installing new tub

I have a couple of questions.

1-are there any instructions to look at to help me change a 2 faucet bath/shower valve to a 1 faucet? I'm installing a kohler k-11748-k, hoping to be able to do it myself.

2-are there any instructions for changing the drain pipes or things I shouldn't "miss" when doing it? I'm needing to put in a cable drain from kohler.

3-How to do you decide when to use a mortar bed vs adhesive installation.

4-When they say to drill small pilot holes through the flange and secure with galvanized screws what size hole and screws would be best?

5-I picked up some copper phosphorus brazing/welding rods at a garage sale. Would they be the right type for soldering copper pipes?

Thanks so much

1. Do you have access from the back of the wall, or are you going to try this from the front? If from the front, you'll need a remodel plate to cover the larger hole needed to make the connections.

2. Plumbers go to school for years...hard to cover everything in a few words. Again, if you don't have access either from below or behind where the drain goes, it's much harder to get it right. What do you have?

3. Follow the manufactuer's instructions, but my preference, when allowed by the manufacturer, is to use a mortar bed. Some piles of sand mix (mostly sand with some portland cement - not runny, more like wet beach sand) strategically placed, then the tub smushed into it to get it level at the desired height.

4. Where are these holes that need to be drilled? My preference would not to use galvanized, but maybe brass or SS. If it is a sheet metal screw, the size depends on the screw (well, it does for any screw fastener). Too big, not enough to bite, too little, you can't screw it in. Normally, on a self-threading screw, the pilot hole should be about the diameter of the shank of the screw so most of the thread cuts into the material.

5. No...that stuff requires way to high of a heat, and will give you a mess. You need plumber's solder and some flux. If you haven't soldered copper/brass much, you need to practice a little first before you attack the real task.

I have total access for the pipes. The tub can be set either way. The holes are drilled through the tub flange into the studs to secure the tub to the wall. What size would I want to use?

does the manufacturer spec drilling the flange? I'm more used to just setting it on a ledger board and using a roofing nail over the top of the flange to hold it in to the wall (loosely), and down to the ledger board, not going through the flange. but, you should follow the manufacturers instructions, whatever they say to do.

I also like the "piles" method of a mortar bed. Do lots of small piles with a little space between them. That will provide a good full support, and not fight you nearly as much as trying to create a complete bed to sit it in.

If they're through holes, you want one essentially the diameter of the outside of the threads of the screw you select so you can tighten it up into the wall stud. You don't want it to be super tight. If it was thick enough, you might want to use a flat head screw and countersink the hole so the screwhead will be flush. I'd call their tech support people and see what they really want. Definately brass or SS in my mind rather than galvanized. There shouldn't be much moisture there, but if it ever did rust (galvanization doesn't last forever and it may likely be covered with an alkaline mortar which doesn't help), you'd end up with stains. You won't ever get that with the SS, but brass, possible, but unlikely.