Hevea Timber fibers go prickly when varnished or wet
I used Hevea timber panels from Bunnings to make my desk top bigger (to work from home). I like the blond colour and fine grain however after sanding it smooth, when I varnished first coat it dried rough and prickly as the timber fibers seem to swell and stick up. Gave it a light sand and second coat and the fibers were prickly again. Sand and coat 3 was better but I can still feel it is not as smooth as when I first sanded before varnishing. I noticed an offcut got a bit of water on it and when that dried the surface was prickly too. Any thoughts on this and how to reduce it? Is there a sealer I should use first?
No photos as it is not something you can see but you sure can feel it.