Cellulose base varnish - compatible with shellac??

[Bluekingfisher]

Morning all,

I am about to build a chimneyl cabinet for the good lady. I have some very old panels of reclaimed English oak which I intend to use for the main carcase. I don’t quite have enough long lengths of the old timber for the cabinet face frame so I will have to use some new kiln dried American oak (as this is what I have in my ws)

In order to tie it all in, I will stain it, partly to match the other furniture but also to disguise the variance in the wood species.

Here is my dilemma fellahs, I was going to use meth based shellac as a sealer prior to staining, colour with a spirit based stain (this I think is OK?) My intended top coats will be a multiple coats of thinned down varnish which is cellulose based. Will the cellulose varnish top coats react with the math based shellac or stain?

Any advice would be greatly appreciated .

 

[chipmunk]

I would say that it would almost certainly be a problem.

Cellulose thinners pretty much dissolves anything from my experience.

I think that staining before sealing may be better, with acrylic lacquer over the top.

Jon

 

[Harbo]

Van **** crystals?


Rod

 

[Bluekingfisher]

Jon - That seems contrary to everthing I have heard before with regards to staining. I believe the shellac seals the open pores allowing for a more even and more controllable means for applying the stain?? with the shellac sealer in place it will even allow for removal of the stain without effect, Staining bare wood would mean an irreverseable process of stain removal.

 

[Bluekingfisher]

Van **** crystals - is this not limited to a dark brown stain, fine I guess if thats the way you want to go.

I'm just unsure of whether the varnish will react with the shellac?

Are water based stains more reliable and easier to control?? if so do they provide good results - you can tell I don't do much staining

 

[Harbo]

More water paler brown.
But whatever you use, different woods take stains differently and it's very difficult to achieve a uniform colour?

Rod

 

[Bluekingfisher]

OK thanks Rod, I guess wood staining is an art all of its own

 

[9fingers]

Agreed, using shellac/sanding sealer is a good way of controlling stain penetration - works very well indeed to help prevent end grain going too dark.
Dump the cellulose - it it quite likely to cause anything underneath to lift.

Quick drying polyurethane floor varnish from Toolstation works very well, is available in satin or high gloss and is about £17 for 2.5 litres.

HTH

Bob

 

[chipmunk]

I've never tried using sealer before staining but I can see that it might help with the end-grain issue. Scrub that bit then :wink:

...but cellulose over spirit is definately a bad idea.

You may get away with polyurethane as Bob says or even another spirit based product, but acrylic will definately be ok over the top.

Jon

 

[Bluekingfisher]

Ok so the cellulose varnish is out but floor varnish on furniture?? I was thinking of thinning it down to wipe it on in multiple coats rather than brush it on. Is the varnish you are talking about spirit or water based Bob, if it is quick drying (I'm assuming some kind of additives to enhance drying time) could it be thinned do you think............there's more to this game than I thought.

 

[Bluekingfisher]

Jon - Have you any preferred brands for your ater based varnish? Do you know if the term Polyurethane raltes specifically to spirit based varnished or could an acrylic be termed as poly??

 

[chipmunk]

I'd go for Chestnut products every time. Acrylic lacquer would be my choice...

http://www.chestnutproducts.co.uk/results.php?cat=Lacquers

Either brush/wipe on or spray.

Jon

 

[chipmunk]

Usually the low VOCs quick drying poly's are water based too.

Jon

 

[9fingers]

Having tried several water based products and found them very poor, I have gone back to traditional solvent based finishes.

The toolstation products mentioned have been very good indeed. I've tried hard wax oils and find them too slow drying. I find finishing a bit of a pain as I have to keep the workshop dust free during drying so quick drying is a must in my book.
Yes water based dries quickly but is slightly milky and WB varnishes with pigments in are difficult to get even.

Bob

 

[studders]

Water based Varnish can be a real pain to rub down between coats.

 

[mailee]

Actually guys I disagree with you. Shellac is a spirit based product and should be imprevious to cellulose. After all barrier coats are spirit based and these isolate the underlying surface from the cellulose. I think you will find it is Ok over the top. You would need to apply the shellac over the stain though as this may discolour. JMHO :wink:

 

[Bluekingfisher]

Thanks for all the replies fellahs, actually I think I may have given you duff info, on part at least.

I started building the project yesterday. As previously mentioned the oak is about 100 years old. Will solvents react differently to timber of this age? The reason I ask is I tested some of what I thought was "Shellac" it is actually cellulose sanding sealer. Why I thought it was shellac I don't know. I bought it a month or so ago from a closing down paint store and had it in my miond it was Shellac and not sanding sealer...sorry about duff info.

Anyway, I tested some finishes/sealers on the old oak. Wnem I applied it, it tured the timber a kind of dark/dirty brown. I tested it with 1. sanding sealer, 2. danish oil/white spirit mix 3. Cellulose Thinner/Cellulose Varnish mix. I applied them last night before coming indoors but all appered to change the wood colour dramatically.

I am thinking the old timber may not be so easy to stain. I was hoping to acheive a dark honey or nutty red colour. Do you think I will have to settle for the brown colour as dictated by the reaction of the timber to the solvents/varnishes I have used?

I appreciate all the advice, many thanks.

David