economical and proper way to weld these parts 2

[valmeidan]

So I am designing a manifold, and I know there are multiple ways to weld a barb to a pipe, however the barb needs to be on a 30-45 degree angle (undecided) so reduce pressure drop, now, I will machine the barb, but would it be best to just drop the barb into an angled hole in the pipe? or cut a wedge shape on the end of the barb and mating pipe and weld or what?

 

[NBrink]

Really depends on the size of the manifold, operating conditions and whether it's being built to any code. There are a lot of ways to do that, some more robust and some easier.

But google "latrolet"....

 

[valmeidan]

anotehr pic, machined barbes, cut off on 45 degree angle, holes cut into pipe at 45 degrees, then the barbs would drop and in weld?? I guess what I am not sure about is drilling into the pipe at a 45 degree angle due to slip or skipping the bit along the round surface??

 

[valmeidan]

I know of laterolets, then I would need to buy the laterolet then three barbs also, so not sure if this is more expensive than machining three barbs then weld them in. plus I cannot for the life of me find any CAD models of these to see if they can even fit into my model and space constraints

 

[valmeidan]

I guess a big question is also, how difficult it is to drill the pipe onto a 45 degree angle to hold the barb in on the correct angle for welding

 

[EdStainless]

You miter the ends of the barbs, so that they are at 45deg and match the curvature of the manifold.
Mounting the manifold into a mill and drilling angled holes is no big deal.
And if the barbs fit against the OD surface then a couple of tack welds is all that it takes.

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P.E. Metallurgy, Plymouth Tube

 

[berkshire]

valmeidan
Ed Stainless has given you the best advice , Hold the end of the barb at an angle in a machine vice, then cut the contour with a milling cutter to achieve what he said. The drilling is easy.
B.E.

You are judged not by what you know, but by what you can do.

 

[valmeidan]

so here is two pics of what I have done. cut into the pipe at a 60 degree angle, then cut off the barbs to slide into the holes, then I would fillet weld around the barbs?

 

[valmeidan]

second image

 

[EdStainless]

That isn't how I would do it. It looks cute and seams easy (the holes are your alignment guide) but it leaves a large crevice inside exposed to the fluid. This makes thorough cleaning impossible and raises the likelihood of corrosion.
Cut the ends of the tubes at an angle, then use a cutter that matches the OD of the manifold to put a radius into the angled end. These will fit on the OD surface.
Drill your holes in the manifold to match the ID of the barbs.
I presume that the barbs have thinner walls than the manifold. This way you can get full penetration welds.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[valmeidan]

That isn't how I would do it. It looks cute and seams easy (the holes are your alignment guide) but it leaves a large crevice inside exposed to the fluid. This makes thorough cleaning impossible and raises the likelihood of corrosion.
Cut the ends of the tubes at an angle, then use a cutter that matches the OD of the manifold to put a radius into the angled end. These will fit on the OD surface.
Drill your holes in the manifold to match the ID of the barbs.
I presume that the barbs have thinner walls than the manifold. This way you can get full penetration welds.

So would you drill straight holes into the pipe instead of angles holes? matching the holes of the ID of the barbs while the barbs are angle cut will be an oval hole on the pipe then?

 

[berkshire]

valmeidan,
Yes the holes in the main tube will be cut at an angle and will generate an oval hole. You can do this by first clamping the manifold in a vice , pilot drilling small holes at the correct locations , then clamping the manifold in a sine vise at the correct angle , use an end mill of the correct diameter to bore the holes at an angle. your correctly shaped barb will sit on top of this hole and match the shape of the outside of the main tube.

You are judged not by what you know, but by what you can do.

 

[Tmoose]

What size are the pipe and barbs?

 

[tbuelna]

It is not a good idea to drill holes thru the pipe wall at the angles shown. The 45/60deg angled holes in the pipe wall should be milled instead.

 

[berkshire]

Tbuelna,
I guess my explanation was not quite clear, the pilot holes I described would be drilled in at 90* to the pipe surface at the correct positions .
These holes are only there to avoid material build up in the dead center of the end mill when milling at an angle into the tube.
B.E.

You are judged not by what you know, but by what you can do.

 

[valmeidan]

so like this

 

[EdStainless]

Yes, that way you can actually get full penetration of your barbs, and have good flow.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[berkshire]

valmeidan
Correct . You can use the method I proposed, or go talk to your machine shop, but the end result should be the same.
B.E.

You are judged not by what you know, but by what you can do.

 

[valmeidan]

The only thing, I was concerned about is them getting the angle correct out of the manifold. but I suppose they can fixture it , tac then weld

 

[btrueblood]

Hard to judge without some sense of scale...but you may need to adjust the spacing to allow a welding torch to access the inside corner.