chemical metal

[pandos]

I have had a bit of corrossion on the plate to which is bolted the seawater pump on my md21b. in theory this is a dry part and once the shaft seals have been replaced it should once again become one.

I have choices....clean and paint it, put it together with copious amounts of Dirko sealant and ignore... smooth over and make good with chemical metal and paint ... followed with less Dirko....

I fear a reaction between the aluminium and rhe chemical metal in the unlikely event of seawater getting near it...

Discuss...

 

[Plum]

I have had a bit of corrossion on the plate to which is bolted the seawater pump on my md21b. in theory this is a dry part and once the shaft seals have been replaced it should once again become one.

I have choices....clean and paint it, put it together with copious amounts of Dirko sealant and ignore... smooth over and make good with chemical metal and paint ... followed with less Dirko....

I fear a reaction between the aluminium and rhe chemical metal in the unlikely event of seawater getting near it...

Discuss...

I repaired a hole in the aluminium water jacket of my 2.5hp 2stroke outboard engine, caused by freezing of freshwater inside, by grinding away the fragments and corrosion then bonding on a plate over the hole with JB Weld high temperature epoxy. I have been using the outboard in seawater for a few years now with no proplems.

Www.solocoastalsailing.co.uk

 

[Lon nan Gruagach]

Chemical metal isn't metal, it's high temperature epoxy.
So no worries about it eating the ally. But, and its a mahoosive but, be mighty sure you are down to clean metal before you use it. Contamination is a real killer here.

 

[Halo]

I used chemical metal on an aluminium job years ago - cleaned the area up, roughed up the surface, applied it, assembled the parts quickly and left it alone for a while to cure - job lasted for the following 10 years then I sold the boat.

 

[GrahamHR]

I've used similar materials for years without problems, even for aluminium alloy components with 6 month+ immersion in salt water ( repairs to outdrive skegs ).

As already indicated, cleanliness and keying the surface is the key to a long lasting repair. If the piece being repaired is subject to bending forces, then metal reinforcement is advisable if the repair material is all that holds things together (rods, threaded bolts etc); "chemical metals" are nowhere near as ductile as the true metals. If bent, they will crack.

 

[Poignard]

I've successfully used JB Weld to repair a corroded BUKH cylinder head that had corroded underneath the thermostat housing. As others have pointed out, absolute cleanliness of the bonding surface is essential.

 

[VicS]

Chemical metal isn't metal, it's high temperature epoxy.
So no worries about it eating the ally. But, and its a mahoosive but, be mighty sure you are down to clean metal before you use it. Contamination is a real killer here.

Actually polyester based. http://www.loctite.co.uk/loctite-4087.htm?nodeid=8802657107969

Whatever is used the secret, and the difficult part, will be getting rid of all the oxide from the corroded areas. Ideally needs to be grit blasted with a soft grit.

 

[pandos]

Thanks for the replies, it will be a dremel and some chemical metal..... grit blasting is not an option for me... used it (CM) in the past but not in a potentially galvanically corrosive area..

Off tomorrow for some new seals the existing were rotted, ( I had a memory of replacing them in the past but it was my previous boat) off to an industrial seal supplier tomorrow...bet I can get the seals for less than from the Volvo Penta dealer...

 

[PaulRainbow]

Thanks for the replies, it will be a dremel and some chemical metal..... grit blasting is not an option for me... used it (CM) in the past but not in a potentially galvanically corrosive area..

Off tomorrow for some new seals the existing were rotted, ( I had a memory of replacing them in the past but it was my previous boat) off to an industrial seal supplier tomorrow...bet I can get the seals for less than from the Volvo Penta dealer...

Make sure industrial seals have stainless springs in them, or they won't last more than a few months.