Clear over old painting

[Billct2]

We're restoring an old carved sign that has a 2'x3' oval panel with a landscape painted on it. It is is surprisingly good shape considering how beat the rest of the sign is. So we have cleaned it and will reuse it.
I want to clear over it, both to brighten it and protect it. I don't know what it was painted with, probably acrylics, but maybe oils or even sign paint.
Not sure what to use. I remember there was a clear coat we would use over old sign that didn't need repainting, something like "Sign Finishing Clear", maybe that or something similar, Frog Juice?
Any recommendations?

 

[Gino]

Not knowing what paints were used or how long they've been on there, I'd be very careful.

I'd first sand it with maybe 1200 sand paper.... ever-so-slightly and then spray a dry coat or two on there and make sure nothing bubbles up or starts reacting to your clear. Once that is established I'd put a few coats on getting heavier each time until you're finished.

I'd use a poly-urethane. Good luck...............​

 

[Billct2]

Yea, I thought about using some 2 part poly I have, but afraid it might be reactive.
I was thinking an acrylic or waterborne finish would be safer.
I can test it on the edge where it will get covered.

 

[Gino]

You can use just about any clear for the dry coats and be sure your poly will work together with that.

 

[insigniagraphics]

There's a great product, sold at lowe's called "clear-seal" #606, made by SEAL KRETE.
This is a water-based, clear acrylic-urathane product, originally formulated for concrete flooring. This makes a great clear-coat alternative to any solvent-based products, and will adhere to almost any surface, be it painted or not. Can be sprayed or rolled on, and usually takes 2-3 coats to create a glossy finish. When fully cured, it is very hard and durable, and uv stable, so it does not yellow. I verified this info by calling the manufacturer, and they told me it is safe to be used as such... This is a great solution for old faded paint.