bobbotron

So yesterday I finally got around to putting the base layer of paint on an aluminum frame I've been meaning to paint. I'm planning on putting on a second layer with some some decals, taking the decals off and then clear coating the entire thing. Now, I was hoping to ride the bike at this Friday's CM, but the paint can I used said you're supposed to wait a week after putting the first layer of paint before putting more paint on it, which means I should wait until next Sunday before putting more paint on it. It's definitely a little tacky still, I was thinking of doing the second paint layer tomorrow, should I wait, or should that be alright?

San Rensho 

Don't understand what you're doing. Why would you put decals on and then take them off to clear coat.

What kind of paint are you using that is still tacky after a day. Paint may be soft the day after, but I've never heard of paint being tcky the day after.

bobbotron

Sorry, tacky isn't really the correct word for it. It is just a little soft now. I was using glossy rust paint.

I'm doing the reverse of a stencil. You make a shape and stick it to the frame. Put a second (different coloured) coat of paint on. When you peal it off afterwords the first coat of paint will be there in the form of the reverse stencil.

The final product should come out something like this (although I will be using a different pattern.)
https://community.livejournal.com/bik...s/2130373.html

mtbikerinpa

The term is dry to touch. There is a window with paints when it can be recoated and when it can't. This window is caused by the solvent 'drying' process. If it is recoated after the initial start of this period, there is risk of the top coat trapping the evaporating solvents in and bubbling. When coated before the start of this period, the top coat and sub coats fuse solventwise as one.
One thing to consider is the directions are based on 70 deg and low humidity with high airflow. In a colder setting it can take a lot longer, but if heat can be added (as much as 350 is alright) it can accelerate the process to mere hours. That is how production lines can do it so fast. Not to mention it makes the enamel a ton harder to scratch.

bluehair

The aviation mechanic is "right on". Painting a bike is a ton of work; you do not want to have to do it over again. Follow the directions; don't guess; don't push it.

McDave

Ah, sounds like you're using Rust-oleum. That stuff takes forever to dry. So yeah, you'll have to wait the full week unless you can heat the parts as others have suggested, especially since the next coat is a different color.

For future reference (it's too late for this project unless you strip back to bare frame), Rust-oleum now makes a Metallic paint that dries much faster and looks fantastic. You start with their Stops Rust primer, follow immediately with a couple light coats of the Metallic, allow it to dry completely for 30 minutes (10 minutes is 'to the touch'), then apply their Clear Coat. In your case of a second different colored coat with stencils, I would wait until at least until the next day so the stencil doesn't mess up the first coat as it may still be a bit soft.

Considering all the coats that need to be applied in rapid succesion for proper bonding (when using the Metallic system), I would wait at least a week before assembling the bike, and even then don't strap anything to the frame for at least a month as it will likely leave a mark. I've done this with a kite buggy and the results are really impressive.

bobbotron

Ah, thanks for the info! I will check when I get home exactly what kind of paint I used. Yeah, I wish I could have done it all in rapid succession, it wasn't possible with the way I was planning on stenciling it. The weather has turned wet here in Ottawa, so from the looks of it I'm going to have to wait a good week before the humidity and rain subsides. (Thankfully it's pretty darn dry in my apartment where the frame is drying.)

McDave

Bummer about the rain and I'm assuming cool weather. Even indoors it's going to take forever to dry and getting a good clear finish will be tough. Note: I edited my last post as you were writing yours to clarify it's going to take a week to a month to fully dry with the *Metallic System*. I did mine last summer when it was sunny and the temps here were in the low 100s (F). Using the slow dry paint that you're using combined with the different colors and poor weather conditions, it's probably going to take at least a couple months to fully complete your project satisfactorily.

bobbotron

Ah, it's not all bad. Normally it's quite warm up here (mid 20's, low 30's) we've just got an ugly spell coming through.

I'm not toooo worried if it doesn't come out perfectly. The frame is part of a fun bike project I'm building up for kicks, not a really expensive frame I will be heart broken if it doesn't turn out perfectly.

Heating the paint is an interesting option, could you do that with a heat gun?

McDave

I doubt that would work. Heating just the paint would make it more brittle and you would likely lose the bond with the cooler metal. Maybe someone here with more paint experience could answer this better. I'm just a lowly wrench (not to be confused with wench).

bobbotron

Yeah, I have my doubts too, but you never know. I am hoping mtbikerinpa gives his two cents!

mtbikerinpa

Somebody summoned

The main thing with the heat curing is you have to make sure it can be consistent. If one zone gets hotter than another it can discolor, and if it heats too fast it can flake. Keep in mind, heat guns are also stripping tools when used with a little more gusto. If no heat source is available(hot sunlight in a saran-wrapped transparent box works) then focus on warm airflow. Think evaporation.

bobbotron

Thanks for the reply, it was really helpful!

55/Rad

Painting patience?

Uggghhhh...

55/Rad