I got a really good deal on some nice shafts. They are older cedar shafts that were sealed with varnish.
What can I use as a crown dip on varnish?
alcohol based, oil based, lacquer based, water based?
From what I have just finished reading you will need to sand off the varnish. I would say the varnish on those shafts is oil based. If I was going to try this I would use 250 grit wet/dry sandpaper wet with mineral spirits. Varnish makes a slick surface and you need to remove that slickness.
As for cap dipping. I would try my Bohning Laq paints first. It what I got. But I would also try their new waterbased paints. No smell.
Not ever doing this before I can not say what works for sure.
You should be alright if you sanded with 220 until the gloss is entirely knocked down, run a tack cloth over the arrow shafts and use oil enamel or lacquer based coating. Latex/acrylic usually would not have the durability you're probably after.
I was wondering the same thing, so far just fletched them up and shot them plain. Really nice shafts for basically half price, surprised they haven't sold out. Bought 5 dozen and fighting the urge to buy more.
Try wiping with a clean white rag and paint thinner. If it comes off then try Krylon or similar enamels. Try experimenting with one shaft, dry some Krylon color paints in 1/2 oz. bottles. I bought some to try because they had lacquer on the bottles, they weren't. The one I tried were enamels soluble in paint thinner. They might work for you.