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By Squallers
#1298233
Morning all,

I'm planning to put together a small side table with a drawer. The drawer and "cabinet" will be made from painted MDF, and I was planning on using an offcut of 40mm oak worktop for the top.

I've used an oil based varnish previously and it made the oak a bit darker than I think I want it for this. What effect on the colour would using a water based varnish have?

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By Mrs C
#1298239
Depends.....sorry!

Can you do a test on the underside? Varnish will darken the finish, but by how much depends on what finish, if any, was on the original piece and the brand of varnish you are using.
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By AndyT
#1298265
Water based polyurethane can give you something pretty close to an invisible finish.
I like this stuff by Polyvine:
https://www.axminster.co.uk/polyvine-in ... y-ax847416

but this is also ok
https://www.toolstation.com/rustins-qui ... ear/p42344
By Squallers
#1298457
Thanks for the replies. The oak is currently completely unfinished so I've got a blank canvas so to speak. I'll have some spare once I've taken what I need so I suppose the sensible thing is to do some test pieces and see which goes best with the paint I've chosen.

Thanks again

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By woodbloke66
#1301269
AndyT wrote:Water based polyurethane can give you something pretty close to an invisible finish.
I like this stuff by Polyvine:
https://www.axminster.co.uk/polyvine-in ... y-ax847416


Yup, I like that stuff too. It's available in plenty of different options and dries really quickly. You can get a superb finish if it's thoroughly cut back between each coat as it will raise the grain. I use a shop vac after cutting back to suck up all the dust....and there will be quite a lot - Rob
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By woodbloke66
#1301283
This Alan Peters linen chest in Olive Ash was completed on Sunday....

IMG_3320.jpg


...and finished with two coats of Satin Polyvine followed by two coats of Matt, thoroughly cut back between each coat with 0000g wire wool - Rob
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By will1983
#1301409
A little tip i picked up from the boating world about applying multiple coats of varnish..

If you want a satin finish use full gloss varnish for all layers except the last.
This builds up the varnish thickness to give good protection but also helps to keep the clarity of the finish and not obscure the grain of the timber.
For the last coat, use the satin varnish to get your required level of sheen.

I've not actually tried this myself but to my mind it makes perfect sense.
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By custard
#1301470
AndyT wrote:Water based polyurethane can give you something pretty close to an invisible finish.
I like this stuff by Polyvine:
https://www.axminster.co.uk/polyvine-in ... y-ax847416


It's not often I'll disagree with Andy T but I guess this is one of those rare occasions.

Polyvine water based Pu provides virtually no protection against red wine or fruit juice, permanent staining from a spillage occurs in around a minute. It gives good water and abrasion protection however, so it really comes down to your particular application.
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By woodbloke66
#1301549
custard wrote:
AndyT wrote:Water based polyurethane can give you something pretty close to an invisible finish.
I like this stuff by Polyvine:
https://www.axminster.co.uk/polyvine-in ... y-ax847416


It's not often I'll disagree with Andy T but I guess this is one of those rare occasions.

Polyvine water based Pu provides virtually no protection against red wine or fruit juice, permanent staining from a spillage occurs in around a minute. It gives good water and abrasion protection however, so it really comes down to your particular application.

It's not often I'll disagree with you Custard, but on this occasion I think you're well out of kilter. Polyvine is 'water resistant, heat resistant, abrasion resistant and microporus'...I know that 'cos I've just read it off the bottle :D

I tried the fruit juice test on an old chest of drawers I made years ago:

IMG_3347.jpg


....and left it for at least 30 minutes, then wiped it off. No staining.

Not having any red wine at hand over breakfast :D I then tried;

IMG_3349.jpg


....some balsamic vinegar, (red grape juice in vinegar) and left that for about the same time. No staining, nil, nada, zip, nowt.

Years ago I also made a computer desk out of pine which took some serious :shock: abuse from the whole family who would cheerfully leave hot coffee, mugs of steaming tea, red wine and other unmentionable stuff (especially at Christmas) by the side of the keyboard with exactly the same result.
No damage to the finish in any way.

I think what's crucial is how it's applied; the instructions writ large on the bottle say apply sparingly with a brush which means that you get a decent thick coat, which then, they say, needs to be 'lightly sanded'. It also says to dilute the first coat on new wood by 10% with water, but I just troweled two coats on neat with a lacquer brush. On the linen chest above, there were two brushed coats of satin, cut back thoroughly with 0000g wire wool (then the detritus was vacuumed off) followed by a few coats of thin matt applied in much the same way as French polish - Rob
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By custard
#1301646
When I set up as a full time furniture maker I decided not to build my workshop with a spray booth, I also anticipated that dining tables would be a fair percentage of my output. Consequently I invested a lot of time in testing and evaluating different finishing options.

Here's a typical test that I conducted, this one is red wine on Sycamore. I tried leaving the wet glass in place for one minute, ten minutes, and one hour on each finish ( I also tested with different fruit juices and with tap and distilled water, but let's keep this simple and just look at red wine).
WineWater-Finish-Tests-05.jpg


I looked at scores of different finishes (always applying according to manufacturers instructions), and that included several water based pu finishes. No water based pu finish performed particularly well against red wine staining, but Polyvine was amongst the worst. Here's the one minute, ten minute, one hour results,
Wine-Test-One-Hour-01.jpg


I should emphasise that this photo shows the result after trying to remove the wine staining with a damp rag. Bottom line is that even 60 seconds of red wine will effectively ruin pale furniture finished with Polyvine water based pu.

This is consistent with earlier experience and with a lot of feedback from other professional makers, here's an Oak dining table with a water based pu finish where the client complained about red wine staining, a call out to refinish a job like this will pretty much eat up any profit you might have made from the job,
Red-Wine-GF-Oak.jpg


I'm not a chemist so I can't comment on why water based pu does so badly in this respect, it's little more than a guess but I suspect that the term "polyurethane" is actually used pretty loosely by finish manufactueres and might actually be acrylic.

Water based pu finishes also have some other issues. It's very easy to overwork them and end up with a cloudy surface, plus several tend to be a little soft, which means matt versions can burnish from normal domestic polishing, resulting in areas of relative glossiness.

Oil based pu finishes are completely different and are relatively bomb proof, although you then have to accept different issues such as yellowing and curing time.

In terms of an easily applied finish with reasonable red wine stain resistance Osmo is worth a look, one and ten minute stains can be completely removed with a damp rag, and even one hour is borderline.
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By woodbloke66
#1301675
Thanks Custard, next time we open a bottle of the Mouton Rothschild 1982 of an evening, I'll try that wet wine glass test and see how the acrylic Polyvine finish does but I suspect it won't have any noticeable impact. Vinegar (acetic acid) and grape juice ought to have affected it, but as I mentioned, it didn't.

Edit: I've just sent off a query to the manufacturers asking about whether or not acrylic wax varnish will prevent staining specifically from red wine...it'll be interesting to see what they say - Rob
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By AndyT
#1301697
I suspect some of us may have different products. The Polyvine range is quite wide and as with many other makers of finishing products, the names don't always make it clear exactly what you are getting. I'll see if I can find time to do a trial with what I have.