Figured we could use one with pictures!
Parts:
From
www.under-the-ice.com;
Braid, flex, and ends, as well as two 7/16" pipe joiners
Process:
We start with the end stubs, careful prepration of these makes the entire process much easier. Start by cutting the length into two pieces, I prefer to make one longer then the other. That way an access can be added to the longer to purge and pressure test without making you cut TOO near later on.
So now we have two stubs;
Deburr then, this also removes a restriction. Your pipe cutter might not have a piece, so go get the tool; deburr every pipe ever. It's a great way to get btter results.
And test fit, should be able to fit snugly.
Sometimes it doesn't fit perfect though, or theres a flange on the flex, I use needle nose to widen and "reflange". This also scrapes at it a bit and raws up the metal for later brazing.
Ta da! She fits!
Here's what I use. I had a access with 3ft of 1/8" tubing on the end, I brazed it into the longer stub, crimping a bit around it. Attach it to your purging kit.
It helps to use a vice, really helps, that way you can hold the work out and balance it. Do not clamp near the heating point though or it will suck up the heat.
Tune your torch in (acetylene here) and go for it, start by heating the inner pipe right before it meets the flex and once red move over the flex. The flex is a bit thinner walled so you don't want to melt thru.
Apply the rod. Since these are copper alloys, I use 15% Harris phos' rods. Apply the rod at the joint, on the flange made with the needle nose and up onto the first ridge. This prevents cracking of the flex at this point later. When you start brazing, and applying the rod, move the torch over the flex pulling the filler in.
Make sure your purging gas is running for that, and check if your holding pressure with your finger after. (Obviously on the unbrazed side!)
Do the other side.
Doesn't she look nice?
Little wet rag, and check for any holes
Time to clean her a bit so you can add the flex. I use a wire brush end in my drill. Clamp her in tight for this.
Now to stretch the braid. Run it over the length, and I pull it an INCH past the flex joint. This again helps for brazing, reduces the chance of hurting the flex joint, and prevent cracking the flex line later.
Slide a coupling over. Then pull it backwards with the flex so that it hits the flex itself and stops.
Push the braid through till its level with the end of the coupling.
Mount it in the vice, your going to be using a bit of rod here and you want it to pool inside the coupling so let gravity help you by bending it upwards.
Light her up!
Here's how the heating goes;
Take the torch to the coupling till its red, then go to the inner pipe. Do not point the torch inside the coupling, youll melt the braid and it will pull away. Get the inner pipe red and then move the torch so that it is perpendicular to the inner tube and connector and is heating both. Apply the rod with gravity downwards inside the two, starting with the inner pipe.
Now this looks good, don't forget the purging gas when your doing this though!
See how it fills inside the cup, the braid is inside the filler.
Do the other one the same, and then give her a clean up!
Remember when you do the other to pull the braid tight, you don't want it loose. If it goes past an inch on your flex, cut it. You do not want loose braid!
Not too shabby.
Now to pressure test. With the open end, crimp it, and just quickly braze the end shut. To do this cleanly, run the purging gear while your heating it up, and quickly kill it and apply the rod, throw the wet rag on it. The nitrogen will stick around long enough without blowing the filler out.
Turn up the regulator! 300 psi for 6 hours and she's good. I've pressure tested to 600 psi without issue.
Hope that helps!
acebook
Guide: Brazing a Braided Flex Line
Linear Mode
