Jump to content

Clear Shellac Sanding Sealer


Recommended Posts

Has anyone used clear shellac as a sanding sealer on their models?  I have used it as a sealer for walnut gun stocks and it works very well for that application with an oil finish over it.  Only problem was that the shellac left a relatively thick layer on the surface that needed to be sanded off to get back to the wood.  Not a problem with a gun stock but might be with a more delicate structure.

Link to comment
Share on other sites

Thanks to all for their comments.  Think I will give it a try.  One reason I used in on walnut gunstocks was that it did a good job of taming grain that wanted to fuzz up when sanded and helped keep splinters under control.  A problem I have had with thin veneer second planking strips.

Link to comment
Share on other sites

I think of sanding sealer as being a thick product.  Useful on open pore wood like Black Walnut, Oak, and A finish plywood to fill the pores and give a smooth even finish.  Intended more for full size furiture.

 

Shellac is an excellent traditional finish.  It can be as thick or thin as you wish.  It is not good for applications where it can come in contact with water.  It hydrates and turns white.  It can be easily repaired, but do not use it to finish a coffee table. 

A shellac finish can be removed with alcohol.

The material can be preextracted and purified and comes as Orange (probably straight from the beetle) to Super Blonde - almost water clear.  The solvent is alcohol (methyl, ethyl, 2-propanol, probably propanol if you can find it).  You can buy it in flakes and make up your own solution as needed.  The more purified are the flakes, the lower the maximium concentration you can make.  The impurities increase solubilitiy in alcohol.  The more volatile is the alcohol (Me>Ethyl>Prop) the less working time if you are using a cloth for application.  Dilute shellac is a good first coat for most any other finish.  It is very compatible with other finishes.  French polish seems to be multiple layers of shellac applied with a cloth that has a bit of Linseed oil in the cloth.  I would guess that Tung oil or Walnut oil might work as well.

Edited by Jaager
Link to comment
Share on other sites

Good stuff

I am guessing but I would think several thin (ie low viscosity for ease of filling wood pores) coats of sealer would be better than one thick one. One question I have would be if you coated a shellac sealed piece of wood with let's say wipe on poly would you still have water sensitivity issues.

Link to comment
Share on other sites

Ahoy Mates :D 

 

I found shellac to be very problematic on my ship model. Not only does it take a long time to dry enough so you won't leave fingerprints but it also seems to react to  laser burn. On my model the caulk lines were laser engraved. I could not get the shellac to fill them or where it did, it would always contain bubbles. I put a coat on every day for a month before I finally gave up. It was like a morning ritual. The lines are still not filled. 

 

Its good to hear that I can go over this with Poly. Thx 

Link to comment
Share on other sites

  • 2 weeks later...

Hi grsjax - to address your original question, the short answer is yes. I like using shellac but have to point out that I do not use the stuff in a can. Depending on what you buy, there will be additives of all sorts to slow down shellac's fast dry time and who knows what else. It's generally too thick out of the can as well. I go old school and disolve the shellac flakes in alcohol - the purer the alcohol, the better. Shellac has historically been the finish of choice in classical and early steel string acoustic guitars and it's that connection that got me using it (i used to repair guitars). I also use shellac as a barrier coat between incompatible finishes. I like using oils to make the grain of bare wood pop, then seal it with shellac and top coat with lacquer on some projects (haven't tried this on a ship and this would only be suitable where a high gloss was wanted). I have not tried top-coating shellac with poly (I would think it would be fine, but I'd test it on scrap). Poly was not a type of finish I worked with on acoustic instruments so I lack much first hand experience with it. All finishes affect the sound of a wooden acoustic instrument and poly damps the sound more than others. Since a ship model only has to look good and not sound good too, poly seems to be a great choice (...if you were to tune your shroud lines...)  Anyway I digress. If you are trying to seal a pourous wood, the use of fine pumice rubbed in with the shellac works great. The pumice goes invisible in shellac. For pictures and more than you may care to know about all this, there is more info in my whaleboat log (link below). 

 

Best wishes,

Edited by Salty Sea Dog
Link to comment
Share on other sites

Why don't you use cellulose sanding sealer (aka dope for model aircraft enthusiasts). You can make it as thick or thin as you like, it dries really fast and if you want you can make a really good satin finish with just two coats. Or you can easily sand it down and put any paint or varnish on top. I grant you that it does darken some wood a bit.

Link to comment
Share on other sites

Jaager and Sea Dog said pretty much what I was going to about shellac. In addition to using at as a sealer I have also used it to control stains, similar to what many use stain conditioner for. A thinned down shellac applied and then scuff sanded can tame even the most difficult to stain woods although the stain will be somewhat lighter than on bare wood. Best to experiment first.

 

As far as using shellac to fill grain, its possible but labor intensive. The first processes of french polishing use a very fine pumice worked into the surface with shellac as a binder. For me I prefer dyed grain filler. Jeff Jewit at Homesteadfinishing.com used to have a great tutorial on french polishing for anybody interested. He also has a great selection of modern and traditional finishing products, no connection other than a satisfied customer.

 

EDIT - Somehow I missed bucks last lines on pumice........... :rolleyes:

 

Just my 2 cents

Sam

Edited by src
Link to comment
Share on other sites

  • 2 weeks later...

The sealer material in model airplane "dope" is talcum powder.

Scalecoat, a model railroad solvent based paint, also makes a sanding sealer. Takes many coats and buffing out with superfine steel wool to turn wood parts into steel siding on a boxcar. But for wood parts looking like wood, it works well.

And some craft store chains, like Micheal's in the States, also carry sealer in aerosol cans.

Link to comment
Share on other sites

I have Always used Poly cut with thinner.  Works great at taking care of the fuzzies.  The thinner helps open the pores so everything sinks in.  I usually do this before I went to work.  When I got home time to buff it out will steel wool.  Then a wipe down with some cheese cloth and a terry cloth towel.  The last two procedures were used to get the finer particles off so no rust marks.  The wood is now ready for anything I throw at it. I have never tried shellac so I have no opinion on it.  Several club members have used it with good results.  Experiment with some scrap from your bin and note what you did.   This sample will give you a good idea for how to use it.

David B

Edited by dgbot
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...