Wind turbine - office chair - welding advice

[EcoElementalist]

Hi,

I made after a couple of attempts a wind turbine from second hand parts and freebies. Spent several months collecting components and learning how-to-build your own wind turbine. Clearly I am a novice and after thinking that I had a really good way of creating the yaw coupling and generator mount from an old office chair, I had a disaster......  the turbine came away from a compressed joint because of the freezing conditions contracting the metals...   Big crash, hence I have built my third turbine now and want to ensure I have a robust joint.

I now have an arc welder, so I can reinforce the joint, but my first attempt are really rubbish. I understand I need practice, but does anyone have any good tips/advise on welding joint of this nature?

Also how do I insert an image to show the problem?

Many thanks

How hard can it be?

[joestue]

I suppose it would be pretty funny if the gas cylinder launched the turbine away from the tower or something.. but I would start over.. not knowing what really happened here.

There should not be enough difference in temperature to freeze any moving parts, but rust may have frozen the joint.

[EcoElementalist]

That would have been spectacular, but I had a method to carefully remove all the gas cylinder and gubbings.

I am new here and trying to upload pics but failing.

Do you know how and experienced in welding?

[joestue]

I know how to weld but I wouldn't be able to tell you what you're doing wrong if you posted the photos.

[dnix71]

Maybe sleeve over the compressed joint after you weld it, as reinforcement?

[tanner0441]

Hi

You say you have an arc welder. is it a MIG welder which uses a wire feed and a bottle of shielding gas. Or a good old stick welder?

MIG is easier to learn with but your not going to learn to weld from emails. Just keep practicing if it is a stick welder practice on flat metal to start with until the flux peels of easily. Practice first on a flat sheet of steel, then try joining two flat pieces of steel, don't worry at this stage about distortion and curling up. Once you have mastered starting and maintaining your ark you can go further. the main thing is keep your weld clean, don't go back over a poor weld without first cleaning off all the dead flux, a chipping hammer and a wire brush are needed preferably stainless wire brush.

Look on the internet you can find books that will tell you techniques but without practice your not going to go far. Plus I think an office chair is going to be a bit on the thin side which also makes welding difficult.

Brian

[EcoElementalist]

Thanks tanner0441 & dnix71 for your suggestions I will try all those.

I think I have worked out how to insert pics so I can explain further. I hope you appreciate I am just a novice at building these and not a big budget, so anything I can lay my hands on free of cheap has to suffice. I work in a big office building so I can get old chairs that are unfit for sitting on, hence my persistence with them.

Below are pics of my first operational turbine which worked to a fashion but crashed and burned after 6 months because of the compression joint. I also include my poor attempts at welding the old joint back together.... this is where i need it, but a smoother weld is required as the collar it slides into rests and spins on it.  Although I did refrain from wrenching out the stem this time!

Old mount with welding attempt.

New mount

I may also look into some sort of self furling if anyone has any ideas.

Appreciate the support in my challenge.

[Mary B]

Cut a large washer to slip over the tube up to the weld. Grind it down to smooth it out somewhat.

[tanner0441]

Hi

Quickly looking at your weld, it looks like the weld is sitting on the top of the metal. Two things produce that. The first one is current too low and poor penetration. the other one moving too fast so the ark doesn't penetrate the base metal. Conversely if you move to slowly you will blow holes especially if the base material is a bit thin. This opinion is only from what I can work out from your photograph.

Look on youtube. Some welder manufacturers have tutorials, but again it will be down to practice. Also don't be frightened to tidy your weld up with careful use of an angle grinder.

Brian.

[EcoElementalist]

Excellent, you both make sense to me.

Clearly I need to get an angle grinder for finishing, but ensure I have good clean surfaces, maintain a constant speed and check my current is enough, right?

I also have a spare washer that fits so maybe weld that on too. I will take a look at some videos and practise like you said.

Thanks!

[dnix71]

Those welds look like a stick weld with either not enough current or too thick a rod. Grind the lumps down and have another go at it.

Now that I see the weld, a tube with a flange or tube with the washer welded to it slipped over the original could be used to reinforce the weld.

[madlabs]

Yeah, no penetration on the lower, heavier part. In those kinds of situations I spend more time on the bottom heavy part and kinda lick up onto the thinker material. Start your arc on the heavy part, get a puddle going, lick up onto the pipe quickly and back down, advance the puddle on the bottom and lick up again. If that makes any sense. That way you keep the bottom hot enough to penetrate and don't blow through the pipe.

Good luck! And don't stand under that thing! :-)

Jonathan

EDIT And like was mentioned, grind off that old weld, don't try to keep laying on top.

[Flux]

Lots of good advice here.

It does look like stick weld but you seem to have got the flux off so I can't be sure. The others are right about the lack of penetration.

Start practicing with a piece of clean flat plate, get rid of all paint. Choose a current setting for your rod (probably a range of current will be indicated on the box, or use Google)

Practice laying down flat beads, keep the arc very short, that is the tricky bit to master. If you go too fast you will have it standing on the plate in a ridge, if you go too slow it will penetrate into the plate, the pool will get wider and eventually it will burn through. Keep trying until you get a nice even bead level with the surface and when it is right the flux will come off easily when it cools. Until you master the speed you will get wide flat bits where you are about right and narrow peaky bits where you are too fast.

Keep going forward, if you get too fast it is tempting to go back over it, but don't you will trap slag in the weld,

When you can lay down a nice uniform bead then try welding two bits of flat plate together, that is more difficult but should come easily. Trying to do fillet welds between a flat plate and a vertical pipe will need more practice so don't be too disillusioned that you haven't got it quite right after one initial attempt, I have seen far worse than you have done.

The other big issue to overcome if you want to make really good welds is to see the parent metal flowing under the flux, you will only get this from practice or instruction form a good welder. In the early stages you will probably lay down respectable flux beads but when you chip the slag off the metal may not have flowed.

This last issue is the reason why MIG is so much easier to master as there is no flux to obscure your view,

I haven't looked on Youtube but I strongly suspect some skilled welders have put some good introductory material there. You can learn a great deal from watching a skilled welder, but to do it from a book is difficult to put it mildly.

Don't be afraid to smash your practice welds to bits, a good strong well penetrated weld  that looks dreadful will function and can be made respectable with an angle grinder. A very attractive bit of cold lap with no penetration may seem good but will fail in a short time.

Flux

[electrondady1]

all that , and make sure your ground connection is clean, down to bare metal and tight .

[EcoElementalist]

Fantastic response people, I don't think I could ask for more and have taken on board everything you guys have suggested.

I will try and post again when I have completed the welding.

Thank you!

[tanner0441]

Hi

I see you live in the UK. I don't know where but if your in a big city look in the local press for courses at night schools or colleges. Your not after a Lloyds certificate so you most likely would get away with one term.

As I and others said earlier practice on a bit of old metal first. Something around 3 mm is a good start, old bed frames are perfect. Make sure your base metal is CLEAN, you cant weld rust with an arc welder. Also look after your rods keep them clean and dry and make sure the end of the rod has flux round it, chipped or flaking flux makes starting the arc difficult to impossible. 

A test we had to do was write our initials on a piece of 3/16 plate that could be read from the other side without loosing definition or  blowing through. Once you can maintain your arc and mastered the current and speed, you will find the flux will curl up behind you. A good rod to start with on a basic home welder with a max of 150A is 2.5mm to 3mm. Most home welders I have used have also been no more than 48V open circuit and the 150A rating is quite generous, I have never managed to measure more than 115A. Good luck with it..

Brian