Urethane is not my favorite finish because it can be tricky sometimes,
and it is a bear to remove, but don't panic yet because chances are what
you are feeling is buildup where you stayed too long in one place with
the spray. This can be evened out by going over the dry finish with a
block wrapped with sandpaper. Take your time and don't be nervous when
seeing "white spots" appearing as this is normal. And don't be overly
aggressive with the sandpaper or you will cut right through the finish.
You probably want no lower than 220 grit or so. After you have
leveled the surface you can then go over it with extra fine steel wool
(000). When you have done your best to even out the surface and your
fingers tell you it is no longer bumpy you can clean up the dust with a
tack cloth made from the same urethane. Just spray a clean, fine cotton
cloth with a pass or too and fold it in half. Let is sit for a bit.
When the cloth feels mildly sticky to your fingers drag it over the
surface. This will remove any residual debris. Next clean the surface
with denatured alcohol in another cotton rag. Don't go overboard here,
less alcohol is better (both for you and your top!)

Now you are ready to continue finishing your top. I like brushing but
to each his own. Make your spray passes very, very light and thin.
Plan on having to do the above steps again and again - likely three more
times. After each coat be sure the surface is completely dry before
going over it. For the last coat use just steel wool (0000) wetted with
alcohol. With each pass of the spray you should be gaining in
confidence about how much to lay down but always remember to err on the
"less is more" side of the equation.

Good luck ..

Rich wrote:
I used Helmsman Spar Urethane spray on a computer desk table top and
although it has been 24 hours it still feels tacky, but my big concern is
that it feels bumpy. The humidity level here in Arizona is 68% so the tacky
doesn't worry me as much as the bumpy thing.

I sanded the table top down reaeeealy smooth, and stained it. It was nice
and dry and smooth before I applied this stuff.

Question:

Did the Home Depot man sell me the wrong stuff? Is this stuff any good for
desk tops? I wanted something really smooth. Am I supposed to sand this
down? This was a spray can and I think I'm feeling the small particles that
sprayed out onto the surface. I followed the instructions.

Is my table top screwed? Should I sand it down and put something else on it?

I'm not a furniture builder, I'm a desperate software programmer who
couldn't find a certain type of computer desk after 2 weeks of searching
funiture shops... I about have this thing finished and it looks really nice
but this surface don't look right.

Richard