Thread: Flex Agent for Paint

Tweet

Anyone ever hear of a flex agent in their paint when painting a fiberglass car ?
I am told it help. Is this true ?

Our buddy Spraytech will be able to give us the full scoop, but in brief, flex agents are intended for use on pliable plastics, such as contemporary bumpers. There are some paints that have enough innate flexibility that additives aren't necessary. If you use a flex additive, you need to follow the manufacturer's mix ratios precisely as this is one of those things where "more is better" is a definite no-no. I don't believe there would be any advantage to using it on a fiberglass piece as glass doesn't flex as much as the various plastics do. The paint companies I used to do business indicated that the film strenghth of the paint is diminished somewhat by the additive (that's why it's an additive rather than just included in the paint).

Well, Bob pretty much summed it up.
But I have found that it can alter the color a bit also ( makes it go a shade dark for some reason) I havent used it in years as it makes your dry time slow way down, plus it only allows it to flex to a certain degree , then it will still crack!

Most Paints today have a pretty good flexability as the hardeners in todays paint have been perfected to a higher level, compared to the Synthetic & Acrylic Enamels of yesteryear.

Fiberglass is solid enough not to require a Flex additive in the paint! As long as you use a GOOD paint product.

Man where do guys come up with these Ideas? ............LOL
I have came across some really scarry stuff in my painting days, because of some one giving bad advice to someone trying to do a paint job and it not being their profession.

SprayTech

Go to a boat shop and buy some gel coat, it's designed for fiberglass.

Gelcoat is nothing but clear epoxy & has no flex .

Made for repairs not completes.
SprayTech

I've been painting (part-time) for a while, and agree with spraytech. Fiberglass is rigid enough, unless it's very thin, to resist flexing. I've hand-built fiberglass bodies for some of my projects and have never added any flex agent to the paint. I used acrylic urethane paint with the appropriate primers and such, and the paint has been on one of them for at least ten years and still looks great. And gel-coat is one of the most brittle surfaces out there, as far as I'm concerned. It's great for its intended use, but should be used in moderation. Just my $.02

See ?
Thats what I get for listening to the troops out here on site (I'm way out in the desert here, building a power plant). Thanks for the great info and keeping me out of trouble guys.

I will be however planning to powdercoat the frame, then have it painted with the body and parts. . . . . . Am I screwin up ?

Correct me if I am miss reading your last post wrong rocknrod , But why are you wanting to paint your frame after having it powder coated?

Powder coat is almost like Porcelin, and doesnt scratch or chip real easy, and is the best way to go, if you can afford it.

There is no reason to go the expense & put paint over the powder coat as it most likely will peal off.
If you want the frame the same color as the body , then just grind all welds smooth and fix all imperfections with some body filler, prime it , sand it & paint it.


Spray

If you talk to your man doing the powder coating you could most likely get the color you want in the powder coat. Please do not paint over powder coat your going to be in trouble later on down the road with a lot of work because the paint will flake off then just continue to flake. Good luck.
MANOCHEVY

Originally posted by SprayTech
But why are you wanting to paint your frame after having it powder coated?

Powder coat is almost like Porcelin, and doesnt scratch or chip real easy, and is the best way to go, if you can afford it.

There is no reason to go the expense & put paint over the powder coat as it most likely will peal off.
Spray

A. I want the protection of powdercoat in all the nooks and crany's that the average painter may not attend to.

B. I like the anti chip and scratch properties that (I thought) powdercoat provides and would be a great base to start with.

So your telling me that painting over the powdercoat will most likely result in chipping of the paint ? Even if it's prepped ?

I was going to pwdercoat the frame (entirely)
Then have the Outside frame rails painted only.

The chip resistance of the powder coat would remain, it's just the paint on top of it that wouldn't have good adhesion that would be the problem.

You could have the powder coater mask the outter surface of the rails that you want to paint, and then do the rest of the frame. Then just do a conventional prep and paint on that outter surface. One other point that hasn't been emphasized, you can't powder coat over polyester filler (bondo), it won't survive the process. As mano says, bring a sample of the paint color you want to use on the outter part to see if the coater can match it, or find out if they have something you can live with and have the paint matched to that.

BTW, if a painter won't pay attention to the details of the frame that you're concerned about, he's probably not the guy to do the rest of the car either. Good paint work depends more on the prep than on the final coats. If he's lazy on one area of detail, he's probably lazy on all of them.

Your right about finding a good painter.
There in lies the rub !
Finding a good painter.

When your a long, long way from the people you knew, finding a good painter is a hard thing to do (wow I made a rhyme

I can't say that enough can I. "good painter, good painter, good painter". Say that three times fast.

Anyway (wow I am loosing it), I guess I'm worried about it, ya think ?