Jump to content
Model Cars Magazine Forum
Sign in to follow this  
Pete J.

Inside of a Tamiya rattle can(photo)

Recommended Posts

I was decanting Tamiya primer yesterday and thought this would be of interest to some of you.  This is what you see if you open up a rattle can of paint and it makes it easier to explain a couple  of tips I give out from time to time.  In this picture you see two main items, the dip tube and the glass mixing marbles.  You can also clearly see the domed bottom.  First thing you may notice is that the dip tube does not go all the way to the bottom.  There fore you will never get all the paint out of the can by spraying it.  You are always going to leave some wasted paint behind.  This is one of the main reasons I decant the paint to begin with.  I am thrifty and want to use all the product I paid for. 

Second tip is to store the can upside down.  As most of you know, if paint sits for a while, it separates into components  and settles out, with the solids going to the bottom and the solvents and binders going to the top.  If the can sits upright a couple of things happen.  First is that the dip tube opening is down in the thicker solids and some of them will migrate into the tube. No matter how much you shake the can they will still be in there.  Then with the first bit of spraying you will get a thick blob out.  By storing the cans upside down the dip tube in not sitting in the solids and you avoid that.  It is also possible that the solids may block the tube and you will have an unusable can.  The second thing to notice is that the dip tube location interferes with the circulation of the mixing marbles.  By storing it upside down all the paint, solids and marbles will be in the rounder top part of the can and mixing by swirling the can will be much smoother and you are less likely to get more propellant mixed into the paint. I hope this helps some of you.

Tamiya can.jpg

Share this post


Link to post
Share on other sites

      Yes, those are very nice marbles that they use.

Only the best put into those cans!!  LOL!!

 

      David S.

Share this post


Link to post
Share on other sites

Very interesting.

Question though. I may not be understanding exactly how decanting works, but I didn't think you could get all of the paint out even doing that? I thought it was just a way to "convert" from the can to an airbrush?

Thanks,

Russ

Share this post


Link to post
Share on other sites

Russ, decanting can be spraying the paint through a straw or other device.  There are other ways to get it out and I am sure someone will gladly explain them. 

My way is a little different and I think much safer but you need someone who can do some machine work.  I made a tool that works like a saddle valve.  With that tool I can safely punch a small hole near the top of the can and slowly release the propellant.    After depressurizing the can in this fashion, I let the can sit over night to let the paint off gas all the propellant.  When that is done,  I move the tool down to the bottom and punch another hole as close to the bottom seam as possible.  I then use that hole to pour all the contents into the paint bottle I am going to store it in. After that I use a plastic pipette to add some thinner to the can and hold my fingers over the holes and shake it to get the last of the paint out. 

The large square hole you see in the can was done after I had completed the process.  I open the can this way so I can save the glass balls and add them to the decanted paint to aid in mixing

Share this post


Link to post
Share on other sites

Thanks.

Yep, I have only seen the through the straw method before.

the kid left in me (I'm 57) wants the marbles from the cans. :D

Russ

Share this post


Link to post
Share on other sites

I use one of those ratcheting clamps. Holding the can UPSIDE DOWN I clamp on the tip and it starts to spew propellant. I hang this in a convenient place(my carport) and let it gas out. When it is completely done I remove the clamp and shake the can. Laying a rag over the top I rip the top off with a good pair of sidecutters. I can then add a little thinner and swirl the can around and dump the paint into a jar. 

I worked at an aerosol valve manufacturer and this task I 've done 100's of time. 

Your results may be different.:o

Share this post


Link to post
Share on other sites

Mike,

So you are the reason for all the "no burn" days here. :D

Seriously, though, where are you ripping the top off at? The smaller part around the nozzle, or are you talking about where the top meets the sides?

Thanks,

Russ

Share this post


Link to post
Share on other sites

I've never heard of storing spray cans upside down, but your explanation makes sense. Any other of you guys do this?

Share this post


Link to post
Share on other sites

I've never heard of storing spray cans upside down, but your explanation makes sense. Any other of you guys do this?

I've been using spray cans for MANY years and never stored them upside down. I don't recall having any problems by storing them right side up. Besides all the stores stock all of their spray cans right side up also.

Share this post


Link to post
Share on other sites

I've never heard of storing spray cans upside down, but your explanation makes sense. Any other of you guys do this?

Yup -me. Some cans sit on shelves for years before you buy them...

Share this post


Link to post
Share on other sites

Russ, The smaller part where the tip goes  in. Look closely and you'll see where the valve is pressed into the can.

Mike

Share this post


Link to post
Share on other sites

Thanks for the clarification Mike.

Will have to try that if I ever get that advanced. I've got a booth and a decent airbrush, and either a model size compressor or I can use the garage one. But it is still quicker and easier for me to just use the cans.

Russ

Share this post


Link to post
Share on other sites

I agree with the basic use of the rattle cans.  I use them frequently, but there are times when only an airbrush will do or there is another reason to decant the paint.  This was such a case.  I generally just spray primer from the can and then dump the little remaining at the end of the can into a bottle to save it.  However, this time I needed to tint the primer blue.  I won't go into the reasons here as that is another thread but as far as I know there isn't any way to tint paint still in the can.  I don't suggest that there is a "right" way and a "wrong" way.  I do the things I do because it works for me.  I always like to hear other options because I have discarded a lot of the ways I use to do it, because someone had a better idea.  In the battle of rattle can v airbrush I would say this.  An airbrush can do anything a rattle can is able to do, but a rattle can can't do everything a airbrush can.

Share this post


Link to post
Share on other sites

Pete, I love the first pic to show the insides of a can, but they make jars too.  Seems like you go through a lot of trouble to open a spray can up when you could just get a jar of paint and thin it down for your airbrush at a fraction of the cost of a can of spray paint.  Then you could mix colors and tint all you like, too.   So why take the risk of opening spray cans ?    Just one little slip and you could have a red room at the very least.  They can be quite dangerous to open by drilling holes in them.

Share this post


Link to post
Share on other sites

Tamiya Jar paint is nothing like the paint in the TS-series spray cans.  Jars contain their "water-based" (mostly alcohol-based) acrylic paints, while the spray cans contain much hotter synthetic lacquers.

Share this post


Link to post
Share on other sites

Yup, that is the reason.  Tamiya paints are synthetic lacquers and I won't even go into how those are much better paints for spraying through an airbrush.  Yes, I use to be able to get lacquers down at my local automotive paint store and I still have some quarts left that will last me the rest of my life.  Automotive lacquers thin down at a rate of 4 or 6 to one thinner to paint.  Unfortunately, here is the Peoples Republic of California, you can not buy either auto grade lacquer or even lacquer thinner any more and it has been a long time since they ban it.  You would not believe the goat rope I went through to get a gallon of the real deal thinner and the darned stuff is made just a 10 minute drive from here.  I had to order it shipped to a friend out of state and they turned it around and shipped it back to me.  So now I have a couple of years of thinner. 

At any rate, rattle cans are the only source here and that requires decanting. 

Share this post


Link to post
Share on other sites

Russ, decanting can be spraying the paint through a straw or other device.  There are other ways to get it out and I am sure someone will gladly explain them. 

My way is a little different and I think much safer but you need someone who can do some machine work.  I made a tool that works like a saddle valve.  With that tool I can safely punch a small hole near the top of the can and slowly release the propellant.    After depressurizing the can in this fashion, I let the can sit over night to let the paint off gas all the propellant.  When that is done,  I move the tool down to the bottom and punch another hole as close to the bottom seam as possible.  I then use that hole to pour all the contents into the paint bottle I am going to store it in. After that I use a plastic pipette to add some thinner to the can and hold my fingers over the holes and shake it to get the last of the paint out. 

The large square hole you see in the can was done after I had completed the process.  I open the can this way so I can save the glass balls and add them to the decanted paint to aid in mixing

I'll probably catch some flak over this (it won't be the first time), but you can buy a saddle valve/clamp combo at your local hardware store. Look/ask for the valve that allows you to connect the ice-maker on your refrigerator (or a humidifier) to a water line.

It allows you to punch a hole, then turn the valve on/off to decant the paint.

Share this post


Link to post
Share on other sites

I've never heard of storing spray cans upside down, but your explanation makes sense. Any other of you guys do this?

Nope, in all my 57 years of using hobby rattle can spray paint on models, I have NEVER felt the need to store spray cans upside down.  As for the heavier solids of the paint settling into the bottom end of the spray delivery tube--RULE OF THUMB:  ALWAYS shake the can vigorously before even touching the spray nozzle--problem solved (again, based on experience dating all the way back to 1959, and the first cans of model spray paint from Pactra.

Art

Share this post


Link to post
Share on other sites

I've never stored spray cans upside down, though the idea does make sense.  Before doing that though, I'd give them a really good shake.  You don't know how long the can has been right side up.  If it has settled prior to your purchasing it, turning it over without shaking will put the settled solids at the "top" with the solvent at the "bottom".

Usually, I give the can a vigorous shaking a day or two before using it, with the as-specified-on-the-can one-minute shake the day it is used.  You should be able to roll the agitator ball/marble/whatever around the bottom of the can.  If you can't do that, there are probably settled solids at the bottom preventing that.  This goes double with primers, especially automotive touch-ups.  They're probably putting more solvent and fewer solids into those lately.  I want to get as much as possible out of the can, and not be blasting solvent-heavy primer onto anything.

Share this post


Link to post
Share on other sites

Usually, I give the can a vigorous shaking a day or two before using it, with the as-specified-on-the-can one-minute shake the day it is used.  You should be able to roll the agitator ball/marble/whatever around the bottom of the can.

Just don't shake it TOO hard!  Rememeber this thread? :D

bottm.Jjpg.thumb.JPG.f2ce72ae1a4f5e95db4

Share this post


Link to post
Share on other sites

I've never heard of storing spray cans upside down, but your explanation makes sense. Any other of you guys do this?

I do. I got this idea from my late father, who always stored spray cans upside down.

Share this post


Link to post
Share on other sites

Russ, decanting can be spraying the paint through a straw or other device.  There are other ways to get it out and I am sure someone will gladly explain them. 

My way is a little different and I think much safer but you need someone who can do some machine work.  I made a tool that works like a saddle valve.  With that tool I can safely punch a small hole near the top of the can and slowly release the propellant.    After depressurizing the can in this fashion, I let the can sit over night to let the paint off gas all the propellant.  When that is done,  I move the tool down to the bottom and punch another hole as close to the bottom seam as possible.  I then use that hole to pour all the contents into the paint bottle I am going to store it in. After that I use a plastic pipette to add some thinner to the can and hold my fingers over the holes and shake it to get the last of the paint out. 

The large square hole you see in the can was done after I had completed the process.  I open the can this way so I can save the glass balls and add them to the decanted paint to aid in mixing

I figured out your saddle valve device Pete. I machined the main body from a block of Teflon. Then bored a hole in the middle the size of a spray can , then split it in half and drilled and taped two holes for the allen head screws and the a third hole for the thumb screw to pierce the can. Works like a charm. 

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

×
×
  • Create New...