seaneee

So I finally found some duplicolor and I'm going to give it a try. My question is: "Do I need to prime the entire frame?"

Here's the details. I'm painting a very close blue over the original blue. I sanded down the frame for better adheasion, but was planning on using the original blue as the base coat. I ended up having to fill a couple of dings with bondo and sand down a couple of chips so they were smooth.

I know bondo requires a couple coats of primer and I want to prime the couple small spots where it was sanded down to bare metal.

But do I need to primer the whole frame, or can I just prime the areas where I applied Bondo, etc?

dbakl

I'd probably prime the whole thing so the paint has a common surface, but if you didn't, it'd probably be ok if you've scuffed the surface for adhesion.

The duplicolor is lacquer, so it goes on pretty thin.

Dr.Deltron

I find it helpful to primer the whole thing. You'll be surprised how many ****ers show up at that stage. With a coat of primer on, you can attend to those ****ers until the frame is perfect. Then a complete FINAL coat of primer before color. The better the prep, the better the finished product.

2 points...
A) Start by spraying JUST the tricky areas, like BB, seat cluster, stay bridges, etc., using little spritzes of paint.
Then come back and "connect" those spots by spraying the tubes.

B) The real KEY to a nice shiny paintjob is getting the spraying done QUICKLY! The idea is to have ALL the paint WET at one time. This prevents dusty overspray areas. It should take 10-12 minutes to spray ONE coat of paint.
The trick is getting the paint thick enough to "flow-out", but not so thick as to cause RUNS!

If you get a good coat on nice & smooth, then wait the minimum dry time between coats, you shouldn't have to do any sanding between coats. All the sanding is done to the initial PRIMER coat. You shouldn't have to sand the FINAL complete primer coat, or any of the color/clear coats.
However, if you get runs, you WILL have to sand them down.
If you sand a metallic color, you WILL have to respray another color coat.

If you DO get some dry, dusty spots, no worries. The next coat will flow that out.

If the final CLEAR coat gets dusty spots, asuming you have sprayed 3 or more clear coats, let it cure completely and then they can be polished out. Oooor, spray one more coat following the B) note above!

Good luck! And as always, ask me anything in regards to paint.

Dr.Deltron

I concur!

In the case of laquer color, I would use laquer primer and ENAMEL clear.
If done well, it'll look like a "pro" job. Still won't be as durable as quality auto paint though.

And NEVER, EVER spray laquer OVER enamel!

Failure to heed that warning will result in you NEVER wanting to paint a bike again!
(although you will most likely HAVE TO!)

dbakl

And that in a nutshell is the $64,000. dollar trick!

Dr.Deltron

WOW, that much?!?!??


I'm seriously UNDERpaid!

seaneee

So If I prime with laquer primer over the original coat of paint, is that an issue? Not sure what the original was...

Also, I picked up Duplicor SUV top coat, but it doesn't say whether it's laquer or enamel, does anyone know or inversely, can you recco a good rattle can clear coat?

Dr.Deltron

Generally not a problem with old paint as much as fresh paint.
But test spray a spot first and see what happens. Problems will usually show up right away. ie; wrinkling or softening of the old paint.

Sorry, it's been so long since I've rattle-canned a frame, I have no idea.
But the top coat being the same brand as the color/primer, you should be good.
I use white PVC pipe to make sample tubes or test compatability.

seaneee

Thanks for all the tips, much appreciated. Maybe post more questions in the next couple of days otherwise will post pics of completed frame. Thanks.

seaneee

BTW, you should write a painting how to book, that the one thing that is missing among home repair and shop manuals.

bbattle

I sanded the heck out of my project frame, then got out a stripper that sprayed on as a gel. Waited 20 minutes or so, then used my wire brushes to get everything scraped away. I did this 3 times, each time wiping the stripper off using a t-shirt rag soaked with mineral spirits. I've managed to get 99.9% of the paint and primer off the frame. It's way too humid to go any further, the frame is safe indoors where it's nice and dry. I'll sand the frame again completely and wipe it down with mineral spirits just before priming.

I've bought some filler primer that should take care of any imperfections in the frame. Two coats with sanding in between and 400 grit paper and steel wool before painting. Alcohol rag to wipe away any dust then several light coats of spray paint.

Autozone sells clear coat in a spray can; made by Duplicolor.

Dr.Deltron

I have to call you on those 2 points.
The "proper" thing to use is PPG's DX330 Wax & grease remover rather than alcohol. This will eliminate any fingerprints etc.
Then use a tack cloth to remove any dust.

A light first coat is OK, but the following coats need to be heavier.
(see the $64,000 trick I mentioned in a previous post above)

Also, sanding is generally NOT needed between coats if you only wait the minimum "flash" time listed on the can. Rattle cans that's something like 2-4 hours. If you wait any longer, it MUST be a minimum of 72 hours, and sanding is then recommended. But you can do that quicker & easier if you use a Fine Scotch-Brite pad instead of 400 grit. And be careful along the edges of lugs, cable guides etc. It's easy to sand OFF too much paint there.

duane041

One of the best PPG products-I love that stuff!

Dr Del. is correct, as always.
I will throw my .03¢ in (opinions have gone up in price)-I wouldn't use lacquer primer at all. The stuff shrinks too much to give really good adhesion. Enamel primers take longer to dry and don't sand out as nicely, but are more durable and give better adhesion. As Dr. says, auto grade stuff (PPG K36 or DP40LF) works much much better, but require more than most want to deal with.
Lacquer topcoats can be buffed out to a remarkable shine, but are about as durable as the skin on chocolate pudding. Much too brittle for bike use.