Delta Valve, can I drill it?

I recently installed a delta shower valve for a shower I'm putting in. It FAILED the water test (pinhole leak) so after searching as I've never had a faulty solder joint, I figured it best to disassemble it completely and start over as resoldering never holds apparently.

So I have TWO questions this time

1. I noticed a VERY small hole to let water go out to the shower head or the tub spout. Can I drill this hole larger to allow more water to flow?

2. I botch the solder job and am wondering a few things. Why didn't it 'take'. I had to keep heat on it constantly after heating it with a standard bottle and point tip (1" long flame) to get the thing to melt solder. What's weird is, it failed at the top where you start your solder.
Also - I'm now putting copper thread on fittings for two reason, #1 it's MUCH easier to solder and #2 There is all kinda solder and gunk that I can't seem to get out of there now so soldering again isn't really an option now?

Thanks gents!

FLUX, Did you use any flux on the copper when you soldered?
That's the only way the solder will flow and cover the pipe and fittings.

If you are only using the valve for the shower head, then yes, you could drill it bigger.
The reason it's a small hole, is to make sure the water goes through the tub spout first.

When the tub spout diverter is pulled up, it then moves water up to the shower head.

Excellent, thanks Terry.

Yes, I fluxed the flux out of it.

I never forget to flux. I also obsessively clean my pipes prior to soldering also.

If anything, I worry that I flux too much if that is possible. I use these little black disposable brushes and usually dab it twice in petro flux for each fitting and go around the pipe till about 3/4" down or in the fitting. And I clean and flux each piece being soldered.

I'm thinking I didn't get even distribution due to poor heat dispersion. But, it's an after thought now as I'm working on drilling that out a bit larger so it will turn out better than before now.

Thanks

S

Delta

Delta valves are symetrical so you can invert it to use the larger spout opening for the shower. Just reverse the cartridge or connect the hot to the right side.

Who says re soldering never holds? Get all the water out of the system, heat that thing up, put some flux on it, run some more solder over it, and keep going until you fill the hole. Very rarely does a leaky piece actually need to be cut out.
Where do you have solder you can't get rid of? On a pipe just heat it up and wipe it with a rag while it's liquid. In a fitting heat the fitting and clean it with a brush while it's liquid (don't push any solder into your shower body though). You may need to work the brush in and out but you should be able to get it. Worst case scenario, clean it, flux it, heat it (melt the solder), put the pipe in the fitting, give it some more flux, heat it some more and solder normally. That's only something you do when your limited on options though, it's always better to just replace the fitting.