[cal50]

I am pressing round slugs into tubing (tube wall thickness is .070" ) and was curious if there is a standard rule of thumb on what size hole to drill for plug / rosette welding ? I am TIG welding and want enough space to get to the bottom of the hole to puddle and fill. Is a 1/4" hole overkill for a .070 thick wall tube ?

I will circumference weld the plug as well but want to put some plug welds indexed around the tube OD.
A couple pieces of tubing have partial threads that the plugs will be pressed in and covering. Any problems with blowing the puddle out from crap in the threads if they can not be completely cleaned ?

[Rick_H]

I'm sure there is a formula but it really depends on design intent and stress.

.250" doesn't seem to large to me, and yes it any thread cutting oil comes up you'll have issues, soak them and dry to get them clean and dry.

[cal50]

There is some never-seize on some of the threads and I can picture those parts being a PITA......

I am trying to avoid plug welding int he threaded area but wanted to make even spaced / nice looking welds.

[Otto Nobedder]

I'd clean those threads with solvent and a wire brush for prepping that size copper pipe fitting. Get a good one in stainless, and it's still cheap in the plumbing department of your local big-box-store. Like a test-tube brush, but tougher. Screw it in, then unscrew it. You'll remove damn near everything.

As for drilling for plug welds, generally 2X the thickness gives plenty of room, since you'll also be melting the tube a bit. Since that would be .140 in your case, I 'd round up to a 5/32 drill (.15625). The finished rosette, then, will be in the neighborhood of 1/4" overall diameter for a neat finish.

Steve S

[cal50]

Thx.

[Jacked800]

I know this thread is a little old but was curious what guys did for plug welds in aluminum. I has six plugs to do today and caught hell doing them. I was going through a layer of 16 gauge over a layer of 1/8" that I was trying to plug into another 1/8" stock on the bottom. I drilled 1/4" hole which is fine when I'm working with steel but this aluminum was kicking my butt. I tried more stick out, more amps, larger tungsten, but nothing seemed to work that great. Wasn't getting enough penetration to anchor into that bottom 1/8" piece, and even had to do it twice because the first attempt completely failed.
My fit-up wasn't exactly the tightest because of it being a repair, but don't think the largest gap between layers was more than 1/32. I was welding for a few hours before doing the plug welds so it's not the machine set up, cleaning or materials. It's just a plug weld issue.
I'm sure if I drilled a larger hole, say 3/8", it would have made it easier, but is it necessary ? Should I be able to do it in 1/4" hole ?

[cal50]

If you have a noticeable gap between layers it's asking for trouble IMHO. If the metal is clean and minimal gap you should have better results. Aluminum is fickle and unforgiving at times.

[LtBadd]

I know this thread is a little old but was curious what guys did for plug welds in aluminum. I has six plugs to do today and caught hell doing them. I was going through a layer of 16 gauge over a layer of 1/8" that I was trying to plug into another 1/8" stock on the bottom. I drilled 1/4" hole which is fine when I'm working with steel but this aluminum was kicking my butt. I tried more stick out, more amps, larger tungsten, but nothing seemed to work that great. Wasn't getting enough penetration to anchor into that bottom 1/8" piece, and even had to do it twice because the first attempt completely failed.
My fit-up wasn't exactly the tightest because of it being a repair, but don't think the largest gap between layers was more than 1/32. I was welding for a few hours before doing the plug welds so it's not the machine set up, cleaning or materials. It's just a plug weld issue.
I'm sure if I drilled a larger hole, say 3/8", it would have made it easier, but is it necessary ? Should I be able to do it in 1/4" hole ?

I believe you have answered your question, yes you need a larger hole. The al is going to melt, flow and fill a 1/4" hole very quick not allowing you to get the penetration you need

[Jacked800]

If I go with a bigger hole, at least I'd have room to wash the sides down into the bottom. I got so caught up trying to make it work the way I had it laid out, that I couldn't stop. Just wanted it done. could barley feed rod down the hole to hit the wet spot without the torch spitting back at me. And my tungstens kept deteriorating (wearing thin) between the tip and collet body. My stick out was about 7/16 using my WP9 which I don't have any gas lens for. I needed that much Stick out to see myself hitting the bottom of the hole.
Next time I think the diameter hole size will be the 2 X the hole depth. Example " 1/4" deep = 1/2" diameter.

['Stang]

I am pressing round slugs into tubing (tube wall thickness is .070" ) and was curious if there is a standard rule of thumb on what size hole to drill for plug / rosette welding ? I am TIG welding and want enough space to get to the bottom of the hole to puddle and fill. Is a 1/4" hole overkill for a .070 thick wall tube ?

I will circumference weld the plug as well but want to put some plug welds indexed around the tube OD.
A couple pieces of tubing have partial threads that the plugs will be pressed in and covering. Any problems with blowing the puddle out from crap in the threads if they can not be completely cleaned ?

As far as the threaded portion-get a tap to match the threads. Run the tap over the threaded portion while applying lacquer thinner or acetone. This will clean the grooves on the threads. Flush away anything that may contaminate the weld.

[geo]

I build a lot of things with what I have, not what I need, so sometimes fit up is not the best. I've found with aluminum (cause it's AC) plug welds (especially thicker stuff) or pipe on flat plate or other deep gap set-ups you need to be aware of the path of least resistance the arc will take.
I use the HF arc to position my electrode angle and arc length initially. It will show you where the heat will go when you finally start to puddle.
In a simple drilled hole to plug weld usually it will HF arc to the top piece on the top edge unless perfectly vertical and tight to the inner piece then there is no room to bring in the rod to the puddle and it just drips onto the lower fitment and deposits scum. Proper fit up and you can get away with wetting the top edges and flow into the plug.

I've found sometimes all it takes is to use a step drill to chamfer the hole or on thicker material, especially if fit-up is real bad, I take my die grinder and make a bit of a tapered slot into the hole to feed some thin filler in once you find the position where the HF is actually contacting the inner piece.
You have to puddle the inner piece first if fit-up is loose.

[Braehill]

On Aluminum, use a router and cut a short slot and fill it in, way easier than a hole. Wood bits do a wonderful job, just watch when they get hungry that all you parts are clear and wear safety glasses at minimum.

Len

[GreinTime]

Somebody is going to post on here one day that they tried that and show us a picture of them in the ER with aluminum chips stuck all over them. I have yet to watch you do this, and I definitely don't want to in the garage at home!

[dirtmidget33]

Somebody is going to post on here one day that they tried that and show us a picture of them in the ER with aluminum chips stuck all over them. I have yet to watch you do this, and I definitely don't want to in the garage at home!

I know couple of people that cut aluminum plate on table saws I thought about trying one day, but just can't picture hot chips flying around and concerned about kick back or chipped teeth. One claims they cut 1/2 6061 I think I will pass on that I like my fingers where they are.

[AndersK]

Somebody is going to post on here one day that they tried that and show us a picture of them in the ER with aluminum chips stuck all over them. I have yet to watch you do this, and I definitely don't want to in the garage at home!

Already done and posted earlier. No ER needed
Aluminum is low density so energy in chips are low and they already have cooled off when they hit you.

Pay more attention to what Len said about when they get hungry, but you learn to avoid and handle that too with time.

4mm diamond plate beveled with a wood router

[Braehill]

I've cut 1/4" 6061 plate with a regular wood blade on a 7 1/4" circular saw on lots of occasions. Being left handed and using it to cut, the chips haven't quite lost their heat by the time they find my hand, sleeves over the gloves are in order for me.

Clean up is not a lot of fun if this is done in the shop and my magnetic broom doesn't help.

Len

[Otto Nobedder]

I've cut 1/2" 6061T-6 with a circular saw.

Cuts like butter, only with shrapnel

Steve S

[GreinTime]

I'm not saying it's not possible, I'm just saying some less than capable person is going to find this thread years from now and we're going to see just how deep a chunk of 6061 gets embedded into a wall lol

[weldin mike 27]

Butter with shrapnel.... Sounds like a food recall is in order....

[Otto Nobedder]

Most aluminum alloys cut beautifully with a 40 tooth carbide blade in a 7 1/4" circular saw.

I do it often.

The "shrapnel" is just chips that a normal grinding shield will handle.

It works.

Steve S

[motox]

just cutting 5/8 cdx plywood chips fly everywhere
and they can stick in your hands or get in your
eyes.
where protection, secure the piece of aluminum
and pay attention, no problem. but regardless of how
informative we are you still can't fix
stupid.
craig

[exnailpounder]

At the nuclear plants, holes in the decking on all scaffolds are filled with aluminum diamond plate that is cut with Skilsaws. Its so freakin loud you can't hear yourself think if you are close. Thank God the Laborers get to do that!

[geo]

You want aluminum chips? Bevel a 1/2" plate of aluminum to a 1/8th" root with a hand held electric wood planer. Wear a full suit though lol.

4', 3 passes, less than min. My side cutting yard is paved with aluminum chips and grinder dust.