Welding Tips and Tricks

So, I have repaired a hundred or so skegs over the last few years. Usually I use 5356 and cast skeg blank from a well known company.

I have in the shop a Yamaha lower unit that I can not get done. I have tried several of my tricks including buttering, knife edge with gap, pre heat, the works.

Question is: is this miracle 4943 filler prone to hot short cracking? I have a few pounds of it but its hard to get and I usually use it for filling corrosion holes is cast transom plates, not joining two separate things together.

Now I can't say if it's more or less prone to hot short cracks than another alloy.

But I have used it to weld cast oil pans and heat exchanger tanks in the past with no issue.

Just welded a rub through on a cast alum oil pan last week and it welded just fine and holds oil just fine.

Didn't realize it was tricky to get it. Must be lucky that a manufacturer is a city over from me.

Curiousity sake the part your working on has zero chance of being magnesium?

Had a few parts over the years that are told to me over the phone to be cast ally and show up and they magnesium....that stuff needs witchcraft to weld I swear.

Yeah, I have a sneaking suspicion that these newer yamaha lower units are either higher in mag content or cast out of a 7000 series alloy.

While welding the new skeg on, (I use tig), I would get the distinctive click, I could feel it in the piece. Classic hot short cracking. After grinding the weld out to try again it turns out the crack was not in the weld or the HAZ. Maybe close to the HAZ.

I am going to try to braze the replacement skeg on if I can't find an answer.

I have done many other Yamaha lowers in the past and never had an issue. I am wondering if this is a newer unit, I know they just bought several new outboards last year or two.

Funny, I live 20 miles from the town they invented 4943 in and its almost impossible to find in a quantity less than a pallet.

Well if the curiosity gets the better of you I see two options.

Tear the casting right down till you find some potential alloy #'s and get on Google to see if you get lucky with some reliable info.

Or if possible/feesible send a chunk to a lab for analysis.

3rd just popped into my head, jump through a hundred hoops potentially with the OE to maybe find out what it is.

And weird you figure its be easy to obtain then.

I have to order in 10LB boxes at a time of 4943 but that's okay since I definitely go through it. Takes a couple days to come on usually.

Jakedaawg wrote: ↑Mon Apr 18, 2022 11:35 pm Funny, I live 20 miles from the town they invented 4943 in and its almost impossible to find in a quantity less than a pallet.

If it helps, a google search turned up several sources for Hobart 4943 filler:

• ebay, cyberweld, bakersgas, weldfabulous, etc.

Search for --> "494309470" or "Hobart 4943 tig filler"

A few options for your consideration -->

• https://store.cyberweld.com/hobart-er49 ... 09470.html
• https://bakersgas.com/products/hobartma ... -494309470
• https://weldfabulous.com/hobart-4943094 ... er-rod-10/
• many more on e-bay

Whatever works for you.
(sorry, I do not have enough experience to comment on your "hot short cracking" question)

Problem solved. I believe there were cracks from the impact that were moving during welding that were not visible to my poor eyes.

Jakedaawg wrote: ↑Tue Apr 19, 2022 2:32 pm Problem solved. I believe there were cracks from the impact that were moving during welding that were not visible to my poor eyes.

If you need to do more like these then perhaps get some dye penetrant kit (cleaner, dye and developer can):

https://www.grainger.com/category/weldi ... ction-kits

Not terribly expensive and will show up any hard to see cracks in base material so you can grind it all out and perhaps drill out the ends of cracks too.

Bye, Arno.