Orange peel with GF HP Topcoat

[Dave Cav]

I finished a table top with about six coats of GF High Performance Topcoat Gloss over a couple of coats of Zinsser sealcoat. I got minor but consistent orange peel over the entire top after shooting each coat. After the final coat I sanded the entire top with 320 with a sanding pad and removed most of it, and will finish with a coat of paste wax, but I'd like to avoid the orange peel effect next time.

I shot the finish with a purple HF HVLP gun which usually gives pretty good results, in a heated, well ventilated shop. Temps were in the high 60s, and the relative humidity is very low. The finish wasn't thinned.

[John TenEyck]

Spraying it unthinned at low RH will do that. You need to thin it probably at least 8% for that gun, maybe more

to get the viscosity down to around 25 - 30 seconds for that 1.4 mm N/N.

Alternatively, or maybe additionally, definitely add 3 - 5% of GF's Extender. It will let it flow out.

Keep your coats thin and let the Extender do it's job. Also, 6 coats seems like 2 or 3 more than you should need. If I've had any tendency for orange peel it always seems to get worse the more coats I spray unless I sand it back flat at some point.

Good luck.

John

[Dave Cav]

Thanks, John. I thought the viscosity might be a problem. Would Flotrol work instead of the GF extender?

[John TenEyck]

No idea Dave; you're on your own. Isn't Flotrol milky? If so, I don't think I'd put it in a clear topcoat.

John

[Jim Becker]

Flotrol is really designated for latex paints, etc. I wouldn't use it with clear coats for the reason that John mentions. The GF extender isn't expensive and a little goes a long way with many finishes.

[Dave Cav]

OK, I wasn't sure, and have some WB Flotrol on the shelf. I'll order a bottle of the Extender.