Thread: Can you over weld ali?

Gday
This link may help Aluminum Welding with a Spool Gun
Thanks caveman

Thanks Captain, I have looked at that one a few times. He does good video that bloke.

Are you on the bio fuels site I am on?
Regards

Chris

Chris, the first thing that comes to mind is the material and or the size/thickness giving you trouble.
Ally is of course very conductive so a small change in material mass can require a bit more power to weld it so without knowing the exact situation with your transom it could be just sucking the heat out of your welders capacity, assuming the material is as specified and weldable, gas is Ok, you may just need some more power in those areas.
Without seeing it is hard to say what is going on.

Thanks johncar,

I think I have just got a mental block on it, I messed it up a bit and now I just cant relax into it. I think I will try to get it to a weldshop this week for some help. Me thinks I need to keep the transom on no matter what,
A because I fish in croc infested waters and
B I would hate to lose my new 13k motor.

When I sand it all back the weld looks good, and it is probably fine, but I want that nice weld look...

I will let you know how it turns out

Chris

Gday Chris
I am a boilermaker/welder and also a member of the biofuels forum,and one day hope to build a 6.8 meter plate ally boat in the future, a good mate of mine has built 22 boats to survey and would be able to help me out, did you buy a kit or is it your own design
thanks caveman
B100 160,000 km

captain, Yep I have seen you on that site.

I bought a kit that was made to my design. I went to a bloke Catran at Plate Alloy in Melbourne with what I wanted. He modified a kit he already made and away I went. It all came to me on a flat pack. I will do a full write up with pics on this site in a few weeks, on how it came and how I went. its not hard and his (and a company CNC Marine in Perth) websites have a great range of kits you can buy, either in plan form or ready cut kits. have a look, they are interesting things. Having no metal work experience (other than building a house frame) I have never put bits of metal toghether to make something so some of the shapes were a bit odd and made me scratch my head a few times. I did the build not only to save $$$ but also as a distraction project while some stuff is going on in my life and it has been a good project for both outcomes.

My words of advice for these projects are, arrange a friend to come around to help you before you need them and expect things to take longer than you think. They reackon my boat should take about 150 to 200 hrrs. I think mine will take about 220 in the end, which I am happy with.

Now back to my problem,

I went to a bloke who repairs aly today with my problem. He was of the opinion I may have been welding too slow in some parts which caused the bite or eating into the edge of my weld into my base metal. He says give it a fill and a sand and stop worrying, so I will do that. He has also assured me that my transom is not ruined or brittle and will not cave in on the first push of the throttle, so I will do some grinding, clean it all up and patch and leak test before starting on the floor of the boat... its getting to the good bit. He also thinks maybe I had not cleaned my ally in one section well enough prior to welding. I am pretty handy with the wire brush, but maybe I didnt spend enough time on it.. Anyway its not all bad, so onwards and upwards.

Its good when a professional bloke takes the time to have a look at what an amature like me is doing and gives you some constructive advice without laughing at my welds. (I should have posted pics here, because I am certain some of you lot would have given me the same advice) One bloke I rang pretty well told me he doesnt fix problems caused by idiots. left a bit of a bad taste when I think of the amount of times I have recommended him or taken jobs to him in the past,

So I willl keep at it and thanks for your words of advice,

Chris

Chris, it would be great to see the photos... sounds like a great project. Regarding your welding issue - it sounds very much like a contamination issue to me. I don't MIG, but with TIG I've often welded ally and hit an invisible section of contamination - it doesn't matter what you do - it has to get ground/burred out and cleaned (acetone) before you can get a decent weld back over that area. Personally, I'd be cautious about embrittlement with any contamination, or softening of the ally due to overwelding but it all depends the scale of your problem vs the structure of the boat. Depending on how critical the weld is, do you have the option to add support struts? Cheers - Mick

[edit: I did a bit of googling - it seems that 5086, if that's what you have, isn't too susceptible to overwelding/loss of temper, so maybe this isn't much of an issue for you after all]

One small comment I read somewhere is that grinding wheels leave contaminent in the aluminium, so maybe make sure you clean it with something else first in case it is that causing the issue.

OK Chris I hope all is good and I guess at the end of the day yes you should be able to cut it out and reweld. Had to do that myself recently on a weld I just was'nt happy with, but if it's not to be seen and structurally sound you could just leave it too.
I too have in mind to build a platey, have a few issues to sort out with shed space and saving up for a precut flat pack etc, being the easiest way form my novice self. I would also like to see some pics of how it is coming together, warts and all if any doesn't matter..

Originally Posted by Trackhappy

One small comment I read somewhere is that grinding wheels leave contaminent in the aluminium, so maybe make sure you clean it with something else first in case it is that causing the issue.

Not really that big an issue usually, on the subject of grinding aluminium, please, please do not use one of the milling cutter wheels available for angle grinders. While they undoubtedly are very efficient at removing aluminium, they are equally as efficient at mincing flesh and bone, (think chainsaw kick back with no chainbrake and far less control at 3.6 times the speed).
Personally I believe they are actually illegal as they turn a grinder into a circular saw, which by law must have a self retracting guard that covers the full 360 degrees of the blade.
One can buy wax impregnated wheels to prevent the clogging common with grinding ally, however I find that a quick touch of a candle on the wheel while spinning is just as good and has little if any effect on the weldability of the ally.
I would not use wax on an item such as a fuel tank though.
A stainless wire brush is textbook for cleaning aluminium, but a steel brush is almost as good and adequate for most applications. Don't use one that has wire brushed paint or grease though as this will really contaminate the metal.
A good lubricant when jigsawing or cutting ally with a circular saw is wd40 or crc, but both these will affect welding if left on the material so a good compromise is methylated spirits applied from a squirt bottle as this dries leaving no residue.

Originally Posted by Karl Robbers

Not really that big an issue usually, on the subject of grinding aluminium, please, please do not use one of the milling cutter wheels available for angle grinders. While they undoubtedly are very efficient at removing aluminium, they are equally as efficient at mincing flesh and bone, (think chainsaw kick back with no chainbrake and far less control at 3.6 times the speed).

I use them all the time at work, I actually think they work great and last a very long time.

I've never had an accident, I generally use a full face mask (or welding helmet) and gloves.

I would only use them on a grinder that has a pedal type switch, not an on/off switch. An air grinder works great for this. A 4" grinder would be best as you can get into tighter places with the smaller blade.

If you use them the wrong way you are going to get kick back, you only want to use the first quarter of the blade from the grinder body.

I guess cutting fluid could leave a residue as well. Just came to mind as I cut ally in the bandsaw where possible.

At the risk of appearing belligerent I would like to reply to your comments as there are real safety issues with the use of these tools.

Originally Posted by Com_VC

I use them all the time at work, I actually think they work great and last a very long time.

No argument, they are both very effective and long lasting, however their effectiveness is just as great at mincing flesh and bone.

I've never had an accident, I generally use a full face mask (or welding helmet) and gloves.

I am glad that you have never had an accident, many have, the results of a lapse of concentration or a slip with these are often catastrophic as opposed to the wounds produced by grinding wheels due to their toothed design. I have seen a welding shield that has been cut by these during a kickback and it barely protected the wearer.

I would only use them on a grinder that has a pedal type switch, not an on/off switch. An air grinder works great for this. A 4" grinder would be best as you can get into tighter places with the smaller blade.

I agree that these switches are far safer, in fact I am not a great lover of any switch that can be locked on. No grinder will run down quickly enough to protect the operator in the event of a kickback due to the flywheel effect of the armature and the chosen cutting tool. A 4" grinder may well be more suited to tight access, particularly if the side handle is not used which of course reduces controllability exponentially, the shape and design of 4' grinders, being of a barrel shape does not lend itself to control unfortunately.

If you use them the wrong way you are going to get kick back, you only want to use the first quarter of the blade from the grinder body.

As with all tools there are techniques for safe usage. Get it wrong with one of these and you will quite possibly not get a second chance, (think of a deep diagonal cut across your face or your abdomen sliced open, these were both actual incidents that occurred with these cutters while being used by experienced operators that had undergone training). Worst of all is the fact that many cheap tool houses are retailing these to novice users.

Let me ask anyone reading this two simple questions.
1/ Would you use a powersaw if it had either no guard or a defective guard? (It would be illegal to do so and would breach your duty of care).
2/ How is an angle grinder with a toothed cutter different from a powersaw in its function?

Originally Posted by jatt

I guess cutting fluid could leave a residue as well. Just came to mind as I cut ally in the bandsaw where possible.

You are correct, cutting fluid does leave a residue. When bandsawing ally, I would usually do it dry up to say 16mm thick, (if it were a soft and sticky grade 10mm), after that I would tend to use metho - no post treatment required or CRC/WD40 then clean with thinners if welding is required.