Welding Tips and Tricks

I am a retired hobby welder (old construction crane operator / heavy duty mechanic) with a Diversion 180 I converted to a WP 20 flex/water cooled torch. I have had it for a few months after using a scratch start setup on a buzz box for the last 10 years. I do pretty well on plate aluminum such as building the tank for my home brew water pump.

My son has a small centrifugal water pump on a sprayer he forgot to drain last winter. The housing is cast aluminum and probably 12" - 14" in diameter. There is a freeze crack on the OD of the housing that is not really open but it leaks.

I plan to V grind the crack before attempting to weld it. I am guessing the metal is not very thick. I have never welded cast aluminum and would appreciate any tips to do it right. What filler rod would be best? Pre-heat? I have on hand EP 4043 1/16" - 3/32" / ER 5358 - 1/16 - ER309L 1/16" - .045 and ER316L-1/16". The welding supply store is close by if something else would be better. Thanks for any help provided. This forum is something I read nearly every day.

Jim
Bellingham,WA

Perhaps John can share his filler rod type with you since I don't see it listed in his forum.

Since you don't care about anodizing:

From Hobart:

1. Service Conditions such as immersion in fresh or salt water, exposure to specific chemicals, or a sustained high temperature (over 150ºF(66ºC)) may limit the choice of filer metals. Filler metals ER5183, ER5356, and ER5654 are not recommended for sustained elevated temperature service


Transmission housing taking high heat input with heavy stress and it's a dirty job.
4943 was the recommendation.
http://forum.weldingtipsandtricks.com/v ... um+polaris


Car rim so heavy pressure low heat.
Clean cast, 5356 was a suggestion but if dirty 4043 was then the suggestion and I'd bet 4943 would be a consideration if it was more available and less expensive.
http://forum.weldingtipsandtricks.com/v ... =5356+cast


Why is 4943 so cool and has had proven higher strength characteristics than 4043 or 5XXX series?
http://www.thefabricator.com/article/co ... ller-metal

Now to hurt your brain with graphs, ksi, heat treatable vs. non, base metal to fillers, weld/part conditions, operation conditions:
http://maxal.com/files/QuickSiteImages/ ... 12_doc.pdf

V groove with a carbide burr if you have it, run a few dry passes over with the torch to help clean the metal if possible, clean. Then the 4043 should be just fine...id recommended peening it as well, lightly so you don't cause any other damage. If this is near the edge you may want to bolt the housing down so you do not cause warpage.