Constant paint can bulges, what to do?

[High octane]

I've been using rattle cans for many years and never recall having that problem, even with having 50+ cans here in the house.

[Crazy Ed]

   Having nothing useful to add, all I have to say is Brian next time I need Margaritas Shaken any chance you might wander by

   Sure hope the solutions you got cure the problem, 'cause that's just plain weird.

[aurfalien]

   Having nothing useful to add, all I have to say is Brian next time I need Margaritas Shaken any chance you might wander by

   Sure hope the solutions you got cure the problem, 'cause that's just plain weird.

Welp, a Margy should not be shaken that much either, you risk cube warp

It's what they told me; I'm shaking too long and too hard.

Now Monsignor Bill eluded to thinner then usual can bottoms.  Who knows, things change many many many times behind the scenes that we are totally unaware of.

I'm getting a new can of that Rustoleum which prompted this post later in the week.  I'll reply with how it looks using my new techniques.

[unclescott58]

Shaking too hard and too long? Interesting. Tempted to experiment with an old can and see if I can replicate the results. I've always though I shook my cans fairly vigorously. And I'm pretty sure I've done it for several minutes at a time before. Now, I'm going to have to try it. I'm not totally convinced that's your problem? At the same time I'm not sure of how many times I've looked at the bottom my paint can when I'm done with them. Maybe this happened to me too? I just didn't notice.

[Art Anderson]

Some of your cans show "dents" rather than a smooth bulging bottom, which leads me to wonder just how you are shaking up the paint before spraying?  I've shaken literally HUNDREDS of rattle cans over the past 50+ years, and have NEVER seen that happen.

Art

[aurfalien]

Shaking too hard and too long? Interesting. Tempted to experiment with an old can and see if I can replicate the results. I've always though I shook my cans fairly vigorously. And I'm pretty sure I've done it for several minutes at a time before. Now, I'm going to have to try it. I'm not totally convinced that's your problem? At the same time I'm not sure of how many times I've looked at the bottom my paint can when I'm done with them. Maybe this happened to me too? I just didn't notice.

I've a laser heat gun at work that I'll use to measure cans before and after shaking.  Should be interesting data.

[slusher]

I've been using rattle cans for many years and never recall having that problem, 

I have never seen cans bulge like your pictures either. I have used spray paint out side in the summer ans set it down between coats and never bulged when i would reshake it...

[aurfalien]

So I was at Home Depot exchanging my can of paint and asked to speak to some one.

Well, a guy whose specialty is spray cans came out and said either improper storage or improper shaking can result in my issue.

He suggested shaking the can upside down and aside to side in a non vigorous manner.

It appears that I've been too hard on my cans.  I'll post results.

[Pete J.]

You aren't using something like this are you?  I can see the damage your photos showed with this type of rig, especially if it doesn't have a timer on it. 

 

 

[aurfalien]

You aren't using something like this are you?  I can see the damage your photos showed with this type of rig, especially if it doesn't 'have a timer on it. 

 

 

No man, that's too much gear.  I just do vertical up and down vigorously.

 

[Chillyb1]

Could you please post pictures of your paint-shaking arm? And do you have any connection with the Planet Krypton?

[aurfalien]

Could you please post pictures of your paint-shaking arm? And do you have any connection with the Planet Krypton?

[Mike_G]

Are you perhaps shaking it so hard that the ball inside is making those dents? I've never seen anything like that

I win

[peteski]

 

 

 

 

 

Wow!  This thread has been the most amusing (and interesting) threads I have read in a while!

To add to all the other responses, I have been using spray cans for decades and this has never happened to any of my cans. I have also never seen anything like that before this.

The above photo seems most telling.  I would say those bulges are caused by the vigorous shaking and the agitators hitting the bottom of the can. The distinct depressions are clearly visible. The odd thing is that the tops and bottoms of cans are made from thicker metal than the side wall, so you must have a superhuman strength to be able to make the agitators achieve enough speed (kinetic energy) during your shake stroke to actually dent the bottom of the can!  Are you a body-builder? Seriously!

I have taken many empty cans apart and they all seem to have couple of glass ball (about marble-size) agitators.  The location of the bulges seem to agree with where the agitator would contact the bottom if it was moving right against the side of the can.

You are one powerful dude!  Ease up on the shaking bro!  Or if you have wife and kids, ask them to do the shaking for you (unless your entire family is atomic - then ask a neighbor)! 

Edited August 3, 2016 by peteski

[Modelbuilder Mark]

I have had this happen as well. Too vigoris shaking, and the mixing ball slams into the bottom, but usually when the can is less than full, but not always. 

[aurfalien]

You are one powerful dude!  Ease up on the shaking bro!  Or if you have wife and kids, ask them to do the shaking for you (unless your entire family is atomic - then ask a neighbor)! 

I'm 6'1", 145, same waist size since 87'.  But I had a wicked forehand and double handed backhand back in the day

[peteski]

I'm 6'1", 145, same waist size since 87'.  But I had a wicked forehand and double handed backhand back in the day

Hundred forty five? Eh, you're just a lightweight, with a wicked good arm!

This brings up something that I have been thinking about for years:  Those agitators are made of glass and when they bang against metal, it might be possible that flakes of glass chip off and contaminate the paint.  The ones I rescued from the empty cans (shaken much less vigorously) do show signs of impact with the metal (small flaws).  I wonder what the onels in your cans look like.  I wonder if you would be willing to cut open one of the cans with defromed bottom (after it is empty and depressurized of course). I'm curious about the condition of those agitators.

[Pete J.]

I also, would like to see them, though I doubt there is any damage.  Glass is really pretty tough and since it is hitting relatively flat surfaces, the chances of a chip are pretty small.  I remember bouncing marbles off of ceramic tiles as a kid and they bounced pretty well and I don't ever recall one breaking or chipping except if you hit the edge of something. 

[aurfalien]

Well, if I was inclined to play with dynamite, how would I go about doing this safely?

Besides ensuring no more paint is left, is it a matter of simply spraying until nothing more comes out?

[Foxer]

Well, if I was inclined to play with dynamite, how would I go about doing this safely?

Besides ensuring no more paint is left, is it a matter of simply spraying until nothing more comes out?

I've sure opening a spray can has been discussed here before, but couldn't find the thread ... someone will have suggestions I know/

this has been fascinating!

[Pete J.]

Invert the can and spray until there is no more propellant coming out and then use and old fashion can opener on the side.  Also a screwdriver will do it.  The metal on the sides is not to strong. 

[Pete J.]

Oh, and one other thing I thought of the other night.  When I store my rattle cans, I always store them upside down.  This does a couple of things.  One of the issues with getting the paint mixed is the dip tube(the tube that runs from the spout to the bottom) is in the bottom and it gets in the way of the glass balls when you swirl it to mix the paint.  By storing it upside down if you swirl the can inverted the balls go around the can without bumping into the dip tube and mix it better.  Also as the solids settle out in storage,  your dip tube in down in that muck at the bottom.  By storing it upside down the dip tube stays clear of the settled paint and is always clear when you go to use it again. 

[BigTallDad]

I've sure opening a spray can has been discussed here before, but couldn't find the thread ... someone will have suggestions I know/

this has been fascinating!

It's often called decanting.

If I want to dissect a can (something I rarely do) I'll use a long woodworking clamp to depress the spray nozzle. When I think the can is empty, I'll set the assembly in the sun for an hour or so, then immerse it in cold water. After a few minutes in the cold water, drill a hole, then use the tool of your choice to open the can.

[Longbox55]

Those agitators are made of glass

Not always. I have pulled agitators out of cans that were metal balls about 3/8" diameter, plus a few that hat metal rods that were about 1/4" around and perhaps 1/2"-3/4' long and rounded at the ends. IIRC, the ones with metal balls were Rustoleum brand, but it's been a long while since I've cut open a spray can.

[Yenkocamaro]

I have had this happen as well. Too vigoris shaking, and the mixing ball slams into the bottom, but usually when the can is less than full, but not always. 

Sorry, I'm not buying the explanation, other wise the top of the can would show the same dents. There is not enough room in the can(top to bottom)to get enough momentum, to create those huge dents. I looked up the reason for the concave bottom, of the can, and it said that its shaped that way for adding strength to the can. It would seem to me, that if it was that easy to dent a can of paint with the mixing ball, I would be afraid of the integrity of that can being compromised. I have 45 cans of model spray paint, new and used, and checked everyone of them, no sign of any damage. I have three cans of recently purchased(last 2 months)Tamiya spray paint. I shook them as hard as I could to get the mixing ball to slam into the bottom, after several minutes of torturing my arm, there was not the slightest dent in the bottoms at all. All I'm saying, is I don't think the mystery has been solved.

Hey Brian, grab a can of your spray paint, that doesn't have any dents in it, shake it as you normally would, and let us know if the dents show up in the bottom. Is it literally every can you use that this shows up?

 

Cheers,

Lance