Fabricating my own complete chassis (civvi S3)

[AR4412]

Hi Sean,

I did look at getting a gasless MIG, with the option to convert it if I wanted, but in the end I went for the 135 as it was a gas set-up and should be powerful enough for chassis repairs. I tested it on some 5mm bar before converting it to do aluminium work and it seemed to stick it together well enough.

Regards,

[minilandrover]

Hello there, wow that's some job you just took on...Are lightweight chassis not available???or the same as a short wheelbase one...

Just a few points strike me..as i have built one from scratch but in 1/2 scale.. to get the full sculpted chassis I used pre formed box tube 4x8 cms ( half size remember ) and mig welded them using a high argon mix to get a flush and deep weld. the chassis I built is 2.25mm thick, plus 0.25 of special rust proof paint, so im measuring 2.5mm overall. I wouldn't think of using anything thinner on a full size one..also if you are welding the sides to the top and bottom first before the cross members and outriggers, then the weld's will have to be deep to avoid a bare edge inside each section that is added. Unless you are going to have it hot dipped (400deg) in galva to protect the inside the thin unprotected plating will rust from the inside. I noticed that there are join welds along the sides as well..did you weld them both sides? By using pre formed box section the chassis can be made far more easily as all the cuts are done at the same angle..and there is no wastage...I used just 6 meters of steel for the chassis. out riggers were of a different section and doubled for strength. I will post some pics for Gordon to tack on...if he would..
You certainly will have a long job and i wish you well with it..and i hope it comes out perfectly flat..
Colin

[Gordon Bennett]

I will post some pics for Gordon to tack on.

Pictures added as requested.

Rgds,
Gordon

[minilandrover]

Thanks GORDON, Sean as you can see from the pictures the chassis follows the same shape just that it has set angles between each section. I used one half of my 6 meters of box tube at a time. The sections were actually cut then each other piece was turned up side down to complete the rail. I then used the other straight section as a jig to set up the sections before welding. Just by tacking the corners first then one run at a time, to avoid warping.. I did use up a lot of argon bottles, I have used about 20 in all to do the chassis, bulkhead and all the body framework..and a few other jobs and my welder is about worn out..So they don't last forever..and cost a lot in gas at 15€ a bottle. I wonder if you could have used pre-formed boxtube ??? Stick welding is ok for many jobs but a continous weld over 10cms usually means a mig is going to be the better option..
Certainly on a new project build I would use it again. or a TIG or as for my next vehicular project ( three wheeler) im going to make a space frame out of tubing and in sections that will actually bolt together..Because the frame will be inside a fiberglass shell. and no weld will be longer than the circumference of the tube used.
If you do get it galvanized don't forget to drill drain holes everywhere as when it gets dipped, you don't want any hot galva to form inside sections into solid blocks...as they charge by the weight of galva used...by weighing the piece before and after dipping..
Again well done and good luck, let us know how much it cost to do in the end and whether you would do it that way again or just buy a new chassis....There is me assuming that lightweight chassis are available...Colin

[Sean7r]

Thanks Neil.
Hi Colin, thanks for those pictures, that Landy chassis looks great, yes these plates were welded both sides, but with only one ground back to keep the strength, the box was made using open corner fillet, so that the weld is right on the corners, we now have a rigid jig now, using the shock mounts to hold the chassis in place, the old chassis was made from 2mm and researching also confirmed this, but if you buy a new chassis it's made from 2.5 apparently , and I will be galving the chassis, my brother has experience here, where he works everything has to be galved, many thanks for your advice as it all helps and please keep them coming.
Sean

[Sean7r]

Update:- stitched the cross members in today, so far so good, the chassis is perfectly straight and level, the weather was against us, luckily I had erected a gazebo the day before.

[Sean7r]

The out riggers are next.

[AR4412]

Coming together nicely despite the weather, good work Sean.

Regards,

[Marty welder]

Well done the chassis looks brill.


Marty

[minilandrover]

high Sean. Coming on nicely.. can wait to see those outriggers on as that will really change the look.

I spent more time on the font ( bulkhead ) outriggers than all the others put togethe.
As it's a very inportant structial part i reinforsed it with double sections. and a substantial
anti crush tube to enable the bulkhead and door pillars to be bolted up so tight they as strong as is possible
to get. Side impact or lifting the complete machine from the bulkhead is no problem. Okthats only a half size one
but its bombproof. im just sayin its an important part and has to be solid..cantwait to see it done and galvanized..