During my Star Trek Captain’s Chair Restoration; I found myself wanting to paint match some powdercoat to the existing color of the plastic side panels on the chair.
Please note: Readers are responsible for their own sacrifices to the blood god. Safety first– if you injure yourself implementation of this guide; expect we’ll take no responsibilities. Commentors at Hack-A-Day have indicated that MEK is flammable (as does the label) – so please take the appropriate precautions.
- Glass or metal mixing vessels (an airbursh jar works well)
- Methyl Ethyl Ketone (MEK)
- A set of Powder Coat colors to mix the colors
- A paint sprayer… HLVP, Gravity fed, or Airbrush
- A Panatone(r) Color Cue(TM) or similar device (optional).
Powdercoat using this method appears to be every bit as robust and scratch resistant as normal powdercoat. The author has seen no negative material properties from using MEK instead of a powder coating gun (electrostatic).
For the beginner; Harbor Freight may be a good stop for the primary colors – they usually carry White, Red, Black, and Yellow. Unsure about Green and blue. I also use HF touch up paint guns, HLVP, and airburshes to apply my MEK solutions. Caswell plating is also a good source for many a color. MEK can be purchase in the paint area of most home improvement stores – I buy mine at Lowes.
While the used of the color cue is a good starting place – it isn’t required; you can manually mix colors by eye until you get it right… as you’ll see; I used the color cue to get initial color suggestions (or base colors if you will); then added pure white to bring the color closer to that of the plastics.
I started by measuring the sRGB color of a retr0bright-ed side panel using my Pantone(r) Color Cue(tm) device which I got off of Ebay several months ago and it came up with r246 g230 b198. I pulled these values into the RGB to commercial Tints page at EasyRGB.com. This gave the closest RAL numbers which to match to. I then went to google and did a search for RAL-1013 powder coat which returned a result to powder365.com for their ” Oyster White ” powder coat. Then using the HTML code #F6E6C6
I also used the RGB browser to convert to “RAL Classic” listed six colors with % equivalent matches to my original scanned color.
|RAL 1015 Light ivory
|RAL 1013 Oyster white
|RAL 9001 Cream
|RAL 1014 Ivory
|RAL 9010 Pure white
|RAL 9002 Grey white
I also did searches for other color combinations and ended up selected the following three colors from powder365.
1lb x RAL 1013 OYSTER WHITE (340/10MIN)
1lb x RAL 7035 LIGHT GREY (340F/10MIN)
1lb x TEXTURED ALMOND (380F/20MIN)
The idea was to put each color on a test piece to see how close to match and pick one which looked the best.
During my research; I also came across a post to caswellplating.com’s forums which talked about mixing the powder with MEK to “melt” the powder into liquid form for the purpose of correct a blemish on an existing powder coated part. This sparked an idea – why not use the MEK to mix powders together to get an even better color match. I have a quart of MEK in the garage – so it was time to experiment.
I knew the grey wouldn’t really match – it was too grey; so I used MEK to melt it and used a hobby paint brush to apply it to the scrap piece. I then used regular power coating equipment to lay down the almond and oyster for comparison. For the last color; I decided to mix some grey, 2 TSP of pure white (purchased at Harbor Freight), 2.5 TSP of oyster together with a generous helping of MEK to turn the powder to a grey-white “milky” formulation. I applied this with a paint gun:
From Left to Right: RAL-7035+MEK (under thumb), Almond, RAL 1013, and MEKMix
The Right most Grey is “uncured” IE that is how it goes on being applied with a paint gun. Looks fully cured already. and the lines were created with standard blue painters tape. Be-aware – that MEK powder liquid acts just like any paint… it will dry on everything. so protect from over-spray and wear gloves. Unlike the powder form of powdercoat; it can’t just be wiped off of surfaces.
The cool thing about MEK powder-liquid is reportedly it can be used on Plastics and Wood… using low cure temperatures. Ideal for paint matching on cases or other non-metal projects.
With MEK; it looks like one could color match any color given enough patience and primary colors to choose from. Now with this knowledge; it was time to do some actual paint mixing for the purpose of matching the side panels.
As you can see the control panels are in need of some TLC. As typical for this machine; the Fire control panel label has begun to deteriorate and is peeling away from the metal. So I removed the label manually – then used Xytol to soak the piece for about 5minutes to soften the label adhesive so it could be removed with a plastic paint scraper. I continued cleaning/soaking the bracket until all the label residue was removed:
I then proceeded to powdercoat the underside to the bracket with the Oyster White Powder coat.
For the front; I did an MEK liquid mix as discussed previously. This time I started with a base of 2.5 TSP of Oyster White powder coat and added 1.5TSP of pure white Powder coat. I then mixed with approx 1/4cup of MEK to form a 2% milk-like consistency. I color checked the mixture by using a small paint brush to apply the color to the underside of on of my plastic pieces. This mixture was nearly a spot on match to the plastic so I decided to go with it. I loaded the MEK liquid powder coat to my touch up paint gun
Once it is dry to the touch / safe to handle (usually about 20minutes); I place the bracket in my powder coat toaster oven for initial curing. during my test runs; I noticed that if you attempt a full cure (400F / 20minutes) with the MEK solution still wet – it will “Boil” the paint leaving rough spots. So I put the piece in the oven at 150F / Warming setting for 10minutes to allow the MEK to evaporate. Then I crank the piece up to 400F for 20minutes for the final cure.
Incidentally; The Color Cue captured an sRGB255 value of 237, 225, 192 for the color matched piece (color code EDE1C0).
Please check out the remainder of the worklog – where I used an airbrush and a laser cutter to create powdercoated labels on the pieces:
1982 Sega Star Trek Captains’ Chair Restoration