Model Boat Mayhem

Technical, Techniques, Hints, and Tips => Engineering Techniques and Materials. => Topic started by: tonyH on March 22, 2021, 01:43:50 pm

Title: Bending thin wall aluminium tube.
Post by: tonyH on March 22, 2021, 01:43:50 pm
Hello each,
Is there any difference and are there any problems bending thin wall aluminium tube? I need to make some rails, ideally using 2mm tube. I propose threading 1.5mm brass rod inside to reinforce the rails so is the ali less "bendable" than brass and should I anneal the tube?
Any thoughts?
Thanks
Tony
Title: Re: Bending thin wall aluminium tube.
Post by: Stan on March 22, 2021, 04:19:11 pm
It may be a good idea to anneal the brass but you may find because the aluminium is thin it may not withstand bending and break. It may be a good idea to do a test piece first.


Stan. {:-{ {:-{ {:-{ {:-{ {:-{ {:-{ [size=78%] [/size]
Title: Re: Bending thin wall aluminium tube.
Post by: tonyH on March 22, 2021, 05:26:23 pm
Thanks Stan,
I thought that might be the case. I'll anneal the brass wire anyway and I'll have enough spare tube to experiment but it might be a case of..... >>:-(
Keep Safe and I'll see you later this year!
Tony
Title: Re: Bending thin wall aluminium tube.
Post by: Subculture on March 22, 2021, 05:32:20 pm
Is there a reason for using tubing and aluminium. Stainless steel rod would be much stronger, but easy enough to bend without kinking up.
Title: Re: Bending thin wall aluminium tube.
Post by: tonyH on March 22, 2021, 07:18:44 pm
Hi Sub,
The item in question is a pulpit for a non-Fairey 1/12 scale powerboat. It consists of a single curved section at the front, two uprights and the two tails curb down to the deck. There are six additional pole uprights on the main deck connected with braided wire so really only one curved section which is, I suppose, a section from a 2 1/2 inch circle. So there are no really tight bends.
The reason for the ali is that it was used on the actual boat.
I tried the brass tube/rod and ringpin method on another smaller 1/16 boat and it was so simple I wanted to use the same method if atall possible and not bother soldering.
 :-)) Tony
Title: Re: Bending thin wall aluminium tube.
Post by: Fred Ellis on March 23, 2021, 05:39:07 am
Hi


In the past to help in the bending of any tube, I have filled it with water then put it into the freezer over night, this way I am able to make tight bends in the tube, when done just run hot water over the tube, all done.


Fred
Title: Re: Bending thin wall aluminium tube.
Post by: tonyH on March 23, 2021, 09:45:37 am
Hi Fred,
I've tried that in the past. My only trouble with it is that I spend so much time fiddling about with the curve that the water sort of dribbles out of the end too early :embarrassed:
Cheers
Tony
Title: Re: Bending thin wall aluminium tube.
Post by: Fred Ellis on March 23, 2021, 11:06:50 am
Hi Tony


Ok I do know what you are saying, it happens I just kept putting it back into the freezer until I had finished.


I must have asked you before, were are you in Suffolk? I was in Sudbury for ten ago and loved every minute of it.


Fred
Title: Re: Bending thin wall aluminium tube.
Post by: warspite on March 23, 2021, 12:19:18 pm
Water in the tube and frozen is how they make musical instruments, though the diameter is bigger, the method is tried and tested
Title: Re: Bending thin wall aluminium tube.
Post by: Subculture on March 23, 2021, 01:08:09 pm
Filling with woods metal is another method.
Title: Re: Bending thin wall aluminium tube.
Post by: tonyH on March 23, 2021, 01:25:08 pm
The trouble with 2mm tube is getting the stuffing inside. I'd tried the water method with a much bigger tube but, as I metioned, without much success. I'll report back later in the week when the tubes have arrived from Cornwall.

Hi Fred, I'm in Framlingham. I've been up here nearly 20 years now. Came up nearly 20 years ago after I lost the plot with commuting across South London for about 15 years. Up to 2 hrs to do an 18 mile round trip! Faster by Hansom Cab >:-o Where in W Sussex? I used to have sites we worked on from Bexhill to Chichester so I know parts quite well, especially the watering holes %)
Cheers for now and thanks all for the input.
Tony

Title: Re: Bending thin wall aluminium tube.
Post by: Colin Bishop on March 23, 2021, 01:28:00 pm
Quote
The trouble with 2mm tube is getting the stuffing inside

Suck it and seal?  %)

Colin
Title: Re: Bending thin wall aluminium tube.
Post by: tonyH on March 23, 2021, 01:32:11 pm
Ho,Ho,Ho! Don't forget that your suck goes as you get older! Besides, it's all your fault giving me the idea of the ringpin method of rail making. :-))
Title: Re: Bending thin wall aluminium tube.
Post by: Fred Ellis on March 23, 2021, 06:00:13 pm
Hi Tony


Have you looked at these K&S Metals KS321 TUBE BENDERS 5 Tube Bending Springs Kit Without Crimping Tube, £5.39 on eBay number 184603431427
Fred

https://www.ebay.co.uk/itm/K-S-Metals-KS321-TUBE-BENDERS-5-Tube-Bending-Springs-Kit-Without-Crimping-Tube/184603431427?hash=item2afb38d203:g:8G0AAOSwvWFf7ipl
Title: Re: Bending thin wall aluminium tube.
Post by: SteamboatPhil on March 23, 2021, 08:07:02 pm
You could try threading soft solder through the tube and after bending if you cannot pull it out just heat the tube and let the molten solder run out.
Its sort of another version of "cerobend"  the very low melting point alloy  :-)
Title: Re: Bending thin wall aluminium tube.
Post by: tonyH on March 24, 2021, 10:07:22 am
No need to use the material inside Phil because I'm making the pulpit as a series of sections so the wire can stay in the bent bit with a leg of, say, 1/2" sticking out of each end so it becomes a double-male section. Fine ringpins are slid on and then the next section is female-male with the male end sticking into the deck. The pin bits of the ringpins drop into the open end of the upright stanchion while the bottom has a piece of rod inserted to, again, stick into the deck.The units will be stuck with epoxy and it takes away all the stress of solder joins on ali!
Hi Fred, I normally temper the brass and form round a pattern so it would tend to get lost in the "I knew there was a reason I bought it" store that we all have. %)
Title: Re: Bending thin wall aluminium tube.
Post by: tonyH on March 26, 2021, 05:03:47 pm
Thanks all for the input. Wire method worked well once I'd "discovered" the bend limit! :embarrassed: