Protecting a new weld

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jav301

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I've had a look through a lot of threads on protecting mild steel but I still feel unsure about what to do. Apologies if the topic is tedious.

Specific case: Getting a new steel shoe welded onto the half inch (thick) bilge plate of a Trident 24. No possibility of fancy cleaning, blasting etc. What treatment would afford best protection for the new metal, the weld and the old?

Also, these boats have a mild steel rudder stock that passes through a stainless tube. Lots of corrosion on the stock. Would wire brush followed by rust converter be sensible?

Thanks for your advice
 
I'm not sure that you can protect it fully, the process of welding will remove most coatings that you put on as a pre treatment, but if it was me, i would try a weld thru zinc primer with more zinc primer after the weld has been done too, then plenty of coats of whatever antifouling you usually use (with a suitable a/f primer too!)
 
jav301 said:
I've had a look through a lot of threads on protecting mild steel but I still feel unsure about what to do. Apologies if the topic is tedious.

Specific case: Getting a new steel shoe welded onto the half inch (thick) bilge plate of a Trident 24. No possibility of fancy cleaning, blasting etc. What treatment would afford best protection for the new metal, the weld and the old?

Also, these boats have a mild steel rudder stock that passes through a stainless tube. Lots of corrosion on the stock. Would wire brush followed by rust converter be sensible?

Thanks for your advice
Click to expand...

Speak to Hempels in Wales,
I deal with them for coatings for offshore material, I havent got the guys name etc as im not in the office, but i was only speaking to them last month.
They have a dedicated marine section as well as Oil and Gas section
Both those disciplines require strict anti corrosion products and you should be able to find something from them to do what you want etc.
I do know the coating i was using for sub sea valves when i asked the question about the complexity of it Trying to find out if i could somehow apply it to my boat if needed, their reply was that it is the same product that most of the worlds navies use to coat their ships.
They also own Blakes paints.
www.hempel.co.uk
phone...+44 (01633) 874024
 
I have been impressed with Zinga which is the next best thing to hot dip galvanising.
It describes itself not as a pain, but a zinc rich resin suspension. I used it on a mild steel frame fabricated and welded in situ in my hull to bear the engine.
 
Coatings will help but a very strict regime is needed to provide 100% protection. You are certainly not capable of this (no disrespect, neither is anyone else.) Your rudder and stock will benefit greatly from having an anode close to the stock weld, although this will not give total protection. On your keel plate you can only do the best possible in coatings but it must be regarded as a sacrificial component. The first time you dry out all the paint will be ground off where it is in contact with the bottom.
 
I had to weld (get welded) a new 'tab' onto my lifting keel last winter. The weld and tab were ground off to shiny metal then coated with Blakes Epoxy that I had left over from doing a hull a couple of years back (SF200?). This winter it still looks as good as when it was painted. So I'd say 2 pot epoxy.
 
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