newbie ish trailer build

[fizzy]

Excuse silly questions and if I have posted in the wrong place - first time on here.
Done a bit of welding but not much!
Have decided on an over the top design - bought a heavy duty axle cheap.
Chassis will be 2x H columns 4x4" for side rails - then a piece of 4" U channel front and back.
Cross pieces to support floor 2x2" angle 6mm.

I assumed that the angle iron would just butt up nicely inside the H column - how wrong I was - the damn things are not nice and square but are radiused on the webs! Now I know it is for strength etc but very unhelpful for me....

So what do I do? There is a good 1/4" gap between the end of the angle iron and the web. Do I grind hell out of it to get it flush? Or just do a plug weld through the top of the column?

Final question - the H column is very heavy duty - 21kg per metre. Top and bottom is 10mm. Will a Clarke 230te weld that if I take my time? I have a 375 amp inverter arc but haven't used it yet - feel happier with the mig.

 

[dan.taylor.1]

Sounds like a hellishly heavy frame, whats the axle/towing vehicle rated at?

Dan

 

[Wozzaaah]

Sorry to wade in with a negative post but I'm probably not alone in wondering if you might be biting off more than you can chew with this if you've only ever done a little bit of welding.
Trailer regs have changed considerably I believe, you can't simply knock one up from scrap anymore.
There are links on here regarding the new laws, do a forum search and you'll find them.

 

[fizzy]

It is a 3500kg braked axle with drawbar and nato style hitch. Will be towed by my Land Rover.

Originally had a compressor or generator mounted on it. It is a complete chassis - i am just building the top half.

I want to build a glorified box trailer on it with aluminium sides and rear tailgate. It will be an 8x5x4 box - feet that is.

Mainly for carrying wood and quad bikes etc but sometimes a forklift or mini digger hence the strength.

I have calculated all up unladen weight will be about 800kg which isn't too heavy for something that is rated at 3.5 tons.

 

[zzr1200]

I doubt you'll ever carry a forklift due to its weight unless its a very small one, what type is it?

 

[feen]

Is this a wind up?

JF

 

[Lawnmowerboy]

Do you know how much even a 1T fork lift weighs! without a counterweight about a tonne add a battery of a tonne and a couinterweight of about a tonne if not more then you are prob over your GTW of your vehicle

 

[fizzy]

Small electric truck 1.5 ton lift - batteries removed weighs 2.5 tons so yes I do know what I am talking about.
All I wanted was some help - not constant critiscism..........

 

[DrNik]

come on guys were not here to judge, id be happy to help you out mate, maybe a pic of two would help see what your problem is, Welcome by the way

 

[Lawnmowerboy]

It's not criticism. There's a lot of people that ask on here impractical questions. Do you realise how wrong things could go if it broke when you're driving it and someone gets 2 and a half tonnes of cast iron and steel through the front of their motor. Do you know what type approval is and the regulations brought in last november about not being able to build a trailer though modifying one is acceptable.

 

[DrNik]

just read your 1st post again,i would round off the end of your angle to sit nice and tight against your "H" beam, welding all the way around is probably sufficient, id consider plug welding too but dont go massive on the the hole for the plug, going to big wouldnt help the "H" beam something like a 20mm hole is fine and get plenty of amps into it,

 

[DrNik]

sorry to jump on this thread, whilst we all care about the safety of what someone is doing if i wanted to build a spaceship and wanted some tips on tig welding, its upto me at the end of the day to risk my or anyone elses life, lets all be cautious but help fellow people with welding advice and not stray onto health and safety, and nanny state stuff, im sure this guy has already done his homework and will research it more

 

[fizzy]

Thanks Dr Nik that is much better. Positive advice at last.

Will my clarke 230te be up to welding this if I V things and go slow or would I be better getting up to speed using my powconn 375 amp stick?

The build on this thing is so over the top I am quite sure the frame will support 10 tons but obviously the axle wont. So maybe my welds wont be quite as strong as a coded welder but 90% at this size isn't going to break.

I have done plenty of engineering so I do have a bit of a clue. Just not much experience of welding big pieces of girder.

I would have thought using a plated chassis and just changing the box on top will be reasonably legal.

 

[DrNik]

230 amps is plenty, i would have thought you dont really need to v prep it id only be doing that if you had a smaller welder and needed some deeper penetration or was going to go over with a couple of passes,
as its only a box your making on the top, i shoudnt worry, its more will the floor take the weight and holding the load (be it digger or whatever) with chains or straps,make good lashing points!!! seen them come off regulary whilst tightening straps,
the sides of the box really are not really going to see any forces, unless something breaks loose,
the obvious bit is to over manufacture as you'll always find something to put on the trailer thats "just that little bit too heavy"

 

[gulf]

the obvious bit is to over manufacture as you'll always find something to put on the trailer thats "just that little bit too heavy"

Yeah,better to build it strong ,Landrover will pull it and a mini-digger no problem.

 

[fizzy]

I am so pleased that my mig should be up to it.
I have cunning plans - will sell off the Powconn and I also have a cebora bi welder 1665 tig - will sell both to get an ac/dc tig - probably an rtech.
I am making the tailgate out of aluminium - that should be a story in itself!

The trailer sides will be 8x4 ally sheets pop rivetted into angle with sikkaflex to stop electrolytic corrosion. Do I go for 3mm or 4mm sheet? There will be top hat stringers pop rivetted down the sides like a mini bulk/coal lorry.

I have given this many many months of thought!