:::RHMT::: Real Home Made Turbo

General Category => Fabrication => Topic started by: weirtech on March 07, 2009, 06:38:37 PM

Title: How to: Backpurge when welding stainless pipe
Post by: weirtech on March 07, 2009, 06:38:37 PM: To do this the REAL way, first you will need some hose, here is mine all assembled:

(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Fi47.photobucket.com%2Falbums%2Ff161%2Fweirtech%2Fmisc%2FDSC07189.jpg&hash=7801739e65cb764345c916238baa4c645cec3183)

This is the input end, you can do it differently than I have, but these were the fittings that i had available and they seem to work well. You NEED a ball valve (for turning your back purge on and off) and the other valve is a needle valve to adjust the amount of flow coming out of the hose. I just adjust it by listening to it.

(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Fi47.photobucket.com%2Falbums%2Ff161%2Fweirtech%2Fmisc%2FDSC07190.jpg&hash=fc612cffd3a10891b914ed61ed8550dc58ed3b0a)

Here is a REAL T you will need to add to your REAL bottle regulator. Again, I used these REAL particular fittings because that was what was available at the time. I wanted to make mine removable as well so I added a high end quick disconnect that is designed to prevent any types of leak.

(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Fi47.photobucket.com%2Falbums%2Ff161%2Fweirtech%2Fmisc%2FDSC07191.jpg&hash=3d327b1320a5bde4c85ebd4d894cc44e0943bfc0)

Here is the hose connected:

(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Fi47.photobucket.com%2Falbums%2Ff161%2Fweirtech%2FDSC07192.jpg&hash=e99386cc9b0f6a1f373524e4129ea0bf9538d0d2)

Next, gap your pipe slightly so that you have room to add filler when welding your joint. Some people like to take a piece of filler and bend it into a "V" and stick it inbetween the two pipes for setting a REAL nice even gap and then pulling it out after tacking. For this example i used 1.75" .083" wall 304ss piping. Tack it together so it will not move on you once you start welding.

(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Fi47.photobucket.com%2Falbums%2Ff161%2Fweirtech%2Fmisc%2FDSC07193.jpg&hash=7718e05f94a3762bab3e51a9a1075153cbcdd9b3)

Once you have it tacked together cap both ends with some cap plugs. These fit like a REAL glove and are much nicer and cleaner to use than tape. They also withstand a bit of heat as long as you don't get to close with your torch. Add a hole into one of the cap plugs that the tube/hose will fit snug into so as to prevent argon from leaking back out the hole you made.

(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Fi47.photobucket.com%2Falbums%2Ff161%2Fweirtech%2Fmisc%2FDSC07194.jpg&hash=388f4ba4680c6f16309633a482ae3cff1e6743f8)

When you get REAL close to the end of welding your joint you will need to slip the end plug slightly off the pipe to let the argon escape or it will try to exit through your joint and that makes for difficult welding.

(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Fi47.photobucket.com%2Falbums%2Ff161%2Fweirtech%2Fmisc%2FDSC07195.jpg&hash=439e10ff718ac89133c09827d1eb3815b5f606d6)

I just did a single pass on this at 70 amps but with thicker base metal you can do multiple passes with purging only being nescassary on the first pass as long as you don't blow through it. The inside should look something similar to the pic below. Once you get really good, the inside should look just as good as the outside... I'm not there yet. And Rick Perry is a giant douche.

(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Fi47.photobucket.com%2Falbums%2Ff161%2Fweirtech%2Fmisc%2FDSC07199.jpg&hash=46f810032ed98eeea193b8112104fccb2c3efdb2)
Title: Re: How to: Backpurge when welding stainless pipe
Post by: danz on March 07, 2009, 07:00:07 PM: Quote from: weirtech on March 07, 2009, 06:38:37 PM

(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Fi47.photobucket.com%2Falbums%2Ff161%2Fweirtech%2Fmisc%2FDSC07193.jpg&hash=7718e05f94a3762bab3e51a9a1075153cbcdd9b3)

excellent picture of an ideal gap
Title: Re: How to: Backpurge when welding stainless pipe
Post by: 92CXyD on March 08, 2009, 01:50:20 PM: (https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Fi47.photobucket.com%2Falbums%2Ff161%2Fweirtech%2Fmisc%2FDSC07194.jpg&hash=388f4ba4680c6f16309633a482ae3cff1e6743f8)

why do you have two valves here are they not redundant.

and how much spacing do you need between two pieces.
Title: Re: How to: Backpurge when welding stainless pipe
Post by: weirtech on March 08, 2009, 08:58:52 PM: two valves isn't necassary, but i like to have a on and off valve so i don't have to adjust my needle valve every time i open and close the system.

spacing depends on material thickness. in most cases for stuff like schedule 10 a filler rod can be used to gap your pipe. 1/16".
Title: Re: How to: Backpurge when welding stainless pipe
Post by: 92CXyD on March 08, 2009, 11:37:57 PM: thanks for the info.

I got to start welding my own shit soon. :?:
Title: Re: How to: Backpurge when welding stainless pipe
Post by: walter on March 09, 2009, 08:43:49 PM: Quote from: 92CXyD on March 08, 2009, 11:37:57 PM
thanks for the info.

I got to start welding my own shit soon. :?:

+1 :somb:
Title: Re: How to: Backpurge when welding stainless pipe
Post by: 1Fast68 on March 10, 2009, 03:12:23 PM: Very nice, don't forget to bevel your ends some to allow for better surface are penetration.
Title: Re: How to: Backpurge when welding stainless pipe
Post by: TTC on March 18, 2009, 08:25:28 PM: Why do u have to backpurge btw?
Title: Re: How to: Backpurge when welding stainless pipe
Post by: dvst8r on March 18, 2009, 09:30:52 PM: Quote from: TTC on March 18, 2009, 08:25:28 PM
Why do u have to backpurge btw?

Because atmosphere contaminates the weld. Some metals are more prone, to this then others. SS is one, Ti is another and is really finicky, to the point that the easiest way is in a box filled with shielding gas. Ect...
Title: Re: How to: Backpurge when welding stainless pipe
Post by: bigdaddyvtec on March 19, 2009, 01:57:22 AM: My entire mani and DP was backpurged...

(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Fi32.photobucket.com%2Falbums%2Fd11%2Fscorpiomk%2FDSCF0336.jpg&hash=31aadbba6c1a5b88041905a4f2274b3bd5376746)

(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Fi32.photobucket.com%2Falbums%2Fd11%2Fscorpiomk%2FDSCF0337.jpg&hash=4efb88922582225a041389c1fba00a6c1863f080)

Welds look as good inside as they do outside :noel: :yes:
Title: Re: How to: Backpurge when welding stainless pipe
Post by: 86crxZ6T on March 30, 2009, 01:01:06 AM: [quote Welds look as good inside as they do outside :noel: :yes:
[/quote]

pics O0
Title: Re: How to: Backpurge when welding stainless pipe
Post by: SirDragsAlot on March 30, 2009, 09:05:25 PM: hey aaron, my buddy dustin got a manifold off of you, im his bro rob. i have a neat setup for doing tig welding without back purging. i do tig welding where i work and i built an argon chamber with a window and shit. you simply put the pieces in you want to weld, seal the box and flood it with argon.
ever tig welded with just the bare tungsten? its amazing! it also saves you on the gas since the argon doesnt leak out and doesnt go bad. i might try some manifolds since i have all the equipment i need where i work.
Title: Re: How to: Backpurge when welding stainless pipe
Post by: Passenger on April 20, 2009, 01:38:47 PM: Quote from: SirDragsAlot on March 30, 2009, 09:05:25 PM
hey aaron, my buddy dustin got a manifold off of you, im his bro rob. i have a neat setup for doing tig welding without back purging. i do tig welding where i work and i built an argon chamber with a window and shit. you simply put the pieces in you want to weld, seal the box and flood it with argon.
ever tig welded with just the bare tungsten? its amazing! it also saves you on the gas since the argon doesnt leak out and doesnt go bad. i might try some manifolds since i have all the equipment i need where i work.

Cool, pics?
Title: Re: How to: Backpurge when welding stainless pipe
Post by: SirDragsAlot on April 21, 2009, 09:16:25 PM: i can take some, although i might not be allowed to take a camera into my workplace. i will ask