new lesson learned - don't mix paints

[BarryK]

well, I was painting an air cleaner housing yesterday.
It was is decent shape so I didn't glass bead it first to strip all the old paint off but I cleaned it well, used a 3M scotchbrite pad to rough up the surface of the existing paint, and to clean up a couple misc small rust spots than painted it with a pint of Rustoleum gloss black I had with a small foam brush. Overall it looked OK except for some minor brushstroke marks from the brush so I wasn't happy about it. After it dried I lightly went over it again with the 3M Scotchbrite pad to flatten down the brushstroke marks and figured I'd hit it with some Krylon gloss black paint I had in a rattle can.

BIG mistake!

The instant the Krylon rattle can paint hit the surface of the housing it immediately bubbled up all the paint that was there like I had hit it with lacquer thinner or paint stripper!

Now I get to sand off all the paint completely now and start from scratch.

I know the Rustoleum paint is an enamel but the Krylon can didn't say what it was (not that I could find on the label anyway) but they way the two paints didn't play well together I'll have to assume it was probably a lacquer paint.

so, lesson learned here......... paint is like alcohol. DON'T mix two types if you are indulging in either activity. :eek
If you don't know for SURE what both types of paints are, play it safe and don't mix them.
By trying to shortcut myself on this part i've ended up doing nothing but create more work for myself in the long run.


Note to 67Heaven: Bob, I know this pertained to a part from my other car, but I posted it in here and i'm hoping you will let it stay because it's an issue that isn't specific for any particular generation but rather a lesson learned about painting parts that may benefit other people like myself that are new to doing things on their own and could just as easily happen while someone works on their C1/C2 cars.

 

[67HEAVEN]

Note to 67Heaven: Bob, I know this pertained to a part from my other car, but I posted it in here and i'm hoping you will let it stay because it's an issue that isn't specific for any particular generation but rather a lesson learned about painting parts that may benefit other people like myself that are new to doing things on their own and could just as easily happen while someone works on their C1/C2 cars.

You getting gun-shy, Barry? otfl

Of course it will stay. It's applicable to all generations.

 

[BarryK]

yep, I guess I am Bob

thanks, that was my feelings also hence the reason for the post

 

[Kid_Again]

Yup, good lesson. I believe Krylon is an oil-based paint very similar to Rustoleum - paint thinner is the recommended solvent for both as far as I know. Standard Krylon doesn't smell like a lacquer-based paint to me and it dries slowly, just like Rustoleum.

Always stay within a manufacturer's brand or use generic equivalents which are known to be compatible.

 

[BarryK]

hi Kid
the rustoleum was very slow drying but the Krylon dries very quickly, at least this stuff I have does, so i'm guessing they are two different types.

i DID know I shouldn't mix types of paint but wasn't sure what the Krylon was and the Rustoleum was already dry so I figured I'd give it a try. In the future, unless I know FOR SURE what each type is and that's it compatible I won't be making this mistake again.

 

[Z28Canuck]

There are so many factors other than just the paint itself. You guys are smart to post these problems so others can avoid them too. Bob (67Heaven), please add your comments but remember how many times you had to remove a coat of paint off of parts because of the unexpected "Reactions" you got on different surface materials (Plastics vs metal). Some bubbled or blistered immediately, some reacted to the material being painted or the paints themselves reacting weird, temperature effects etc. The dash components were finicky, some took the first spray and others had to be repainted 2 or 3 times. Some part preparation varied before priming, not just cleaning with thinners etc but actual blasting or scuffing rough otherwise the primer won't take at all. Mixing brands was didn't give the best results sometimes and there was even one gloss paint that was still wet 3 days later and you had to strip that off. That Krylon is wonderful stuff to work with though. So much to know! My hat goes off to you guys doing your own work and learning through trial and error, you have quite the patience! You have so much knowledge and experience to share! Good luck with your results.

 

[BarryK]

My hat goes off to you guys doing your own work and learning through trial and error, you have quite the patience!

patience??!!
that's something I DON'T have!

 

[Kid_Again]

BarryK:

'Fraid not. I checked the MSDS (Material Safety Data Sheets) for both formulations and there are similarities/differences.

One can use the same "thinner" for either. However, Krylon contains more acetone which has a lower boiling point than the solvents (Stoddard Solvents) used in Rustoleum. A lower boiling point means that the flash-off is more rapid. So, if you applied a base of Krylon and let it flash/dry (probably overnight), then you clearly can overcoat it with Rustoleum. I've done that so that's why I didn't understand your post. You can't easily put Krylon on top of Rustoleum unless you let it dry for a long time (or oven cure it) and use a very thin coat. Otherwise, the acetone flashing-off will lift the Rustoleum.

I guess you're right about drying times, now that I see the MSDS. For rattle cans, so much paint is applied that it is impossible to control the flow so the Krylon may skin over earlier than Rustoleum but it's not "dry". I gave up rattle cans quite a while ago. A $15 air brush from Harbor Freight does a hell of a lot better job than a rattle can and color/texture are infinitely variable to suit your taste.

 

[67HEAVEN]

A $15 air brush from Harbor Freight does a hell of a lot better job than a rattle can and color/texture are infinitely variable to suit your taste.

That is certainly the way I'm going on the next project.

 

[BarryK]

Kid

that second senario you mentioned is exactly what I did - I applied the Rustoleum THAN I applied the Krylon. The Rustoleum must not have been completely dry yet although it was to the touch.
It bubbled up the instant the Krylon hit the rustoleun and that was after a single second of spraying so only a very, very, very light mist of the krylon hit the unit.

If I continue working on cars like this, I'm seriously considering the investment when I can afford it in a nice air compressor. That will allow me to get my own glass bead cabinet but also some spray guns. I won't paint a whole car of course but for all these dozens of little parts I can spray and not worry about rattle cans anymore. Just on this project SO FAR i've spend almost $300 on various paints. At least $200 of that has been on rattle cans and most of that is on basic semi-gloss black.
I bet a gallon of semi-gloss black thinned out and sprayed would end up being a big savings over all those d*mn rattle cans!

 

[wishuwerehere82]

From my experience with Krylon paints, they are very aggressive on most surfaces. If you paint styrofoam with Krylon, it will dissolve before your eyes.
I think it is geared to a wood or metal application, and never should be used on plastics. Plus it stinks from the solvents they use.

 

[Viet Nam Vett]

Bob (67Heaven), please add your comments but remember how many times you had to remove a coat of paint off of parts because of the unexpected "Reactions" you got on different surface materials (Plastics vs metal).

Yeah.. and tell us how many times you had to beat your headers with a hammer to make them fit....or how many times did you have to grind on your splatter shield to clear your high beam switch...and so on..

 

[67HEAVEN]

Yeah.. and tell us how many times you had to beat your headers with a hammer to make them fit....or how many times did you have to grind on your splatter shield to clear your high beam switch...and so on..

The solution always seemed to involve a bigger hammer.

 

[Z28Canuck]

Yeah.. and tell us how many times you had to beat your headers with a hammer to make them fit....or how many times did you have to grind on your splatter shield to clear your high beam switch...and so on..

Yeh! And how many times has he told me not to give you an opening like this to jump in and how many times has he told me "Mark doesn't miss a thing!". Thanks a lot!!! How many times indeed!otfl

 

[firstgear]

patience!!

What is that??????????????

 

[firstgear]

The solution always seemed to involve a bigger hammer.

and that works for me as well......sometimes a much bigger screwdriver that gives more leverage also works well.....

 

[Viet Nam Vett]

Yeh! And how many times has he told me not to give you an opening like this to jump in and how many times has he told me "Mark doesn't miss a thing!". Thanks a lot!!! How many times indeed!otfl

Couldn't help myself..When I read the post I got a chubby....

 

[BarryK]

When I read the post I got a chubby....

that's REALLY more info than I ever needed to know..........

 

[John Mcgraw]

Barry,

There is another little lesson that you will learn with Krylon or Rustolemum either one. When you read the can, it says to recoat within 1 hour or wait at least 48 hours. Guess what? They mean it!
I have tried to recoat after only 1 day drying time, and have had it just curdle up all over!
Most times now, I will just mix up some single-stage black urethane in the detail gun and use it instead.



Regards, John McGraw

 

[BarryK]

John
you mean this stuff has instructions? who reads those?

yep, I'll be sure to follow all instructions from now on!
The rustoleum can says you can recoat when fully dry - about 24 hours, but it felt dry to the touch so I was too impateint to wait I guess.

I should no better since almost everytime I DON'T follw the instructions on something I screw it up but I guess that's what happens from being impatient by nature.