Water-based varnish - advice ?

[pragmatist]

We need to re-varnish a lot of the interior ply on our catamaran. Water-based varnish is essential as HWMBO is severely allergic to anything oil-based. Most of the interior is ply in a palish blondish colour (ash ? certainly paler than pine coloured varnish) and is silk. We would like to match it as closely as possible. Some areas will need to be sanded right back to remove marks where there used to be leaks so I think it's going to be essential to use a coloured varnish rather than just clear to match the existing colour.

When we re-varnished the last boat we used, I believe, Ronseal water-based interior varnish and got a good match for the existing teak. However we noticed that if a horizontal surface got wet the varnish (even when thoroughly dried out) would turn a milky colour until it was completely dry again. Mostly the interior is kept dry but it maybe that there may be condensation from the windows or the odd glass of something spilled.

Does anyone have any recommendations ? A varnish you swear by ? Or any way to stop the Ronseal going milky ? All ideas very welcome.

 

[footsoldier]

When we re-varnished the last boat we used, I believe, Ronseal water-based interior varnish and got a good match for the existing teak. However we noticed that if a horizontal surface got wet the varnish (even when thoroughly dried out) would turn a milky colour until it was completely dry again

I can't help with other products, but I'm very surprised at this issue with Ronseal. I have used it in several applications without any similar problem. Either I have been very lucky or you had a bad batch. I shall await others' experiences with interest.

 

[VicS]

When we re-varnished the last boat we used, I believe, Ronseal water-based interior varnish and got a good match for the existing teak. However we noticed that if a horizontal surface got wet the varnish (even when thoroughly dried out) would turn a milky colour until it was completely dry again. Mostly the interior is kept dry but it maybe that there may be condensation from the windows or the odd glass of something spilled.

Does anyone have any recommendations ? A varnish you swear by ? Or any way to stop the Ronseal going milky ? All ideas very welcome.

You probably need an outdoor varnish.
ITYWF Ronseal do a matt and a satin finish water based outdoor varnish but it is clear, not coloured.

 

[Tranona]

I have noticed that with the latest Ronseal formulation, but only in isolated spots. Otherwise it still seems to stand up well.

 

[thinwater]

I've used a good many. I have never used, nor seen a test of (I just searched a few) water-borne varnish that was good. As you note, they don't like water, and it is a boat.

I suggest using a good oil-based varnish and then giving the boat a long dry and air-out period, with a fan running on slow speed continuously. You may not get to use the boat for a few weeks.

 

[B27]

Rustin's from Toolstation seems OK to me.

I've heard of water based paints and varnishes 'blooming' if they get wet, when the finish is new. It should happen less as the varnish fully hardens/ages a bit.

I might dye the wood then use clear varnish?
You might want a UV resistant varnish to avoid the dye changing colour.

 

[rotrax]

I revarnished our large folding table with Ronseal.

Despite having a very dry boat it often feels 'tacky' and the non slip mat we use on it loses bits that adhere to it.

I shall re-do it over the winter with another more traditional product.

It was recomended by some on here but I found it was crap.

 

[B27]

I revarnished our large folding table with Ronseal.

Despite having a very dry boat it often feels 'tacky' and the non slip mat we use on it loses bits that adhere to it.

I shall re-do it over the winter with another more traditional product.

It was recomended by some on here but I found it was crap.

There are dozens of flavours of 'Ronseal'.
Those sticky non-slip mats are chemically quite aggressive.

Personally I have found that the 'traditional' products are often a bit crap now, because post 2010 or so, they were all re-formulated to lower VOC due to EU regulations.
In about 1999, I used a major brand of 'floor varnish' and found it very good. A few years ago, I bought the 'same' product in the same style of tin and it was terrible. Took ages to dry, scratched easily, stank the house out.

The world has changed, you may need to move with the times.

I still use 2 pack international for varnishing carbon masts though.

 

[arcot]

On unfinished wood modern acrylic. / water based varnish minimally darkens wood.
.
Oil based varnish darkens wood.

 

[coopec]

Is Bondall Monocel sold in the UK?

https://www.bunnings.com.au/bondall-1l-monocel-waterbased-clear-varnish-gloss_p0079564

 

[pragmatist]

You probably need an outdoor varnish.
ITYWF Ronseal do a matt and a satin finish water based outdoor varnish but it is clear, not coloured.

Thanks for that - I wondered about trying the water based Ronseal and then, if any of it turned milky, adding a single coat of oil-based varnish. Other than varnishing just before we leave the boat I have no other option than water-based below - other than ditching the skipper

Anyone tried oil-based over water-based ?

 

[pragmatist]

Rustin's from Toolstation seems OK to me.

I've heard of water based paints and varnishes 'blooming' if they get wet, when the finish is new. It should happen less as the varnish fully hardens/ages a bit.

I might dye the wood then use clear varnish?
You might want a UV resistant varnish to avoid the dye changing colour..

Thanks for that - it appears to be clear but again, might do for a top coat if I have problems with Ronseal,.

 

[pragmatist]

Is Bondall Monocel sold in the UK?

https://www.bunnings.com.au/bondall-1l-monocel-waterbased-clear-varnish-gloss_p0079564

Not as far as I can tell - its shown on ebay.co.uk but with a proviso that it may not ship to the UK - weird ?! Thanks for the thought though.

 

[Humblebee]

Quite a few points being raised, Pragmatist, but time is on your side if, like me, you won't be boating much before next spring.
You mention marks where water has stained the ply. I would clean/bleach these off before considering any new coatings. A small jar of oxalic acid solution might be the best way, or serious sanding/scraping and sanding again.
I would then try to approximately colour match the areas thus treated with areas where the existing coating is in better state, and personally I would rather use - judiciously - wood stain rather than coloured varnish. With the latter it is hard to achieve an even colour and it often gives a streaky effect.
As for choice of varnishes, I tend to use those from smaller, independent makers rather than Dulux/Crown or whatever. Ronseal is good but can remain milky until thoroughly cured which means up to summer like temperatures. Don't give up on it, their Diamond Hard Floor Varnish is economical and can give good results.
Otherwise, have a look at products from Flag, Blackfriars, Rustin and the like. Purely a personal opinion but I wonder if they spend less on advertising than big makers, but more on product quality.
Anyway, good luck and post some pictures and feedback so we know how you are getting on!

 

[Iliade]

I used Rustins' two-pack 'plastic coating'varnish about four years ago. It's great on the worktops at home but distinctly average on the boat and hopeless outside. I went back to 'proper' varnish, which thankfully overcoated the Rustins' readily.

 

[pragmatist]

Quite a few points being raised, Pragmatist, but time is on your side if, like me, you won't be boating much before next spring.
You mention marks where water has stained the ply. I would clean/bleach these off before considering any new coatings. A small jar of oxalic acid solution might be the best way, or serious sanding/scraping and sanding again.
I would then try to approximately colour match the areas thus treated with areas where the existing coating is in better state, and personally I would rather use - judiciously - wood stain rather than coloured varnish. With the latter it is hard to achieve an even colour and it often gives a streaky effect.
As for choice of varnishes, I tend to use those from smaller, independent makers rather than Dulux/Crown or whatever. Ronseal is good but can remain milky until thoroughly cured which means up to summer like temperatures. Don't give up on it, their Diamond Hard Floor Varnish is economical and can give good results.
Otherwise, have a look at products from Flag, Blackfriars, Rustin and the like. Purely a personal opinion but I wonder if they spend less on advertising than big makers, but more on product quality.
Anyway, good luck and post some pictures and feedback so we know how you are getting on!

Thank you very much for that. I hadn't thought of oxalic acid but as the ply is blackened it might be ideal. Since the boat is built to be fairly lightweight the ply is probably not up to lots of sanding (unlike our Rival 41 with lots of solid teak). I will also have a look at stains and post some pictures. Thanks for your help.