Painting question, color coat is too soft to sand Options

[Gudhjem]

I've begun painting my car, panel-by-panel, starting with the trunk lid.
I'm using Interlux Bridghtsides paint. Yes, I'm rolling it on, mostly because I don't have a large compressor and because I am hoping to avoid all the mess of spraying in my garage.

I spent a few days patching holes (luggage rack once upon a time I think), and spent a few days putting on a few coats of primer. Sanding the primer was no problem, and I've now started with the color. Problem is, when I try to sand the paint, it sticks to the paper. There's no dust created, the paper just gets clogged right away. It's as if the paint's not dry. The can says leave it at least 16 hours, I've left it 28, and it's not cold in California.

Anyone know what's going on? (IMG:style_emoticons/default/confused24.gif)

--Steve

Here's before primer


After Primer


Sanding Block after trying to color sand

[Gudhjem]

Thanks for all the replies.

Why would I use a single part polyurethane marine finish on my car, and not an automotive finish? Because all the info I could collect indicated that if I were not going to spray, the Interlux boat finish was best. It wasn't cheap, in fact probably cost about as much as good automotive paint, but the word on the forums where people discuss roll-on paint jobs is that this is the best one. It's supposed to be the logical improvement from the Rustoleum so-called $50 paint jobs. Part of the supposed advantage over Rustoleum is that, ulinke Rustoleum, this polyurethane can be painted over without the need for fully stripping. I was not aware that it did not have the hardeners that automotive paints have, or that it in general did not have the same wearability, or that it would stay gummy. In fact, this is exactly the opposite of the experiences posted by dozens of anonymous users. (IMG:style_emoticons/default/confused24.gif)

My point was not to save time. I expect this method would take significantly MORE time than spraying, particularly considering the extra wet-sanding that would be required to get a decent finish. I also didn't do it to save money, at least that was not an important part of it. I did it because spraying creates a mess. I doubt any of you guys with tons of experience but without a booth can argue otherwise. I've done enough of it to know the fumes WILL get from the garage to the house. I also would have to buy a compressor, and woudl be limited to 110v, which means I couldn't even buy the one I would really want (that would allow me to set up a media blaster as well).

Why not let a pro do it? Two reasons: 1) I'd have to fully strip and prep the whole car at once, which means way more time with the car out of commission - I prefer to work on things a bit at a time where possible; and 2) Whenever possible, I want to do it myself. It's the same reason I've never taken my 914 to a mechanic in the 14 years I've owned it. I enjoy driving a car that I keep running and I restore and I upgrade.

I didn't go into this haphazardly. I get why several of you replying think that, since you are of the firm (and it appears correct) opinion that my roller job will not work. I must have spent dozens of hours reading about the best way to go about this before starting, including reading every post I could find on this board about painting (including everything I could find written by Scotty B.).

So, that's a long-winded way of explaining how I got here. I tried sanding the trunk again today with pretty much the same, paint-is-too-soft, result. I may give it another day or two and try again, but based on what I'm reading in these responses, I'm not optimistic.

The good news is that I started with the trunk because it's easy to start over on it. All I've lost is the week I spent priming and painting, whereas most of my bodywork and prep will still count. I may have to just give in a buy a proper compressor (hopefully I can get a good enough one in 110v) and deal with the mess.

Thanks again for all the replies. This forum is, as always, a huge help. (IMG:style_emoticons/default/shades.gif)

--Steve

[rick 918-S]

Thanks for all the replies.

I was not aware that it did not have the hardeners that automotive paints have, or that it in general did not have the same wearability, or that it would stay gummy. In fact, this is exactly the opposite of the experiences posted by dozens of anonymous users. (IMG:style_emoticons/default/confused24.gif)

Thanks again for all the replies. This forum is, as always, a huge help. (IMG:style_emoticons/default/shades.gif)

--Steve

Steve,

The key word is anonymous users. I have read about the roller jobs too. The british car forum where I hang out had a guy or two try this also. From what I read the guys that do this have little to no experience with any of the paint products they use. They are not the guys you want to take advise from.

Again, You will be able to roll acrylic enamel with a high temp reducer and hardner. (high temp reducer will slow the dry time and allow "some " flow out. You will be able to cut and buff the finish.

The paint won't care how it's applied. It doesn't know if it's sprayed or rolled. Only you will know when the paint is ruff as a cobb and full of trash from the roller process. It will dry the same as if you sprayed it. So it will sand and buff the same.

Also, If I rolled a car and sanded it and buffed it I would tell everyone that it looks show quality. But the truth is compared to what? Most likely the answer will be compared to the next guys rolled on paint job. Or when confronted the guy would say " well it's show quality for a rolled on job!"

The reason paint is applied with spray equipment is it is easier to control the end result. Rolled paint will never be trash free. Chunks of lint are bi-product of the process.

If you want to continue to roll the finish do yourself a favor and at least use car paint.

Good luck!