Sweating larger copper plumbing valves & fittings?

admin

I have to replace the main water shutoff valve for my house. The handle broke off while doing other repairs. It's on a 7/8 inch copper pipe in a hole about 2 feet in the ground. I had to replace another valve in my garage, and used a single cylinder MAPP gas torch to sweat another valve, fitting and pipe together.  This is not the shutoff valve by the meter, the meter is about 1/4 mile away. The temp was around 10 degrees, and the torch didn't seem to put out enough heat to allow the solder to make a complete 360 degree seal on the joint in the sweat valve the first attempt.I have a full size oxy/acetylene welding/cutting/brazing/heating kit. It has a "rosebud" tip. Can this be used to sweat some of the larger fittings together? The little tank of MAPP gas doesn't seem to put out enough heat for larger pipes and fittings. It seems to do fine for things 1/2 or less.
Reply:I have never tried  doing that in that cold a weather, however, I would try again and maybe put up a wind block to keep the heat where you want it. I would also use some flux to make it flow easier. The OA set up WILL do it, but you have to be careful cause it will mess it up(warp/melt). You might also heat the valve up in an oven just to get it warm and wrap it up while you get it where it needs to be. The pipe  should have no prob heating, there is just more material to heat up in the valve.
Reply:The pipe is probably 3/4" not 7/8". I have also seen 1" copper used in newer homes as a supply.One thing you will need to do is to get all the water out of the line first. Even a tiny amount will usually keep the solder from bonding. You can use the old piece of white bread trick, but I generally don't like to do that unless I can push it right out of a faucet. I've taken a shop vac and vac'd out a line, The air compressor and pushed the water out down stream with a blowgun and a piece of rag to keep the air in. They also sell special tools "jetsweats" that go inside the pipe and plug the pipe so you can solder. You use a gate valve or full dia. ball valve and insert the jet sweat thru the valve to block the down side pipe. You can then remove the jetsweat and close the valve and solder the 2nd side, keeping a wet towel or filling the other side with water to keep that side cool. Jet sweats ain't cheap however. Usually I'll just prep everything, vac the line and solder fast.You also need to be sure the fitting and pipe are well cleaned and fluxed to get a good joint.I have used an O/A torch with a rose bud on big (3") fittings. You have to be very careful not to over heat the copper. You might be better off with a large welding tip than the rose bud. I use a dedicated air/acet plumbers torch most times. I got it after running into the same issues with larger pipe with mapp that you are finding. Some torch kits come with an air/acet tip as well as the standard O/A tips. Most plumbers tips have a large diffuse flame to spread the heat, as opposed to welding tips that concentrate the heat, or a rosebud that cranks out mega BTU's.One other thought. Use a ball valve (1st choice) or a gate valve instead of a normal valve. Neither the ball valve or gate valve use washers, so they don't generally go bad and leak. If this is in a box pit out front like many I've seen, you can also use the newer valves that don't require solder. HD sells them as Sharkbite, Lowes as Gatorbite. You need to have the room to work, and have to be able to spread the pipe a bit to get them on, or you have to use a repair coupling also if the pipes won't move. I keep a couple of these fittings on the truck for emergency's. Cut pipe, chamfer end, install fitting and done. No wrench required, no solder, works on copper, PEX, and CPVC. On new homes with PEX, they are the best solution most times.Edit; tx_swordguy Usually you heat the fitting not the pipe. The fitting will heat the pipe. Flux is a requirement, not an option to do this right. When the pipe/fitting is hot enough, the solder applied to the pipe will melt and get sucked in by capilary action. You don't heat the solder with the torch to melt it. the heat of the pipe will melt the solder. If you melt the solder with the torch, and the pipe isn't yet hot enought to meltthe solder, you will get a cold joint and it will almost always leak..Last edited by DSW; 01-11-2010 at 12:42 PM..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Normally mapp gas works fine for 1/2 and 3/4" copper but the proper tip is needed. The fitting should be heated from the bottom and the flame should wrap around the fitting for best results. One drop of water can cause problems. The valve must be open or pressure can build blowing the solder out. Over heating of valves can also cause problems by warpping or melting teflon seats in ball valves.
Reply:I've found that the swirl mapp torches that run on the disposable canisters -can- sweat up to 1" new/clean pipe, but just barely.  I get better results with my real mapp torch (which uses a 7lb mapp bottle, regulator hose, sized tips, etc).  This may just be out of your torch's reach.  If the hole is large enough, you could use two torches, and have a friend hold one on the opposite side.Since you've already got an acetylene bottle and regulator, here's your best bet:Get a turbotorch or prest-o-lite air-acetylene torch.  No oxygen required.  The flame is MUCH softer and more diffuse than a rosebud, and more conducive to a good solder joint.Used ones can be had on CL or eBay for not too much.  This is what most plumbers use.The prest-o-lite uses tips that screw in, and has a soft/quiet flame.  I tend to use the #3, but for this, I'd reach for a #4 or #5 tip.  The turbo-torch, uses swirl flame quick release tips, with a LOUD, jet engine like flame, and runs a bit hotter for the same sized flame.  A #5 will eat acetylene (still less than a rosebud though), but will have plenty of heat.  A #7 has enough heat to sweat that line, even with water slowly dripping through it.
Reply:Isn't it the water dept's problem to the main shutoff??????   how do you shut off the water from the street???opps! re read the OPLast edited by fredf; 01-11-2010 at 11:14 PM.-- fredLincoln 180C MIG
Reply:Usually the water dept is responsible to the meter. It's not as common as it once was to have meter outside the house with the house side valve. I've had several customers in older, late 40's early 50's tract homes in Levittown with meter boxes and house shut offs in the front yard, rather than it the house. That's just the way they did it back then..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:The ticket is to use the Proper cleaning method, the right Flux, Solder and you're good to go.Best way I know how is to use 'Plumbing strip cloth' (maybe called something else...)  Kinda' like a very narrow roll of metal 'cheesecloth'.  Clean outside and inside of the pipe really well, until it looks like new.  That stuff will REALLY give it some tooth without taking away a bunch of the copper.  If all else fails, 80 Grit or a Dremel sanding band will do the trick also.I clean a good two to four inches of Pipe on the outside and recommend the same to anyone trying this for the first time.  The 'Bare Copper' will allow you to see the 'color changes' as the pipe heats up and you can better judge when that piece of pipe is ready.Apply a 'liberal' amount of the Plumbers Flux.  It changes color at the proper temp to help you know when to start applying the Solder.Heat slowly and EVENLY until the flux starts to turn and then at FIRST, dab until you notice that the solder DOES indeed flow into the joint using the HEAT from the PIPE, ONLY.  If you can melt your solder this way, you'll create a really nice bond from proper Capillary Action.  By this time you should be moving the flame quicker now so that you can continue around the pipe, keeping the heat as uniform as possible.  I like to hold the spool in one hand and the flame in the other.  In order to get around the pipe properly, I like to take out about 7 inches or so and make a HOOK at the end of the solder, about the size of the end of a small wire coat hanger.  I find that a VERY easy way to reach those 'Hard to Get' places on the copper joint!If you get TOO much solder in a blob all at once, or it doesn't look right, heat it up and wipe it off with a NON-Flammable towelette.Anyway, that's how I do it !Cheers,/Jman..Miller Diversion 165120 amp Buzz BoxVictor Oxy/Ace Oxy/LPGSmith "Little" Oxy/LPGHypertherm Powermax 30Lot's of Misc. tools n' crap....