View Full Version : Tomahawk made in France

12-09-2013, 08:39 AM
Hi everybody,
For several months I'm thinking of riding a recumbent bike.
I have watched second-hand bikes but they are still very expensive.
So I've decided to build my own bike and I found Atomic Zombie.
The builds here doesn't seem to be too difficult so I bought plans.
First I chose the Highroller but now I think I will build a Tomahawk.
I have a few questions about the build:
I own an arc welding machine and I wonder if it's possible to weld a bike
with this material for a beginner ?
I have square tubes at home which are 30mm wide and 1,5mm thick:
is it good enough ?
I haven't got many spare time to do it but I hope my bike will run for
next summer.

Thanks for your answers.

Sorry for my english, I'm french :rolleyes4:

12-09-2013, 10:08 AM
Welcome to the Group Fabz56. Your English is very understandable. The 1.5mm thick sounds good. The 30 mm may or may not work as the plans are looking at 38 mm imperial. I cannot say if it will workout for you or not as it is dependent on you and your mass. IF your under 90 kilos then you should be fine. If your over I would move to the 40 mm tubing. And if your pushing 136 Kilos or more then you may want to consider thicker tubing and larger tubing all together to give you the support. As to arc welding the material that is how Brad welds everything. Brad is the site owner and if you check out his videos you will see in dodging the rain video he is Arc welling either a Spirit frame. However if your not used to welding yet, I would practice running beads on similar thickness material, and check out the online welding videos. ChuckE2009 on YouTube just created a series of arc welding videos that another member mentioned yesterday. It is all about control of Amps and speed and using the proper arc stick. There are several forums discussing that so I will let you read the forums for more information. But the data is there. Hopefully you can understand my poor English skills to welcome you to the group.

12-09-2013, 10:35 AM
Hi Fabs 56,
Welcome from China! I can assure you that your English is far better than my French, or my Chinese for that matter!!
Arc welding is fine with a bit of practice, you just use more grinding wheels when you first start .
If you do use a thicker tube on this first build it will be much easier to weld. Not too sure on the 30 square--sounds like it could be a bit small. I would have to jump on a piece to see what happens. This is , of , course, a very scientific test for stiffness.
Better to see if anyone can tell you not to do it from experience, as my LWB use 40x40x2 as its all I can get here at the moment, even though alf the worlds supply is made in China.
Have fun, share pics of you progress, and include pics with any questions, as it often makes it a lot easier to giove the right answer first time1
Steve G,

12-09-2013, 05:50 PM
Thanks for your quick replies ;-)
I can find 40x40x1,5 tubes easily so I will not take risks...
I'm not heavy but if I take bagages with me or if I lend the bike I don't
want an accident.
For the welds, I will train myself before the build.
I will post my progress with pics soon, don't worry :-P

01-02-2014, 06:38 PM
hi all,
I give you some news about my project.
First I had a beautiful gift for Christmas : a arc welder inverter !
I should have been a very good boy this year :santa::santa::santa:


I found some square tubes 40x40x1,5 mm near my home so it's a good news.

I wonder if I may build a Highroller before a tomahawk because it's easier and there are less welds to do ...

I am training with my welder, my welds look not ugly but I think they're not strong enough. I think I may be too fast, I'm not sure...
How could I test the strength of my welds ? I don't understand how fast I have to apply the weld.
I use 1,6mm rod and 35 amp.
Here is a pic with a weld :


I 've just started cutting some pieces and killing my donor bikes.


So I'm going on, slowly, but I'm going on :builder2:

01-02-2014, 07:04 PM
I forgot : I wish you an happy new year and many new builds :jester:

01-02-2014, 07:41 PM
That weld actuall looks pretty good from this angle. Looks like you burned through at the end of the weld. But you may want to run some more beads till you can make them the same width. Look like the speed starts out fine but then you either slowed down or started zigzaging creating a wider weld bead.
To ensure your geting a good weld- try cutting a tube in half and then rejointing it with tacking first then full weld all around. Then clamp one half in the vise and hit it with a hammer as hard as you can a few times. It the weld shows no cracks and the metal bends then you have good joint. Welding tips and trick on YouTube and Chuckee have some nice begining welding tricks and you can see what a good bead is going to look like.