extreme newb question.....

[jazzcornet]

first f all, i'd like to say thanks for looking at my thread. I am totally new to powdercoating but I understand how it works and the process associated with it. what I dont know is how to do it. I bought the caswell starter kit with the curing lamp and I'm hoping that will be sufficient for what im doing. I'm trying to coat a bike frame in a pastel yellow. I dont see any colors that caswell offers close to it, but i figured i could take the super yellow and mix some linen white with it. any tips or tricks?? I've prepped my piece very well. first i bead blasted it, then blasted with aluminum oxide, then 1000w sanding, then 2000wet sanding. i think im ready for it.

now the question is, how do i go about spraying my piece and curing it? specifically what steps do i take? any tips on hanging the frame and still ensure it's grounded? how far away should i be when i spray? do i need to heat it up before i spray it to prevent that nasty gas thing? what temperature and how long should i cure it? all these questions and much more. I have searched this entire forum for a basic how-to, but came up with nothing except the sticky for chrome coating (which I'll follow when I decide to start chroming stuff). Should I use some of that phosphate primer?

any info you can shed would be greatly appreciated here. I am kind of in a time crunch at the moment

edit: here's a pic of what i'm trying to do


except the wheels, chain guard, and sprocket will be in white linen while the rest of the body is in that pastel yellow color

[jtagger19]

i try and help as much as i can
there is a sticky on mixing colors take a look .
you don't need to wet sand the part after blasting
powder need something to grab on to the surface
for hanging the frame and curring with a lamp
you'll need to hang it horizontal to cover as much area as you can with the lamp
as lamps don't shot down ,you'll need to keep a contant eye for the part temp and cure
temp
you have to cure one side of the frame and then turn the lamp to the other side of the frame and cure it , curring with lamps take a very long time so be patient
hobby guns have a GND clip just attach it to the frame and it will be grounded .

now from my experience i have never been able to cure with lamps bacause of the time it takes and i have never been able to mix powders (you can always see spots of both colors) how ever there are people doing it , i just don't bother trying anymore.
i would advice to practice first on something small .

[jazzcornet]

thanks for your input. any idea on the specific temperatures and times for curing? what about the temp required before i spray it

[jtagger19]

cure temps are on the lables of the powders you buy
most powder cure at 350-380 for 20 minutes at part temp
part temp is when the part reaches 350 or the cure temp you start counting the 20 mins.

with hobby guns there is a rule that never fails , the 150 rule
coat the parts at 150 degress, it saves a lot of headaches.
but with a lamp that will be hard to do because the lamp only heats up the area in front of it .

[jazzcornet]

what happens if you over cure a part?

[PCT17522]

The color will change...usually begins to turn a yellow or tan. It will be hard to notice this with a yellow colored coating. In my experience, a slight over-curing doesn't really comproimise the performance of your coating much. I've never used a lamp.

[PCT17522]

jtagger19 is right about the sanding. You don't want your base metal to be too smooth. Adhesion is better if the powder has a texture to hold on to. You shouldn't have to pre-bake it. You usually only have to worry about outgassing with castings, not with steel tubing. As a general rule, you should hold the gun about 6 to 12 inches from the part when you're spraying, but that changes depending on what you're spraying. For spraying a bike frame the distance from the part shouldn't be that critical. Also, the thread about mixing colors is informative. I've done it occasionally, but usually i can see the color specs...sometimes it looks nice, but it depends what you're going for.

[jazzcornet]

thank you! so should i just take some sandpaper to the smooth metal to rough it up a bit?? or reblast it and clean it off? what about the prep, any tips? fyi, the bike frame is cast aluminum. shouldn't i have to heat it up a little to prevent outgassing?

[PCT17522]

Blasting will give you the best results, if re-blasting isn't too much of a problem. Sandpaper would work in a pinch. Since the frame is cast aluminum, you should outgas. Read up on some of the posts about that. A general rule is to heat the part up to 50 degrees hotter than what you will cure at and allow it to remain at that temperature for about 45 minutes or longer. I'm not sure how to achieve that with a lamp...as I've never used a lamp. Also, I have had mixed success with outgassing procedures in my experience. I would say- The more thorough you can be, the better chances you give yourself. Many people endorse the OGF additive.

[jazzcornet]

thanks again. i'll give it a shot and post my results