Rocket Sidecar Bike - The Build

loopybike

Über Member
The original build thread on Rat Rod Bikes (http://ratrodbikes.com/forum/index.php?threads/when-a-crazy-idea-becomes-reality.101557/) unfortunately doesn't have all of the photos, so @Shaun emailed and offered to recreate the thread here along with all of the photos for all of the CycleChat members to enjoy, so here goes:

[Dec 29, 2016]

Where to start!

OK, I am building a rocket inspired sidecar out of aluminium sheet. It will be mounted to a bicyle.

There. I've said it.

I'd like to take you along for the journey if that's ok with you.

I'm hoping to get it finished by next summer.

It's going to look like this

20161212_215421_zpsk5zmykqn.JPG


It needs to be big enough for a 5 year old to ride in.
 
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loopybike

loopybike

Über Member
[Dec 29, 2016]

So yesterday I popped into the workshop ( where I work restoring bodies for classic cars) to make a start.

The idea is to have a aluminium "capsule" which is mounted to a frame with a single side wheel. The frame is then fixed to the bike.
First I need to make a simple "buck" the shape of the capsule. As I make the panels I can offer them up to this and check they are following the right shape.
Using the drawings I made, I've cut out discs to make up the shape. These are mounted to a free standing pole (2" box section). This isn't the normal way to make a buck, but it will give me access all round.

20161228_131603_zpsm7kpr9zv.JPG


Taaadaa! I've made a giant kebab!
 
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loopybike

loopybike

Über Member
[Dec 29, 2016]

Next I lay on some brown paper to gauge the size and shape of the metal.

20161228_135538_zpsyhpsxhhp.JPG


I'm starting with the underside. I'm having to do it in two sections to keep the pieces manageable.
The paper template is then transfered to the aluminium sheet.

20161228_140744_zps6wjlrfux.JPG


Then I simply bend it round the buck to make the shape......er no, it doesn't work like that!
 
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loopybike

loopybike

Über Member
[Dec 29, 2016]

Ok for those new to metal shaping I need to explain what I'm doing. For those experts please skip this bit! :smile:

If you imagine a rolled out piece of pastry ( mmmmmm pastry....) and cut it into a 1" disc. Now push you finger into the centre. The edges are going to lift up off the table. That's because you have squeezed and stretched the middle and it's forced the outer edge upwards. Now gently squeeze the edges all the way round. This "shrinking" will force the pastry into a small bowl shape. That's basically what I will be doing with the metal, stretching and shrinking.

For the stretching I'll be using an English wheel

20161228_140931_zpsl7grnkqw.JPG


The metal is rolled between the wheels and squeezed. The lower wheel can be changed to suit different curves. The pressure is also adjustable. Some people say it takes decades to truly master this. They are right!
 
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loopybike

loopybike

Über Member
[Dec 29, 2016]

For the shrinking I use an attachment in the power hammer:

20161228_142640_zpssqvd52dx.JPG


This squeezes and pinches the metal.
By using this round the edges I start to get the curved shape I'm after.

20161228_143202_zpsuvecbocx.JPG


This was after one pass. Multiple passes are made, moving closer to the edge on each pass.
 
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loopybike

loopybike

Über Member
Notes: I use 1050 aluminium which is a semi soft grade. However recently this grade has been getting harder. The suppliers in the UK say it's the same as always but it is definitely a harder alloy. Work hardening isn't a problem. Sometimes when I need to do some fine detailed shaping I anneal the metal. This process softens the aluminium which makes it very soft to work. It will age harden in time.

Notes: It's going on an Electra bike.
 
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loopybike

loopybike

Über Member
[Dec 30, 2016]

Did a little more today.
This is the rear of the underside:

20161230_130513_zpsreudgoqk.JPG


Made in the same way as before.

This is just the rough shaping, I have loads more to do to smooth it all out. The two halves don't quite flow together, so I'll work on this before I weld them together.

20161230_124747_zpsxyixziaj.JPG


I feel like I've made an aluminium canoe! Good job it's not snowing here or I might have been tempted to use it as a sledge lol
 
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loopybike

loopybike

Über Member
[Jan 7, 2017]

Done some more today :smile:

Once I was happy with the fit on the buck of the two halves, it was time to weld them together. With aluminium tig welding cleanliness is everything, so the edges that are to be welded are chemically cleaned then gone over with a rotary wire brush :smile:

20170107_131624_zpsvstdsfc2.JPG


Then, after a final fit check, they are tacked together:

20170107_132935_zps5udkx11q.JPG


Then fully welded:

20170107_143046_zpsvcurcte3.JPG
 
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loopybike

loopybike

Über Member
[Jan 7, 2017]

The welds are then crushed between a hammer and dolly:

20170107_145247_zpsljplnrni.JPG


At this point it was obvious that there was a flat spot on the main part. Rather drastic measures were called for as it's now too big for me to get into the english wheel. Out came the big hammer lol

20170107_151121_zpsonb6ywrw.JPG


Again more smoothing out with a flat hammer and dolly, then the body file is run over the area:

20170107_152640_zpsutex98ne.JPG


This highlights the high and low spots. The low spots are stretched upwards, again with hammer and dolly. This is known as planishing and it's boring!

After a while the panel starts to come good:

20170107_155157_zpsq2tuhxyi.JPG


I plan to have this sidecar in polished bare metal so much more planishing lies ahead ..... :sad:
 
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loopybike

loopybike

Über Member
[Jan 17, 2017]

Planishing planishing planishing......

I am working on this but not bothering to post photos........"oh look, that bit is now slightly smoother" lol
I spend half an hour or so on it most mornings as a "warm up" for work :smile:

Nearly finished the underside now. The next job is to start making the sides. These will be smaller panels and (hopefully) quicker.

I plan to spend half a day on it on Friday so I should be posting pictures then.
 
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loopybike

loopybike

Über Member
[Feb 28, 2017]

Right! I'm back on this again :smile::smile:

Started the top front panel this morning:

20170228_085944_zpsrjp7sb1c.JPG


Same as before, English wheel then shrinker round the edge.

I tried the lower panel on the buck to check how far the panel extends at the front. I was horrified to find that the panel fit to the buck was terrible! It hardly fitted at all! Then I realised I'd got it back to front! Doh! Lol
 
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