What is the best way to weld pin holes in tinnies

[ahoj]

What is the best way to weld pin holes in tinnies

Ahoj

[Owen]

TIG

Requires an AC machine with HF. Anything decent starts at about $4,000
If you have three phase power you could pick up an old "pie warmer" for about a grand.

cheers,
Owen

[SunnyCoastMark]

Definitely with a TIG Welder.

If you don't have one or know someone who does - you can MIG It. Hold a lump of brass or copper on the other side - but you'll have to be good!

Whatever you do, don't be tempted to use silicone as a quick fix. Makes welding it properly later on a pain in the backside, because no matter how much you peel and srcape that silicone off - there is always a bit left that puts porosity into the weld.


Mark

[Owen]

For those that want a bit more in depth info try
http://www.millerwelds.com/education/bookspamphlets.html

cheers,
Owen

[tommyt]

were abouts is the pinhole in the boat ?

[SunnyCoastMark]

For those that want a bit more in depth info try
http://www.millerwelds.com/education/bookspamphlets.html

cheers,
Owen

That is an excellent site - thanks Owen

Mark

[lippa]

if there that small, welding would ugly and most likly make small holes, big holes, try devcom it will seel the holes up no worries

[SunnyCoastMark]

if there that small, welding would ugly and most likly make small holes, big holes, try devcom it will seel the holes up no worries



If you turn turn small holes into big holes while welding - better get someone else to do it. ;D

Devcon will seal up small holes temporarily, however it won't solve the reason for the pin hole - corrosion - this has top be dealt with or it will spread.

Mark

[bazzacuda]

Pinholes are pretty small, they really only let in water as an inconvenience if you have an open floor although with a floor in the boat it's a different story. I used aluminium epoxy on the pinholes in my 5.2 tinnie, worked like a charm. Plenty on either side of the hull, sand down to an acceptable finish. Tigging them was way too extreme for me, given that welding makes the metal brittle - I felt that it would make things worse not better.
good luck,
Bazza

[Owen]

Bazza,
Welding itself doesn't make the metal brittle. In fact you will actually get local annealing (softening) of the metal. The temper will return to close to normal over a period of time. What welding does do is make that area stiffer. This can be a problem in an area that flexes a lot as aluminium has a low tolerance to being flexed. i.e. If you continually bend it beside a rigid point it will crack. However, typically a tinnie will be made from 5083 or similar grade material with a relatively low temper so that it can be folded in the first place without cracking.
The question asked was what is the best way to weld the holes, which is TIG.
The question of whether you should weld them at all depends on the condition of the hull (is it old and already showing signs of stress fatigue), where the holes are and your budget.

Regardless of whether you decide to weld or use an epoxy the main consideration is to stop the corrosion. So before you do either you must drill, grind (use a tungsten carbide burr) and buff the metal with a stainless steel brush untill all the corrosion is removed. Often localised corrosion is a result of steel or other contaminates being imbedded into the aluminium during forming. Tiny bits of metal that may be sitting on the former of a die or the blade of a brake press get formed into the metal and start to corrode.
If you don't get rid of it, it will continue. So if you want to save some money with getting it welded, do this bit yourself. It'll cost you around $80 an hour for someone to weld it and 90% of the time involved is preparing the metal.
Personally I would NEVER MIG weld the bottom of a tinnie unless it is on the chine or keel extrusions. Plenty of people do it with varying success, but I don't believe it's the right process to use on light guage metal that is subject to those loads and stresses.

cheers,
Owen

[Brenno]

my mate has the same problem with his boat. can anyone tell me where he could get this welding done in the Brisbane/ Ipswich area, (the site is american)

thanks

mark

[Owen]

Mark,
I haven't been in Brisbane for a few years, so I'm a bit out of touch, but Aquamaster boats at Browns Plains would be a good start. You want someone who knows boats.. not just a general engineering shop as they my not haave the experience on light guage alloy.

cheers,
Owen

[ahoj]

Advice i have since resieved from a sheetmetal works that specialises in allu-welding
Since the metal on a 12 ft De haviland boat is relatively thin and corroded was best to clean with a small air operated fibre grinder -- tip the boat upside down and use
Aluminium Solder (availabel at welding shops) and oxy have tried on some new allu and it holds well and stuck deep.. will try on my tinny on monday and see how it goes and will report.. there are many alternatives with mig one will expect too much heat and possible burn-through inless the metal was thicker like 3mm
Thank you all for your input -

Ahoj

[Fishing_Freddy]

Hi Mark there is a place Yamanto called Nissan Welding they specialise in aluminium welding Alec has been around for years and if you talk to him Im sure he could do the job for you Ken ;D ;D ;D

[Brenno]

thanks guys i'll let my mate know, while the wholes arent big, it takes 2 min for the water to run out once you get it on the trailor, and thats after 10 hrs,

[ahoj]

Well.. the result of allu solder was not satisfactory on a boat because 30years ago the ally was stronger and not as soft as late allu when soldering 2 sheets together il looked good and holding.. so instead decided to use plastic steel as used in motor industry on corroded water pumps allu heads fuel pumps etc.. For the plastic steel to set hard needs 24 hours with 2 coats. then a gentle grind and coat of paint then a test and report----- if the pinholes are small and surrounding metal strong drill a size to fit hammered allu rivets and plastic steel together will be another option....( not with rivet gun) need 2 people to hammer the rivets and 2 hammers..... This problem is not easy to fix but some alternative systems will uncover the best way for such a repair

Cheers Ahoj