Decanting aerosol paint into a small container for touch ups - Why, Problem, Method

Discussion in 'Hints & Tips' started by Jim Freight, Apr 24, 2021.

  1. Jim Freight

    Jim Freight Full Member

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    Why do it?

    The painting of my cement works buildings has been carried out mainly with aerosol paints, Expo primers being used as primers and top coats for my corrugated panels, handrails and concrete walls.

    The texture as sprayed is good to me for buildings subject to a dusty atmosphere, even using the white primer as a dusting for cement dust, and silver dusting to give a hint of some galvanising left on the corrugated sheeting, however I digress from my topic.

    Girder work on my buildings is generally made from Plastruct sections, with some leftover Walthers parts and Knightwing International sections. Some assemblies can be sprayed after assembly but in general I spray up a number of strips straight from the packet (after washing to remove potential mould release agent film) then cut to length.

    Cut ends and removed paint for gluing, (never worth trying to glue through paint in my experience) leaves bright white exposed ends (Plastruct) which needs touching up, I never seem to have the right grey for touching up.

    The other day I had a real Homer moment spraying plastic primer paint into a small container, messily, it was plastic, doh!

    Engaging my wrinkly brain cells and finding a small glass honey jar with lid kept from a cafe visit back in 2019, remember that pleasure, I tried again.

    The Problem

    As most will know you cannot spray into a corner or a small space because, and especially with an aerosol can, the force of the gas jet blasts it straight back out before it sticks. The following approach got most of the paint into the jar and it's quite simple.

    The Method

    First I wrap the jar in masking tape because the outside will still receive some and keeps the cap thread clean. Then with gloves on I sprayed the paint through a 12mm bore, 60mm long piece of PTFE (Teflon) tubing. Position one end of the tube against the can nozzle and the other end just above the neck of the jar, pointing into it.

    The paint loses velocity in the tube and what hits the bore runs into the jar, yes, some will still escape by blowing back but much less than just spraying directly into the jar.

    The dimensions of the tube are just what I had to hand and being PTFE cleaned easily, longer may be better, so next time you want a bit of aerosol paint in the assembly area for touch up why not try it, it's also easier if the can is low on gas. :scratchchin:
     
    Last edited: Apr 25, 2021
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  2. Jim Freight

    Jim Freight Full Member

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    As a postscript to my Homer moment above.

    I tried putting some DeLuxe Materials Brush Magic into the plastic pot I had put some plastic primer into yesterday as an experiment.

    It initially started to lift the primer which hadn't cured, so I left it overnight on a metal tray, with only a small amount present, glad I did.

    This morning I found the bottom of the pot was a grey gooey mess stuck to the tray as I lifted the pot. :facepalm:

    Looks like Brush Magic is good at dissolving solid plastic as well as acrylic residues on brushes, could this be useful for making a plastic filler from sprues to match the plastic you are filling, admittedly the plastic pot may have been acrylic?

    I have found that white Expo primer has little covering power compared to the greys and black, in fact it amplifies the whiteness of filler against the plastic, so with my concrete structures I second coat with Amsterdam artists aerosol paint in either Warm Grey or Titanium Buff Deep and then 3rd coat with "The Army Painter" brand white which is a denser primer to tone back towards white. The two 2nd coat colours give quite a subtle but noticeably different concrete tones when placed next to each other.

    I have seen other posts about using dissolved sprues as fillers, I think I will give this a try, to see if it dissolves polystyrene.

    Jim :scratchchin:
     
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