I am painting my model using Brodak dope, paint, clear and retarder. The only thing that is not from Brodak is the MEK that I used for thinner. Yesterday I shot several coats of approx. 10% retarder, 35% clear and the balance MEK thinner and got most of the wing and tail surfaces shiny red but - there were spots where the red was matt looking. I tried to spray it again this morning and all hell broke loose! Everything blushed and now looks like it was painted with dust. What am I doing wrong? What advice can you give me please?
Thanks
Joshua

Yep,  should have stayed with Brodak thinner.   

Weather...


W.

If you're bound and determined to save pennies on thinner, look into getting it from Wicks or Aircraft Spruce (Brodak dope is just relabeled Randolf's).

I mean -- I'm known for doing wacky things in the interest of saving money, but I at least use something that calls itself "lacquer thinner" in my dope.

All these points are well taken, however: how would you gentlemen explain the fact that I painted another plane with MEK as a thinner and had no problems at all?

 Pure luck.

You sure?  I'm not saying no -- it's just that when you look on the Randolph's website, Brodak is in their list of distributors along with everyone else.  I thought that Brodak's dope was just Randolphs packaged into small containers in specific colors.

Tim,
I am pretty darn certain it is different,, at least on some level I KNOW its different,, as in for one thing, it has a different viscocity than Randolphs does

Joshua,, with all due respect,, absolutly without a doubt,, using MEK to spray Dope is a bad idea, for many many reasons,, to list them all would take a series of articles,, ( oddly enough I happen to be writing just such articles,, and as such really dont want to rewrite them here)
Please, for your own sanity, use whats DESIGNED to be used with the product,, You dont put gasoline in your two stroke glow engines for a reason,, what you are doing with MEK is exactly the same process,

I couldn't agree more, Mark.  Also, MEK (in addition to being completely inappropriate for use as a dope thinner - simply being able to act as a solvent in dope doesn't make it a good thinner for application) has become extremely expensive so there is no reason to use it in place of the proper butyrate thinner.  I can't figure out why so many people insist on trying to find alternate (and for the most part unsuitable) solvents to use as thinner when the correct thinner is readily available.  And yeah, the price of butyrate thinner has gone way up in the past few months, along with the cost of all solvents - just bite the bullet & spring for the correct thinner and you won't be complaining about the "mysterious, bad, & unpredictable" results that you get when using MEK or Acetone or whatever for the thinner.

Trying to save a few dollars on thinner and shipping and maybe a couple of days waiting for the stuff to arrive doesn't mean much when you consider the hours of labor you have in your project up to the point of applying the finish.  This reminds me of the old saying (paraphrasing here): "There is never enough time (or money) to do a job right but there is always enough time (& money) to do it over."