How many times have you opened a can of polyurethane wood finish and found it coagulated or skinned over? Or maybe you’re using some old varnish and it isn’t spreading well as it should. Most likely the finish was being stored in contact with air, which can diminish its performance and properties.
A few in-can solutions exist to help keep air from getting to the finish, such as: filling the can with marbles or rocks until the liquid reaches the top again, or using an air replacement gas like Bloxygen when sealing the can. Those methods assume the can seals properly though. Sometimes, and even much of the time, the rim of a can might be filled with finish, or it might be damaged, which ruins the airtight seal.
StopLossBags are new storage bags that are designed to store your wood finishes with minimal air contact. They can hold up to a full quart of liquid. You can use StopLossBags to store oil, water, and alcohol-based wood finishes, but not lacquer. Lee Valley’s product description also mentions methyl ethyl ketone and acetone as non-compatible chemicals.
Lee Valley’s description also says that the bags are made of 7.5-mil thick three-ply plastic with strong electro-welded seams, although StopLossBags doesn’t mention this on their site.
StopLossBags remind us of collapsible Platypus water bottles, and like those bottles StopLossBags also have a gusseted bottom. Once you pour liquid into a StopLossBag, the gusseted bottom will expand to help them stand upright for even easier filling.
When you first open a can of finish, you transfer the contents over to the StopLossBag using either a turkey baster, or a funnel. If this sounds a little difficult, the StopLossBags website posted instructions for making a simple filling station. Then, once filled with finish, you squeeze all the air out of the bag before screwing on the cap. When you’re ready to use the finish, simply unscrew the cap and pour out the amount you need.
You can purchase the StopLossBags directly on their website. Small orders of bags come with one grey vinyl filling tube for attaching to medium-sized funnels, and one red adapter tube for use with larger funnels. One bag will run you a little more than $8 shipped, two bags shipped run a little more than $11, and the pricing only gets better from there.
Buy Now (via StopLossBags Website)
You can also find StopLossBags over at Lee Valley, which has better pricing for one or two bags, but $8 shipping pretty much erodes any savings unless you purchase these as an add-on to a more expensive purchase.
Compare (via Lee Valley)
This might be a good time to remind you that Lee Valley has “free shipping on $40+” promos a couple of times each year.
The other approach is to blanket the varnish etc. with an inert gas. I’m not sure how either concept works out – but for home use I try to buy the least amount that I can get away with. When I end up buying too much (either because I miss estimate or the minimum can size is more than I need) what’s left usually gets stored, sometimes forgotten and usually thrown out when my town has a hazardous material collection day.
Here’s a link to one of the inert gas products:
Yup – Ben mentioned Bloxygen in the post. Replacing air with an inert gas works, but likely loses its effectiveness when a seal is compromised.
Maybe it’ll lose effectiveness, maybe not. Bloxygen is pure argon which is heavier than air, so even if air slowly leaks in over time the argon should stay at the bottom and insulate the finish.
Are these reusable?
Well if you replace the finish in the bag with the same finish, you can just keep refilling it. Otherwise you are going to have to clean out the bag, which might be tedious, but probably doable.
Inert gas does work. I usually transfer my finishes to glass jars when the rim gets too gummed up to guaranty a seal. I’m also careful to not gum up the jars’ seal either by using disposable mixing cups to extract the finishes.
I do run out of jars sometimes even so. At least they are cheap. On occasion I have bought a bulk load of something on sale at the grocery store, just for the jar size I wanted, and, horrors, threw away the baby food or garbanzo beans that was in them.
These bags can also be filled up with booze and packed in your suitcase when travelling. 🙂
I use canning jars. They come in many sizes. They have 2 piece lids with a rubber seal. The lids can be easily replaced if they get gummed up. I normally put some plastic wrap under the lid to make them easier to get off and they don’t get gummed up. I’ve never used bloxygen but may try it since I’m confident about the seals on my jars.
If I put something in a clear jar or container I make sure to store it in a cardboard box to prevent light from getting to it. It’s my impression that light is not good for some finishes, though I may be wrong.
I’d probably order a few of these next time LV has free shipping. I like the idea of the filters, though and it doesn’t look like LV carries them.
I use freezer zip-lock bags and put the bag back into the can. Probably does not preserve as long as this bag but on latex it works real well.
So it turns out you can actually get similar bags for around a dollar a piece. go on ebay and search for “spout pouch” I have not however seen any with a spout that faces straight up, most have a spout that comes off the corner at a 45.
The three plys of the wall construction are formulated to prevent transpiration of VOC’s. Before we had tried all sorts of wall construction (think Edison and the light bulb…) but varnish in normal bags turns to jelly over time.