Curious if anyone has a suggestion on how to number a large quantity of ping-pong balls?

I need to create 2 different forcing options on balls numbered 1-49 (using clear force bags).
So, I will need one set of balls consecutively numbered 1-49 which will will then be split into 2 lots, to fill one side of the (two) clear force bags.
I then need 25 of one (force) number and another 25 of a second (force) number (as an optional out) to fill the other side(s) of the bag(s).

I can have these professionally printed, but it's not cheap - the entire order looks like it will be close to $200. Since I can buy the blank balls for 1/10th of that, I'm wondering if anyone has an alternative numbering suggestion or an another idea entirely (or a supplier that's more cost effective).

BTW, I've tried marking them by hand, but it doesn't look nearly as 'clean' as I would like.
Also tried adhesive vinyl numbers...they don't seem to stick very well with edges curling off after time.

Appreciate any suggestions!

Have you looked at "dry transfer" or "rub-on" lettering?

A Stencil:

Make 2 sets of stecils 1 though 4 and 0 through 9.

Make a jig to hold the ball, a box so that it is covered from overspray.
The jig top should be curved to match the curve of the ball.

There shoud be 2 slots that hold stencils in the top.

Switch out the stencils to make your numbers.

Spray away.

The dry transfer or rub on lettering would work also, but I would think you would have to seal it with a clear coat to keep it from rubbing off in the bag.

I wonder if the stick on numbers lifted because you did not wash the balls 1st before applying the numbers?

Amazon has numbered Ping Pong Balls for sale, lots of choices. Here is one:
http://www.amazon.com/Bingo-Balls-White-......ng+balls

Thanks, Bill.
The balls were new/clean. They seem particularly susceptible to temperature changes. They were in a cool basement and when I brought them into a much warmer environment (contraction/expansion), the problem occurred.
I saw the amazon listing(s) as well as similar ones on eBay, etc. Problem is two-fold. This gets me the initial set, but not the multiples of one number (X2) for the force balls.
Also, I would prefer that they do not have letters on them (b.i.n.g.o.) so that it looks more like an authentic lottery ball.

I will explore both transfer and rub-on....thanks for the suggestion.

Spray painting seems a logical and efficient method. Not sure if the template would have to reflect the curvature of the ball. If so, I wouldn't even know where to begin attempting to jury-rig that kind of thing!

Appreciate the suggestions (so far)!

I'll head back to the 'lab/workshop,' this weekend to do some more testing.

Maybe these folks can help:

http://www.nationalbingoonline.com/store......LLS.aspx

Yes, was going to suggest buying a lottery/bingo type set.

As indicated, I am trying to avoid bingo balls, as they have letters and the number sequence is not quite right.
That aside, one of my main hopes was to be able to do this cost effectively ($36 for 10 numbered balls is crazy)...needing 25 X 2 specific numbers makes this particularly challenging.

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