How do I treat this?

A

AlistairM

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The varnish on my small dinghy has flaked away leaving bare wood. Do I simply varnish straight on and sand untill a decent finish is achieved, or is something required in preparation. The boat is completly covered with a tarpaulin but "natural moisture" still penetrates.

Also can some one please settle some confusion once and for all. Can epoxy be used to fill cracks and splits in the wood, or is this a definete no no.

Thanks

BareWoodCloseUP.jpg


BareWoodOverview.jpg
 
Take all the varnish off and start again. I would use epoxy to fill the cracks, but lots wouldnt. Might need something more flexible.
But really all that varnish needs to come off, the wood has bleached also, I think it's Mahogany, so will come up a lovely reddish colour, once all the varnish is off and it's sanded. The whole boat probaly needs re-varnishing, if the varnish is all that old.
 
You Shouldent Really Rub Bare Plywood Down They Usally Add A Diluted Coat Of Varnish First, This Stops It Splintering,
You Can Use Epoxy For Filling If You Mix In A Filler ie Silica.
 
Thanks for the info, I will sand off all the varnish and reapply. This is my first "project" boat so I am looking forward to getting into it.

I am one of those rare occurances of being young(ish) and interested in wooden restoration jobs instead of out and plastic tubs.

Anyway thanks again
 
Alistair - the black marks are fungi - probably a 'blue stain-in-service' fungus . The fungus itself often blows the varnish, use oxalic acid to bleach it and sterilize the spores. And then revarnish.
 
Hi
It looks as though the varnish has been blown off by damp penetrating from the inside of the boat, possibly rain water gathering against the transom. I would certainly look to the inside as well, and consider the quality of your rain cover. Damp may be getting in under the drain plug fittings and rudder hanging, so make sure that the wood under them is well sealed and bed them properly in something appropriate before refitting them.
 
Thanks for lots of good advice, this being my first wood project its alla bit of a learning curve.

I plan to cover the transom in Oxalic acid as indicated above then sand down and revarnish

What would be suitable for bedding the rudder pintle on??

Oh and take on board the cover issue too, I will look to enhance that also.

Thanks for the patience.
 
I would use Nitromors to remove the varnish...makes it a very quick and easy job.

In case you havn't used it before, be cautious as it gets everywhere and of course use latex or similar gloves.

If its warm and the nitromors is tending to 'dry out' to quick, cover with cling film or ali foil to keep it 'working' longer.

Possibly with a dinghy sized job it might be worth applying with a mini roller.

Regds Nick
 
[ QUOTE ]
a 'blue stain-in-service' fungus . The fungus itself often blows the varnish

[/ QUOTE ]

Even if blue stain was found in hardwood ply it is a non structual defect that will not blow the varnish . Sometimes i think you guys make this stuff up for fun /forums/images/graemlins/blush.gif /forums/images/graemlins/grin.gif
 
Cuchillo - I’m not making it up !! “blue stain…. will not blow the varnish “ – I think it will -

Here from my BRE ‘rot’ book – there are photos similar to AlistairM’s but I’m no good at loading them:

“Blue stain in service fungus

Commonly - Aureobasidium pullulans and others

Damage characteristics -

Disfigurement of the wood and especially of clear finishes; early failure of surface coatings caused by rupture of the fruit bodies.
Discolouration caused by sap stain which has occurred in the log may still be detectable after drying and conversion of the timber…… Damage to coatings will occur through the growth of blue stain in service.

Cannot grow below 20% moisture content

Treatment - …. Dry the timber , treat with preservative containing an additive specifically active against these fungi….: apply new coating….’
 
Sorry i wasnt very constructive there . Blue stain as i know it has no structual effect on the timber and is only found in pine . It is a fungus that attacks the sapwood and feeds on the sugars in the timber and ray cells if i remember rightly ..... It was along time ago ......Bluestain is not regarded as a defect in the timber as all it does is make the timber look blue . The staining in the Hardwood ply shown looks more to me like the start of wet rot .
 
Wet rot ? I think you are right.

On closer inspection there would seem to be more than one type of rot on the go.
The problem with blue stain is that it lies dormant as spores which then errupt as small flecks as in the photos, these break open the protective coating and let in more water and so white, brown, wet & dry rots ( take your pick !) are able to get a hold.
So the fact that it, in itself is not structurally damaging, doesn't put it on the 'harmless' list .....and it loves hardwood as well - spalted beech and ash being classic examples.
 
Whoops !

We've all been there......

Nice piece of timber.....

Thats not wet rot starting on the RHS is it ?!!!! /forums/images/graemlins/smile.gif
 
Strange thing to say. I gave my Heron an epoxy coating when I rebuilt her and most plywood boat builders do the same. They also use fillets of epoxy to bond the panels together.

Fyne Boats for one.
 
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