New Tool - Sort Of

With all the rain, boredom quickly sets in. Decided to see if I could make my own refillable spray cans using the fluids of my choice. I know you can purchase these at HF, but want to see if I could make my own.

The first step was to take the old valves from replacement of cracked ones on the old pickup (never throw anything away, might use it someday). Burned off the rubber after removing the cores, then polished with 400 sand paper. Cleaned with isopropyl alcohol, then tinned with rosin core solder and additional past flux.

Second step was to drill a hole in top sidewall of can, slightly smaller than valve stem, just below the plastic valve depression in top of can. Removed burrs at hole and polished area around hole with 400 sand paper. Cleaned with isopropyl alcohol, then tinned with rosin core solder with additional paste flux.

Next step was to screw the valve stem into the hole in can. With the smaller hole and solder coating, the valve stem screwed tightly into the hole. Cleaned with isopropyl alcohol, then soldered the stem to the can with same soldering procedure. Was very careful to keep propane torch flame away from the plastic valve area in top of can. Filled the top depression for valve with water to help block heat.

Let cool, inserted valve core, and pressure tested all 3 cans. The factory cans are rated to 200 psig and are generally filled with propellant to 100-110 psig. Set air compressor discharge pipe regulator at 100 psig and filled cans with compressed air. 2 were fine but had a pin hole in third that had to be resoldered and repeat pressure test.

Removed valve core slowly to exhaust air, then filled with fluids of my choice. I filled the cans to their original weight using kitchen food scales. Converted weights to grams for more accuracy (grams=liquid weight oz x 454/16). Fluid filling very slow as air has to vent as liquid displaces can volume. I used an old manual oil can with a small spout that would not seal with opening in valve body. Reinsert valve core and pressurized cans with compressed air.

The first spray can was for my home made starting fluid for the diesel tractor, 75% diesel and 25% gasoline. This gives a nice rolling start in 5-10 seconds in zero weather, not the harsh clatter if using Ether. Everything worked great. When the spray can starts to put ou a liquid stream instead of spray, I give it a shot of air.

Nice to know that the old dog still has a few tricks left.

Nice job!

I would have never thought one of those cans could take 200 PSI!

That's a nice job you did. Looks almost like it came that way.

This also works when you run out of propellant before contents in one of those cans. Just pump in a little air.

That's a great idea for all the WD 40 cans that have 1/4 fluid left but no propellant. Why didn't I think of that?

(quoted from post at 10:08:55 08/02/20) Nice job!

I would have never thought one of those cans could take 200 PSI!

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I was also. But that is the the FDA standard for aerosol cans burst pressure. I have a friend that works in a plant that makes the top valves for aerosol cans and he confirmed that pressure rating. He also cautioned that the cans be loaded to a max 100 psig, or 1/2 the burst pressure rating. I think I will reduce my loads to 75 psig and re air more often. He also told me the valves they make are injection molded and the spray hole is machined to spec for the various customers. Never would have guessed that part.

(quoted from post at 19:34:29 08/02/20)
That's a great idea for all the WD 40 cans that have 1/4 fluid left but no propellant. Why didn't I think of that?

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WD40 cans are kind of notorious for that, aren't they.

I've never heard of the Food & Drug Administration having ANYTHING to do with pressure ratings on
pressure vessels. But I know ASME, American Society of Mechanical Engineers is ALL about pressure vessel
design, testing, and manufacturing. I worked at a food and chemical processing equipment company buying
parts for production for 5-6 years. The ASME spec refers to an ASTM spec in most cases but EVERY T must
be crossed and every I dotted or else! We even built a continuous flow rocket fuel mixer that eliminated
the o-rings in the solid rocket boosters for the Space Shuttle. Talk about Red Tape! And ASME got
involved with that too.
You can buy factory made sprayers you can fill with your fluid of choice and pressurize with compressed
air, and the ones I've seen are WAY heavier built than a single use aerosol spray can. WAY too many
places that thing can fail and blow up in your hand. My Uncle was never good with tools, equipment, or
cars, trucks, or tractors. He bought a small portable air compressor to keep in the corner of his
attached garage in his new house. A 1 or 2 hp, 15-20 gallon tank. He NEVER even knew he should drain the
water out of the tank, eventually, one day him and my Aunt came home, house looked "funny", opened the
garage door and the compressor was sitting clear across the garage, there was daylight shining up from
the foundation where the exterior wall on both the garage and living room of the house blew off the
foundation, even the interior wall between garage and living room was off the foundation. The pressure
tank basically turned itself INSIDE-OUT. That's what 90 to 120 psi can do. So wrap your bare hand around
a modified paper-thin spray can with 100-120 psi in it!

+ 1 could not agree more , how could that little savings be worth you health or life

That's very creative, crafty, and cool!
You are talented.

(quoted from post at 16:32:25 08/03/20) I've never heard of the Food & Drug Administration having ANYTHING to do with pressure ratings on
pressure vessels. But I know ASME, American Society of Mechanical Engineers is ALL about pressure vessel
design, testing, and manufacturing. I worked at a food and chemical processing equipment company buying
parts for production for 5-6 years. The ASME spec refers to an ASTM spec in most cases but EVERY T must
be crossed and every I dotted or else! We even built a continuous flow rocket fuel mixer that eliminated
the o-rings in the solid rocket boosters for the Space Shuttle. Talk about Red Tape! And ASME got
involved with that too.
You can buy factory made sprayers you can fill with your fluid of choice and pressurize with compressed
air, and the ones I've seen are WAY heavier built than a single use aerosol spray can. WAY too many
places that thing can fail and blow up in your hand. My Uncle was never good with tools, equipment, or
cars, trucks, or tractors. He bought a small portable air compressor to keep in the corner of his
attached garage in his new house. A 1 or 2 hp, 15-20 gallon tank. He NEVER even knew he should drain the
water out of the tank, eventually, one day him and my Aunt came home, house looked "funny", opened the
garage door and the compressor was sitting clear across the garage, there was daylight shining up from
the foundation where the exterior wall on both the garage and living room of the house blew off the
foundation, even the interior wall between garage and living room was off the foundation. The pressure
tank basically turned itself INSIDE-OUT. That's what 90 to 120 psi can do. So wrap your bare hand around
a modified paper-thin spray can with 100-120 psi in it!

Click to expand...

So single use spray cans are too dangerous for any one to use. We will see how soon they are taken off the market. An automatic pressure relief system is required on all pressure vessels, including the home air compressor. If not tampered with , these provide adequate protection of the air compressor tank. I test mine twice a year to make sure it is functioning properly. It has popped twice in 35 years due to pressure control failures and malfunctions. People who own equipment should be thoroughly familiar with their operation, maintenance and safety procedures. If you are unable to adhere to these widely published procedures, you should not own the equipment. Does he also leave a chainsaw running on a bench or floor while not at home? I am a registered chemical engineer who has dealt with life safety issues for the past 45 years. I do not take risks and shortcuts on projects. I confirmed the can pressure ratings before starting, and pressure tested the finished cans remotely at 10 psi increments. I would not post a procedure that was dangerous for the forum members. Everyone is entitled to an opinion. Yours went straight to file 13.

I don't think using a valve stem like I showed to pressurize the can is dangerous. I guess it could be if one was an idiot. But for getting that last little bit out of a WD40 can, one needs only give the can a quick little shot of air. After all, you're only trying to get it to spray the stuff out. One doesn't not need a precise spray like in a paint can. I don't recommend trying to bring a spray can back up to factory pressure with that valve stem. I'm talking about the rubber valve stem that I showed.

(quoted from post at 02:20:19 08/05/20)
I don't think using a valve stem like I showed to pressurize the can is dangerous. I guess it could be if one was an idiot. But for getting that last little bit out of a WD40 can, one needs only give the can a quick little shot of air. After all, you're only trying to get it to spray the stuff out. One doesn't not need a precise spray like in a paint can. I don't recommend trying to bring a spray can back up to factory pressure with that valve stem. I'm talking about the rubber valve stem that I showed.

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Just put Dr Evil's post in the proper file, #13 where the sun don't shine, and the rest of us will go on our merry way.