Rivet woes

**phearless** · November 25th, 2008, 08:39 AM

I have an old smokercraft 1240 that I love.
The only problem is 1 popped rivet.
It has a couple of small 1/8th" long spiderweb cracks as well.
I have been gooping it up for years and it doesn't leak at the moment, but it bugs the crap out of me!
I had the boat on a boat rack in the back of my truck and was loading light items from a club trip I was on over at saltspring for smallies.
One of our members brought her son, I told him not to get in the boat.
I turned around to get something and heard a POP. Guess who is in the boat!
Bummer.
Anyway, has anyone out there ever dealt with this problem?
I know I could get the rivet replaced, but what about the cracks.
Welding woud be a pain in the arse. Thin, old metal isn't the best to weld for aluminum.

**Superwebby** · November 25th, 2008, 11:49 AM

You could bring it by a welding shop that could TIG weld the rivet hole and cracks, or even weld on a small metal patch. An experienced aluminum welder should be able to make quick work of the problem. (most don't mind quick cash jobs) I don't know about Vernon shops but Aqualu in Kelowna specializes in aluminum welding, and I was impressed with what I've seen from them.

**knotnot** · November 25th, 2008, 04:57 PM

If you are not into welding it or pop rivet aluminum stock try these.

http://www.cabelas.com/cabelas/en/te...324&hasJS=true

Or JB Weld's 'Marine Weld' from anywhere Can tire, Lordco.

prep, prep ,prep...

Knotnot

**Chilkootangler** · November 27th, 2008, 09:48 PM

Another option is to use a product called Rec' Repair Material.

www.recrepair.com/

We used it here for rental boats run to h#ll and back by German Tourists (God love Em). It works incredibly well and only requires good prep work and a heat gun.

The problem with welding is the aluminum surrounding the cracks and loose rivets becomes brittle and is prone to failure.

I fixed the transom of my sled this fall with Rec Repair and ran it into ice up. The patches remain bombproof.

Steve

**phearless** · November 27th, 2008, 09:58 PM

All of these patching suggestions are pretty dam good.
Now just to figure out which one I will go with.

I have been thinking about maybe drilling the rivet out and putting a nut and bolt with a fender washer on it with a liberal amount of Sika Flex.

Sometimes bush repairs are just so right.

**Chilkootangler** · November 27th, 2008, 10:03 PM

I just like to cover 'er up with a patch as it is hard to get a perminant fix in a drilled out rivet hole.

Let us know what you finally do Fred.

Steve

**phearless** · November 27th, 2008, 10:08 PM

Hey chilkoot, how long is that rec repair supposed to last?
They call it a " temporary " repair in thier ad.
I to would love to just cover it up and be done with it.

**knotnot** · November 27th, 2008, 11:07 PM

The Recrepair product Chilkootangler linked sounds awesome.

Aluminum is not an easy medium to weld properly.
Aluminum is an active metal and it reacts with oxygen in the air to produce a thin hard film of aluminum oxide on the surface. The melting point of aluminum oxide is approximately three times the melting point of pure aluminum and as it becomes thicker, will absorb moisture from the air.
Moisture is a source of hydrogen which is the cause of porosity in aluminum welds. Hydrogen may also come from oil, paint, and dirt in the weld area.
Hydrogen will enter the weld pool and is soluble in molten aluminum. As the aluminum solidifies it will retain much less hydrogen and the hydrogen is rejected during solidification. With a rapid cooling rate free hydrogen is retained within the weld and will cause porosity. Porosity will decrease weld strength and ductility depending on the amount.
Aluminum conducts heat from three to five times as fast as steel depending on the specific alloy. This means that more heat must be put into the aluminum even though the melting temperature of aluminum is less than half that of steel.
Because of the high thermal conductivity, preheat is often used for welding thicker sections. If the temperature is too high or the period of time is too long it can be detrimental to weld joint strength in both heat-treated and work-hardened alloys.
The high heat conductivity of aluminum can also be helpful since if heat is conducted away from the weld extremely fast the weld will solidify very quickly. This with surface tension helps hold the weld metal in position and makes all-position welding with gas tungsten arc and gas metal arc welding practical.
The thermal expansion of aluminum is twice that of steel. In addition, aluminum welds decrease about 6% in volume when solidifying from the molten state. This change in dimension or attempt to change in dimension may cause distortion and cracking.
The final reason why aluminum is different to weld from steels is that it does not exhibit color as it approaches its melting temperature.

from my notes and booklet.
knotnot

**phearless** · November 28th, 2008, 07:32 AM

Old , thin aluminum is shitey to work with.
I know from experience.
I took an old 1965 smokercraft and turned it into a work of art.
( In my eyes )
Probably put over 150 hours welding into it.
This is why I am looking for alternatives.

**SalaR** · November 28th, 2008, 08:29 AM

Great source of info'...who knew?
C

Originally Posted by knotnot

The Recrepair product Chilkootangler linked sounds awesome.

Aluminum is not an easy medium to weld properly.
Aluminum is an active metal and it reacts with oxygen in the air to produce a thin hard film of aluminum oxide on the surface. The melting point of aluminum oxide is approximately three times the melting point of pure aluminum and as it becomes thicker, will absorb moisture from the air.
Moisture is a source of hydrogen which is the cause of porosity in aluminum welds. Hydrogen may also come from oil, paint, and dirt in the weld area.
Hydrogen will enter the weld pool and is soluble in molten aluminum. As the aluminum solidifies it will retain much less hydrogen and the hydrogen is rejected during solidification. With a rapid cooling rate free hydrogen is retained within the weld and will cause porosity. Porosity will decrease weld strength and ductility depending on the amount.
Aluminum conducts heat from three to five times as fast as steel depending on the specific alloy. This means that more heat must be put into the aluminum even though the melting temperature of aluminum is less than half that of steel.
Because of the high thermal conductivity, preheat is often used for welding thicker sections. If the temperature is too high or the period of time is too long it can be detrimental to weld joint strength in both heat-treated and work-hardened alloys.
The high heat conductivity of aluminum can also be helpful since if heat is conducted away from the weld extremely fast the weld will solidify very quickly. This with surface tension helps hold the weld metal in position and makes all-position welding with gas tungsten arc and gas metal arc welding practical.
The thermal expansion of aluminum is twice that of steel. In addition, aluminum welds decrease about 6% in volume when solidifying from the molten state. This change in dimension or attempt to change in dimension may cause distortion and cracking.
The final reason why aluminum is different to weld from steels is that it does not exhibit color as it approaches its melting temperature.

from my notes and booklet.
knotnot