For years we dispensed blue from a barrel by putting an elbow in the bung with a length of PVC pipe and rotating it down to let the glue flow. Then we would tip it back up and plug it. We changed glue vendors and the new glue seems to clump up towards the end of the barrel. We think it is drying and leaving a skin.

We recently tried a knife valve so we know we are getting a seal. We still have clumps and the valves sticks and does not seal well. Does anyone know a better way?

My guess is the make up air thats coming into the barrel as you pour off over time is enough to create a large thick layer on the top just as if you were to leave that surface area of glue out on the bench. Would seem other than to use the glue faster, buy in smaller containers, you'd just have to deal with it, stir, mix, or perhaps invest in a small cylinder of Argon and periodically remove the small bung at the top of the barrel and feed a bunch of Argon into the drum to displace the air thats in contact with the glue.

Have a MIG welding setup in the shop and I will top off partial gallons/quarts of paints/finish, bottles of polyurethane glue that are going to sit for a while, of the mig tank and it works fine. My cylinder is a 75/25 Argon/CO2 mix and Id imagine straight argon would be best but I think Argon or some other inert is all thats in products like Bloxygen. Around here the small cylinders can be purchased outright (no lease) for around $100 bucks. Small regulator, and you could give it a try.

We have used glue in barrels for years and never had this problem even when we went through glue much more slowly. National Casein went out of business and forced us to change vendors.

Is there a better valve scenario?

The knife style is the only other style Ive seen for viscous materials. I wonder when the glue companies will come to their senses and start selling bulk quantities of glue in large totes like box wine where the material is contained in a sealed bag that collapses as its used and the contents never see a molecule of air.

I agree.

Buy a 35 dollar barrel pump from Harbor Freight.They work great for about a year or so. Then you throw it away and buy another one.

Mark B,

I agree as well with having the glue come in the sealed bag the way box wine comes. It just doesn't cost that much money and it sure does seem that that would give an adhesive suppler an advantage in the market place.

I made this post to try to build support for this idea just in case a supplier comes across this thread.

Mark

Bill, It does seem strange that you're having this problem now, but never with your other supplier.... I would have to say that it's got something to do with the chemical make-up of the new glue. You could check with Jeff or Eric at CP Adhesives - those guys know a LOT about glue and offer all kinds (even custom adhesives):

https://www.cpadhesives.com/

And Mark E., CP may already have your glue bladder idea in production, or if not, may be interested to hear about it.

One other option to consider is the LK glue systems from Lamello, designed for water-based glues. They're self-contained, pressurized, stainless steel tanks where the glue is always under pressure, right up to the pistol. I've had glue in my system for 3 months (with no use) in between trade shows, and the glue has been just fine. Lots of other advantages too, but that's the one the addresses your concern.

Lamello Glue Systems