Epoxy Primer questions

[Hooch]

Hey guys...looking for some advice..I'll start by saying I'm not a painter but I'm trying to learn...

I'm building a touring bike...slowly. I currently have enough parts to put it on the road, but it isn't "final". I plan to add some different body parts in the next year. Rather than painting every part as I get it to match, I was going to spray the bike flat black, and then shoot the final color once it's complete. I spent some time at my local PPG dealer yesterday, and they recommended just shooting epoxy primer on the bike.
I've spent quite a bit of time reading about it, and I've found that the initial coat can be reduced by 10% and sprayed as a sealer. If I understood correctly, once cured it was a thicker, more durable coat?

If this is true, could I spray 3-4 coats of "sealer" on the parts I have, and as I add parts do the same to them, or is this bad? If so, why? (just want to understand)

The plan is that if the bike is properly primed, it can be ridden for a few months next year, sanded well and shot with color.

Is this safe (no damage to parts or future paint) or a really bad idea?

Thanks!
Shawn

 

[TAZ]

Well, primer is never intended to be weathered as a topcoat BUT Since your primer has a hardener, you should be all right. back in the lacquer primer days, this did not have hardener and it would absorb moisture which is not good.

Also, no need to over-reduce. You can just prime it, then when it comes to paint it, just sand it, seal it with a sealer that is a good shade to use under the base color you plan on painting your bike.

 

[Hooch]

Thanks!

It won't be a permanent thing...probably until next winter. I just want to put a few miles on it while I acquire the rest of the parts I'm after.

Shawn

 

[Kong]

You will be able to get away with that over a winter, or some similar short period. The epoxy should be waterproof, though some chemicals (acetone) will attack it. What will cause it to breakdown will be UV light. There are no UV-Inhibitors in the primer and the paint will only hold up a few months in the sun. So you will definitely have to re-sand it before you re-seal and paint in the spring. For whatever its worth I had to replace the main tongue for my log-splitter. Its a 4"x4" tube about 6' long. After I cut it to length, drilled the appropriate holes, welded on a jack stand, and so forth I shot a coat or two of PPG's MP-140 epoxy primer on it. That was two years ago and that thing has been out in the sun, rain, and snow every minute of those two years. There is just now a little rust starting to creep through.