Varnish bands (streaks?)

[MitreKnown]

I'm varnishing some Meranti window boards (internal cill) and am pretty sure its creating some banding. I am using Rustins Quick Drying Clear Satin varnish applied with a 1" foam brush. For the first coat, I am following the guidance on the tin and brushing across the grain and then with the grain. I can only put on about 100mm or so of varnish along the board before I have to then switch to brushing along the grain. I think this is creating the banding (photo below). First I thought it might have been some water damage or machining marks I hadn't noticed before varnishing, so I sanded off the varnish and sanded the board again before starting the varnish again and getting a similar result.

How can I get a better result? I need to get the boards done as the plasterer will be plastering around them soon. Consequently I want to use the varnish I have. I do have a 4" foam roller. Should I forget the guidance and just roller the whole thing?

As you can tell, I'm pretty new to the finishing side of things.

 

[Doug71]

I would use a normal brush (suitable for acrylic finishes), probably 2" so you get it on a bit quicker and just go with the grain.

I have never used the Rustins varnish but the above works for me with other brands.

 

[MitreKnown]

I would use a normal brush (suitable for acrylic finishes), probably 2" so you get it on a bit quicker and just go with the grain.

I have never used the Rustins varnish but the above works for me with other brands.

Thanks. I'd not used foam brushes before but was led to believe they are the way forward. Seems not.

I like that the Rustins is food safe, not that anyone will be eating off the window cill but still.