Sanding sealer confusion

[OldWood]

I'm still feeling my way on turning and getting a good finish is something I'm not achieving yet.

We had a demo at the club on Saturday which did help, but having looked at the Axi pages I'm now confused more !!

The demonstrator sealed with a brush while the item was stationary. His comments were to thin the sealer down 30% sealer, 70% cellulose thinner. I queried why cellulose as I use meths when french polishing; his reply was that meths dries too fast. Now the confusion - Axminster says the other way round - and they sell both cellulose and meths based sealer.

Guidance please guys.

Rob

 

[jpt]

If I am using cellulose sealer I thin it with 30% cellulose thinners, If I am using Shellac sanding sealer I thin that with 30% meths.

I prefer shellac sanding sealer but most turners seem to prefer the cellulose.

john

 

[wizer]

This is a controversial subject. The manufactuerers DO NOT recommend you thin sanding sealer.

I would only thin it if I was using it to harden some punky wood and I wanted it to seep into the grain. But even then, I'd apply a full strength second coat.

 

[Bodrighy]

I have a bottle made up of sealer diluted 50% which I apply with a brush, stationary, before the final sanding on practically everything. It toughens the grain and gives a finish that can be shiny with no added polish etc. Diluting it allows it to soak into the grain and it does what it says on the tin, it seals the wood for sanding. Manufacturers won't recommend it be diluted as it lasts twice as long. Put on neat it can tend to go gooey and leave streaks which then have to be sanded of DAMHIK

Pete

 

[OldWood]

Pete
Is that meths based or cellulose based ? And is that a tin from someone like Chestnut ?

And just to add another element to the discussion, isn't anything cellulose based now meant to be hazardous? Isn't the case that cellulose paint is now being phased out ?

Rob

 

[CHJ]

I normally dilute cellulose sanding sealer approx. 30 % with cellulose thinners for use on the bulk of my turnings because as Pete says I get a better burnished finish without undue build up streaks. Applied with a brush, machine stationary.

If using it to stabilize really punky wood sometimes diluted 50 %. but nothing critical for either use, any one batch could be anywhere in between and it's not unknown to modify the percentages in the bottle to suit the task in hand.

On small items I occasionally use it undiluted.

In my experience cellulose dries off quicker than meths.

Same with meths based shellac sealers/polishes, all depends on wood type and whether I want to just seal it or build a friction polished surface.

 

[wizer]

Here's the official line on it

https://www.ukworkshop.co.uk/forums/fini ... 64-15.html

 

[Turn It In]

Rob,
It does not do you any good inhaling any hydrocarbon solvent.
I use cellulose sanding sealer that I buy from one of the local trade decorative material suppliers for about £15 for 750ml and dilute it as required by 50% with best quality fast cellulose thinners as used for applying cellulose undercoat.
This is not the cheap type that contains a lot of water and is also known as Gun Wash for cleaning out spray guns.
Quality thinners smell almost sweet and if you find they smell unpleasant you can guarantee you have been sold a cheaper mixture of solvents.
Plenty of ventilation is what is required and the fast thinners speeds up the turnround time.
As a guide I buy the thinners at an auto jumble from an auto-motive paint supplier and pay £10 per 5 litres of quality fast thinners as opposed to £10 for 25 litres of cheap gun wash.
Hope that helps,
Regards,
Ian

 

[Woodfinish Man]

£15 for 750ml of Cellulose SS, wow that's steep, I wish we could get that rate.

Over the years we've had many people confuse sealers. I think the key is to call them by their full names.

Ian

 

[pete honeyman]

I remember reading the 'official line' from the manufacturer, but I still thin cellulose SS with cellulose thinners about 70/30, as it flows and sinks into the grain better. If I use it straight it sits on the surface in places and creates lumps and bumps which have to be sanded off. With it thinned I can cut it back slightly with wire wool or even paper towels, put ona couple of coats if necessary and get a shiny finish. The only time I use it straight is to 'cure' slightly punky patches or end grain before cutting it again.

 

[Terry Smart]

I'm not sure if the point of the original post hasn't been missed...

Cellulose Sanding Sealer is diluted with Cellulose Thinners.
Shellac (meths) based sealers/polishes are thinned with meths.

The confusion arises, as said, when a product is referred to as just 'sanding sealer' - we do three different types!

It doesn't really do you any good inhaling any sort of solvent, our cellulose based products don't contain aromatic hydrocarbons but you still need to be careful/sensible with any solvent based product.

'Official Line'? Hmmm..

No, we don't recommend against thinning the sealers because it makes them last longer; we advise against the habitual thinning 50/50 because it stops the sealer from doing its job. Yes, it makes it soak in. No, that's not what you want it to do.
To seal the timber it needs to form a film on the surface which it can't do if it's all soaked in under it. After all, there's an expectation to sand the sealer but if all of it is under the surface it's the wood you're sanding. Similarly, the surface isn't sealed, some of the lacquer/polish/wax is going to have to soak into the timber to meet the sealer.
We know that thinning the sealer makes it easier to use and we don't say you shouldn't do it at all, we're just trying to not perpetuate the myth that you have to thin it 50/50.

Cellulose based products have always been hazardous; that's why there are loads of warnings on the back of them.
And let's kill that rumour here and now... cellulose based products for this type of use are not being phased out, nor are there any plans to do so at this time.

 

[wizer]

I can honestly say I've never had a 'lumpy bumpy' finish with full strength CSS.

 

[Blister]

Do you water down your beer with 30% water ?

Use it as it comes out of the container , its fine :lol:

 

[Weasel Howlett]

Thread hijack, sorry about this...

I am new to the use of sanding sealer. Untill now i have relied on the grades of sandpaper to get to a high lustre finish then a coat of good old briwax.

Now for a newby question... what are the benifits of using sanding sealer? Do you apply then sand it down as normal?

I'm intrested in getting some to see for myself what the results are.
Where is the best place to buy Cellulose SS and maybe some thinners so i can clean the brash and matybe even, heaven forbid, thin the stuff down

Cheers

 

[Terry Smart]

Timber is, generally speaking, porous. The purpose of the sanding sealer (any type) is to seal the wood so that when you apply a top coat (wax, polish, lacquer) it doesn't soak in, it stays on the surface. This will generally give you a hard wearing finish and use less topcoat. The latter is very beneficial when using polishes and waxes as the less of these products present the less likely the finish is to damage easily.

Sanding Sealer contains a sanding agent (akin to french chalk) and once the sealer is dry it is this that you are sanding back - denibbing really. This is an advantage when using lacquer as it will sand easier. The aim is to smooth the sealer, not cut through it. As a general rule, I suggest using the same abrasive that you last used on the timber.

Most woodworking shops will sell Cellulose Sanding Sealer and Cellulose Thinners.

 

[Richard Findley]

Hi all,

I've heard this thing about cellulose finishes being phased out but if you talk to any pro sprayer it's all they'll use!! Now we've heard it from a man in the know: They're not being phased out!!

I sometimes use Cellulose SS and apply using a cloth and thin with around 30% Thinners, purely to assist in applying a nice even coat. Tom, if you've never got lines in your SS without thinning you're either some kind of genius or doing it wrong :wink: :lol: :lol:

HTH

Richard

 

[OldWood]

I'm the guy that raised this topic and I think you have all covered most of the points on sanding sealers - many thanks for that.

Actually '..most of the points..' has missed the one that I was really wanting the answer too, but didn't clearly ask.

Dial up 'sealer' on Axminster or any supplier and you will find thee types -
Cellulose varnish based, shellac with a meths base and acryllic.

Acryllic is I understand water based so clearly is undesirable as it will take time to dry, but must have its uses otherwise it wouldn't be sold. What is the difference then between shellac and cellulose ? Time to dry with these is near enough the same in the end, isn't it ?

By the way one thing that hasn't been mentioned is that any fluid on wood will raise the grain, so that one of the purposes of the sealant process is to raise all the grain to effectively the same level so that is can be sanded back.

Thanks everyone for your help.

Rob

 

[Terry Smart]

It's all about compatability.

Cellulose Sanding Sealer is more-or-less universal and can be used with any topcoat that benefits from a sealer, where Shellacs should only be used with french polishes, waxes and Friction Polish.

 

[CHJ]

......
Acryllic is I understand water based so clearly is undesirable as it will take time to dry, but must have its uses otherwise it wouldn't be sold. What is the difference then between shellac and cellulose ? Time to dry with these is near enough the same in the end, isn't it ?

In my experience, Acrylic tends to be harder wearing once cured, but I get more raised grain, Cellulose dries harder/more brittle and quicker than Shellac.

......
By the way one thing that hasn't been mentioned is that any fluid on wood will raise the grain, so that one of the purposes of the sealant process is to raise all the grain to effectively the same level so that is can be sanded back.

..
If you sand the sealer back enough to remove raised grain then you more than likely need to re-seal to repair the surface seal.
I burnish all sealants during the drying process to a gloss finish if possible, blend in with solvent or abrasive if I've been ham fisted enough to get build up streaks, then cut back surface with finest abrasive or nyweb to remove trapped surface dust etc. before applying polishes.

 

[CHJ]

From day one of my turning following advise from Terry at a Yandles show, I just used Cellulose Sealer and Soft Wax. I think this very simple easy to use method did wonders for my ego and provided the encouragement I needed to firmly get stuck on the slope.
Had I embarked on the turning scene trying to use some of the differing treatments I now use I think I may well have given up in frustration.