Varnishing tip

Javelin

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Southwold
www.southwoldboatyard.co.uk
We've been running tests for numerous years on various varnishing techniques and products.
In the yard we don't usually get much time to get a great finish as the customer wants his boat NOW.
So we needed a way of getting the look of 10 coats of varnish fast.
However we also need the finish to be durable as most of our customers come back and boy we'd hear about it if the varnish peeled off or discoloured after a season or two.
I thought I'd let you know what is currently in vogue.

For individual pieces or sections that won't endure much expansion/contraction.
Sand smooth, clear dust and then wipe with acetone.
Then we use three or four coats of Bonda Wood Hardener.
This soaks into the wood so usually you'll need 3 or 4 coats on bare wood or 2 or 3 on old sanded varnish.
Different woods soak more than others.
It's not actually designed for doing what we're doing. We kind of found out by accident.
It goes off using the moisture in the wood and the air and not with heat.
So we coat in the morning and then at the end of the day.
Use disposable brush as acetone, white spirit, turps doesn't seem to clean the brushes.

Once we've got a nice depth we use 1000 or 1500 grit wet n dry and then two coats of tipped off International UV varnish.

For us that gives us a 10 day finish in less than a week.
 
I think that is the same as Ronseal Wet Wood Hardener - a single component acetone-based carrier with resins.


A useful tip, which I shall look forward to trying this weekend on some cockpit locker lids. Thanks,
 
I think that is the same as Ronseal Wet Wood Hardener - a single component acetone-based carrier with resins.


A useful tip, which I shall look forward to trying this weekend on some cockpit locker lids. Thanks,

I thought the ronseal stuff was cellulose based (or is cellulose thinners just acetone? I dunno as I failed chemistry o'level) where as the bonda stuff is moisture cured?

Edit. found his for cellulose thinners
http://www.birdbrand.co.uk/msds/Cellulose%20Thinners.pdf
and it is mostly toluene (30-50%)
and acetone (1-10%)

Still unsure if the two (ronseal v bonda) are the same though, anyone any ideas?
 
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The wood botherers at work assure me that Bonda is not the same as ronseal or any of the other wood hardeners.
It is however similar as a now discontinued International sealer.

It is very glossy after the third coat but overcoating with satin varnish does dim it down.
I've coated some teak pads for some of my Clutches a couple of days ago and they look superb.
I guess it slightly darkens it but not much. A very deep shine.

Bonda is Polyester resin based but for some reason acetone seems to have little effect.
I does go a very long way as well which given a lt tin is around a £10 makes it pretty good value.
 
I'm just about to varnish a mirror dinghy will this work on plywood? I don't want to be putting hours worth of varnishing in to her because the weathers not predictable and I have her stored outside so I'm dependant on the big shiny thing...

By my understanding I could use this Bonda wood hardener and if the heavens open put the cover back on and expect it to finish its job without any problems?
 
Sounds good and I'm minded to give it a try. Is it OK on teak? My grp yacht only has a small a amount of external wood (teak handrails etc.) but what little there is I like to keep looking bright.
 
I would think that from the description the product you are "building " with is a moisture curing polyurethane similar to the old International product UCP.
Many years ago when I was building GRP dinghies and looking for a rapid finish for thwarts I used a product that was designed to be used on shuttering concrete formers, a real "one coat magicote"!!!
 
Thanks very much for the tip,which I have noted down in 'My jobs to do' little book.
Would be interested to know what 'tipped off' means relative to the International varnish.
 
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