Spraying bin shellac

I have used BIN as a primer numerous times with great results. I spray it with a Fugi 4 system and love the ease of application and cleanup. But i wonder if i am doing something incorrectly in that the BIN coat is always 'rough' to touch and so I end up sanding it smooth before spraying the next finish coat. (Usually Advance.) Is this roughness normal or is my application technique lacking?

If you are spraying it on a porous substrate it might come out a little rough for the first coat, just like Sealcoat shellac will on some substrates. But if you are spraying it on something like maple or your second coat is rough then it's not the substrate, it's more likely you aren't spraying a heavy enough coat, your gun is too far away from the work, or over spray is falling onto the freshly sprayed surface.

John

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Originally Posted by John TenEyck

If you are spraying it on a porous substrate it might come out a little rough for the first coat, just like Sealcoat shellac will on some substrates. But if you are spraying it on something like maple or your second coat is rough then it's not the substrate, it's more likely you aren't spraying a heavy enough coat, your gun is too far away from the work, or over spray is falling onto the freshly sprayed surface.

John

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I got a pebbly finish the first couple of times I used BIN too. Spray out on my driveway, no booth, 4-stage HVLP turbine rig.

But that wasn't the issue. The issue for me (at least) was gun setup and technique.

As John notes:

* Feeds and speeds!

You need sufficient material coming out. (Feed)

You need the pattern adjusted to the right shape. (Feed)

You need to move at the right rate. (Speed)

Airflow to remove overspray (Speed) -- I'm outdoors so I usually set up on days with a light breeze and try to work with the breeze at my back. Not always successful there!

Moving the gun at the right rate is probably the hardest for me since I always have to tell myself to slow down.

BIN should spray pretty dang smooth and without any alterations right from the can.

Oh, and do filter it while pouring into the can.

Dang, so it is my technique. Will modify and practice a bit to see if I can obtain a smoother finish. Thanks

It may not be the technique. I've had two fresh batches recently that were full of non desolved particles. Normally there is a bit of a texture to the finish but this was enough to clog the strainer in the gun and leave a gritty finish. This was all after running it through a cone filter.

I’ve had the bumps happen on first coats over MDF. 2nd coats and other substrates come out better, but I still sand before top coating.

Make sure you’re stirring well enough. DO NOT leave it in the gun/cup over the weekend. Ask me how I know.