Aluminum engine blocks

[Mowjunk]

What would be the best cleaning procedure to use when welding on a used aluminum block? I would imagine that there would be oil in the pores of the aluminum and was wondering how much cleaning is necessary. I have a small engine block that has a small cut in the crankcase that was made when the connecting rod gave way and would like to see if I can weld it shut. Any suggestions on preparing it for welding?

[Guest]

Re: Aluminum engine blocks

Originally posted by Mowjunk
What would be the best cleaning procedure to use when welding on a used aluminum block? I would imagine that there would be oil in the pores of the aluminum and was wondering how much cleaning is necessary. I have a small engine block that has a small cut in the crankcase that was made when the connecting rod gave way and would like to see if I can weld it shut. Any suggestions on preparing it for welding?

We use acetone for local cleaning, and a rotary file to get the joint down to clean metal...even then you may find oil boiling out. Steam cleaning will help, too, and I would do that first, but there will always be some residual gunk in the joint. Try to weld it after you clean it, and you will know right away if you can get something to stick on it. A lot depends on the casting, as to how porous it is, but they are normally weldable. I would use 4043 weld rod on it.

With that brand new 180SD, it should be childs play for ya!

[Mowjunk]

Thanks Rocky, I'll give it a try. It's not very thick at that point. I don't know if that's good or bad. And I think the 180 will have no trouble with it - I just don't know about me!

I don't have ready access to a steam cleaner, but it's small enough to put in a pot and boil it for a while. I wouldn't think that boiling it would hurt it.

Thanks again....

[rangerod]

Aluminum Engine

Mowjunk

If the part is not that thick & you can get to both sides of the crack, I suggest you rotary file the entire crack out removing minimal amount of material as possible. After it is ground out backup one side of the crack with a copper plate & fill the crack as required. Doing this will ensure all contaminants out of the parent material.

Rangerod

[rangerod]

Aluminum Engine

Rocky D

I missed the part where you advised Mowjunk to rotary file the crack out. Did'nt mean to jump on your wagon.

Rangerod

[Guest]

Re: Aluminum Engine

Originally posted by rangerod
Rocky D

I missed the part where you advised Mowjunk to rotary file the crack out. Did'nt mean to jump on your wagon.

Rangerod

Hey, no problem....repetition is a great teacher!

[Mowjunk]

Hey Rangerod, thanks for the reply. How thick should the copper strip be? I don't have any copper so what thickness should I start looking for?

I have the acetone and the rotary file. Looks like I'm two thirds of the way! Thanks again......

[chip hayden]

don't know if this might help, but i often use solutions similar to mag wheel cleaner. any aggresive liquid cleaner with sodium hydroxide will degrease it well. just neutralize with fresh water, dry and it should weld quite well.

[rangerod]

Aluminum Engine Block

Mowjunk

I recommned 1/8" if you can get it. What the copper plate is going to do is act as a heat sink. It will help to keep the molten puddle from falling out as you are welding and the molten aluminum should not stick to the copper unless you put some serious heat on the part. If you have previously welded aluminum parts that were not very clean you know what I'm talking about. Alot of heat will start to build up until you get some of the contaminants burned out of the area, causing alot of heat transfer to the surrounding area. Good luck with your repair, just have patience with it.

Rangerod

[Guest]

Originally posted by chip hayden
don't know if this might help, but i often use solutions similar to mag wheel cleaner. any aggresive liquid cleaner with sodium hydroxide will degrease it well. just neutralize with fresh water, dry and it should weld quite well.

Chip, where I work has an extensive chemical processing area where they clean aircraft parts, made from Inconel, stainless, aluminum, and titanium. The chemicals they clean them with vary greatly. Some real nasty stuff to deal with. Quite often I have to fix or weld on the processing baskets made from 316L and there remains residual chemicals on the baskets sometimes. It has always been a concern to weld on this stuff, because there are NO studies as to what gas you are making when you weld through these chemicals. I have had occasion to get rather dizzy after welding them. This is real dangerous stuff to deal with and nobody will tell you what is going to happen if you do weld on it. That is why I am concerned when you say you clean your parts with Mag wheel cleaner or Sodium hydroxide. Even though you wash it with water there is always a residue. Just be careful and be safe, and breathe clean air!

[chip hayden]

Rocky D,
i concur with your concern regarding chemicals and the residue. Sodium Hydroxide is the main ingredient in many water soluble type cleaners for aluminum wheels and leaves no residue. i use to use TSP[trisodium phosphate] but the phosphate can be an environmental issue. i also try not to use acetone too much because of it's volatility[ and the fact it raises **** with my old hands].
years ago i use to work for a commuter airlines and had a product called "ultra-solv"[it was a purple liquid] it also contained NaOH and that's how i discovered how well it worked for cleaning and prepping al. parts for welding. it seemed a little safer than MEK and acetone. just my two cents.