Epoxy & fibreglass matting as temp fix on steel hull?

[Conachair]

Found some unwelcome rust inside of the transom in lazerette and now have pinhole approx 1' above waterline. Rusty bit is about 2' high by 1' wide, all above waterline (pinhole's at the bottom of the patch). Ultrasound showed down to 1.1mm in places. Rest of the area seems pretty resilient to thumping with a hammer. Don't really want to get a new piece welded round here so question is - Has anyone tried epoxy and fibreglass matting as a temp solution for such a problem? Or any other thoughts?
Ta

 

[Poignard]

[ QUOTE ]
Or any other thoughts?

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For a temporary repair, what I would do is to get a piece of steel plate large enough to overlap the corroded area and bolt or rivet it to the hull, with Sikaflex or similar between the plate and the hull.

Then get a proper welded repair done when time/money allows.

 

[Bajansailor]

All of the old ex North Sea coasters that ended up trundling around the Caribbean have always made extensive use of a two part epoxy putty called Navicote (there is a similar product from the USA by the Marinetex people) for patching holes in their hulls - that, and also what are referred to as 'buttons' - the steel plates that Twisterowner mentions above.
And they seem to keep going for years like this..... /forums/images/graemlins/grin.gif

 

[boatmike]

It's not impossible to bond to steel as you suggest but it needs to be entirely clean and corrosion free. If you can't get it welded it's a good idea to use such a method with one modification. It might sound drastic but open up the area where the pinhole is to give a clear hole through. Then preferably drill a few holes around it in good metal. Clean inside and out thoroughly and abrade before laying up inside and outside with epoxy /matt as you suggest. The holes will ensure a bond between both sides which will ensure your patch stays there OK even if the bond between steel and epoxy breaks down. I once surveyed an old dutch barge in Holland that had duff areas like this but was structuraly sound otherwise. We patched her this way and brought her over the channel to be properly rebuilt in a UK yard. Conversely if it's flat, then a plate on both sides bolted through with sealant would be better but don't rely on bolting a plate on just one side unless you know you are bolting into good plating. Even then use big penny washers! Hope this helps. Good luck!

 

[Conachair]

Thanks everyone. Part of the problem down here (La Gomera, Canaries) is even finding a piece of plate. No luck so far, only huge piece in tenerife which ain't really going to happen on the ferry /forums/images/graemlins/frown.gif
Here's the offending area

Hole is at the bottom just in front of the wire brush.
I've already cleaned up the rust using anglegrinder and wire cupbrush (fun that was!), then cleaned with strong detergent followed by por-15 metalready (zinc phosphate/phosphoric acid?) then after several good rinses and a really good dry (fan heater)put 1 coat of interprotect. Seems to be adhering well but you can see some of the existing paint where there was no rust bleeding through. Quite like the idea of epoxy/matt both sides - would epoxy stick to abraded international perfection topcoat?
Ta

 

[boatmike]

Quite like the idea of epoxy/matt both sides - would epoxy stick to abraded international perfection topcoat?
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Er: Not very well I am afraid. You need to abrade back to bare metal. Preferably quite aggressively like with an angle grinder or flap wheel. Wire brush will only polish it. Wear safety specs wont you? /forums/images/graemlins/cool.gif