SKarosser Copy Scratch Home build?????

[wonkywheel]

Aluminium Welding

As an engineer I think that if I can read the book then I can do it

After having quotes for between £400 to £800 or £25 /hour to weld up the frame work I have decided to do it myself
The cost of the equipment will probably end up more than the high end quote but at the end of the day I will have the satisfaction of having done it all myself. My view is, I know it will not be as good a job as a professional welder, and it might look like S**t but it will be my S**t.

It does mean that I will be able to assemble and weld up various sections making the build and final assembly easier.
If anyone knows anything about welding aluminium
I an thinking of purchasing an R-Tech 180amp inverter welder with a spool handset running on neat argon
After a bit of research it seems a capable economic set up.

Meanwhile, I have again run out of the angle fixing plates while I continue to cut and build up the top half.

On a completely different tack.
I have seen some quick release ratchet/ turnbuckle securing clamps Any one know where I can get them from?????

That's all for now.....back to the CAD

[Big Jim]

I have welded ally using a standard MIG using argon gas . I am used to welding steel . The ally welded quite nicely and not to different to steel . With a bit of practice you should achieve a good job . If you can't get on with it you could just tack it all together and pay for 2 hours work to weld it up .

[wonkywheel]

Thanks, Jim,

I'll give it a try, I did a bit of stick welding on my teardrop trailer that worked out ok(after quite a bit of practice).

Regards,

Mark

[wonkywheel]

Well, Jim,

I think a couple of hours might be a bit optimistic



This is the trail build without the cab over bed or the internal cupboard frames or doors.

I will be happy with a couple of days

[wonkywheel]

Managed a bit more at the weekend. Cut and put fixing holes in place in the 2"x 1" ready to beef up the rigidity



Now the outer base frame is in the 10swg 2x1. There will be extra bracing spars under the seat /tub side over hang. I have also cut 2x1 sections for the jack fixings.

I have almost settled on the jack mechanics.
At the minute I plan to use a single start 14mm by 4mm pitch trapezoidal thread lead screw 750mm long. I will adjust the lengths as necessary.
This will be driven by a pair of mitre gears (2 MOD 16 teeth). I aim to use Plastic gears but have not decided between the different grades of material yet.
At present, I have not been able to source suitable motor economically, so as yet....hand cranked.
The mitre gears being 1 to 1 ratio mean that 4mm pitch screw will need 6 turns for a 1-inch rise, while rough calculations based on a 1000Kg unit lead me to believe a foot long handle will need a maximum of 8lb (8Ft/Lb) to lift the front jacks. If my centre of gravity guess is anywhere near close

p.s. Before anyone comments, its chained to the apple tree in case it trys to get away

If anyone has any constructive criticism it will be welcomed

Welder and spool gun should arrive tomorrow
Then it will be test welds to see if I have wasted my money

[Alexd]

Constructive criticism (around here?)



no sorry I haven't any either, coming along quite well though isn't it

do you have any pictures of the gearing you are using, or are you building like a little beatbox to house these cogs inside?

[wonkywheel]

I'll post some pictures as soon as I get them. Still undecided on material for the gears. Metal would be fine but expensive so I will be looking for input from a plastics technologist I know for the best choice between Nylon 6, Delrin 500 or Hostaform C all of which are only about £6 a pair. As long as I make provision for a drive socket on the end of the lead screw if the gear fails I can still raise and lower. The friction in the screw, even with a roller thrust bearing, will be high enough to stop the camper weight running down the screw. I had considered using ball screws as they are a lot free-er running but they really need a brake to stop them getting away. They go up easier but come down even better

I suppose the best I can expect is destructive sarcasm.

[wonkywheel]

A Bit More Today

Drilled and de-burred the fixing holes in what I hope is the last batch.
The welder is promised for delivery tomorrow. I am hoping I will be able to remove the ones in place as I weld and reuse them as I go along. They have been invaluable in the build process as it's only a drilled hole that is out of place after any build correction.
(There have been quite a few, and no doubt many more to come. I just hope I spot the mistakes or MODIFICATIONS before I weld it together)



The drilling jig plate I made to help position all the fixing holes is now looking very second hand I didn't harden it or put bushes in although it was made from gauge plate. I used it clamped in position on every corner and joint in the build but it is little more than a rough guide now as drilling has elongated or generally made the holes larger.

[wonkywheel]

The Welders Arrived

The welder arrived as promised. With it came with a transport trolley flat pack and a spool gun. Gas, face mask and other bits and pieces came last week



All assembled and ready to learn how to weld aluminium. Something I have to confess I have never done
Very first go made a fairly passable attempt at being a cutter rather than a welder

It helps to turn the Argon shield gas ON



After trying a few different thicknesses of material and fiddling with power and wire speed settings managed to make quite a mess



After more fiddling I am slowly showing some improvement.



The session only lasted about half an hour so I am not too worried by the results so far because I have learned a lot from it.
In my attempt to research what I needed and how difficult it was going to be, I might have over thought it a bit.

I had read that 1mm aluminium wire stood far less chance of bird nesting than the 0.8mm. So I chose 1mm wire.(Big is always best )
I had also read aluminium heat transfer if far greater than steel so it is possible for the aluminium to expand enough to jam itself in the tip. To avoid this use a tip 1 size larger than standard.(1.2mm)

Both of these assumptions were wrong, I think
This resulted in me needing to use far too much power for the thickness of aluminium box section I am using(16swg or about 1.5mm). Part of the reason for the blow though. Also the larger tip allowed the wire to wander about too much to control it effectively.
More wire on order, 0.8mm this time also I will put the 0.8mm tip back in the gun

The 1mm wire will come in use when welding fixings for the legs as the wall thickness is 4mm+ (3/16")

[wonkywheel]

Disappointing

I took what I considered my best 3 attempts to work this morning to bash the **** out of them to see how good they actually were.

Two out of the three separated at the joint meaning the weld had not penetrated the parent metal enough. Only one managed to break the parent metal .

Its true it was a big hammer, but, the 0.8mm wire arrived so will resume with renewed optimism and ensure the joint area is thoroughly clean before welding.

Onward and inward