Help - Clear Varnish Touch Up made Oak Stair Balustrade Go Dark - Reacted ??

[jiknot]

Hi All in the forum

I am not a wordworker by any stretch of the imagination.... my best was at highschool nearly 40yrs ago....... though I thought I was doing ok to touch up a blond Oak upright on a stair balustrade ..Sanded then applied a clear varnish to touch up... my shock ...the wood where varnish was applied almost went black on contact. So its gone from blond to near black in touch.

Varnish product was from Boondall - Clear Varnish - Gloss.

Really need to understand what happened and what can I do to get the job back on track.

its like it had some kind of reaction has taken place!?..(see picture)

I can sand it back when it dries ..but then what to apply to the wood ?

Thanks in advance to all responders.

[Alkahestic]

That is quite the change - I haven't used Bondall Clear Varnish but no oil based varnish is 'colorless'. I would hazard a guess that the Bondall product has quite a tint to it. The part of the balustrade you've applied the varnish to is endgrain as well, so it will soak up the varnish and become darker than the side grain even if the product had less tint. It looks like there is darkening down the side grain as well, I'm at a bit of a loss to give you an explanation there so I'll leave that to my betters.

You'll have to sand it back to the bare wood. Wait 8-12 hours for the existing varnish to dry completely or you'll get 'corn' on your sandpaper and make the job harder than it needs to be. Basically when you sand, the varnish should be coming off as dry powder, if it feels gummy or wet, let it dry further. I'd start with 120, then smooth out the surface with 180, then 240. The lowest grit is to remove all of the varnish, then the higher grits to remove the scratches left by the lower grits.

If you sand the endgrain up to 320/400 grit but leave the side grain at 240 grit, it will have a much more even appearance. Sanding to a higher grit reduces the ability of the wood to soak up a finish. If you want a colorless clear, use a water based polyurethane product. Water based poly dries really fast, so put it on and leave it alone, attempting to tip off and work the product as with oil based will give very poor results.

[jiknot]

Thankyou for your reply Alkahestic

Sanded it back today.... took another look at it... now I can see that the wood has been previously tinted blond/honey... See the new sanded photo

What type of wood do you think I really have here?

Any suggestions how to match existing colour ?
I was thinking a honey, sandy colour maybe in stain-varnish ?! Where is a good place to try and get a match?

Many thanks

[Alkahestic]

I could be wrong but that timber looks more like Meranti. My 2c would be on the original finish being a tinted lacquer. Unfortunately I'm no expert on tinted products so wouldn't be able to give you a definite answer

[jiknot]

Thanks again Alkahestic ! Im not sure where to go for help...does an expert shop exist from where to get advice...would a paint place have such knowledge?

Failing that all I can think of is sanding the whole of the upright so that I dont have to match the existing colour on the upright - and then finding/using water based stain-varnish colour that is as close to the original colour as I can find...but that is quite hit n hope as far as matching goes...I think Id be very lucky to get a match close enough....quite wish Id left it as is !

[auscab]

That looks to me like the finish has either been well effected by sunlight and faded . Or when it was polished it may have been bleached then stained or had a light tint in the finish as well to keep it light . And its possibly sun faded as well . One way of testing that is dissolving finish off only back to wood and if timber was bleached it will still look bleached. If timber is darker under finish then its the light staining or mixing of light colours or pigments in the finish . I can see at the base of where you have sanded natural warm colour where finish looks like its flaked off so I think its light coloured finish and fading and possibly not bleaching . Sanding wasn't a good idea. Recognizing what was going on before anything was done and testing with a tiny bit of fluid( Spit )on the tip of the finger would probably shown what the end grain top was about to do.

Id say your either going to have to touch out and blend in light colours within a binder / polish with possible bleaching first to match and patch . Or sand the post and try and match that in a similar way . Or sand the lot and redo it . The more you sand something like this the harder it gets to fix the problem. I hope its your woodwork and not belonging to some client .

[jiknot]

Thanks for your reply auscab
this is my stair.....as said I wish I had not touched it...i think it has a tint and is sun affected as you say.

Im thinking I have to try and get a colour match ..and sand the whole post...there is way too much work involved in doing the complete wooden structure...

my word again I wish I had just left it for what it was... let this be a lesson to myself...one I wont forget.!

My big question...where is the best place to try and find a colour to match .. can I get a custom tint made up ? if so where is it possible to do so ? thanks in advance... to test there are a few places under the stair which are still bare... what a Pain!

[auscab]

Im not sure where to go for help...does an expert shop exist from where to get advice

A busy Antique shop with french polishers , some of them old and experienced.

Failing that all I can think of is sanding the whole of the upright so that I dont have to match the existing colour on the upright - and then finding/using water based stain-varnish colour that is as close to the original colour as I can find...but that is quite hit n hope as far as matching goes...I think Id be very lucky to get a match close enough....quite wish Id left it as is !

The way its done is not looking for a can of anything . If there is one thing that may do it that way its a can of some sort of lime wash paint effect used a s a stain . The right ingredients need to be on a shelf in front of you and you mix and experiment . This is a almost impossible thing to make right though.

See how the colour looks warm where the finish has flaked off . It looks to me to be flaky from here . That's telling that the fading or colour is all in the thickness of the finish . Its a common thing on original finishes of Antiques and happens in all sorts of finishes.

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[auscab]

If there is one thing that may do it that way its a can of some sort of lime wash paint effect used as a stain .

Im taking that back . probably wont work . Id probably make one up and try it to test and see and end up wiping it off soon after.
To touch it out as a french polisher does on damaged furniture. Without all the things you need to experiment in front of you. That's making things harder . You have to try and re create whats going on with the rest of it so imagine sealing the wood , letting it dry , and painting with a thin wash of the right colours , a thin yellow mixed with white , let that dry or rapid dry with a heat gun . then seal that in with a thin clear . The thin yellow mixed with white could be thinned down acrylic paints. I do it with the raw dry pigments mixed with a binder like shellac. I'd expect to have to mix and do this three times testing to get it close. I also have most all the pigments and colour types within reach to try the lot if I need. If you can match it then seal it in and match the shine it can work . Its a hard one though.

Something like this is what I would do on the top original repair you wanted to do on the top . Being end grain though It may have needed to be sealed to stop the soaking into end grain and darkening . I like doing the sealing like that with wood glue . Or whats known as a glue size . Its faster .

Yeah its a pain . Been there plenty of times and learnt when to spot it before I start on other peoples valuable antiques.
Ive looked at Antique finishes a couple of hundred years old with magnification and some old varnishes or shelac jobs not only fade with sunlight but also minutely crack and sort of crystallize. Its not just the faded colour of the finish giving the look of such things but the minutely crazed cracked crystallized finish reflects the light in a way that nothing new can simulate.
That happens in ten or twenty year old new finishes as well . Its the impossible to fix part of it .

I'm really relieved its your woodwork ! phew !!

Rob

[jiknot]

Thanks again Rob Very Informative Post! a few more queries if you can ..thanks once more

so imagine sealing the wood , letting it dry , and painting with a thin wash of the right colours , a thin yellow mixed with white , let that dry or rapid dry with a heat gun . then seal that in with a thin clear . The thin yellow mixed with white could be thinned down acrylic paints. If you can match it then seal it in and match the shine it can work . Its a hard one though.

You mention sealing the wood first....would a clear waterbased varnish (satin?) be best?

With thinning Acrylic Paints - Water or Spirit best ?

Bunnings do a lime wash by feast and watson which can be tinted with their 'proof tint' colours...perhaps worth a look.

Something like this is what I would do on the top original repair you wanted to do on the top . Being end grain though It may have needed to be sealed to stop the soaking into end grain and darkening . I like doing the sealing like that with wood glue . Or whats known as a glue size . Its faster .

With Glue Size - DIY version is watered down woodglue 10:1 or less water ? use only for the end not for the sides?

[auscab]

You mention sealing the wood first....would a clear waterbased varnish (satin?) be best?

Best is going to be what ever works. if you can apply that and dry it off quick with heat it may work . Ive never needed to use it though, so cant say .I mainly keep shellac in two or three variety's at hand . Flake . Button and Blonde. And oil based estapol . A sanding sealer. I have at times also had spray on nitro cellulose laquer .

With thinning Acrylic Paints - Water or Spirit best ?

Same as above , what ever works . I think they both work , water may be best as you can add white pva glue just a tiny amount and it hardens it or tempers it . Pva and metho dont like each other. BTW in the old days Hide glue was used for this and its probably the best . Warm water and glue . its been recorded in books from the 1500's as being a glue size. Some of the modern guitar makers use two pack glues for this as grain filling and some guys only use shellac .

Bunnings do a lime wash by feast and watson which can be tinted with their 'proof tint' colours...perhaps worth a look.

well the chance of bringing a can off a shelf home and that doing the trick is one in a million I'd say

With Glue Size - DIY version is watered down woodglue 10:1 or less water ? use only for the end not for the sides?

10 water one or two glue, more glue if needed. To much and the glue shows up to strong . Each job and timber requires experimenting with for you to be able to get the hang of it . After ten tries your going to know if you need to take another direction . Its one hard fix that's for sure . The guy who has ten different directions he can take is the one who would maybe solve it . Ive watched them and done the same myself when I got older, and at times when I was young, the rest of the workshop stood around and just about clapped the old polisher that pulled off some miracle of disguise like that in the center of some Walnut veneered Loo table or Rosewood Card table that had been water damaged to the point that center veneers had soaked off and long been lost . The new wood repair require laying and re colouring in .

I liked what Alkahestic siad in post 4
"I could be wrong but that timber looks more like Meranti. My 2c would be on the original finish being a tinted lacquer. Unfortunately I'm no expert on tinted products so wouldn't be able to give you a definite answer "

Tinted Lacquer , That put on with a spray gun deposits the tint nice and even . Then with fading you get what you have .
Ive been suggesting brush and rag repairs. That works but an even repair takes more skill by thinning things down and being careful. If you could spray and had just the right colours to add in you could probably pull of a better repair.

Id better go and chop up more wood. Ill look back tonight to see whats going on .

Rob

[jiknot]

Hi Rob thanks again for your most helpful post.

Is their anyway to tell if its lacquer over shellac thats on there for sure ?
Lacquer - anyway to tell what type of lacquer its likely to be? Nitrocellulose ?


Have another picture...it shows the top rail ...it seems like a different wood...I assume the uprights had to be blended in for colour with the rails...at some point needs to be all done again (but not yet!)

[auscab]

I doubt the original would be Lacquer over shellac.

If for some reason there was shellac under it it would be pretty hard to detect it . Lacquer can give off a smell if you rub with metho or thinner possibly and scratch with a finger nail . It disolves like lacquer. Thick and creamy . Lacquer gives off a smell sometimes if you lightly sand it .

Have you put something on that ? If your putting anything on, and its already darker, then your either going to have to paint it lighter , colour it up lighter or start again and bleach it lighter.