Electrode Oven

[System-f]

Could a small toaster oven be used as an electrode oven (redrying?)? Most I have seen are capable of decent temps.

[Glenn Long]

Electrode Oven

Yes, but a light bulb left on in a box or an old refrigerator will do just as good and more cost efficient.

[ross932c]

I don't see why not. If it reaches descent temps. People use ovens so that should work fine. I have never done it though.

[System-f]

but is a lightbulb oven going to get hot enough to redry low hydrogen electrodes? It should keep them stable, but everyone keeps telling me to re-dry 7018s around 500F+ before use, or they are worthless?

[Sberry]

There is a reheat schedule floating around here somewhere. You can only reheat once or twice. They are meant to be stored at 300. Its 550 for an hour or 2 depending on a couple things. Dont think it would be very convenient to bake without having some storage. I am not sure about some of the technical date, but I can tell you for a fact hundreds of thousands of pounds of them are used without storage, mostly on mild steel single pass limited thickness though. I have only seen a few times where it looked to be underbead cracking or embrittlement and it couldnt be totally isolated to that cause. I know the dangers are greater on harder steels and thicker with multi pass. I would certainly like to see some test results on common steels.

[stever]

What Sberry says about hundreds of thousands of pounds of low hydrogen being used without being heated or redried is true.

I don't know why some of the Hobart moderators haven't jumped in, but the manufacturers that use the AWS numbering code generally state the same heating or redrying parameters.

The low hydrogen electrode is manufactured to maintain the lowest possible hydrogen content. Hydrogen is a major cause of hydrogen embrittlement and underbead cracking. Hydrogen being present in the air that you breath can condensate on the flux of the electrode just like the dew on your car window. When an arc is struck the arc can break the water down into it's base elements of hydrogen and oxygen. The hydrogen then mixes with the molten weld metal in solution.

Low hydrogen electrodes, not just E-7018, must be kept at 250ºF to 300ºF for storage. Water boils at 212ºF, so it stands to reason that above that temperature water should boil out of the flux. I guess I should say enough water shouldn't be present at this temperature so that it will get into the flux. Electrodes that have been fresh out of the water resistant packaging/box can be left out in the atmosphere for no longer than 10 hours, then replaced into the hotbox. Some say 4 hours max exposure time. If the electrode is out of the dry manufacturers container or heated box longer this AWS states that the electrodes should be redried at 750ºF for one hour, then put back into the hotbox at 250ºF. The electrodes must be brought up to 750ºF to break the molecular bond of the flux and water. Anything below 750ºF will not break that bond. As Sberry said this can be done ONLY once. Of course, this is for critical or code welding. Welding up a BBQ grill or work table doesn't quite make the critical list. I don't think a toaster oven would get to 750ºF.

Never store an electrode, such as, E-6010 in the 250ºF hot box. This rod has a cellulose bonding agent in the flux. Cellulose, which is a wood product such as paper, will burn out of the flux rendering the electrode unusable. This electrode can be stored using the light bulb for heat as long as the heat doesn't get above 150ºF.

This information is available from any manufacturer that uses the American Welding Societies numbering system. This info is also available from the American Welding Society.

[Jmb]

If anyone is interested, there is a company out of Houston that is selling used Phoenix rod ovens on Ebay.

I bought one of the model 300,s that holds 350 lbs of rod with a temp control from 100 to 550 with a 1000 watt element. I checked with my local welding rep and he said the model 300 lists for close to $800.00. I paid $135.00.

There is also a 50 lb. and 10lb Phoenix by the same seller. There were several of these and they seem to be going for more than the larger ones.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=11774&item=2589243466

Here is a link to Phoenix if you want to ckeck em out!