Varnish refinishing - crash course

captainslarty

captainslarty

N/A
Joined
12 Aug 2007
Messages
2,008
Location
Currently La Coruna Spain
Visit site
Well, as part of the refit, rebuild, conversion, life changing experience lol.. I had to do a Varnish 101...

After MUCH testing and experimenting.. heres what works for US..

Cleaning old varnish................................................
(Courtesy of Don Casey (This old boat).. mix 1 inch of bleach with 1 inch of washing up liquid in a washing up liquid bottle .. empty of course /forums/images/graemlins/smile.gif.. fill with water..
Squirt onto the panel or part.. rub with a scotch brite washing up pad..... after 30 mins.. wash with plain water...

WOW !!!.. super.. then add a coat of varnish..

If the old varnish is captain cooked... strip with paint stripper.. sand with 240's production paper... then varnish again.. 6 to 10 coats...

Oxalic acid DOES work.. not on sun stains, but on crappo stains. rinse with borax solution..

A Spanish varnish, available worldwide me thinks (Hempel) is simply the mutt's nuts... really really good..

Molly (The one eyed cat) has one foot with a glossy finish... ah well.. she has to learn too... /forums/images/graemlins/laugh.gif
 
Appreciate the tip there Cap'n, I've been wondering what to do with the cabinetry on my old Nic-38, as it's quite dull & has possibly been darkened further with what looks like wood-stainer, of all things, rather than varnish.!
I tried a scotchbrite pad & some warm water on a test area some time ago & the amount of 'brown stuff' that came off was amazing but underneath was some really nice teak, which I haven't done anything to yet. Wasn't sure whether to go for the same dull matt-finish or a gloss-finish.

BTW, Any pros' or con's with matt or gloss finish, i.e...gloss showing up dirty handmarks or fingerprints...also possible camera flash reflections from gloss when taking pic's inside.???

Jock
 
To add to the above and with lots more trials and tests completed /forums/images/graemlins/wink.gif............................

Re Don Casey and cleaning old varnished teak.. to just CLEAN, and not prepare for another coat..
Use the same mixture of bleach, detergent (Washing up liquid) and water.. apply this time with a cloth, an old tea towel is great.. rub well in, leave for 30 mins, then clean with fresh water.. I tried this on some old panels that were not bad enough to re-varnish.. it really is excellent, all the polish, crap, oil, dirt etc etc just goes leaving the natural shine. try it !.

Using oxalic acid - bought in crystal form.. 1 kg here for 10 euros.. mix two table spoons in a coffee jar of similar full of warm water until the crystals dissolve.. use for removing water blackening on wood where the varnish has been removed.. also use on grey teak to bring out the natural colour.. leave until a powder forms on the wood (Apply it btw with a scotch bright pad or similar.. stainless steel wool is good too ) .. then rinse with a borax solution.. sand with 120s outside - 240's inside.. then re-varnish.. luvverly..

Marks behind pictures etc - this is sun lightening of the exposed timber - not a lot you can do.. even stripping and sanding and oxalic will do nothing..
Put a picture back or leave it for a few years to lighten in the sunshine. /forums/images/graemlins/frown.gif

As for finish, my personal preference is satin panels with gloss trims / edgings.. with care a mirror finish can be achieved by using a quality brush for the final coat or two.. it is worth paying 10 to 20 quid for a quality brush.. use ONLY for varnish, dont leave in thinners - wash after use with thinners - then when dry, soak in engine oil for a few mins.. tie a couple of pencils to the handle with laggy bands so the bristles dont squash on the bottom of the container.. wrap in cling film and stow either flat or hand up..
Wash in thinners before use.
Before the final coat, sand with 400 wet n dry to achieve a totally smooth surface. Have two tins, one for varnish from the main tin (Never dip the brush in the main tine - decant some to a clean container for use and reseal the original) the second tin is the wiping the brush after use and loading with varnish.
The finish I have managed to achieve is super, really nice.
A tip - learnt by doing it !!!.. if it says on the tin 24 hours between coats - wait 24 hours.. just cos it feels dry - DONT try to recoat - it needs time to flash off and dry.. if you do not wait, it will look fine, but the varnish will NOT dry properly and will be soft.. even a week later a small dint will damage the varnish.. let it dry as per the instructions.
AND keep the dust down !.

DOnt sand old varnished panels to remove varnish - strip them then sand by hand with 120's or 240's.. dont use a power tool as it may leave too smooth a surface - the varnish needs to be able to adhere.. you can thin the first coat on bare wood with 50% thinners for the varnish in use.
To see what the wood will look like prior to varnishing - wipe it with thinners or turps.. now is the time to look for marks in the wood or sanding marks.. if they are there - remove them otherwise you will have them for ever lol..

Hope that helps somebody out there.. it works for me. Patience is the key, and of course PREPARATION.

Its not the varnish, the brush, the sand paper etc.. although they all play a part .. it is a methodical and patient approach that gives the results.

Joe
 
The point I would make is that I've renovated 2 Nics and an agressive approach was not required to get down to a good base on which a decent finish could then be applied and the Colron was the dogs danglies for that.

In a number of areas of boat cosmetics a lot of effort is expended unnecessarily with sanders and polishers and other potions and tools when something as simple as Sugar soap can provide a good starting point.

Don't amputate a leg when the toenails need cutting!
 
Friends have recently bought a boat in our marina. They have a problem with some of their varnish - it has remained tacky even though it is years od. Anyone any ideas as to why this would be? They have no idea what sort of varnish it is.
 
I agree. Or more likely, because this is Cyprus and it was probably appled in the summer, the guy working for the previous owner left out some of the hardner to stop the varnish going-off too quickly. One of the reasons we have gone back to traditional varnish for everything, including the floor-boards, more work over time but it is easier to correct mistakes.
 
Hi Col'
Not disagreeing with you at all.
I tried sugar soap, and it worked ok. but the don casey mix and method was far far better. - as I said above -

--------------------------------------------------------------------------------------------------------------------------
"Re Don Casey and cleaning old varnished teak.. to just CLEAN, and not prepare for another coat..
Use the same mixture of bleach, detergent (Washing up liquid) and water.. apply this time with a cloth, an old tea towel is great.. rub well in, leave for 30 mins, then clean with fresh water.. I tried this on some old panels that were not bad enough to re-varnish.. it really is excellent, all the polish, crap, oil, dirt etc etc just goes leaving the natural shine. try it !."
-----------------------------------------------------------------------------------------------------------------------------------

Also, the tip re applying a wipe of turps etc to a panel to see how it would look with a coat of finish.

I agree much needless work can be expended, but sometimes it is necessary.
Hapy varnsihing.. tis actually quite therapeutic really
/forums/images/graemlins/smile.gif
 
This is how I varnish interior wood :

Warning, do not try this on a yacht build after 1946, wood will be ply and destroyed.

After 6 to 10 years, depending on how much sun gets into the cabin, the surface of the wood under the varnish will become yellow-grey. ( UV destroyed cellulose ) Varnishing on top of that dead surface will produce a shiny but still “Shabby” look.

On massif wood

with a modern tungsten carbide scraper not wider than 20 mm I scrape off the varnish and a thin layer of wood. The surface of the wood is yellowed by UV, remove until nice fresh red mahogany is on the surface. Generally 0,5 mm of old wood needs to be removed.
Scraping is fast, produces no dust. Tool not wider than 20 mm so the applied force is enough to go in one stroke to the healthy wood. Sanding is possible but takes ages, masses of sanding paper and creates lots of dust.
In the old days we used to scrape with a piece of broken glass, those days are over, thank God. Scraping is hard work, needs a bit of practice but is ten times faster than sanding.
Corners in the panelling are cleaned with a small sharp chisel.
Sanding, with grid 80, then 120.
First coat of diluted ( 50% ) varnish. I prefer Epifanes.
Five more coats of pure varnish. In between roughing up with a sanding pad.
 
Thanks for that - the yacht is a 3 masted schooner that has just been refitted regardless of cost with all teak and brass fittings - a relation is crewing on her and the owner has asked him to take a course to maintain the woodwork in top class condition, that is why I asked about a course - any ideas greatly appreciated!
 
You must log in or register to reply here.

Share this page

Top