# cellulose sanding sealer.



## Phil Pascoe (9 Sep 2016)

I didn't want to derail another thread, so I'll start a new one. Why do so many people favour sanding sealer as a finish? As someone (something to do with one of the wood finish companies iirc) posted before - why choose for a finish something that is specifically designed and made to be scratched? That seems logical to me.
I must admit a bias - I don't like the stuff at all and avoid using it when possible even when sanding it off.


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## MattRoberts (9 Sep 2016)

I believe it's about smoothing the grain of the wood so that further applications of finish (such as stain) go on smoothly and evenly, opposed to soaking into the pores unevenly


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## CHJ (9 Sep 2016)

I personally don't understand why you would not use a sanding sealer to provide the sealing of the wood pores and control final finish absorption on anything other than a piece where you are using a polymerising oil to do the same.

Do you also advocate applying a high gloss paint or lacquer to something without an appropriate surface treatment such as etching or undercoating?


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## Phil Pascoe (9 Sep 2016)

It makes sanding easier - it would be surprising if it didn't, that's what it's made for.

Do you also advocate applying a high gloss paint or lacquer to something without an appropriate surface treatment such as etching or undercoating?
That is a little superfluous, as there is not a wood finish other than a paint (afaik) that actually requires any undercoat at all. I do use oil finishes virtually exclusively, which may colour my opinion. I can see the point of sealing the pores to control the absorption of the final finish - but no one can explain to me why it is wise to use something that is purpose made to be scratched (sanded).


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## Random Orbital Bob (9 Sep 2016)

Well you just said it Phil....it's because (as Chas points out) it creates a uniform surface in terms of absorption of the final finish eg polish etc.

The red herring in your thinking is just the name of the stuff ie "sanding sealer". Forget what it may at one time have been designed for and instead see it for it's alternative useful function which you yourself freely admit you can see the point of.

It does have another thing going for it that you're all missing which is it's drying time. Like...all of 2 minutes  (Cellulose anyway). I'm wondering what's not to like???


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## MattRoberts (9 Sep 2016)

You need to bear in mind that you're supposed to lightly sand across the grain after sealing - this ensures that the high spots are sanded, without removing the sealer from the low pores


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## Austinisgreat (9 Sep 2016)

It's all about levelling.

On most timber products it's not necessarily an issue.

BUT, try making a soild body electric guitar with a (hopefully) flawless laquer (painted) finish. You need grain filler, followed by sanding sealer, followed by primer, followed by coloured laquer, finished with clear laquer. Obviously flattening (levelling) in between each process. Then very careful sanding and polishing.

Miss out any of these steps (*especially sanding sealer*) and you get horrible pits in the finish.

Don't ask! Been there done it - and re-finished a couple too.

Sorry if this went off topic. Anyway HTH

Andrew


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## CHJ (9 Sep 2016)

phil.p":iyby3j6j said:


> It makes sanding easier - it would be surprising if it didn't, that's what it's made for.


A function that I've never used it for, (Cellulose or Acrylic) only ever as a sealer post sanding/scraping.



phil.p":iyby3j6j said:


> That is a little superfluous, as there is not a wood finish other than a paint (afaik) that actually requires any undercoat at all. I do use oil finishes virtually exclusively, which may colour my opinion. I can see the point of sealing the pores to control the absorption of the final finish


This is where by your own admission you are missing the point, (virtual exclusive use of oils) there are many lacquers both primary and enhanced composition that require a sealed and blemish free base for foundation as do many waxes that otherwise would have an uneven absorption into the wood due to grain orientation.

As a matter of interest a burnished cellulose sealer is a very wear resistant finish especially if finished with a high melt point wax. Acrylic sealer is even tougher and higher wear resistant once it has completed its cure cycle.

If you are regularly having to seal the wood to obtain a decent sanding finish I'm surprised, and as far as my turning experience is concerned something to be avoided at all cost if intending to subsequently apply a polymerising oil due to the probability of it restricting even oil absorption.


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## Phil Pascoe (9 Sep 2016)

I suppose it depends to a degree whether you call wax a finish. To me wax is something I put on top of a finish. many turners at the club use sealer and wax for goods that are sold - I'm surprised they don't get more than a few back. Everything I've ever finished this has marked sometimes badly, sometimes within days.

Austin - I see the reason in your case, it has a purpose. 
Matt - so that means I wax bits of bare wood in fruit bowl - the first rotten grape or plum and I've got a vivid purple stain unless I use another finish, which renders s/s largely redundant, anyway.

I've never had uneven absorption of TruOil, Finishing Oil or Danish Oil cause the awful unevenness that s/s has. I don't think we're ever going to agree on this, I avoid it unless absolutely desperate. If I had patience to wade through the search system I would find the original post, and who was by.

CHJ - I use s/s as a sanding aid about once per 100 items.
Many waxes require a perfect base ... yes, probably, but they are harder waxes that actually constitute finish, not a soft furiture polish over s/s - that's not a finish in my book.

Sorry, I'm not meaning to rude or abrupt, there are several posts crossing each other.


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## CHJ (9 Sep 2016)

A hard fully cured and burnished sanding sealer finished off with a soft wax containing primarily Bees Wax is fine for a shelf display item that gets limited handling, regular handling of such can result in a dulled blotchy surface due to the wax melting at hand temperatures. I personally have never seen such pieces exhibiting any undue scratch problems in use though and have several that have been displayed and in use for dried subject display for 10 years plus.

If finished off with higher melting point wax such as Carnauba it will withstand handling much better and rarely shows handling blemishes unless contaminated with water exposure, the use of a Microcrystalline wax over a sealer is an improvement over a Carnauba finish for handling and moisture resistance.

For a Fruit Bowl that is likely to see soft fruit exposure I finish with Melamine enhanced lacquer which definitely requires the pre application of a sanding sealer if anything like an acceptable application routine and finish is to be experienced.
The alternate that works best for me is a Hard Wax oil without any surface sealer.

The only items I have had back for refinishing have been when someone has left an item in full sunlight and it subsequently faded and an item someone decided to wash in detergent having left soft fruit in it for a couple of weeks while they went on holiday.

I don't see a sanding sealer treated surface as any more vulnerable than the average commercially sprayed or varnished surface to scratches or the placing of a cup or damp item without a coaster.


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## MattRoberts (9 Sep 2016)

Not quite Phil - it works like this image filling the pores but creating an even layer over the whole surface


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## woodpig (9 Sep 2016)

As a point of interest the three most popular finishing products at my wood turning club are cellulose Sanding sealer, Lemon oil and Renwax. Barely anything else gets mentioned by the membership.


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## Phil Pascoe (9 Sep 2016)

MattRoberts":38q2qw7u said:


> Not quite Phil - it works like this image filling the pores but creating an even layer over the whole surface


Certainly, Matt. If you apply it as a finish and not a s/s. As a s/s I'd usually sand through it again no matter how many coats.


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## Phil Pascoe (9 Sep 2016)

"the use of a Microcrystalline wax over a sealer is an improvement over a Carnauba finish for handling and moisture resistance."
Yes ... but, curiously, m/c has a lower melting point than carnauba.


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## custard (9 Sep 2016)

phil.p":3e1c8kar said:


> Why do so many people favour sanding sealer as a finish?



Cheap
Really fast, four or five coats within an hour
Stores fairly well
Easy to apply, basic french polishing's easy too but it's surrounded with loads of alchemy and mumbo jumbo which scares a lot of people
Gives that satiny smooth finish that many people associate with a "professional finish"
Simple "one product" solution for both finishing and grain filling
Makes sanding a breeze
Hard enough for many products
Usually low odour

Afaik it's not actually the sanding sealer itself that's especially soft, it's all the stearates that are stuffed into it for easy sanding without clogging up the paper.

I take the view that no finish is perfect. The best you can hope for is an adequate compromise that ticks _most_ of the important objectives on your finishing list. Seen in this way it's easy to understand why cellulose sanding sealer has carved out a place for itself in a very crowded market.


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## Phil Pascoe (9 Sep 2016)

woodpig":268n0ovc said:


> As a point of interest the three most popular finishing products at my wood turning club are cellulose Sanding sealer, Lemon oil and Renwax. Barely anything else gets mentioned by the membership.


Much the same, only the s/s and m/c. Actually no one uses Renaissance, everyone uses Chestnut. (See what I did there, Terry?. Cornwall Association of Woodturners ...any freebies welcome  :lol: )
I think for most people there it's the speed that matters more so than anything else, and of course it's rare for a newcomer to question the status quo. Why is that done? Well ... dunno, really ... it's always been done.
We won't get into a discussion whether lemon oil is a finish or not.


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## AJB Temple (9 Sep 2016)

"Usually low odour" - I quite like the smell of cellulose! Brings back memories of making model aeroplanes when I was a kid.


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## Phil Pascoe (9 Sep 2016)

I remember a late friend telling he'd formica'd a long bar counter without know what Evo Stik could do. He could drink for England and said it was the only time he'd ever left a bar on his hands and knees. :lol:


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## CHJ (9 Sep 2016)

phil.p":e97gb73e said:


> Yes ... but, curiously, m/c has a lower melting point than carnauba.



I don't know which Microcrystalline specification you have been referring to but dependant upon grade they usually have a melting point of 60deg. C. min. usually nearer 80 deg.C. for laminating grades and up to somewhere nearer 95 deg. C. max. for hardening grades.

Pure Carnauba being in the low to mid 80's C. I believe.

Maybe it is the fineness of the particulates, contiguous nature of their coating, the hardness of them or whatever (I'm no Chemist) but items finished with a good Microcrystalline Finishing wax (as opposed to release versions) do not readily appear to mark with skin acids or grease during handling and shed water droplets without undue water droplet marking which I have seen on Carnauba and Bees wax finishes.


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## Phil Pascoe (9 Sep 2016)

The melting point of the one I used is 73c and carnauba (where I saw it) is 83c. The two 50/50 make a nice polish.


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## CHJ (9 Sep 2016)

I like to use Carnauba on open pored wood such as Oak and sometimes Ash before finishing with MC. I like the look of it, I think it's because the carnauba acts as a filler for the grain, much like using shellac friction polish and this is what gives it the softer look to me.

But who knows what's on most of my items as I use the same polishing mop for both so I guess it's a blend of constantly varying proportions.

But always applied over a skin of sanding sealer


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## RobinBHM (9 Sep 2016)

Ive always understood that sanding sealer is what the industry gives to a basecoat that has stearate added to make the coating easy to sand back.

It could be made in any type of finish, if it is a solvent based product like a pre cat, then it will be very quick drying. The first coat always has to be rubbed back as the first coat seals all those bits of grain, loose dust etc that make it feel rough to the touch. A foam pad with 320 grit is used to de-nib and this is easier to do with a sanding sealer with stearate as it cuts easily and clogs the paper less. 

both solvent and waterbased finishes can be used as coat on coat without a sanding sealer, but the denibbing is more work.


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## Peter Sefton (9 Sep 2016)

I have a small Ash dovetailed box I made when at college, I remember we often used cellulose sanding sealer for our smaller test jobs. Bob my polisher hates the stuff when he sees it in my polish cupboard.

We don't tend to use it anymore on any of our finished work but we do use it for coating up laminating jigs to stop the veneer sticking (or parcel tape)

The other place I have used it for years is if I have a painted MDF job, I find it great to brush onto the moulded edges. Two or three coats cut back in-between really strengthens the moulded edges whist keeping them crisp, great to then paint over with oil paint. I have found using the edge grain MDF fillers just looses all the mouldings definition.

And the smell reminds me of Pear Drops!

Cheers Peter


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## Phil Pascoe (9 Sep 2016)

Yes, I use it on mdf and jigs. Pear drops?? Nah, that's acetone, not cellulose.


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## CHJ (9 Sep 2016)

Peter Sefton":1rfxmfxi said:


> The other place I have used it for years is if I have a painted MDF job, I find it great to brush onto the moulded edges. Two or three coats cut back in-between really strengthens the moulded edges whist keeping them crisp, great to then paint over with oil paint....


Well you are basically using it to do a similar job to that it was intended to do, only in an extreme role. I find PVA also good for the MDF consolidation and sealing.

From a reliable source:- 


> Sanding sealer is to even out the surface, seal the pores of the wood and bind the loose fibres of the wood together to provide a solid foundation.
> It has an agent (a lubricant mostly) to make smoothing it back easier, but the idea is to just smooth it, not sand through it.



So basically Sanding Sealer is to provide a contiguous sealing skin to the wood, burnished to a smooth surface if necessary prior to the application of any final protection, which has always been the premise I've worked under be it Cellulose, Acrylic or good old Shellac.


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## Peter Sefton (9 Sep 2016)

Sounds like it does what it says on the can Chas, not that I ever read the can myself.

Cheers Peter


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