Standard Redrying Oven Spec

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Hi everyone, any spec for redrying oven for consumable electrode? After redrying at 300degC, I found out there were some rusty found at the electrode holder end. My redrying oven capacity is 120kg, I put in 60kg and 10kg found rusty at holder end. Thanks for your advice.
Reply:theres often rust on rod end straight out of the can.    300c would be to hot, and damage the flux
Reply:I'm no expert, but 300°C sounds awfully hot. The upper end of what Lincoln recommends is only half that: http://www.lincolnelectric.com/en-us...es-detail.aspx-Chris
Reply:According to the chart linked above 300c is too low for redrying and too high for storage.Mike
Reply:Originally Posted by leightrepairsAccording to the chart linked above 300c is too low for redrying and too high for storage.Mike
Reply:wow, it does.     hmmm.      i got a hard time believing it though
Reply:Originally Posted by 123weldwow, it does.     hmmm.      i got a hard time believing it though
Reply:Originally Posted by leightrepairsAccording to the chart linked above 300c is too low for redrying and too high for storage.Mike
Reply:in the eighties they said the redrying process was 400f for four hours .      now its double?     i don't understand how its ok to weld w/ a freshly opened can for 4 hrs w/ no heat, open to the atmosphere, but a day old can heated up to 300f isn't good enough ?     i think someone from lincoln needs to stick there little wee wee in a 300f rod oven for an hour, then explain to me that its not sufficient to remove the moisture out of flux
Reply:i'm not saying it isn't true, i just cant comprehend.
Reply:Originally Posted by 123weldin the eighties they said the redrying process was 400f for four hours .      now its double?     i don't understand how its ok to weld w/ a freshly opened can for 4 hrs w/ no heat, open to the atmosphere, but a day old can heated up to 300f isn't good enough ?     i think someone from lincoln needs to stick there little wee wee in a 300f rod oven for an hour, then explain to me that its not sufficient to remove the moisture out of flux
Reply:Sounds like a sales gimmick to me anyway.     Just think of the all the rod that gets discarded and sold w/ this line.
Reply:Originally Posted by 123weldSounds like a sales gimmick to me anyway.     Just think of the all the rod that gets discarded and sold w/ this line.
Reply:Originally Posted by 123weldi'm not saying it isn't true, i just cant comprehend.
Reply:Thanks for sharing. I'm using E7016 and E7018, the redrying temperature is 300~350degC which recommended by vendor. I just couldn't understand after redrying, some portion found rusty holder end but some not. I tried to pre-heat oven at 120degC for 1.5 hr, but the result was same. I'm wondering my oven spoilt or some other problems on stick electrode, sigh....
Reply:Originally Posted by MinnesotaDaveThe moisture chemically bonds and therefore needs the high temperature to break those bonds.If it were as simple as drying something that is wet, anything over 212f would work fine.
Reply:Originally Posted by 123weldinstead of commenting/answering  on my valid points in my 9:48pm post, it appears to me you have some scientific understanding of moisture chemical bonding, or your just repeating something some salesman led you to believe, which you cant explain, therefore, knock me as "closeminded", and say goodbye.
Reply:Hi kingnero, thanks! I don't see any ventilation in my oven, I will search for it. Btw, humid air is visible as vapour? which we can see obviously?
Reply:basically, it's steam, but in such small % that it won't be visible.Can you check the tech specs of your oven, or ask the manufacturer? Or give us the brand, model and type?The air feed is sometimes nothing more than a (slow) passage in a labyrinth in a double sidewall, driven by a small fan, the system is not hi-tech or fancy on most models.
Reply:Originally Posted by 123weldinstead of commenting/answering  on my valid points in my 9:48pm post, it appears to me you have some scientific understanding of moisture chemical bonding, or your just repeating something some salesman led you to believe, which you cant explain, therefore, knock me as "closeminded", and say goodbye.
Reply:Originally Posted by MinnesotaDaveAh, closed mind - no point in showing you any of the technical info then Have a good night
Reply:Originally Posted by HakiroThanks for sharing. I'm using E7016 and E7018, the redrying temperature is 300~350degC which recommended by vendor. I just couldn't understand after redrying, some portion found rusty holder end but some not. I tried to pre-heat oven at 120degC for 1.5 hr, but the result was same. I'm wondering my oven spoilt or some other problems on stick electrode, sigh....
Reply:Originally Posted by kingneroAlso, make sure your oven has a ventilation option, as I've seen ovens where the humid air stays inside, and this is no good. Humid air needs to escape, and pre-dried air needs to be fed into the oven.This is also the reason why your household oven won't work (maybe better than nothing, but not as it should)
Reply:Ive heard of ionic bonds, covalent bonds and hydrogen bonds. IIRC ionic bonds are when the molecules outer shell electrons completely fill the outer valence. NaCl is a good example of ionic bond. Covalent bonds are when molecules share an electron. Hydrogen bonds are when hydrogen (1 electron) attaches to a molecule that does not have a full valence band. Interesting thing about hydrogen is it has a valence that is not full (missing one electron) so two hydrogen atoms easily bond and become deuterium H2. I'm not familiar with water crystallization or moisture chemically bonds.
Reply:Originally Posted by InsanerideIve heard of ionic bonds, covalent bonds and hydrogen bonds. IIRC ionic bonds are when the molecules outer shell electrons completely fill the outer valence. NaCl is a good example of ionic bond. Covalent bonds are when molecules share an electron. Hydrogen bonds are when hydrogen (1 electron) attaches to a molecule that does not have a full valence band. Interesting thing about hydrogen is it has a valence that is not full (missing one electron) so two hydrogen atoms easily bond and become deuterium H2. I'm not familiar with water crystallization or moisture chemically bonds.basically, it's steam, but in such small % that it won't be visible. Can you check the tech specs of your oven, or ask the manufacturer? Or give us the brand, model and type? The air feed is sometimes nothing more than a (slow) passage in a labyrinth in a double sidewall, driven by a small fan, the system is not hi-tech or fancy on most models.Hi kingnero, thanks for your advice. My oven was actually custom made, as couldn't find a suitable oven for re-drying of electrode. I will counter check with my vendor, thanks.
Reply:Sounds like your 7018 isnt low hydrogen anymore and the heat (heats of formation) and the CaCO3 (calcium carbonate) form steam.  From the chemical formula for 7018 we see that water and CaCO3 create a chemical reaction and give off heat thru an exothermic reaction. I would dry out your oven before putting any 7018 in it. If it keeps making water, then you may need a fresh box of 7018.
Reply:Hi OkieDave, thanks for sharing but it was quite difficult for me to understand. Basically the rust on the metal surface is oxidation, can I insert a rusty piece of metal inside my oven (my oven structure was stainless steel made) to capture some electron which loss during heating? It may just a temporary measure....
Reply:Originally Posted by HakiroHi OkieDave, thanks for sharing but it was quite difficult for me to understand. Basically the rust on the metal surface is oxidation, can I insert a rusty piece of metal inside my oven (my oven structure was stainless steel made) to capture some electron which loss during heating? It may just a temporary measure....
Reply:Hi OkieDave, sorry for my poor explanation. My intension was preventing my stick electrode holder end from oxidation during re-drying, so I was thinking to put a rusty piece into oven while re-drying of electrode. As rusty piece is more tendency to happen oxidation, it shall attract the electrons which release from covering flux during re-drying, and prevent oxidation happen on my electrode holder surface. Is it feasible?
Reply:Hakiro, heres the MSDS for 7018 if you dont have it. There may be differences in percentages between manufactures.  The most abundant ingredient in the flux is iron (Fe). The 2nd most abundant is calcium carbonate (CaCO3). As OkieDave said, "rust is a red oxide" and I believe the hydrogen disassociates from the water to form the oxide with iron. http://www.weld-techproducts.com/msd...018%20MSDS.pdfOkieDave, thanks for the good explanation/correction. I thought deuterium was an ionic bond (2 electrons in valence) but as you explained it is covalent and only one electron. I thought water was also ionic but I see now that it may be missing an electron in the outer valence. Have to look into it. I would be interested in why ice floats but I think it has to do with keeping the fish alive. Actually all life for that matter  To stay on topic, I would like to hear more about rust. I started a thread about rust a few years back but your explanation here would be useful IMO because iron is the largest portion of 7018 flux. I know 7018 doesnt weld good with rust or hydrogen from water , oil or whatever (acetone?).  My thoughts on low hydrogen rod was that; moisture contaminates 7018. The H from water bonds with CaCO3 and releases the Oxy to atmosphere. Kind of reverse of water contacting iron and creating the oxide while releasing H into the atmosphere. These would be exothermic chemical reactions. When an endothermic reaction happens(weld arc) , the CaCO3 gives off 2O to become CaCo and the 2O's bond with H to become steam and therefore remove H from the weldment. Flourine or flouride is also in the flux. The F or 2F also bonds with 2H to become 2HF and further removes H from the weldment.  OkieDave, can you explain further for us?