When to apply sanding sealer

[Prdc]

Sorry if this is a really simple question but maybe I’m over thinking this.
My project has been sanded to 120 and I’ve got dust off with tack cloth.
Should I apply sanding sealer before applying a stain or afterwards ?
I read somewhere to seal, then prime then top coat but maybe that is for paint. I’m thinking if I seal it, how can the stain get into the wood
Thanks in advance for any responses

 

[Phil Pascoe]

Yes, you'd stain first. There is an argument that if your piece is finished to the point of staining it doesn't need s/s anyway, as it's usually used to facilitate the process of sanding. I personally use the stuff only in desperation, but some use it as a finish in its own right under waxes. Many years ago I made a lectern from elm with a turned column and used s/s - the finish went horribly blotchy and and of course I couldn't refinish it as the turned part would have been impossible. The s/s impregnated the end and cross grained areas easily, but sat on the surface of the straight grained parts, leading to very uneven absorption and patchiness in both the s/s and the finish.
I assume you're going a fair bit finer than 120, so get that done before you do either.

 

[Prdc]

Hi Phil
Thanks for the advice and yes I’ll spend more time sanding to 240 and then apply the stain. I guess I can do the same to a scrap piece and then try out different top coats on that first.

 

[Phil Pascoe]

If you have a problem finishing something, try wetting it - steam or water is quicker - let it dry then carry on to the next grit. it's surprising how much grain it can raise and it can't do anything to affect the final finish, no matter what it is. Timing is everything - if you time the wetting to coincide with a tea break, bog break or whatever the wood'll be dry when you get back.

 

[Prdc]

Thanks Phil, good advice that I will use. Could I also ask you about sanding past 120. Is fine steel wool 000 as good as wet and dry 240 and 400?

 

[Phil Pascoe]

Abranet is better than w&d on wood, but there are many other good abrasives - Cubitron is brilliant, but seems only to be available as discs not rolls. You tend to get much what you pay for although Bosch, DeWalt, Makita branded stuff doesn't come out very well in tests. W&d is better kept for metal. 0000 wire wool is very fine and would probably be used after 400g - don't use it on tannin containing woods like oak, chestnut and sapele, you're likely to end up with little blue black marks all over your work. Look at the instructions given with your finish - sometimes, like for some hardwax oils they'll advise you not to go that fine with the grit.
Incidentally, my post on s/s is only my opinion - others will tell you they use it regularly and don't have a problem with it.

 

[Vintage Frames]

Sanding sealer is usually just a shellac solution in alcohol with some zinc solids added, The zinc lubricates the surface for ease of sanding.
Applying it to bare wood will seal the wood surface and prevent the stain penetrating, so you would always stain first.
As with the excellent advice already given, I would wet the surface with water after sanding - I usually work up to 180 grit first. When dry, then finish with 320 grit.
After staining, apply two coats of sanding sealer diluted 50/50 with meths, leave overnight and then sand lightly with 600 grit wet n'dry.
The zinc will come up as a white powder which can be wiped away when finished. Don't worry about any residual whiteness, it disappears completely when you over-finish with either wax or varnish.
Only use a s/s from a wood finishing brand. Not Screwfix own or other.
Be careful not to cut in too deep with the 600 grit and so tear into the wood stain.

 

[XTiffy]

Completely agree with Vintage Framers for his method. I would stay well away from fine wire wool, the tiny particles are a pain and you don't want to breathe that in. The proper "scotchbrite" pads are so much better.

 

[Prdc]

Thank you so much to you all for the great advice, really appreciate it.