So, it seems vinyl dye is not completely idiot-proof. I was painting a bay cover yesterday. Now, normally, the dyed surface dries to a semi gloss. This time, there is this completely flat area right in the middle--you can see it in the picture. By this point, there are some 5 layers of dye on that thing, and every single one dries in the same pattern. Any ideas what's going on?

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The only times I've had any trouble out of vinyl dye has been humidity or temperature related myself.

If the weather was cold and/or damp I've had some issues with blotches in the finish somewhat like yours, but not quite as large.

[Edit for below] Like already said no primer is needed on the plastic.
I've also used dye on both sanded and unsanded parts without seeing an advantage either way really. (I've only sanded when the part had a logo or something applied which was slightly raised, like cd drive bezel).

Curved piece, could be running, try painting it on its side or from underneath or something....

did you do any prepping at all.

you might wanna use a little primer to get the plastic to have an even undercoat.

I don't mean to get off topic at all here but with vinyl dye you paint it on right?

Quote: Originally Posted by Zer0s did you do any prepping at all.

Only prep work was cleaning it with some detergent.

(BTW, you don't use primer underneath vinyl dye.)

you spray it like most other paints used by modders....

and correct me if I'm wrong here but you dont primer your area to be painted with Vinyl Dye.. you simply clean it as its meant to soak into the platic and the purpose of primer is to etch/seal the surface....

I persoanly would think you would sand it down even if it's just lightly with 320 sand paper just my $0.02 though X-/

I have had alot of experience with vinyl dye. Here are the basics:

1. The only prep needed is to scrub with a green scrubby and dishsoap. You may want to wipe with a tack cloth immediately before spraying.

2. Vinyl dye is not a paint. As the name would suggest, it is a dye. It soaks into the plastic and changes the colour, it doesn't sit atop the plastic like paint. Therefore, there is no sanding required. If you take a beige driveand vinyl dye it black (without sanding), it will look like you bought the black version of the drive.
If you sand the drive flat first, you will loose the "pebbling" that almost all commercial plastics have.

3. You do not need to, nor should you, prime a piece that is to be vinyl dyed. The primer clogs the microscopic pores that the dye is meant to soak into, effectively "sealing" the piece and preventing the dye from working properly. Similarily, do not try to vinyl dye a piece that has been previously painted.

Judging by your picture, and the fact that you can see dye pooled in runs along the side of the piece ........ you are putting your dye on way to thick.

Hold the rattle can about 6 inches away from the work. Start spraying off to the left of the piece, and SWIFTLY move across the piece. Stop spraying after you clear the piece on the right hand side.

Each coat should be very thin, no more than three swift passes. If you are painting beige to black, your piece should still look beige after the first coat, and still somewhat beige after the third coat. What is am trying to say is ........ you want really, really thin coats.

After the first coat, wait 5-10 minutes, and then apply coat two. After 5 or so coats you will have a nice uniform piece (it took seven coats to make a black keyboard yellow). Let stand a few hours and you are done. Do not handle during the standing time, as the dye chemically reacts with the plastic and softens it making it prone to disfigurement.

Hope that helps.

Quote: Originally Posted by putwig I have had alot of experience with vinyl dye. Here are the basics: 1. The only prep needed is to scrub with a green scrubby and dishsoap. You may want to wipe with a tack cloth immediately before spraying. 2. Vinyl dye is not a paint. As the name would suggest, it is a dye. It soaks into the plastic and changes the colour, it doesn't sit atop the plastic like paint. Therefore, there is no sanding required. If you take a beige driveand vinyl dye it black (without sanding), it will look like you bought the black version of the drive. If you sand the drive flat first, you will loose the "pebbling" that almost all commercial plastics have. 3. You do not need to, nor should you, prime a piece that is to be vinyl dyed. The primer clogs the microscopic pores that the dye is meant to soak into, effectively "sealing" the piece and preventing the dye from working properly. Similarily, do not try to vinyl dye a piece that has been previously painted. Judging by your picture, and the fact that you can see dye pooled in runs along the side of the piece ........ you are putting your dye on way to thick. Hold the rattle can about 6 inches away from the work. Start spraying off to the left of the piece, and SWIFTLY move across the piece. Stop spraying after you clear the piece on the right hand side. Each coat should be very thin, no more than three swift passes. If you are painting beige to black, your piece should still look beige after the first coat, and still somewhat beige after the third coat. What is am trying to say is ........ you want really, really thin coats. After the first coat, wait 5-10 minutes, and then apply coat two. After 5 or so coats you will have a nice uniform piece (it took seven coats to make a black keyboard yellow). Let stand a few hours and you are done. Do not handle during the standing time, as the dye chemically reacts with the plastic and softens it making it prone to disfigurement. Hope that helps.

yeah.... what he said

Thanks for suggestions, guys. I know the layers are supposed to be thin, but after the first two dried in exactly the same pattern (shiny around the edges with a huge flat area right in the middle), I just freaked out and started slapping on one layer after another (it's the only bay cover of this kind that I have, so it has to turn out perfect. Thus the streaks.

Anyways, I figured that Jinx may be right (the weather was kinda crappy yesterday), so I sanded the whole piece down with 600-grit and reapplied the dye. And, magically, the problem went away.

Jinx, Putwig--thanks for the input. Appreciate the help.

Quote: Originally Posted by unholy Only prep work was cleaning it with some detergent. (BTW, you don't use primer underneath vinyl dye.)

I realize that. i just suggested it because the plastic might have a little inconsistency in it so that the die isnt soaking in properly.

i said that it might help in getting a smooth layer of it so that the die doesnt soak differently at different places.

Quote: Originally Posted by Zer0s I realize that. i just suggested it because the plastic might have a little inconsistency in it so that the die isnt soaking in properly. i said that it might help in getting a smooth layer of it so that the die doesnt soak differently at different places.

Bad suggestion:

Quote: Originally Posted by ME 3. You do not need to, nor should you, prime a piece that is to be vinyl dyed. The primer clogs the microscopic pores that the dye is meant to soak into, effectively "sealing" the piece and preventing the dye from working properly.

Well that was my suggestion and if you dont like it putwig, then fine. but i would try it if i my die job came out like that, like i said it was "my suggestion" not me "telling you to do this or else" you need to back off.