How many coats of clear urethane?

[blind pew]

In refinishing the woodwork on my International, I bleached the wood X2 with the "A and B" bleach treatment. When sanded, the wood looked new. However, if I applied an oil based varnish, the wood darkened excessively (after drying of course). 

 

My Dad (93) used to run a paint store and did quite a bit of furniture finishing on the side through his career. He suggested (after the bleach and sanding) using one initial coat of a water based clear urethane, allowing to dry, sand, and then apply as many coats of oil base as you want. This really seemed to get a nice effect with the wood still slightly toned and not dark at all. The frame is a little lighter than my other woodies (3), but I like it. 

 

So I have 7 coats of oil based urethane and one coat of water based. I've sanded between each coat and am on 600 grit. The finish looks great (to my eye) and glassy smooth on both the ash and the mahogany plywood panels. The question is................... how many coats of exterior urethane (for those guys who use marine urethane rather than varnish) do you guys use for the exterior? Is there a downside (other than time) for more than 12 coats?

 

I essentially have an infinite amount of time, as this is a retirement project that I started well before retirement. I know some say urethane gives a "cold" and "blue" hue to wood, but I like the look. 

 

PS- This is being built as a resto-mod driver, therefore "original" appearance is not at a premium, although I am maintaining all the woodwork pretty much as it was originally. Mechanically, I simply don't trust old split rims, drum brakes, gear steering, old under powered engines, and knee shocks if I drive a car 300-400 miles in a single trip. 

[blind pew]

No ideas?

 

I know most here prefer to use varnish and hold some disdain for urethanes, which is cool. Certainly the varnishes are more traditional and create than nice, soft amber appearance. 

 

I use marine urethanes as they are a little tougher than varnish and probably provide better UV protection.