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Cleaning an ally oil pan for repair

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  • captkipp
    replied
    Crack prep

    GT6:

    When you are done preping your crack prior to commencing the weld, what does it look like? Do you have an open root of about a 1/16 to 1/8 of an inch? Or is the base metal still very tight together along the crack line?

    Leave a comment:


  • captkipp
    replied
    Low heat

    Originally posted by GT6Steve View Post
    Thanx Jim,

    I was using a small stop drill and filling with 4043 rod.

    I'm wondering if my 3/32 rod and #7 cup are too big for this job. Thinking about the HAZ. Material seems to be about .100 thick.

    I made a big effort this morning to keep heat as low as possible. 135 Amps is the max on my pedal. Which sometimes seems right then as it gets hot it goes to **** cuz I'm not yet smart enough to modulate it correctly.

    Getting better though, I'm now remembering(mostly) to maintain post flow and I can testify as to the mess it makes when you forget to turn the gas on

    I'm still hopeful and encouraged. Appreciate the time you experienced folk waste with these repetitive questions from every noobie...
    GT6:

    It's also quite possible here, and I hate to say this, that the heat isn't high enough to get good penetration. And this can cause the crack to remanifest itself almost immediately. Is this a cast aluminum pan? or is it made from die formed plate?

    Cast requires a bunch of heat to start, but you have to modulate the amperage as you continue the weld. Otherwise the retained heat in the base metal will continue to escalate and can actually blow the base metal away.
    I suspect that the crack is in cast aluminum as 6061 is a structural alloy and although possible, 5052 is a pretty soft alloy. I've built a ton of fuel tanks for the boat and marine industry from 5052 plate and repaired a bunch of them as well. Generally 5052 doesn't 'crack' like your describing. But cast aluminum will. 5052 will crack along the weld seam if the penetration isn't good. It also melts together real well and I use 4043 wire on this alloy, but according to the weld charts 5356 wire will work. 5356 wire and some cast alloys don't get along well. Neither does 5356 wire and 6061 base metal as the metallugical composition of the resultant puddle and weld...well putting it simply, ALLOWS it to crack.

    If the heat is correct and the penetration is good, then this alloy may require a slow cooling process to avoid re-cracking. Cover it with some non- flammable blankets or slowly cool it in a hot oven by adjusting the heat down over a period of several hours. I doubt that you would have a commercial heat treating facility there, but if you do....

    Leave a comment:


  • mastiffs
    replied
    i have done some oil pans. i agree with clean clean and acid tone and carbide bits ,alot of time i found even after all the cleaning,when you weld you have dirt rise up .i usally use a stainless wire wheel and dremel .pre heating helps to prevent more cracks .if i have a real broblem i have even put them in the oven (dont tell wife). when im done i ether cover it with lether or put it back in the oven to cool slow.. nothing like hearing that crack/pop when you think your finished .also if you have to shape something after if you dip your carbides in parifen wax the aluminum wont clog them as fast

    Leave a comment:


  • GT6Steve
    replied
    WooHoo....

    First stack of dimes. Crappy at either end but looked good in the middle!

    Using a 3/32 stop drill and every effort to keep heat out now.

    This'll be a $5000 oil pan by the time I'm done and half of that will be filler rod and sanding discs

    Leave a comment:


  • GT6Steve
    replied
    Thanx Jim,

    I was using a small stop drill and filling with 4043 rod.

    I'm wondering if my 3/32 rod and #7 cup are too big for this job. Thinking about the HAZ. Material seems to be about .100 thick.

    I made a big effort this morning to keep heat as low as possible. 135 Amps is the max on my pedal. Which sometimes seems right then as it gets hot it goes to **** cuz I'm not yet smart enough to modulate it correctly.

    Getting better though, I'm now remembering(mostly) to maintain post flow and I can testify as to the mess it makes when you forget to turn the gas on

    I'm still hopeful and encouraged. Appreciate the time you experienced folk waste with these repetitive questions from every noobie...

    Leave a comment:


  • 4sfed
    replied
    Originally posted by GT6Steve View Post
    Excelllent idea and so obvious. I've got one on the stand ten feet away.

    I am clamping it to the steel benchtop and the normalizng took some of the curve out. The cracks look just the same after stop drilling. If I weld one side they merely migrate to the other side.
    It may well be time to cut it out and patch it....
    Since this is a sheet metal pan, it could be from one of two common structural alloys that are crack sensitive when welded autogenously (i.e., without adding filler metal) . . . AA6061 or AA5052. You must dilute the puddle with the correct filler . . . for AA5052, use 5356, and for AA6061 you can use 4043 or 5356. Even then, if you leave a crater at the end of a bead it may crack. Try a larger stop drill . . . 3/16 . . . which will require you to add extra filler at the end of the bead. Also, drilling a little beyond the visible end of the crack may help as the full extent of the crack may not be visible to the naked eye.

    Jim

    Leave a comment:


  • GT6Steve
    replied
    Excelllent idea and so obvious. I've got one on the stand ten feet away.

    I am clamping it to the steel benchtop and the normalizng took some of the curve out. The cracks look just the same after stop drilling. If I weld one side they merely migrate to the other side. I pondered gasketing the pan to the bench and putting argon into the pan, presumably at the same pressure as the torch but I would have to vent it so as not to overpressurize. That however, is not the root problem here.

    It may well be time to cut it out and patch it....

    Leave a comment:


  • 4sfed
    replied
    Originally posted by GT6Steve View Post

    From your comments I learnt of the HAZ and am starting to think of that because it's probably where I'm suffering now.

    After the frustration of this evening I noted the flange was getting even more warped so I said a good normalizing was needed. Thusly I coated the whole pan with soot and burnt it off ala Fournier so maybe there will be less stresses in the metal tomorrow? I'll put it into the Phosphoric acid in the morning too.
    I'd bolt it to a block while welding.

    Jim

    Leave a comment:


  • GT6Steve
    replied
    I'll have another shot at it today and if I can't whip it I'll try a patch. I hate to give up though.

    Maybe try a square insert and butt the edges? Another learning experience

    Leave a comment:


  • Sberry
    replied
    Just out of curiosity, how about welding a patch over it?

    Leave a comment:


  • GT6Steve
    replied
    Hi guys,

    You predicted this would be a difficult learning project You were right.

    Initially it went well with the big messes and holes being closed up OK. Ugly but OK.

    From your comments I learnt of the HAZ and am starting to think of that because it's probably where I'm suffering now.

    I am grinding, drilling, welding, repeat, chasing cracks and pinholes. I just can't get ahead of it.

    After the frustration of this evening I noted the flange was getting even more warped so I said a good normalizing was needed. Thusly I coated the whole pan with soot and burnt it off ala Fournier so maybe there will be less stresses in the metal tomorrow? I'll put it into the Phosphoric acid in the morning too.

    I can't remember a thing from college Thermodynamics beyond Body-Center-Dot. Do I need to go back to school again to get this done?

    Leave a comment:


  • Blondie_486
    replied
    I don't use chemical cleaners for such things. Normally with some patience I'm able to get all of the oil out of a casting prior to welding with my trusty O/A torch and grinders (mostly the die grinder).

    Leave a comment:


  • Grumple
    replied
    Important to know

    Read the link below. It appears to be true so I would rather everybody is safe and not sorry by using the wrong cleaners etc...

    http://www.brewracingframes.com/id75.htm

    Hope that helps,
    Dave

    Leave a comment:


  • Chuck U&R
    replied
    Just what I've read -

    Guys that weld repair Harley engine and tranny cases say to wash the case,

    stick it in an oven low heat, bake it till oil comes to surface, wash repeat.

    Keep doing till no more oil.

    Leave a comment:


  • Fortyfords
    replied
    When we do repairs on our stockcar (modified) ,we have to boil out the oil pans.Then clean the cracks with acetone.
    we had a steff's oil pan give us fits until we did the above.

    Rich

    Leave a comment:

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