Woodworking Tips: Finishing - Why Use a Sanding Sealer

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Woodworking Tips: Finishing - Applying a sanding sealer to your raw project is a great way to seal the surface and allow your final topcoats to lay on the wood much smoother and with finer luster. A WoodWorkers Guild of America (WWGOA) original video.
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[@perrys5954]

Ive been watching a number of videos to get the understanding of Sanding Sealer and this was easily the best, most clear and most helpful so far. Thank You!

[@bluespoppa]

Thank you. Short and to the point. It was enlightening to learn that sanding sealer is important for ease of obtaining a flat surface (no corns) so you do not have to sand the laquer coats (well, maybe the last one of course). . (I'm doing a guitar body, and this video was very helpful!).

[@Wwgoa]

Sanding sealer would help seal edges on MDF, as would shellac. On paint grade MDF projects I have often sealed edges with Zinsser 123 primer. Home centers carry it in an aerosol can. Sand the edges first, then prime them and paint over. Results are great.

[@paulaaliasp.k.o4862]

I learned enough to make this door EASIER WORK & LOOK FINE!!. THANK YOU 4 your Info

[@Wwgoa]

Great to hear!

[@sigogglin]

I watch so many guitar building videos, I see several of them use this but was not sure what it was. Thanks for this I am going to do a guitar kit and will use this for sure!

[@stclairstclair]

I came here because of wood turning, but this helped me understand the basics.

[@roydass3597]

Thanks for the information much appreciated thankyou.

[@Wwgoa]

Our pleasure!

[@rickfitzgerald4426]

Good video. To a point. Many unanswered questions here to be completely informative though

[@Wwgoa]

Thank you for watching. I will forward your feedback to the proper department. We will continue to listen and work hard for your satisfaction.

[@paulyosef7550]

THANK YOU, YOUR GREAT

[@Wwgoa]

Yes and yes. You can get sanding sealers that are in the lacquer family and the shellac family. If you use shellac be certain it’s dewaxed, such Seal Coat from Zinsser, available at home centers.

[@patch7481]

Helpful demo... thanks!

[@Wwgoa]

Glad it was helpful!

[@davidnleeh4]

Thank you for posting this video!!! I was in need of this information because I am about to apply lacquer to a project & probably would not have used sanding sealer on my Walnut piece!

[@Wwgoa]

Sanding sealer is almost always beneficial under top coats. You need to make sure your sealer is compatible with the top coat, whether it’s water based or solvent based. The best way to do that is by contacting the top coat manufacturer and checking with them.

[@georgewilson1354]

Varathane at Home Depot makes a sanding sealer that works with water based or oil based, and can be used on bare wood or over stain. I am getting ready to use it over stain on a guitar kit I am building.

[@Alabdulaly]

always lookup to your videos , taught me a lot , thank you Sir, and thank you WWGO America

[@James_Haskin]

Excellent tip. You're gonna save people a lot of head scratching. For one of my first "woodworking" projects I refinished a basswood guitar body with a relatively thin topcoat (opaque 'blackhawk' black) and 1mm thick sealer coat O_O

[@jas20per]

I just thought that I should like to say that if you want to use a wax finish on wood, rag on a couple of coats of sanding sealer before you apply the wax. This will do two things firstly it will stop the wax soaking into the wood and disappearing over a short time, two by keeping the wax finish on the surface you can build up the wax layers to produce that wonderful wax luster.

[@CPatwal]

My polisher did not use sanding sealer and I saw him using up a lot of sanding paper wasted which were clogged with wood particles. Now I now how to complete some small wood working projects.

[@mijit.859]

Sanding sealer actually works to fill in open grained timbers or the wood surface so as to avoid the final paint coating or Clear finish from ‘Sinking’ into the wood surface(s) etc 😨

[@CynergyDiva]

Can I use sanding sealer before painting?

[@Hijason74]

if your going to stain your project a darker color would you use a sanding sealer? and if so when do you apply the sanding sealer before the stain or after? also will the sanding sealer help stop blotching?

[@georgewilson1354]

Use Minwax Pre-Stain treatment for blotching and you can use Varathane SS over stain.

[@ethanf.6848]

Stain before sealing. Yes, sanding sealer does control blotching but it also stops penetrating stains. One method is to apply blotch control, stain then seal.

[@hastingb]

I'm painting some wood and I don't want the grain to show through the paint. Will sanding sealer help to make the surface perfectly smooth?

[@age_of_reason]

For that you need AquaCoat sealer.

[@vento1523]

Thank u very much sir,u save me.I was about to use it as a pre vanish coating''YES U CAN LAUGH'' lol

[@ThekiBoran]

I've got a couple of those sanding blocks. The Time Shaver Preppin Weapon. They are the absolute best.

[@Mike-bh7sh]

Sanding sealer is usually simply lacquer work zinc stearate added (there are other types of sanding dealers). Stearates are basically a soap.. in fact zinc stearate is also called zinc soap. It basically lubricates the lacquer making it easy to sand... but, BUT, this means it is also pretty weak... after all it crumbles... that's the point. The finish on top of the sealer will be more susceptible to damage (since the sealer is its foundation), water rings, etc. You can NOT use this type of sanding sealer with polyurethane or the like as the soaps will prevent the finish from adhering (in fact it will crawl on the surface. Once nitrocellulose lacquer is cured is really sands well anyway. So really no need for the sealer. The special sealers for polyurethane and the like make more sense as those finishes do not sand well.

[@johnjagels8110]

Just curious, would you use this under an epoxy finish?

[@Wwgoa]

The ‘Ask an Expert’ section is for members of our online community. I would be happy to send your question off to the experts. Please forward us your question to [e-mail]. Thanks! Great question!

[@Wwgoa]

@Alabdulaly Thank you for the feedback! We are so glad you are enjoying the videos! Have you registered to be a WWGOA member yet? As a member to get tons of great benefits, including a free newsletter, video clips etc. Happy Woodworking!

[@markj7924]

If I apply a lacquer paint coat after Shellac sanding sealer, should I apply a second coat of Shellac sanding sealer over the lacquer paint coat before applying a clear lacquer coat?

[@rcnarcisisstickillthewaves5946]

I have a sand sealer.. and i want to apply it on wood which has been stained by vinegar and cofee.... I tried applying but it thick so much so that it is coming off like a adhesive.. I read the instructions that say a use thinner to dilute it.. tell me the ratio of thinner and sand sealer to be used

[@MrBritrider]

Would you use lacquer based sanding sealer if you intend to add water based or oil based stain?

[@Wwgoa]

No. In that case you should consider a more universal sanding sealer such as this one: amzn.to/3wxJwnf to avoid any compatibility problems between the different finishes. Paul

[@cynthiaornelas4903]

I put Miniwax Clear Brushing Lacquer on a piece of oak. I didn't know about the sealer having to be used first. Now, I have several areas that are really rough. Should I sand those areas and apply a sealer to the entire board? Thanks!

[@Wwgoa]

Yes, that’s exactly what I would suggest doing.

[@Mike-bh7sh]

NO. You do not need sanding sealer. If you have rough areas then either the wood was not smooth enough, the grain was raised (possibly high humidity), or you got dust (or such) in the finish. Simply sand the lacquer smooth with 220 or 320 grit sandpaper, wipe clean and apply another coat.

[@rebeccalankford8573]

Do you use sanding sealer over stain and before top coat. Is it only used with lacquer? Is it ised with other types of top coats?

[@123Rockchild]

What is lacquer? It would have been nice to have seen an application of both of the products you are talking about! 🤔

[@Wwgoa]

I would be happy to send your question off to the expert. To get started, please provide the email associated with your membership.

[@Mike-bh7sh]

The lacquer he is referring to is nitrocellulose lacquer. (There are other products that will be called lacquer though they really are not so you have to know what exactly the person means. I have people say they are using lacquer when they are actually using catalyzed "lacquer"). Anyway... Nitrocellulose lacquer got started after wwi when everyone had a bunch of cotton and nitric acid (used in making gunpowder). It was found this could be dissolved in a solvent and when the solvent evaporated the cellulose remained as a durable coating. It basically became THE finish until more modern finishes like catalyzed finishes were developed (though we still use it a lot). It is an evaporative finish, like shellac. As supposed to a polymerizing finish like polyurethane... or a coalescing finish like water born products. This means the finish can be redisolved by its solvent. Which means easier to repair but, in some ways, easier to damage. As I tell customers, all finishes will damage, lacquer and shellac are easy to fix when damaged.

[@NORTE0912]

I can apply polyurethane after lacquer or sanding sealer

[@Oakleaf700]

Very helpful! thanks.Can you use sanding sealer under Danish Oil?

[@squigglyline2813]

I realize this is 10 years old but curious if you ever tried it.

[@larrydugger6878]

this is not a comment, but a question. I have applied minwax water based sand and sealer to my newly built ceader table top. I now want to apply a 50 to 50 mineral spirits and oil based polyurethane finish on top. Are these two processes compatible.

[@Wwgoa]

Hello Larry, Thank you for contacting us. It says on the label that it is compatible with any Minwax polyurethane product. amzn.to/3KHjkN3 This Minwax product is essentially a 50/50 mix of poly and mineral spirits, and it works great: amzn.to/2FhLSvn If you have any other questions, please chat, email, or call Customer Service.  Sincerely, Paul Wood Workers Guild of America Video Membership

[@oletruk]

So...it's ok to put lacquer under or over a shellac and/or a shellac under or over a lacquer?

[@noguisolano]

Hello do you mind letting me know what is the brand of the primer you used in this video? and also if you could let me know if I can get it in a gallon would be great thank you

[@QuantumLeap83]

Hello. Should I stain before or after sealer. I'm using minwax poly sealer under spray max two part poly clear coat for topcoat. Stain is Unicorn Spit, a gel stain that is water based. Wood is maple. I will be sanding to 12000 grit with micromesh before applying topcoat.

[@Wwgoa]

Hi Daniel. Stain should go down before sealer. Thanks Paul-Woodworkers Guild of America

[@QuantumLeap83]

@@Wwgoa Thanks!

[@paulsbored1701]

Is sanding sealer what I should use to stop air bubbles in the finish when using a 2 part epoxy coating on a bar top for example?

[@Wwgoa]

+Pauls Bored We haven't used this form of finish, so it's important that you do some additional research. However, it seems that most two-part epoxy companies recommend that all coats are epoxy, and make no mention of sanding sealer as a base coat. It seems that some people use a propane torch in proximity to the still-wet epoxy to help get air bubbles out. But this something that needs more explanation, which we're not in a position I to provide. I suggest you contact the manufacturer of the epoxy you're using to see what suggestions they have. (ZD: 3522)

[@paulsbored1701]

+WoodWorkers Guild Of America Thanks, i'll do some more digging. The torch works but sitting for 4 hrs watching for bubbles is very boring lol.

[@alvidrez7956]

Pauls Bored more coats is better . Try to keep your coats not as thick . What it's doing is solvent popping

[@paulaaliasp.k.o4862]

I can give u a bit of advice! Stir 2 part epoxy together gently. Paint using even strokes to cover Just 1 time. DO NOT" try to Rid of air bubbles by stroking over & over. When completed. Wave HEAT over Epoxy to POP BUBBLES. Either a Heat Gun OR Propane Torch. Keep Heat distance about 6 inches away, u dont want it ti get HOT & SMOKE. GOOD LUCK

[@47veilside]

will wood glue still create a strong bond if apply sanding sealer to the wood parts before putting a project together after sanding?

[@Wwgoa]

Great question! Please allow 1-2 business days and our experts will respond here. Thank you!

[@Wwgoa]

No. Sanding sealer will fill the wood pores and prevent the glue from achieving it's full bonding strength. Paul

[@squigglyline2813]

I got a sanding sealer and it behaves similarly to shellac. Are they similar?

[@Wwgoa]

Great question! Please watch this space for experts' response. It typically takes 1-2 business days. Thank you for watching!

[@Wwgoa]

Dewaxed shellac is a common sanding sealer.

[@Mike-bh7sh]

What you are seeing in their similarities is that they are both evaporative finishes... meaning their solvents will re-desolve the cured finish. They act very similar. Lacquer is a little more durable in some ways... but shellac also has advantages. Shellac is made by the resinous... umm.. well... poop off the lac bug. It is simply filtered and dissolved in an alcohol. Nitrocellulose lacquer is made of cellulose (usually cotton) and nitric acids. This is dissolved in lacquer thinner. In the end though, application is almost identical (lacquer is easier to apply since the lacquer thinners can be adjusted to produce certain evaporation rates)... shellac can be dissolved in lacquer thinner but this removed its ability to block issues like silicone contamination.

[@JC-jk8en]

Hi, where do I find this sandpaper now?

[@rancidiot]

just curious if sanding sealer has an protective properties? If I want a non shiny clear coat to protect it from water rings and oils from cooking will a sanding sealer suffice as a finish?

[@SuperWoodyboy]

no..

[@ThekiBoran]

rancidiot I also say no.

[@MindsEyeVisualGuitarMethods]

Would this help fill the grain on a raw mahogany guitar body? Going for a smooth polished solid color

[@grubbetuchus]

Sanding sealer isn't a good pore filler. It's function to to lay down a smooth folm that's easy to sand, one that is a part of the foundation of building your film finish. If you use it to fill wood pores, it's likely to shrink over time and your pores will no longer look filled. Any sealer, whether it's sanding sealer or vinyl sealer, can't be more than 1/5 dry mils thick or you will weaken your topcoats significantly.

[@mjombaupholstery4970]

Use auto body filler and or automotive putty

[@robira1313]

Does the sanding sealer act as a pre-conditioner for oil stain? (for pine)

[@EdGutierrez69]

you can use sanding sealer as a wood conditioner, mix 50% sanding sealer with 50% lacquer thinner then spray it

[@thediplomasta5891]

Ya didn't explain this sanding sealer stuff too well, as you can see by all the question comments. I need to know about interactions with other finishing products. Do I only need Sanding sealer if the wood is raw? Is spray shellac a good substitute, since it is so expensive? If the wood is pre-stain sealed, and then stained, do I even need this product? Does this help with blushing? Or does it only makes the wood easier to sand? Gimmie details, man!

[@Wwgoa]

Hello, There are a lot of different sanding sealer products out there, so it is best to check with a manufacturer of your particular product to inquire about compatibility. You can use shellac as a sanding sealer if you are comfortable using shellac in general. Some people are intimidated by it, whereas dedicated sanding sealers are pretty user friendly. Use dewaxed shellac to prevent an adherence problem. Paul Wood Workers Guild of America Video Membership

[@TheEgg185]

Sanding sealer is expensive. Can I use water sealer instead?

[@CapitanoGUC-gf6el]

Can i use the sanding sealer to fill the poors and to build up ?

[@Wwgoa]

Sanding sealer doesn't have enough body to be effective at filling pores. For that I'd suggest a product such as this: www.google.com/shopping/product/17091423582636312878?lsf=seller:1135568,store:5810661711218091826&prds=oid:12246686115571683731&q=grain+filler&hl=en&ei=IGP_WJzbF6WXjwSsuI2QAw&lsft=gclid:CjwKEAjw5_vHBRCBtt2NqqCDjiESJABD5rCJ1M-0FWm9yajuiVWp4dpMOtbuYBmxOewNsekKxEEDEBoC4XLw_wcB

[@MrApaHotel]

Would sanding sealer work for sealing the edges on MDF? And then smoothing the edges with some kind of wood filler/putty?

[@randypontony1683]

Stodoys plans has very useful instructions with all details I need

[@dunboozin]

Is this OK to use under a UV polyester gloss finish ?

[@Wwgoa]

When it comes to finishes and compatibility, it's always best to contact the manufacturer and ask them. Please check with the polyester gloss finish company.

[@grubbetuchus]

Polyester or polyurethane? Under a polyester coat you also use polyester. There are times/situations when you will need to lay down an isolante under your polyester. An isolante is just that, a barrier coat. Regarding polyurethane, if you are talking about a solvent polyurethane, they make a solvent polyurethane sanding sealer. You would use that. Under a waterbase polyurethane, each manufacturer has their own best system, some use a sanding sealer undercoat, some use one coat as a self-sealer.

[@YouTuber-hc6rx]

What kind of sandpaper? @1:23

[@Wwgoa]

Great question! I have forwarded it to our experts and they will reply here within 1-2 business days. Thanks!

[@Wwgoa]

It's a stearated product, something like this: amzn.to/36tJv85 Paul

[@oletruk]

So...what exactly is sanding sealer?....a lacquer?...a shellac?

[@keliweisgerber3896]

I recommend Woodprix to every beginner and not only.

[@scoopmason7139]

M'

[@bandutube]

is it possible/ necessary to have sanding sealer under water based polish??

[@squigglyline2813]

Yes, but make sure you get one that specifically says it's compatible. My Minwax one says it does both water & oil based.