welding cast aluminum

By Lawrence (*****)

Date 01-09-2007 21:17

I'm gonna let some others pitch in first on the data but I really want to ask you to take pictures of this project from fit up to finish and post them here on the forum..

Really sounds like a challenge!

By bjstorm69 Date 01-09-2007 22:12

yes it is, but it is easier then casting it from scratch, although I might consider that later.
thanks

By yorkiepap (***)

Date 01-10-2007 03:48

Hey bj,
Welcome to the forum and you need no pardon. You will find a vast array of knowledge here so just ask any question anytime......keep it to welding...not women... :>))

I have done a lot of welding repairs on cast alum. transmissions. Also, these transmissions are newer ones from the '70s-90's, so I don't know about the older Powerglide if their composition is the same. I would tend to believe they should be. These were only repairs, so I just want you to get an idea of a start and maybe an idea to pursue your project. Most of my repairs were broken mounts, cracks, and straightening/reinforcing. With broken mounts, I clean thoroughly and wire brush, and grind a bevel on the entire mating area. I find that a preheat works the best on the welded area, but I take a precaution to heatsink all surrounding areas with steel plates. Also, I use steel plates clamped to the mount and body area to maintain alignment. After setting up and cleaning thoroughly, I preheat to 350-400f using a surface temp. gauge. I MIG weld with .035, 5356, with Argon at 32cfh and heat at 140A & WF@600ipm.

Since your project is quite extensive, I would suggest that your best results would be TIG, and someone who is very experienced. Your best approach would be to do small sections at a time to try to maintain a lower overall heat saturation on the entire unit. You may find using some 1/2" alum. angle to reinforce your joining of the two units. Aluminum is not difficult if you proceed with careful forethought. I would definitely do some hard practice on some scrap material or a junker transmission to work out any bugs and allow yourselves the opportunity to examine your efforts and parameters.

This sounds like an interesting project and I know others here would be interested in your results and if success is obtained. Please keep us up to date on your progress.....Good Luck...Denny

By bjstorm69 Date 01-10-2007 15:20 Edited 01-10-2007 15:22

thanks denny,
this a project that I have been working on for several years. I had a need for a right angle drive transmission for either v8 motorcycles or dune buggies. I have concentrated on the original design of the powerglide transmission which proved itself to be a golden child. My plans are to eventually cast or machine a case out of solid metal. Of course, I want to be sure that everything works the way I want it.....so I am welding one togather as mentioned. My plans are to clean the metal, preheat, and tig weld it with my miller syncrowave 350. I plan on using 1/2 to 3/4 stock beveled to the case, tack welded, then several quick small weld until finished. I would use an approach that I use when welding quarter panels on a car so as not to heat up the metal to much. A lot of complex maching is invovled here so that is why I am taking it slow. There is to much work here for me to screw it up.
Question,
I am using a syncrowave 350, what rod should it use? 5356?
Any thoughts on the type of stock I should weld to the transmission?
Is there any process that can heat treat or harden the work piece after welding is complete?

thanks for all of your inputs.
storm

By jwright650 (*****)

Date 01-10-2007 15:33

Don't forget that the tranny case is a casting that is probably not very clean. What I mean is that the cast material is porous and oil is easily soaked into the case making it difficult to remove the grease and, as was mentioned in another thread, the grease keeps coming out as you heat it while welding and then porosity rares it's ugly head.

By aevald

Date 01-10-2007 16:04

Hello bjstorm69, as Denny said, it does sound like an interesting project. As far as the rod goes, the 5356 will be a stronger filler material, however, it will be more prone to cracking. 4043 may end up being a better selection for filler rod. It was also mentioned that you are working with an aluminum casting and as castings go there is almost a guarantee that you will encounter oils and other impurities that will be present in the porous surface of the material. If possible use some acetone, even to the point of submersing the parts in it, to help remove these oils and contaminants. Let it soak for a day or so, then let it dry thoroughly. Since you are working with aluminum, warpage and distortion issues will be more pronounced than with many other materials, as you were also told, try to go at the welding on this slowly and jump around so as not to concentrate the heat in one spot for too long. On one of my first experiences with welding on transmission cases many years ago, I was repairing a Turbohydramatic 350 case, it took me four times of welding, grinding and rewelding the case, before I was satisfied with the results. That was before I was made aware of chemical cleaning and other methods of preparation for welding on aluminum castings. Good luck and regards, aevald

By webbcity (***)

Date 01-10-2007 16:59

bj . long story short - while on road trip in 87 broke down i-5 truck lo-boy cat dozer had to be towed to shop . a hydraulic pump with broken mounts had to weld it at a truck shop in los banos ca. when their welder was done with what he was doing he came over to the bench that they let me use to disassemble pump on , looked at it and said it couldn't be welded because it had needle bearings pressed into the casting and get too hot . i said i don't know what you have to work with but i can weld it with what i have at home and it looks like you have much more here . one of the owners said give him what we have we may learn something . i put it into a pan of water above the bearings for a heat sink did short welds kept changing water to keep it cool worked great . also i fixed fuel transfer pump on their cat loader ,
was offered a job invited to tour their entire operation where their r&d was developing new harvesting machinery - lots of aluminum welding in there , while our truck was being repaired . i some times wonder if i should have stayed . good luck . willie

By aevald

Date 01-10-2007 17:14

Great points, Willie, sometimes you have to get creative and take the plunge. Often you won't know if you don't try. Have used water in a similar fashion on other items to keep from burning up electrical coils and other sensitive parts, works really well. Nice tip Willie. Regards, Allan

By webbcity (***)

Date 01-10-2007 17:27

allen , we used to put cat rollers in a stream and build them up keeps the bearings from frying one of my dads old tricks . good luck . willie

By Sourdough (****)

Date 01-11-2007 02:02

Only in Alaska. . .

By yorkiepap (***)

Date 01-10-2007 20:15

Hey willie,
Your mention of a water bath is an excellent way to maintain coolness. I know several outfits that have large circulating tanks made to do that exactly. Of course, the work is on a completely bare casting and they have done transmission castings that way.....good thought....Denny

By XPERTFAB (**)

Date 01-11-2007 04:26

In another life I did product deveolpment for a major racing trans comapny. We modified a lot of cases as prototypes for new products such as a special trans for offshore race boats and such. Used powerglides in initial development and a lot of welding involved. We were also very able to perform corrective machine work to pump register at front of case. Additionally we could machine / repair band anchor lug in case midsection. Lot of deforrmation from weld shrinakge when you began to weld at locations other than bellhousing and extension housing extremities. If you must use GM Powerglide case, then help yourself emensely and have the thing thoroughly cleaned in a Vapor Degreaser if at all possible. Baring this, multiple passes through a very hot transmission type pressure washer with FRESH!! cleaning concentrate. Remove case while warm from pressure washer and steam clean further if availbile. Otherwise rinse with HOT!! water at pressure. Preheat case to approximately 300 degrees with the pump (cleaned thoroughly also) installed into case with bolts fully tensioned. (No pump gasket). Small welds with spoolgun set up seem to have given best success (4043 wire) I used mixture of Argon and Helium for TIG process (non square wave machine) Heat treat in case will be essentially nil after much welding on the central portions of the case. Better bet would be to order new poweglide case from DEDENBEAR and have it machined undersize at rear output support bushing and pump register. No heat treat either, just as cast. Weld away at this point; then heat treat and finish machine bores and registers to spec. Some extra cost involved for sure but you will wind up with a component better able to transmit power as I understand you want to do. Won't leak or chew up pumps/planetary either. Valve body will even seal as it should. Hope this reply doesn't kill your enthusiam for this project. Just don't want you to suffer the development woes and have to redo your work twice.

By yorkiepap (***)

Date 01-11-2007 21:07

Hey XPERTFAB,
Now that is some pertinent information. That is quite generous of you to offer this kind of info. and it is what makes this forum such a great arena for welding knowledge and experience......Denny

By bjstorm69 Date 01-12-2007 02:23

I think we are on the same page here, thanks for the response. I understand the use of the dedenbear case, my current reasons for not using it are expense and initial prefab is more applicable to a standard case. But I have extensively pondered that thought. I understand the concern for cleanliness, but I would like addition comments on the following if possible. I am thinking way ahead on this and do not want to attempt to this job until I clearly have a good procedure down.
This is what I'm thinking.

I am planning on having much of the transmission assemebled. No oil or gaskets of anykind inside it. I plan on having the gussets and weld stock clamped and jiged in place. Next I plan on preheating the transmission with a large propane torch 300 to 400f surface temperature. Next, I plan on using my syncrowave 350 and spot weld about every two inches being careful not to heat up the transmission and stock to much. I plan on stitch welding it, taking several cooling breaks until it is welded. Which will take a hell of a long time!

Confusion:

per other responses:
should I keep the trans in water, keeping it cool while spot welding? I thought I would preheat it so it wouldn't take me a month of sunday's to heat it up with the tig tourch before welding.

Also, can anyone tell me what base metal I should use to weld to the trans.

thanks alot guys, I really appreciate all of your ideas. I have found it impossible to get advise in most of my welding questions. I have read what i could and practiced, still outside experience it difficult to come by and greatly appreciated!!!!!

thanks

By aevald

Date 01-12-2007 04:03

Hello bjstorm69, I'm going to take a small shot here at giving a like or slightly different take on some of your questions. You ask about the preheat question regarding whether it is better to go with the 300 to 400 degree preheat, I feel you will encounter varied opinions as to whether this is the correct way in which to approach this. From a weldability standpoint, I do believe that it will weld easier but not necessarily better with the preheat, the argument here would have to do with softening or taking any sort of heat treatment of the casting out by doing so and also introducing possible additional distortion. There has been much discussion on the forum regarding preheating of aluminum alloys and the benefits or damages caused by doing so, I believe many would argue either way.
   You mentioned that you would like to tack the pieces every couple of inches or so, the manor in which you make these tacks could have a great influence on whether you end up with internal root cracking or crater cracking that could be very difficult to deal with when you are trying to have sound welds. Be very careful to take note of how you end your tacks to ensure that they are filled in the crater and not prone to crater cracking. Also watch carefully to notice if you are seeing any centerline cracking due to the type of filler rod that you are using. 5356 may work, but if you are seeing a lot of cracking you may have to switch to the 4043.
   The 6061T-6 alloy will be a stronger type of material to use for your peripheral parts and pieces but it is also a heat treated version and the strength would likely be lost with the high preheats and welding temperatures required to achieve sound welds. 6061T-6 can be prone to cracking while welding in a lot of instances. 5052 might be a better alloy to work with in this particular case but I am not specifically aware of it's strength characteristics in this particular application. I do know that it is not so prone to cracking from welding, mostly due to it's metallurgical composition.
   Keeping the case cool during the welding process by immersion in water or other types of cooling methods will certainly make for less distortion of the case and allowing it to hold pre-machined tolerances, at the same time it will make for a more difficult welding challenge.
   Overall I think that there will be give and takes to whatever methods you choose to use in your project here. Unfortunately there could be some things that will come up that will cause results that will not be acceptable. In those cases you will end up scrapping some cases and going back to square one a little bit. As some of the other folks have said, keep yourself focused and likely you will find a balance that will bring success to your project. Good luck and regards and certainly keep us all posted of your progress, Allan

By XPERTFAB (**)

Date 01-17-2007 05:26

Give some additional thought to use of alumium MIG processes to complete this task as in real life practice this provided fantastic results with minimal risk of overheat woes to case. I have even used a ReadyWelder spoolgun for this task with great results at low cost. Also remember to install casesaver for reverse clutches into case after welding so that you don't have clutch engagement issues. The rear of case where you are most like to be welding will become softer than factory unit and will allow reverse clutch pack to chew up the case making for erratic operation. About a $22.00 part from most racing powerglide parts suppliers. See National Dragster weekly magazine for good sources.
Regards,
Xpertfab

By Eutectic (**)

Date 01-14-2007 06:33

bjstorm69,

I.t.o the job I am not knowledgeable at all. But for the welding, I may have small contribution.

GTAW if done correctly will be clean. Preferably Square wave with Zirconiated Tungsten ( 100%argon or Ar/He). If the welds can be welded in Flat position GMAW pulsed will work very good ( same gas, depends on how "hot" you want the arc to be)

As stated earlier, clean clean clean!! if you have oiled parts (casting) someone a while ago stated submerging it in water while boiling and then scooping the oil off until it stops coming to the surface. (I have not done this but it sounded like a good enough idea) just make sure the water is out after this process!!

The filler rod is firstly dependant on your base material composition. this restriction applies to metallurgical factors of certain alloying that are not so compatible with others and might lead to unwanted precipitations- hardness and all the other things that can contribute to a really bad day.
After you matched your compositions I believe you will be able to play around a bit on what exactly you want in-service ex. heat resistance, corrosion resistance, strength etc. then match that criteria.
This applies to selecting any metal (aluminum) you would like to weld to the casting.

if you are totally unfamiliar with aluminum welding, there are a lot of small precautions to be taken. There are some very good document from TWI or else mail me.

Regards,
Hanre