Electrode Positive (DCEP) vs Electrode Negative (DCEN) welding with E6012 electrodes

April 13, 2018

E6012 vs E6013 elctrodes have an interesting difference, the E6012 is AC and DCEN only. Where as the E6013 electrode is AC, DCEN and DCEP.

What is the difference between AC, DCEP and DCEN? DCEP, or Reverse Polarity is the standard polarity for MIG and for Stick welding.

As for the required polarity welding with electrodes, almost all stick welding is done with Reverse polarity or DC electrode positive (DCEP). This is because the electrons flowing from the negative work to the positive electrode help to deposit the metal at a regular pace and, though it is counter-intuitive, it actually helps to increase penetration.

DCEP provides a more stable arc in general in stick welding, but for welds requiring light penetration, use DCEN if the electrode is designated to run either polarity.

Direct-Current-Electrode-Positive.png

What would happen if you would weld an E6012 on DCEP? Instead of the prescribed DCEN. In this case I used a 3,25 mm Smitweld Resistens 100 E6012 electrode (AWS A5.1-91 : E6012, EN 499-94 : E 38 2 RA 13) on 90A with a GYS 207.

During welding in DCEP you notice a bad start and little control over the puddle. The electrode also seems to burn off on the site if you loose angle.

The result is quite stunning. On the DCEN, as supposed to, the bead is nice, tight and equal. On DCEP you will notice that the slack is much harder to remove and the bead has gone everywhere and there is a crater at the end, because stopping the weld causes a long arc. Also there is a lot more spatter.

DCEN vs DCEP

The slack looked actually the same, but the result is so different.

2018-04-13 20.32.22.jpg

Here is an overview of AWS A5.1 (E60xx) electrodes and their polarity based on their coating. Notice that the E6012 has a specific preference for DCEN.

AWS-A5.1-Chart-SMAW-450x356

e6013-electrodes

Side note: cheaper welding machines with fixed cables mounted for the earth clamp and the electrode holder, commonly have a configuration that is DCEP. That means that for common welding with these machines, E6013 electrodes are recommended.

Advertisements

Issue with my HP L1955 LCD Flat Panel Monitor

March 20, 2010

I had a big issue with my HP L1955 LCD Flat Panel Monitor (TFT)

While using, the screen would fall away all of a sudden.  It seemed that if it was cooled down, it would work again for a few minutes.

Searching the internet brought some answers. It could be the capacitors or even worse.

First I replaced all the 3 Elite 1000uF 25V capacitors on the board. It is a Benq inverter board with version number 48.L1A02.A00 They could be bulged, although they seemed ok from the looks of it.

I also saw that the solder of the 220V external power connector on the board was broken, so I repaired that too by resoldering the pins. With high hopes I put everything together and crossed my fingers. It looked ok, but that was false hope. After 10 minutes the screen went black again 😦

So time for more investigation. After deep investigation with a magnifier I discovered that the solder of the same pin of each of the 4 inverter transformers was broken. Very hard to see, but there was a crack line.

Resoldered them, and guess what 🙂 the monitor works again

Memory leak issue on an Ipaq HP 6915 in combination with a Audi A4 carkit

January 11, 2009

I have an issue with my HP Ipaq HW6915 PDA, together with my Audi A4 built in carkit.

After analysing I came to the conclusion that the Ipaq cannot handle the phonebook synchronization towards the carkit.

After connecting the phone to the carkit, it starts to synchronize the contact in your pda with the carkit. Due to what ever reason, the pda starts to consume internal memory, causing the pda to crash after all memory is allocated. This can happen between 5 and 20 minutes…..

The concept however works… because the contacts are available in the carkit.

As far as I can see find on the internet, there are more similar issues with Parrot carkits and Ipaq’s. Some Parrot carkits  have the option to disable the sync of the phonebook. The Audi carkit has not….. 

Does anyone know how to overcome this issue?

Update: I have been in contact with Audi support in Germany. It’s a known isse with HP. The bluetooth driver of the Ipaq has a memory leak.

Geforceerde koeling bouwen in een Ferm Concept 1500 lasapparaat

January 4, 2009

Read the rest of this entry »

Bluetooth toggle on an Ipaq HP 6915 with hardware buttons

January 4, 2009

ipaq_hw6915

I had the issue with my Ipaq HP 6915 that I sometimes forgot to put on my bluetooth when I’m in the car. For receiving and making calls in the car, I use a jabra bluetooth handfree set.

The real issue occurs when someone calls you and the phone is not yet connected to the bluetooth carkit, due to the fact that the bluetooth on the phone is not turned on. On the Ipaq you are not able to turn on the bluetooth quickly when a call comes in.

I solved this by downloading a small bluetooth toggle application from http://www.freewarepocketpc.net/ppc-download-bluetooth-toggle.html

Put the downloaded .exe program in \windows\startmenu\applications (via the file explorer)

Via Start, Settings, you are able to connect applications to hardware buttons. I choose to use the button on the left side (that is standard used for starting up the camera).

I’m now able to toggle the bluetooth on and off by pushing that button 🙂

Solved.

Read the rest of this entry »

Reason why

January 4, 2009

This is my first post. The reason for me to start blogging is to share knowledge on things that I came across, found out or solved.