Thanks: 0
Needs Pictures: 0
Picture(s) thanks: 0
Results 1 to 14 of 14
Thread: Another welding question
-
19th February 2015, 01:17 PM #1
Another welding question
Hi there! ......... I have yet another welding question. Have to make two new anchoring points for my pontoon since I don't trust the one I have in aluminium. I have to weld two flat bar 100x15, 150 long to a plate that is 150x300x10. This is a rather critical weld since it will hold the whole structure. Conceded there will be 4 of this flat bar welded to two plates..... How much chamfer should I give the flat bar and what sort of angle, in order to get a complete weld to the plate? ... your replies as usual are very appreciated.
“We often contradict an opinion for no other reason
than that we do not like the tone in which it is expressed.”
Friedrich Nietzsche
-
19th February 2015 01:17 PM # ADSGoogle Adsense Advertisement
- Join Date
- Always
- Location
- Advertising world
- Posts
- Many
-
19th February 2015, 06:01 PM #2Senior Member
- Join Date
- May 2009
- Location
- sydney
- Posts
- 235
-
19th February 2015, 08:11 PM #3
Yes at right angle.
I am thinking to grind the edges of the flat bar so that the weld penetrates all the way inside the joint.
Just not sure at what angle I should grind the bevel and how much to leave without grinding.
Also preheat or not?“We often contradict an opinion for no other reason
than that we do not like the tone in which it is expressed.”
Friedrich Nietzsche
-
19th February 2015, 08:44 PM #4Philomath in training
- Join Date
- Oct 2011
- Location
- Adelaide
- Age
- 59
- Posts
- 3,149
Rule of thumb is that anything over 3mm should have weld prep if you want full penetration welds, so if you are chasing full pen on a 15mm thick bar I would say prep minimum 6mm each side. The angle is not necessarily anything special. The narrower it is the less weld is needed to fill the "hole" (and so less heat). It just needs to be wide enough that you can get in to weld.
As for preheat, you are going to be putting a lot of heat into one side of a plate so there will be a tendency to distort. I think it would be one of those things that you either preheat and weld at a reasonable pace or don't preheat and wait between runs for things to cool.
Michael
(far from a welding expert)
-
19th February 2015, 09:19 PM #5Senior Member
- Join Date
- May 2009
- Location
- sydney
- Posts
- 235
woodworm.
-
20th February 2015, 07:49 AM #6
I understand that the plate and the bar make a 90 degree angle and that I can weld a fillet around it. I was wondering if grinding the bar I would have a better weld because it will penetrate between the end of the bar and the plate.
“We often contradict an opinion for no other reason
than that we do not like the tone in which it is expressed.”
Friedrich Nietzsche
-
20th February 2015, 08:49 AM #7Senior Member
- Join Date
- May 2009
- Location
- sydney
- Posts
- 235
To get good penetration in a Fillet weld you need a flat clean fit, eg. NO gap and high amperage on the root run. For 15mm plate I would use at least 150amps and good quality hydrogen controlled rods, 3.2 for the root run and 4mm for the others. Make sure you have solid tacks on both sides before doing the root pass and then alternate each weld from one side to the other.
woodworm.
-
21st February 2015, 06:44 AM #8
Forgot to say I will be using a mig. 250 amp
“We often contradict an opinion for no other reason
than that we do not like the tone in which it is expressed.”
Friedrich Nietzsche
-
21st February 2015, 04:05 PM #9Senior Member
- Join Date
- May 2009
- Location
- sydney
- Posts
- 235
-
22nd February 2015, 08:20 AM #10
No problem with the set up, thank you for that.
the other two anchoring point I made where similar, with 12 mm plate and a 25mm shackle welded to it, to take a stay cable. The way I did that one was cutting the shackle above the eye where the pin goes in and leaving just a U. Then I drilled 2x 26mm holes and put the shackle through it, so I could weld from the back and a fillet around at the front. Turned out real good.
Applying the same logic with the flat bar I thought in making a tenon in the flat bar and a slot in the plate and weld front and back. May be I am overthinking this.
i have to make two of this. If I tack weld the two plate back to back before welding the flat bar at 90 to it, would that stop it from buckling or do I need something more substantial?“We often contradict an opinion for no other reason
than that we do not like the tone in which it is expressed.”
Friedrich Nietzsche
-
22nd February 2015, 09:35 AM #11
Marc
From my reading of your set-up you will have a foot of weld on each joint. If that doesn't hold the two pieces together then a tenon, back welded, isn't going to make it any better. It just complicates the whole set up.
-
22nd February 2015, 04:22 PM #12
Yes, well not a foot but 230mm however I get your point. I know no one does that sort of plug welding, if it is even the right term. Like I said, I probably am overthinking it.
What about backing one plate against the other to avoid bending?“We often contradict an opinion for no other reason
than that we do not like the tone in which it is expressed.”
Friedrich Nietzsche
-
22nd February 2015, 04:37 PM #13Senior Member
- Join Date
- May 2009
- Location
- sydney
- Posts
- 235
-
22nd February 2015, 04:43 PM #14Senior Member
- Join Date
- May 2009
- Location
- sydney
- Posts
- 235
Similar Threads
-
OK, not a welding question but ...
By Legion in forum WELDINGReplies: 3Last Post: 26th July 2011, 03:54 AM -
welding gas for aluminium question
By northerncat in forum WELDINGReplies: 3Last Post: 14th May 2009, 02:00 PM -
Welding question
By Marc in forum WELDINGReplies: 15Last Post: 15th July 2007, 11:10 PM -
Welding question ? ... Is this dangerous ?
By JDarvall in forum WELDINGReplies: 36Last Post: 9th March 2006, 12:29 PM -
Welding question
By JDarvall in forum HOMEMADE TOOLS AND JIGS ETC.Replies: 8Last Post: 16th May 2005, 11:43 PM