Painting fiberglass

When all the sanding and filling are done, what is best to wipe the fiberglass down with before shooting paint? Mineral spirits? Lacquer thinner?

 

years ago the go-to was dupont prep-sol , I'm sure there are others

 

What kind of paint?

Mineral spirits is loaded with oils. The last thing you'd want to use.

 

The paint is high-fill primer with hardener, followed by single-stage urethane color coat.

 

Acetone would work fine on the raw glass and bodywork.

Laquer thinner can leave a residue behind.

I'd use a PRE wipe made by your paint manufacturer before the sealer and color.

 

By "sealer" I mean that high build primer is just part of bodywork and is really just a sprayable body filler that's meant to be blocked.

You'll still want to go over that with a primer/sealer before your finish color.

 

What CC said , some paint sytems require that you use a sealer before the[ color coat , best to find either a helpful auto paint supplier or helpful body shop , they can point out what works & what doesn't ..
I have no idea what caused that ^^^
You can also have your sealer tinted so it covers quicker/less material

 

Though expensive, I would use whatever the manufacturer of your paint products recommends.
At the cost of today's paint products, the last thing you want is to put something under your paint that is
incompatible with whatever is going over it. Mineral spirits was a fine thinner/cleaner back in the day, but it
a petroleum based product, which is an absolute no-no in today's paint world.
In the absence of other approved products, acetone is a safe bet.

 

FYI, test a spot before wiping down the car. Some products like lacquer thinner, acetone, etc can etch the primer, sealer. We used to use fast lacquer thinner while doing body work, PRIOR to applying the sealer, we then used the reducer that the sealer required that was to be applied, but NEVER after it was applied. We then used the reducer for whatever the top coat or next coat was, i.e., base, clear, whatever. The logic is that the subsequent coats were designed to cover the prior, so the chemicals worked and didn't destroy the prior coat or negatively affect the next. The reason to always use a fast reducer for cleaning is you want it to evaporate quickly, not soak in. Also always follow the wet wipe immediately with a clean, dry, lint free wipe, then tach rag. Now, that was with acrylics, and high solids that we were used to working with. There are various prep solutions sold for this, just ask the paint dealer what is reccomended. Prep sol type solutions will remove all oils, etc, but not desolve the undercoat or react with the top coat. Not many things are more aggravating than having your paint job go south and realizing how much time, effort, and cash you not only just wasted, but now get to reinvest!