Shellac Cut Rate for Our Hobby

[ChrisLBren]

Hi Group,

 

I bought some blonde shellac flakes at Rockler to experiment with on Black Friday.  I am wondering for those of you who use this finish what sort of cut rate you use.  Many recommend a two lb cut rate however I wonder if this is too thick.  I created my first batch at a 1lb cut rate and would rather build up a finish than lay on one that is too thick.  

 

Any advice is appreciated !

Chris

[Jaager]

The raw dark shellac has a wax component.  The wax increases solubility in ethanol.

The more refined the shellac, the more wax is removed.

There is a shellac that is one step more refined than super blonde,  super blonde is pretty refined.

I think amber is close to saturated at 4 lb cut

I think super blonde is about saturated at 2 lb cut,

1 lb cut is a good concentration if you have the patience.

 

If you round 

1 gal = ~ 4000ml

1 lb =  ~ 500g

500/4000 = 12.5%    10% is easy to make if you get a 100 ml graduated cylinder  and Amazon has electronic scales for~$15

so small batches are easy to make.  I like round numbers 10% 20% .....

 

[RossR]

I have had good luck with a two pound cut.  I get a flat finish with two coats and a rubbing down with steel wool after each coat.   Steel wool is messy, but I like the finish it leaves.  I always head to the garage or out side when I use it.  

[Dr PR]

One user on the Forum cautioned about steel wool. It can leave tiny pieces embedded in wood that will eventually rust. So be sure to clean thoroughly after using it.

 

I love #0000 steel wool for producing a fine satin finish.

[vaddoc]

There are other alternatives to shellac which you might want to try. Search water based sealer, Decoart multipurpoce sealer. Self life is years, dries in 15 min, straight from the bottle. Really nice stuff. I use two coats, seals wood and leaves nice smooth surface.

[Bob Cleek]

3 hours ago, Dr PR said:

One user on the Forum cautioned about steel wool. It can leave tiny pieces embedded in wood that will eventually rust. So be sure to clean thoroughly after using it.

 

I love #0000 steel wool for producing a fine satin finish.

A lot of commercial finishers, particularly in the auto painting business, are now using Scotch-Brite abrasive pads instead of steel wood or superfine abrasive paper. These are the same things you see on the back of dishwashing sponges, except that they are available in a range of ten abrasive grits. One big advantage they have, which perhaps isn't all that big a deal in modeling, is that they can be used wet and hung to dry and be used over and over again. The Scotch-Brite ones are color-coded as to the grit size. There are now other brands besides the ones made by Scotch that are available at a lower price point. They are carried by any auto paint supply store and a lot of paint stores.

 

As many know, "satin" varnishes are just gloss varnish with chalk added to it. "Satin varnish" is marketed to mimic a true hand-rubbed finish achieved with rottenstone and pumice, which can be a lot of work. Now, a good "hand-rubbed" varnish finish can be achieved with a lot less "elbow grease" using these plastic abrasive pads. 

 

 

[ChrisLBren]

So far after two coats of 1lb blonde shellac on some scraps Im not happy with it - I think I will mix up to a 2lb cut.  Its almost a "non finish" at this point after buffing in between coats with steel wool.  

 

I do like the pure tung oil finish better at this point however dont want to give up yet.  I also understand many modelers use a wax finish as an alternative.  I am a fan of more natural finishes than a poly finish.  

 

Any tips are appreciated as always.

[RossR]

i am going to give Scotch Brite a try.   Love the finish but hate the mess with steel wool.   Do you know if  the fine Scotch Brite pads available at box box home improvement stores?

[rcweir]

I was taught to use 1/2 lb cut as a wash coat and sealer.    It raises the hairs so they can be lightly sanded off, and it's thin enough that you can use any topcoat over it.

[Jaager]

2 hours ago, ChrisLBren said:

I do like the pure tung oil finish better at this point however dont want to give up yet.

Tung oil will go over a shellac base, so you have burned no bridges.

If you do not wish to wait for pure Tung oil to polymerize naturally

Sutherland Wells offers a variety of already partially polymerized Tung oil - and now they have 4 oz sample sizes that will not break the bank.

https://www.sutherlandwelles.com/original.html

[ChrisLBren]

6 minutes ago, Jaager said:

Tung oil will go over a shellac base, so you have burned no bridges.

If you do not wish to wait for pure Tung oil to polymerize naturally

Sutherland Wells offers a variety of already partially polymerized Tung oil - and now they have 4 oz sample sizes that will not break the bank.

https://www.sutherlandwelles.com/original.html

Thanks for the tip Jaager - I just want a full proof finish on a fully framed model other than poly or tung - I may try some darker shellac flakes and or a wax finish to try to achieve the look I want with my pear wood.  Stand by for some more tests.

[Jaager]

Lee Valley sells small packages of 3 shades of shellac flakes

The dark amber looks pretty garnet-like to me -  I plan to try it on Maple.

https://www.leevalley.com/en-us/shop/tools/supplies/finishing/finishes/76311-shellacs?item=56Z4028

[Roger Pellett]

A number of years ago I bought shellac flakes to make my own shellac.  I still have most of  them.  Here in the US, ready mixed Shellac is widely available at paint, home improvement, and hardware stores.  It is not expensive.  It can be easily thinned with alcohol if necessary.  I, therefore, see no need to make my own stuff or to worry about the Cut.  For most applications the eyeball can be a good guide to thinning.

 

Roger

[Bob Cleek]

6 hours ago, ChrisLBren said:

So far after two coats of 1lb blonde shellac on some scraps Im not happy with it - I think I will mix up to a 2lb cut.  Its almost a "non finish" at this point after buffing in between coats with steel wool.  

 

I do like the pure tung oil finish better at this point however dont want to give up yet.  I also understand many modelers use a wax finish as an alternative.  I am a fan of more natural finishes than a poly finish.  

 

Any tips are appreciated as always.

It sounds like your shellac sealer coat is working exactly as it should, so don't feel bad at all. It appears that you aren't happy with your shellac job because you are expecting it to do something it's not able to do if you expected it to look like a "pure tung oil finish." (Which is more a product of the finish coating manufacturers than it is the seeds of the tung tree, but that's a story for another night.) 

 

It appears the use of shellac as a finish requires some clarification. Shellac can be used as a finish and is, most famously in the "French polish" method of traditional fine furniture finishing. Shellac can also be used as a finish by building up successive coats, much as one would with a varnish, and then wet-rubbing them down with very fine abrasive powders or simply attempting to apply thick shellac as one would a varnish, which is very difficult to do without encountering brush strokes, given the speed with which alcohol evaporates. These now antiquated finishing methods have been widely replaced by modern finish coating materials over the years, beginning with sprayed clear lacquers and more recently polyurethanes and epoxy finish coatings. The classic shellac finishing techniques are only seen in very fine custom furniture and in refinishing antique pieces these days. 

 

When we talk about shellac as often used in ship modeling, we are generally talking aboout using shellac as a sealer, rather than a finish. This is to say that many of us use shellac on our models precisely because it's "almost a non-finish." That's how it's supposed to look. A coat or two of thinned shellac soaks into the surface of the wood and seals the pores, but does not build up a thick coating that would serve as a finish coat with any of the depth needed to accomplish what one would consider a finish on the wood. A very thin varnish application will, also bring out the figuring in figured woods, but enhancing the figuring of wood is decidedly not something one would want to do on a ship model and figured woods are avoided wherever possible in any event. What a thin coat of shellac does as a finish on a ship model is to mimic the appearance of bare wood while invisibly protecting bare wood from exposure to the elements, dirt, and greasy finger stains. (Heavier cuts of shellac are also used as an adhesive and medium cut shellac is particularly useful in cementing knots in rigging work and stiffening lines to create realistic catenary shapes.) 

 

When used as a sealer shellac on a model used to portray bare wood is theoretically a "finish," but not one intended to be seen. When shellac is used solely as a sealer, it is exceptionally effective beneath subsequent finish coats of paint or varnish. I know of no finish coating which will not adhere well to shellac. It is compatible with everything. Shellac is a particularly effective feature if subsequent coatings are water-based because water will soak into the pores of most wood species and, to one extent or another, "raising the grain" of the wood as the water-wet wood expands, which makes achieving a perfectly smooth finish virtually impossible. Shellac does not raise the grain when applied to bare wood and when dried may be lightly sanded without creating the "fuzzy surface" that results when sanding many softwoods, such as basswood, commonly found in ship model kits. While no coating is entirely impermeable to moisture, shellac is recognized as one of the most impermeable coatings we have available.  Shellac's ability to slow the exchange of moisture between the wood in a model and the ambient humidity of the environment in which the model is kept is often a valuable contribution to the life of a wooden model which otherwise must endure the shrinking and swelling, however microscopic, of its separate parts as the moisture content of its wood fluctuates, a process with can, over time, weaken glue bonds and cause the structural integrity of the model to deteriorate. 

 

Now, if one desires a "finish" on their model, I would not advise attempting to achieve a "finish" on a ship model using shellac simply because the intricacy of the parts virtually preclude the rubbing and polishing required to achieve a traditional "hand rubbed" shellac finish and because the thickness of the shellac coating required would, in any event, operate to obliterate the fine detail on the model, a fault commonly seen in models built by modelers inexperienced in the nuances of finishing miniatures.  If your model is now shellacked, and providing you haven't sanded off the coat you applied (another mistake often made and easily corrected by applying another,) you've properly prepared and sealed your surface for the application of the finish coat of your choice. That choice is entirely up to you and will depend upon what you want the finished product to look like. If you are seeking to portray a compelling impression of reality in miniature, a "furniture finish" would not be appropriate and, in fact, the "bare wood" appearance of shellac alone would serve the purpose well. If on the other hand, you want to finish the bare wood on your model as if it were a piece of furniture without regard for the actual opaque paint colors applied to the prototype, an artistic effect which seems in vogue to some degree these days, you will have to either hand-rub wax over the varnish sealer, a traditional furniture finishing technique that is best left for flat table tops than any modeling application, or use a varnish or polyurethane coating. These are quite subtly varied in appearance, and you will have to experiment to determine which product creates the finish appearance you like best. A lot of modelers who prefer the "all wood look" on their models use what's called "wipe-on poly," This product is apparently not available in Europe, whether this because of VOC content regulations or some other reason, I don't know, but "wipe-on poly" as marketed in the U.S. is simply thinned clear polyurethane coating, produced in a range of stain tints. As it says on the can, it may just wiped on with a soft cloth and it will yield a matte finish of whatever depth one wishes to apply. 

[Bob Cleek]

7 hours ago, RossR said:

i am going to give Scotch Brite a try.   Love the finish but hate the mess with steel wool.   Do you know if the fine Scotch Brite pads available at box box home improvement stores?

They are and will be found in the paint department. That said, I have not seen the full range of grit sizes in the DIY warehouse stores that will be found in an auto painting supply store. The pads in the big box stores are for general prepping for house painting and are fairly coarse for model finishing work. The grit size you want for modeling is much finer than that, down around the 300 to 600 sandpaper grit range. The abrasive pads are available in auto painting supply stores down to ultra-fine grit sizes suitable for "rubbing out" auto body finish defects. Most towns of any size will have an auto painting supply store nearby, or even a DIY auto parts store, that will carry a range of different grit grade abrasive pads. You might also stop by a local auto body and fender repair shop and ask if they have some they will sell you. Like most abrasives, I'm sure there's a big price break on purchasing larger quantities. The pads last quite well, so it's not like you need to buy more than a few at a time in a small range of grit sizes (or in just one grit size, depending on your uses...) if they are only going be used for modeling work. If all else fails, you can always make a donation to Mr. Bezos' retirement savings account and buy them from Amazon. Beware of the peg-rack packaging prices in retail stores, though. There's a huge difference in price between the "civilian" retail prices and the "commercial" lot-packaged prices, as well as between the "Scotch" brand pads, which were once all that were available, and the wide range of generic brands available now.

 

Scotch peg-rack package of one pad: $8.88

Amazon.com: 3M Paint & Body Scuff Pad, 03193, 6 in x 9 in, 1 Per Pack : Everything Else

 

Tonmp 10 Pack 4.5 x 10 Inch Hand Pads Coarse Medium Fine Superfine 5 Different Specifications Assortment General Purpose Scouring Pad: $8.99 ($.89 per pad)

Amazon.com: Tonmp 10 Pack 4.5 x 10 Inch Hand Pads Coarse Medium Fine Superfine 5 Different Specifications Assortment General Purpose Scouring Pad Ideal for Garden Tools and Grills,Automotive Body Tools : Health & Household

 

[RossR]

Thanks for the info.  I also found ones sold by Rockler Woodworking that are labeled with steel wool grade equivalents.