i had need to fold & anneal some alli for my albatross

[LOTUS30]

I thought it might be of help to some one repairing there aluminium boat. Lather up a bar of soap rub the soap bar on the aluminium heat with a blow lamp on the other side until the soap turns black as picture allow to cool naturally do not quench and thats it done. ANDY B

[Healey75]

Great tip here, I've used before...don't try it without the soap though, the aluminium will just drop into a huge hole if overheated without warning, unless you use the soap trick you risk it happening. A further tip with soap I've found if you're mig welding aluminium heat the job (with soap) then as soon as it's dark brown/black and before it cools dive in with mig welder...it worked a treat with my mini mig at home. Anneal the weld after as well, the weld seems very hard with mig. I did a lot of aluminium car body welding restoration like this and none cracked afterwards in years of running the car.

Another tip comes to mind...if you mig weld aluminium the weld will be raised and need grinding down...use a 40 or 60 grit disc in the angle grinder but make sure you load it with some lard, tallow or fat, it's very messy but cuts a treat and the disc does not clog with aluminium.

Yet another tip... if the aluminium is thin and to be butt joined with mig welding, place a thin piece of steel sheet behind the join and the molten weld wont be able to drop though in to a hole. Once it all cools the steel will just spring off as you can't weld aluminium to steel this way.

It worked for me

[Tatra Man]

Brilliant tips. - Thank-you.

[LOTUS30]

this is the plate i annealed folded and riveted in the rudder bearing area on the hull as it had fatigue cracks. i cut out the bad alli fitted this plate and fitted a repair patch on the other side and riveted it all in. plus i made new rails as those were cracked where the P bracket bolted through. all done now on repairs now down to paint prep.
ANDY B

[LOTUS30]

Just a pic of the hull repair on the other side tried to ali solder and weld it but the cracks would fail again when the ali cooled so i cut out the old ali. before riveting up i got every thing ready and mixed some DEVCON aluminium putty and spread it over the repair panel bolted it first and riveted before the paste set.

[LOTUS30]

The boat as it is this w/end 4th aug pics show the hand held sand blast gun great for getting in where you cannot get at to prep for paint.

[Rapier]

Nice looking work; am very impressed with your skills

[Healey75]

Just a pic of the hull repair on the other side tried to ali solder and weld it but the cracks would fail again when the ali cooled so i cut out the old ali. before riveting up i got every thing ready and mixed some DEVCON aluminium putty and spread it over the repair panel bolted it first and riveted before the paste set.

Another tip that worked for me...re cracks before mig welding run a hacksaw down the crack to open it up and clean the joint, drill a small stop hole at the end and then weld up as per previous posts, I'm not a trained or professional welder but it worked for me, I think the preheating is very important plus annealing after.

You're Doing a nice job on the boat

[Tatra Man]

I had the same trouble with the cracks reappearing. I ground them out with a cutting disc and found that what they say about using the stainless steel rod to scrape the alli beneath the pool of "solder" is essential. I managed this on a vertical surface:-



Mine had already had a plate added on the inside which covered the whole area between the stringers all the way from the transom to the cross-brace.

[LOTUS30]

I gave the matter a lot of thought before i cut out the damaged area, i came up with if i was say driving along at 30mph would i be able to hold a piece of material out of the window and hold it at an angle the against the wind i probably could not let alone throwing water at it from the prop also it is 50year old alli with metal fatigue so no brainer for me it had to be replaced and supported to keep it as small as the first plate that was fitted to the out side by a previous owner which had to go. John Fildes done a great repair in this area and re done a large piece of hull bottom with the riveting all along the back to support the rudder bush, as i had such a small area around the bottom rudder bush which had failed i gave it the support it needed and put the plate inside and up the back picking up on the original rivet line.MANNY THANKS TO JOHN FILDES FOR HIS HELP AND ASSISTANCE AND LOAN OF HIS RIVETER I HAVE BEEN ON THE PHONE TO HIM NEARLY EVERY DAY MAKING A REAL NUISANCE OF MY SELF. THANK YOU JOHN. ANDY B