Extending the Shelf Life of Your Finishing Products

I often get inquiries from fellow woodworkers about finishing products, particularly about the best way to extend the shelf life of various products:

Hello David,

 Speaking of finishes, I was never a fan of poly but I tried the wipe on poly you recommended by General Finish.  The sealer is very good and lasts a long time in the can, but the other poly products (gloss and semi) coagulate in the can after just a few weeks.  Is this normal?  Danish Oil, on the other hand, keeps for many months without setting up.  One other thought, can the coagulated poly be reconstituted by thinning with mineral spirits?  I tried but am nervous about applying it.  Thanks for your help.



Hello John,

General Finishes makes great products and it’s good to hear that you have been working with them.  The coagulation’s or “skinning over” in the cans that you have been experiencing is quite normal.  This process occurs due to the fact that Arm-R-Seal is made up of a blend of oil and polyurethane as well as solvents and driers. Polyurethane is an “air oxidizing finish” which means it dries by reacting with the oxygen in the air. As you use some of the finish and air begins to replace the loss of liquid in the can, the oxygen in the air, begins to react with the polyurethane in the can and the result is “that gel” that thickens and hardens on the top of the liquid.

My recommendation is to use a product called “Bloxygen” which is an inert gas containing Argon. Argon is heavier than air and when you lift the lid of the can and spray a 4 second shot in there, it will settle on top of the liquid and force the oxygen up to the top of the can.  In my experience this product really works well and is worth the cost. 

Here is a good YouTube video on Bloxygen: 

I would also advise you to dispose of any any cans of finish that have skinned over. Using skinned over finishes is inviting trouble and they most likely will not dry or fully harden. I take my disposable finishes to the Sonoma County refuse area. Check out the attached photos and have fun at the recycle facility if you need to stop there.

Entrance to Sonoma County (California) Refuse Area

Entrance to Sonoma County (California) Refuse Area


Sonoma County Refuse Facility

Sonoma County Refuse Facility

Things you see at the Sonoma County Refuse Facility

Things you see at the Sonoma County Refuse Facility

 One last piece of advice: always use the gloss finish for building all of your coats. If you want to dull the finish to a semi-gloss or satin, than apply one or two coats of a semi-gloss or satin finish for the last couple of coats. Another method is to use 0000 steel wool and some renaissance wax to lower the sheen and smooth the last coat of finish.

Working Out the Bugs

The good folks at Popular Woodworking magazine invited me to do some demonstrations at the Woodworking in America show in Pasadena last October.

One of my demos was on double bevel marquetry so I decided to make a small sample of something to show the people in my class.

I decided to try and make a “bug”.


Yellow heart made a great background color and I love the graphic qualities of the end grain of black palm wood from Indonesia so I used it for the main body. Ebony was my choice for the legs, Pernambuco for the eye with that amazing orange color, purpleheart for the face and a lapis substitute I purchased made from powder and resin for the head.

The horn seemed to need something to make it stand out so I used a piece of 60 thousandths thick abalone shell that my good friend Larry Robinson gave to me. Abalone is very hard so when it was all glued up, I used a hardwood block and wrapped some 120 sandpaper over it to block sand and level the surface.

After hand sanding to 600 grit, I applied Arm-R-Seal wiping varnish to the surface and using a rubber block, wet sanded it with 1000 grit. It really smoothed the surface and made the colors come out.

My wife Victoria and I really enjoyed the show and I finally got to meet renown woodworker Roy Underhill for the first time. What a cool guy he is. My only regret is that I was too busy teaching to get much of a chance to walk around and see the rest of the show. So much great woodworking going on and not enough time to see it all.

My  DVD “Double Bevel Marquetry” explains the technique of creating pictures in wood step by step.

You can find this DVD at my estore located at my website: