheat the metal. The problem with aluminum, the anneal temperature is close to the melt temperature, so it's key not to overheat. You don't need a full anneal to repair the tube end, just soften it enough. The work you do to repair the shape will harden it. If you use pliers to get the opening right for your tool, do it gently and not more than necessary. Get the mandrel, swage or re-rounding tool in, and use a mallet to shape and work harden from the outside.

Also think about your application, and how important is the integrity of those pipe ends. Preformed and hardened material has integrity which you can't be 100% certain to restore by repairing the damaged shape.

Some reading:

https://www.tinmantech.com/education/articles/aluminum-alloys-annealing.php

https://app.aws.org/forum/topic_show.pl?tid=9456

There are lots of videos of pipe annealing for bending, lots of blogs and forum threads.

https://www.cloudynights.com/topic/338218-annealing-aluminum-tubing/

Aluminum melts at:

1,221°F 660.3°C that is a long way from 650-775 F. I totally agree about the need to pre-anneal, and post-anneal.

Maybe a long way, but not a long time difference when using a torch, IMO. That's what I would guess to explain the words, since just about everyone cautions how easy it is to heat too much and melt it instead.

Also that's a crazy low melting point (compared to silver which I usually work with), so I don't find it hard to imagine how easy it is to breeze right past the anneal and into the melt point. Even with a butane torch, it doesn't take long to get higher than that. But depending on the size and weight of the piece of metal of course.

I find it really interesting that people commonly "spot anneal" when fabricating with aluminum. Where we would normally have to heat the whole piece to anneal or do anything with the torch... Just reading about it has piqued my curiosity and I think I need to play with some aluminum...

Yes, I have some special braze rod for joining aluminum, even used it to join aluminum and copper (after tinning with electronic solder). Worked until prolonged contact with alkaline material. Aluminum not alkaline friendly, no sir it is not.