Using a Jar for vacuum storage

[stryped]

I am wanting to start powder coating small items on my projects I am always working on around the house. To keep the small quantities of powder paint useable for as long as possible, I had thought about storing the paint in zip lock bags inside of a mason jar. I would install a rubber tire valve on the lid of the mason jar and use my harbor freight ac vacuum pump to create a vacuum to remove the moisture from the jar, which I hope will make the paint last longer.
Do you think this will work? Would the mason jar hold a vacuum for an extended period of time?
If not, is there another type of inexpensive container that would?
Any help is appreciated!

 

[Baluncore]

That should work if you grease the rubber sealing ring.
The zip-lock bags may burst and spill powder when the vacuum is created.
How will you mount the tire valve, backwards in the lid, and still make a vacuum connection?

 

[hutchphd]

Why not "can" the paint in the jars using the lids as the valve as one does making jelly. You would need to build a small vacuum chamber that could hold at least one jar (perhaps a dedicated slightly larger canning jar or a bell jar?). Lightly tighten the lid, put into chamber, evacuate chamber and release vacuum slowly. Jelly seal lasts for years. No valve required

 

[anorlunda]

Why do you need to think beyond what the manufacturers provide?

If moisture is the primary concern, you could also put a desiccant in the jar. A simple one is uncooked rice grains. That's how I store salt in humid environments in a small boat at sea. Fill the salt shaker half with rice and half with salt. Shaking before use breaks up clumps. And the sieve action of the shaker top filters out rice grains and remaining clumps.

 

[f95toli]

Instead of pumping a vacuum you can just replace the air with a heavier than air gas, say argon. This should be much easier and just as efficient.

There are commercial products made specifically for preserving paint using this method. In the US there is e.g. a company called Bloxygen that sells products of this type (I've never used it myself since I live in the UK, but I've seen it used on many of the woodworking Youtube channels that I watch)

 

[stryped]

View attachment 320960
Why do you need to think beyond what the manufacturers provide?

If moisture is the primary concern, you could also put a desiccant in the jar. A simple one is uncooked rice grains. That's how I store salt in humid environments in a small boat at sea. Fill the salt shaker half with rice and half with salt. Shaking before use breaks up clumps. And the sieve action of the shaker top filters out rice grains and remaining clumps.

I am just trying to make the paint last longer in my garage

 

[stryped]

Why not "can" the paint in the jars using the lids as the valve as one does making jelly. You would need to build a small vacuum chamber that could hold at least one jar (perhaps a dedicated slightly larger canning jar or a bell jar?). Lightly tighten the lid, put into chamber, evacuate chamber and release vacuum slowly. Jelly seal lasts for years. No valve required

 

[stryped]

Would this “boil” off the moisture similar to pulling a vacuum for ac work?

 

[hutchphd]

Do you wish to "pull" moisture from the powder or minimize future ingress? If you pull 75% of the air from a container you remove 75% of the water vapor too. Seems equivalent to your original technique......

 

[anorlunda]

This source says that you can store for several years with 50-60% humidity.

https://tcipowder.com/media/2605/powder-coating-storage-requirements-3-17-21-1.pdf
Powder Coating Storage Requirements

These comments apply to uncured powder coatings as sold. Product storage life depends upon the storage conditions. When stored properly, the storage life should be more than six months from receipt. Experience has shown that many products can remain useful for periods of up to several years. Proper storage requirements include:
• Keeping product at temperatures less than 80 degrees F (26.7 degrees C) with the relative humidity in the 50-60% range
• Store product in a cool, dry, well ventilated area away from heat, ignition sources, and direct sunlight • Keep containers tightly closed
• Protect from physical damage
• Do not expose product to damp or wet conditions
• Avoid contaminating product during storage and use

Following these guidelines will optimize product storage life and application performance. Generally, older product is often usable if it displays good fluidization. Agglomeration and chunking indicate the product has deteriorated. Questionable product should be application/performance tested to confirm acceptability before use.

 

[stryped]

This source says that you can store for several years with 50-60% humidity.

I live in southern ky. In the summer, our humidity is way above that.

 

[Lnewqban]

Could you inject an inert gas or Nitrogen into the jar rather than mechanically evacuating air?

Please, see:
https://en.m.wikipedia.org/wiki/Nitrogen#Applications

 

[stryped]

Could you inject an inert gas or Nitrogen into the jar rather than mechanically evacuating air?

Please, see:
https://en.m.wikipedia.org/wiki/Nitrogen#Applications

I have an argon/co2 mix for my welder. I could use that but not sure if it would do something to the powder or not.

 

[hutchphd]

Could you inject an inert gas or Nitrogen into the jar rather than mechanically evacuating air?

I think the seal on the canning jars is much more robust if the inside is at lower pressure than outside. Particularly if ambient temperature is allowed to fluctuate.

live in southern ky. In the summer, our humidity is way above that.

So, in the humid summer time use air from your freezer (at 0F) to fill the jars, put on the lids "finger tight" and remove to vacuum chamber. The remaining internal air will be dry.

 

[Baluncore]

I live in southern ky. In the summer, our humidity is way above that.

And you call that living ?

Buy a bag of silica gel crystal cat litter. Put the gel in a paper bag, in the container with the powder.

 

[sophiecentaur]

The spec for your storage is not so tough. Why not use one of those storage bags for clothes which you put the clothes in and suck most of the air out with a vacuum cleaner? By the time the bag has clung round the outsides of the tins (arranged in a sensible way, the total mass of air (and hence, water) inside will be very small. A flexible envelope would do the same job as a rigid container with 'less of' a vacuum.