On Sun, 30 Aug 2015 16:50:02 -0500, "Terry Coombs"
wrote:

Gunner Asch wrote:
On Sun, 30 Aug 2015 15:37:59 -0500, "Terry Coombs"
wrote:

Gunner Asch wrote:
On Sun, 30 Aug 2015 13:13:51 -0500, "Terry Coombs"
wrote:

Here are some photos of repairing the hole in my tractor crankcase
. Welds looked kinda ****ty , but this is a piece of aluminum
that's been soaking in oil for over 30 years . I'm happy enough
with it that I'm going to send the one I bought* back and use this
one .
http://s991.photobucket.com/user/Sna...?sort=3&page=1

Nicely done! Good matching of the plug as well as the scarf.

If you do much of this..Id strongly suggest you find a small bead
blaster, regular sand will work...to clean up the area around the
weldment. Clean it up well and it prevent that porosity as the area
will be squeeky clean and fresh metal. TIG I expect and you did
preheat well with a torch, right?

Nice job!

Gunner

Thanks ! It was still warm from the oven and yes I used TIG . I
baked it at 350 for a while - after 2 cycles of scrub with gasoline
then with detergent . I fitted the patch with about .003 clearance
to help avoid weld shrinkage causing warpage . I do have a small
sand blaster setup , I never considered using it to minimize
porosity . I wasn't sure this was going to work , I don't usually do
well with oil-soaked aluminum . I did take more care to clean up the
piece this time .

As you of course know...clean aluminum is what you are needing before
you ever strike an arc. So blasting the area around the weldment will
take off all the scum, the oil and the trash. Blast it..take it
directly to the bench and heat it up. You did a pretty fair job with
what you had to work with. Kudos. Better next time...its all a
learning experience.

Gunner

That case was scrubbed 4 times , gas/detergent/clean gas/detergent , then
baked in the oven at 350 for about 45 minutes . Now if I had a vapor
degreaser ... I knew there was going to be carbon contamination floating up
out of the welds , just a question of whether I'd have to grind it out and
re-do . And how many times . That was the first try , looked better than any
I've done in the past and so I said to myself "Self , you better quit while
you're ahead." . So I did .

You didn't do an acetone soak?

--
The mind is like a parachute. It doesn't work until it's opened.
--Frank Zappa