Topic: MEK Solvent Rub Test

Does MEK Solvent Rub Test (normally used for checking proper curing)

holds good for Hybrid Structure powders. It fails after curing at 200

deg. for 10 -12 mins - What could be probable cause.

Travis Stirewalt

Re: MEK Solvent Rub Test

Can you give me a little more information. I will try to help you.

Is that 200 F or C?

Was the part cured for 10-12 minutes after reaching 200 degrees?

Are you referring to a polyester/epoxy blend?

I will do my best to help.

Travis Stirewalt, CSI, NASF
Senior Sales Manager, Eastern US
TIGER Drylac USA Powder Coatings


Re: MEK Solvent Rub Test

I am refering to Hybrid (Epoxy/Polyester) post dry blended Strcuture

powder. We keep object at 180° C for 15 mins (Maintain Temp of

180 for 15 mins). Also tell me exact procedure of test of MEK.

Travis Stirewalt

Re: MEK Solvent Rub Test

The actual SOLVENT RUB MEK TEST that is the industry standard can be obtained through the Powder Coating Institute Handbook. Book is a wealth of knowledge. It is quite a detailed test description that I would not want to list out here. You can access them online at

Now, for our method of onsite testing, I simply take a bottle of MEK and dip a q-tip into into it. I shake off the excess and then with one hand I hold the q-tip and without much pressure (as if I was writing with a felt tip pen) I go back and forth over a 1 inch area approx 5-10 times. What I look for is a dramatic lift of pigment to the q-tip or a dramatic drop in gloss. These can be indicators that the part is under cured.

That said, I want to make it clear that some pigments lift easier than others and some powders lose gloss easier with the solven rub. The only TRUE cure test by solvent rub that I rely on is when it is done under lab conditions with other testing as back-up.

I hope this helps.


Travis Stirewalt, CSI, NASF
Senior Sales Manager, Eastern US
TIGER Drylac USA Powder Coatings


Re: MEK Solvent Rub Test

Hi There,

May I ask you whitch kind of hemistry is able to fullfil and MEK rub test of a minimum of 200 cycles (back and forth)


Paul Fisher

Re: MEK Solvent Rub Test

Here is a list of things you'll need for your MEK Rub test (AKA ASTM D4752)

Cotton cheesecloth
32 oz. ball peen hammer
Methyl ethyl ketone (MEK)

Wrap 16 layers of cheesecloth around the ball end of the hammer and attach with a rubber band.

Saturate the cheesecloth in MEK and place on the panel to be tested.

Place the hammer handle in the palm of your hand and hold the handle parallel to the floor.

The length of each stroke is to approximately four inches.
Count a forward and backward stroke as one rub (a cycle).
Perform the rub pattern in the same location.
No additional weight should be added to the hammer.

Results are to be reported as a range of double rubs (cycles) required to initiate failure (where a few pinholes can be observed) to general coating failure. Ignore the two positions at the beginning and ending of the hammer stroke where the rub direction is reversed.

Yea OK I know there is no hammer in this pic - but I thought it was cool that I found something similar anyways.



Re: MEK Solvent Rub Test

May I suggest that a Craftsman Brand 32oz ball peen hammer be used?  Due to superior workmanship and quality, you will get more consistent results.**

**Note: more consistent results are in no way implied nor guaranteed.



-Dustin Gebhardt, CEF

Advanced Manufacturing/Finishing Engineer


Sanford, NC


Re: MEK Solvent Rub Test

A cure of 200 deg F [?] seems too short at 10 to 12 minutes. And I think that is shown to be true by the MEK rub failure.

I had a 9 minute gas fired indirect cure oven with H.B. Fuller #40 gloss [dead flat black] at 650 deg F for heavy wall tube and up to 1.25" dia mild steel black iron rod stock that was formed, coined, pierced, with some wire induction heated and double hot head hit, after being pulled to size, heat treated, straightened, cut off, racked, washed, rinsed, zinc phosphate, rinsed, seal coated, in an immersion?batch programmed hoist pretreatment basket line. About 1,800 to 2,000 pieces to a basket about of about 16' x 10' x? 12" expanded metal. The light grey zinc coating felt like a cat's tongue.

All pretreatment tanks flush to the floor in a pit and were hot and indirect steam heated with pipe, not steam coils. Baskets?were set on the floor to steam dry [so we had no dry-off oven] before being forked over the the load area of the 4"-#458 overhead chain 4" open trolley monorail conveyor where our prison labor at 75 cents and hour [The State made up the difference for mandated minimum wage] loaded and unloaded the conveyor running at 15 fpm. "Them boy's was busy." They loved to get out for the day.

The work would exit the oven shiny black and would finish curing to flat black during the cool down.

Yes we passed Ford Q-1, S.P.C. and 100 double wipes with MEK, the scratch and pull, the reverse anvil, the impact and the salt spray test just fine.

I pulled the trigger on the GEMA powder gun in our home built p-coat booth. This line did approximately 33,000 pieces a day on various work hanging racks. We burned our work hangers clean in a pan of diesel fuel at dusk. "Hard to see the flames, hard to see the smoke." It ain't legal but this got the job done.

My other two liquid lines, a 15 fpm, 280 deg round Randburg Loop with the old style large dia 10"? disc with the isolated liquid paint delivered via a gear pump to the bottom of disc. Maurer-Shmacker liquid paint in to a 15 minute oven. About 21 seconds on a #2 Zahn cup. One 55 gallon drum of paint cut with? fast solvent was equal to about 100 lbs powder recycled with virgin added when the fines became too fine and electrostatically dead.

The third line [same paint] was a two respirator outfit with two

HVLP manual spray guns each with an air actuated trigger. A home built affair to spray 100" long H-M rods vertically at 15 fpm with friction work hanger rotation of 1-1/2 turns per foot of conveyor.? I built this oven on top of the randsburg line oven and used exhaust from the oven below to heat and supplemented the upper oven heat with a small packaged burner of 400,000 or 800,000 btu and a double inlet, double outlet, non-over loading fwd curve recirculating fan.

This third oven was also sized for 33,000 pieces per 10 hour day, 60 hours a week. So nearly 1,000,000 pieces a day painted. We also hot dipped oil over the same zinc pretreatment.

And our girls still used our original slow manual dip line for those short run? in-between-batches.


Last edited by skip (Today - 10:55 PM)

Last edited by skip (02/01/2010 - 05:24 AM)

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Re: MEK Solvent Rub Test

May I ask, normally after application of inorganic zinc rich silicate, how to have to wait before MEK rub test can proceed with satisfactory result?