fiberglass/laminate prep

[jeff15]

I have a '03 2475. Some of the decals were showing their age due to sun. The wife had me take off the decal on the front window cover. Now she wants to paint her own design on it and the 2 cargo doors. I have sanded all 3 so there is no gloss. Do I have to prime the entire panels before she does her design? She would be using either Rusteloum oil based or acrylic to hand paint her designs. FYI... in case there is something different now vs the 90's. I did the same thing to our '77 Holiday Rambler and didn't prime it.

[Sunline Fan]

Personally, I would wipe it down with solvent first, like lacquer thinner or maybe even rubbing alcohol. Something that won't leave residue but will remove any of the sanding dust or other contaminants. By painting with a brush and having multiple colors, touching up should be easy if there are any spots that don't adhere well.

[jeff15]

Do you think it would be ok without priming the whole thing? After it's sanded and wiped off with mineral spirits, just letting her paint her design directly on with Rusteloum oil based or acrylic?

[johnnybgood]

I wouldn't prime it. Like Jon said wipe it down good. I'd personally use mineral spirits followed by denatured alcohol. And I'd use a top of the line exterior acrylic paint like Sherwin Williams Emerald or Duration.

[jeff15]

Very good, thank you so much, appreciate the help

[JohnB]

Hi,

I am not exactly sure on the primer but I am really interested in what you are doing as I wanted to repaint my 2 entry doors and the rock guard

I do know a little about trying to get paint or adhesives to stick to plastic. The automotive folks had to solve this problem too. It can be really hard to get paints or adhesive to stick unless the surface tension is raised. At work we would treat the plastic (polypropylene in this case) to raise the surface tension and then self-adhesive stickers would stick. Similar issue as paint. In our case we used plasma technology to raise the dyne level of the plastic surface. Other technologies use flame and corona.

On the camper, I can't afford that kind of technology just to paint the rock guard and 2 entry doors.

This spring I painted the inside roof plastic vent shrouds and had a large learning curve using primers to raise the surface tension. It was painful. I had to quickly remove all what I just put on when I applied the top coat. After trying many products I found the Zinnsser Bull Eye All project primer Plus worked the best on the plastic shrouds. The other plastic primers I tried this one, http://www.rustoleum.com/~/media/Dig...Spray_TDS.ashx while it primed nice when the top coat was applied, the paint crinkled really bad in a matter of minutes right before my eyes.... It was like as the top coat dried, it pulled on the primer and broke the bond free and shrunk creating the crinkled surface.

This chart may help some

http://www.rustoleum.com/~/media/Dig...ngPrimers.ashx

This is the product below I used that worked well on the plastic vent shroud and it is listed in the spec sheet for outside fiberglass doors.

http://www.rustoleum.com/~/media/Dig...rimer_TDS.ashx

On cleaning prep, if you use mineral spirits to clean with (I do as well) you need to go over it again to get the petroleum left over reside off. This can be lacquer thinner, denatured alcohol or even home rubbing alcohol. It needs to be a high flash cleaner that will take oil and grim off. Acetone works too but be careful on the white aluminum paint. It will soften the white paint but clean the fiberglass OK.

If and when I do my entry doors, I am going to try can contact Rustoleum and ask them what product of theirs do I use. http://www.rustoleum.com/pages/help-...oduct-support/

Their Rustoleum plastic specialty primer spray I used did not give good results but their Zinnsser Bulls Eye 123 Plus primer did work well. It was a painful learning curve I had and I'll throw in the towel to call then rather than trying to figure it out from their product specs.

Hope this helps

John

[vcrt]

One prep that I didn't see mentioned is a wax and grease remover which is made by Dupont, they call it Prep-Sol and by PPG, they call it DX-330. It won't harm paint and will remove all waxes, silicones etc. for better paint adhesion. I have used acetone on plastic parts with good results, but as John said, keep it away from painted metal. It will soften some plastics, but not fiberglass.
I don't think mineral spirits is going to do the job.
Rich