Good welding techniques

[vanair]

Hi

I have bought my welder some months ago and have tack welded a Lotus chassis. At this point I am ready to start welding.

There is a questions as to what is good practice and technique:

I need to weld the rear shock mount and rollbar box using 3mm steel plate.
On this type of structure do I weld only on the inside or on the inside and outside of the same tow plates as well?

Regards

Pieter

 

[malcolm]

Difficult to say what I would do without seeing photos. Shock mountings are normally the highest stressed parts of a car. There's a big fatigue stress, so it's probably as important how you treat the ends of the welds as whether you'd weld both sides or not. Is there an accepted practice among Locost builders or is it every man for himself?

 

[fingers99]

Pictures would help (and be fun!). Is it Lotus or Locost?

What weder are you using?

 

[vanair]

I am building the Haynes Roadster.
The welder I am using is from China and is called a Matweld 200.

Here is a picture of the box.

 

[vanair]

Here is a pic of one of my test structures that were inspected today.

 

[fingers99]

So, it's not a lotus or a locost, but a Haynes!

malcolm will be along later and you should take his advice rather than mine.

As I see it, the welds at the bottom of the photo of your test piece are fine. You can see the penetration. The ones at the top are a bit marginal.

On this basis, I think the suspension mount should be done again, or done on the inside as well. I think you need more amps.

 

[vanair]

Sorry I havent mentioned, the two upright plates have only been tack welded in place. No welding from the outside.
I will probably weld them tonight after receiving all the comments and advice.

I suspect that it is only necessary to do a good weld on the inside ....

Lets hear.

Pieter

 

[zardoz]

Can i ask, who is "inspecting" the welds ?

 

[vanair]

Structural Engineer