Sanding Sealer

[rick7938]

I have built some small wine racks - 1 each from pecan, walnut, and cedar. These woods are so different, I am wondering if I should use a sanding sealer on them to get a consistent finish with satin polyurethane. I have used the satin poly wipe on a couple of pecan wine racks before, sanding between each coat with 220 paper, but the fine was not consistent.

Any suggestions? These need to look as nice as possible since they are going to be Christmas gifts. Thanks in advance for any guidance. I am still very new to woodworking and will appreciate any advice.

 

[DaveO]

You're working on X-mas gifts already, you're a far better man than I :lol: :lol:
Poly is a film finish and will sit on top of the wood, sealing it won't do a lot of good. But what I think you are wanting to happen is a grain filler, to give as smooth of a surface as possible. I would try a few coats of Zinnser Seal-coat (dewaxed)shellac. Put down two coats and sand smooth, then a final coat. it will fill the grain a little and give you a much smoother surface to lay your poly on top of.
Wipe on poly leaves a very thin layer with little build per coat. I would also apply several coats then a light sanding so you don't cut too far through the film. Probably 3 coats then sand, 2 more coats and another sanding with 0000 steel wool and then a final coat over everything.
My .02, Dave

 

[rick7938]

Thanks, Dave. I see the Seal-Coat in the Woodworker Supply catalog. I will order some and give it a try.

Again, many thanks for the advice.

 

[jeff...]

I think the purpose of sanding sealer is to seal or prime bare wood, used to provide a base for finishing coats. With it's high solids count it makes sanding easier and enough coats could eaisly fill grain and small defects in wood.

I would consider sanding sealer as a base for water based finshes, like water based poly for example. Water and wood don't mix very well. So I would think a good base coat of sanding sealer applied before any water based finish would help if not eliminate the raising of grain, that seems to be one of the water based finishes down side.

Also consider use of sanding sealer on thirsty wood such cedar, pine, etc.

Turpintine is made out of pine, so one can just imagine what pine does to a finish over time...

My 2 cents...

 

[DaveO]

jeff... I agree with you, when I first read the original question I was thinking wood conditioner. You are right a sanding sealer would give him the same results as the shellac I suggested, so it's probably just a matter of cost and availability. What is sanding sealer made of???? I see it all the time at Lowe's, is it any different than shellac??
Dave

 

[jeff...]

BTW - wanted to add, I use sanding sealer quite a bit in repairing funiture. Light scratches and other defects can easily be filled and leveled with sanding sealer. Somewhat deeper scratches, dents and other defects may need to burned in with shellac sticks, grained and blended but even this will required the use of sanding sealer to level the patched area.

Once the patched area is leveled by lightly wet sanded with 400 or 600 grit wet/dry sand paper, apply the correct sheen top coat finsh and rub out (blend in) with 00 or 0000 steel wool.

Because of it's high solids content and quick building characteristics, sanding sealer is a very useful touchup and repair product aswell...

I'm not a salesman, but would recommend Mohawk products to anyone, their sanding sealer line can be found here: http://search.atomz.com/search/?sp-q=sanding+sealer&sp-k=&submit1=Search&sp-a=sp1002b326&sp-p=all&sp-f=ISO-8859-1

 

[Howard Acheson]

You want to be very careful with sanding sealer. For example, you never want to use a lacquer based sanding sealer if you plan to use a oil based poly or any waterborne finish as your final coats. Poly and waterborne will not adhere to the stearates in lacquer sanding sealer. There are sanding sealers specifically made for certain types of finishes and you should use the correct type compatable with your final finish.

You can use the Minwax Sealcoat under anything but it creates a very thin film that does not do much in the way of filling the grain. Also, you don't want to apply too many applications of shellac or it can lead to cracking and crazing. Minwax makes an oil based, non-stearate sanding sealer which is OK to use.

Permit me a little rant.

It is my opinion that using a sanding sealer sacrifices quality for expediency. Sanding sealer is used simply because it contains lots of solids, is fast and easy to sand. It contains a zinc stearate soap that sands like a jewel. The lacquer based dries fast and finishers can get to that final sanding sooner. However, adding the stearate to the sealer coat provides a very weak base and the stearates cause the product to have little or no resistance to water or water vapor. While one could use the finest finish ever made as the final finish it will never be better than the base it is on.

Lacquer based sanding sealers are primarily used by high production furniture companies where time is money. They do not experience adhesion problems as they use lacquer finishes, not polyurethane varnishes.

Things get even worse with multiple coats of sanding sealer. Now you have a very soft finish underneath a hard surface. This will cause cracking and crazing when the surface is dinged.

If the intent is to level the surface of open pored wood, then a grain filler is the correct thing to use. It will quickly level the surface with minimal affect on the clarity of the grain.

Finally, there is no reason why you should have any variation on the woods you refer to. If wiping on, you should apply two coats and let it dry 24 hours. Then use 320 paper (220 is too course) and a sanding block to level the surface. Now you can apply 3-4 more coats without sanding between coats as long as you apply them shortly after the prior coat is tack free. At this point let it dry again for 24 hours, lightly sand with 320 on the sanding block and then apply a couple of coats of well stirred satin. You should end up with a nice finish that is consistant with each of the woods.

 

[rick7938]

Great information, Howard. Thanks. I learn a little more with each project.

Is the process that you describe above after I use the grain filler or in lieu of using the grain filler? Again, thanks for the info.

 

[jeff...]

Howard, thanks for your reply - your right, use the correct sealer to match the topcoat product. I was vague and should have been more detailed... I think the most important thing is to try new finishing techniques on a piece of scrap first, I surely do want to see anyone mess up their master piece.

 

[sapwood]

Howard,

Thanks for taking the time to "rant". :icon_thum

But I prefer to call it "sharing" knowledge it would take me many years of mistakes to acquire :lol:

Sapwood

 

[Ray Martin]

I agree with Roger. Ranting is just knowledge sharing, done at a passionate level.

As for the idea of filling the pores of wood, I've tried filler a couple of times and I seem to either obscure the grain or spend an aweful lot of time sanding ... and then not leaving enough filler on / in the wood. I must be doing something wrong... I just don't know what.

Ray

 

[Travis Porter]

I have read to use burlap to clean the wood before it dries out, but where do you get burlap?

 

[DaveO]

I got more burlap than I know what to do with...balled & burlaped trees, and a passion for oysters in the fall. I you want some I'll give you enough to last a good while. You can probably buy it at Agri Supply, too
Dave

 

[Howard Acheson]

Great information, Howard. Thanks. I learn a little more with each project.

Is the process that you describe above after I use the grain filler or in lieu of using the grain filler? Again, thanks for the info.

Let me say first that I am not a big fan of grain fillers. They are used primarily to get a perfectly flat surface on woods with large pores or grain. Woods like oak, ash, etc. are the best candidates. Walnut is sort of in between but IMO, grain fillers tend to obscure the grain figure in walnut. Cherry and cedar should not be grain filled. Again grain filling is to give that very formal, flat, piano finish type of look. Many folks today would rather have a finish that still feels like wood.

That said, with the woods you are finishing, I would first concentrate on getting a flat surface by scraping and/or sanding. Sand up to 180 grit by machine--I much prefer a 1/2 sheet orbital sander to get and keep a flat surface--then hand sand with 180 attached to a rigid sanding pad. Sand in the direction of the grain.

After sanding to a flat surface, apply the first two coats of wipe on. Let ist dry and using 320 paper on the sanding pad, sand the surface flat. Now apply the additional coats. This process should assure you get a flat surface and one that will bring out the beauty of the wood.

 

[Roy]

I sometimes use a grain filler on red oak if the piece needs a smooth surface. I have tried several brands with poor results, since most of the stains and finishes I use are water based, until I found a product called Timbermate, which is made in Australia. It stains as well as the wood and is easy to sand. The only dealers that carry it on the internet are Woodcraft and Perkins Supply, but you can go to Timbermate's web site and look at the list of brick and mortar dealers. Here it is: http://www.timbermate.com/