blueldr wrote:It looks like a gas or TIG weld. The gaseous welding shield must keep the magnesium from igniting unless it is done inside some sort of a compartment filled with an inert gas. Magnesium burns like hell, but I suppose it must have to have an oxygen source for combustion.
Mag fires are very easy to put out, we have a squirt bottle of plane old water, If you do get a fire you simply squirt it with water the steam will blow away the burning material, and cool the rest. and the sparklers burn out on the floor.
But in reality the mag never should get hot enough to catch fire. but when it does, it will provide its own O2 and fuel to continue to burn in any atmosphere, Plus the more material burning the harder it is to extinguish.
Another tid-bit, Tungsten Inert Gas welding (TIG) was invented during WWII to weld Mag parts for the war effort. and it does a fine job in the right hands.
FAR 43-A states that welding on an engine structural component is a major repair, now the question is, is the sump a structural component?
Bruce Fenstermacher wrote: It is a shame there isn't a coating that could easily be put in over the weld to seal what seems to be the inevitable crack you might get around the outside of the weld..
Cracking around the parameter of a weld area is caused by the use of the wrong filler material (rod), it will swell and shrink at different rates and cause the crack.
And yes, the OAE repair coating can be done over a weld repair.
spduffee wrote:Well, I'm glad my posting brought about so much good information and comments. It is done, and I am sure the solution I chose may not thrill others, may enforce the view of its proponents, but it is done. I had the pan welded at a specialty shop - not DivCo - (I'm already putting of one their kids through college with the block repair) and below are the results. Fire away...
Once they got into it, it was worse than I suspected. The first pick at the corrosion brought daylight through the body. From then on it was a struggle. I guess I'm happy with it, I mean, it's like the first welded Magnesium oil sump I have ever seen, so....
That looks like a fine job of welding the sump to me.
George I have to share with you that you had me for about 5 minutes. I was thinking "if he knows it's not Glyptal, I wonder if he knows what it is and if we can get our hands on it". Then I thought "wonder why the green stuff would slow the corrosion better".
CAUTION - My forum posts may be worth what you paid for them!
Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
Bruce Fenstermacher wrote: It is a shame there isn't a coating that could easily be put in over the weld to seal what seems to be the inevitable crack you might get around the outside of the weld..
Cracking around the parameter of a weld area is caused by the use of the wrong filler material (rod), it will swell and shrink at different rates and cause the crack.
And yes, the OAE repair coating can be done over a weld repair.
We were told by OAE when we visited about 2007 they couldn't or wouldn't coat a welded repair. They didn't say why. Maybe they just hadn't tried or or had the approval to do it when we were there. Are you sure of this Tom?
CAUTION - My forum posts may be worth what you paid for them!
Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
Bruce Fenstermacher wrote:
We were told by OAE when we visited about 2007 they couldn't or wouldn't coat a welded repair. The didn't say why. Maybe the just hadn't tried or or had the approval to do it when we were there. Are you sure of this Tom?
No I'm not positive but I see no reason it can't be, They told me they dye check the sump prior to adding the coating. If it is a good weld I see no problem.
Bruce Fenstermacher wrote:George I have to share with you that you had me for about 5 minutes. I was thinking "if he knows it's not Glyptal, I wonder if he knows what it is and if we can get our hands on it". Then I thought "wonder why the green stuff would slow the corrosion better".
Thats an appropriate payback.....for the oneupsmanship you got on me in the Directory.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention. An originality nut (mostly) for the right reasons.
I'm reviving an old thread with updated information.
I recently acquired a spare oil sump for my C-145, so I decided to call Okanagan Aero Engine to get the latest information on their epoxy treatment/repair. I spoke to Dan, who was really helpful. Here's the latest:
They are still doing the epoxy treatment/repair, and report continued success with it. It is approved by Transport Canada, and you will receive an 8130 with the treated/repaired unit. I asked him what kind of damage can be repaired, and here are his responses:
Corrosion pits? Yes.
Hole? Pinhole only, but nothing larger and assuming their preparation of the sump does not open the hole further.
Crack? No. They can't touch it.
Previously welded sump? No. Dan said that in their experience, all welds on the sumps crack. So they will not treat a previously welded sump. (Note: I've edited this answer from my original post because Dan subsequently emailed me that after further thought, they decided they won't treat previously welded sumps.)
He said that they have not had any issues with overhaul shops accepting sumps with their treatment. In fact he said many send sumps to them for treatment. As far as how long the treatment lasts, he said that they have been doing it since 1987, and during overhaul run across sumps that still look inside like the day they were treated. Current cost is $500 Canadian (about $375 US at today's exchange rate). Turn around time is 5-10 work days.
Here's their current contact info:
Okanagan Aero Engine
#1 550 Aerospace Drive
Kelowna, BC Canada V1V1S1
250-765-9718
Dan recommends that if you are interested but not sure your sump can be treated, take a picture of the inside and email it to him at danokaero at shaw.ca (of course, substitute @ for " at " in that address).
Last edited by gfeher on Thu Mar 14, 2019 5:11 pm, edited 1 time in total.
Gene, thanks for the update. I recently bought a backup sump, I had my current sump welded some years ago and it seems to be holding up but decided having a spare would be a good idea. I am thinking of sending the spare in for the coating as an extra precaution.
I just received an email from Dan at Okanagan Aero saying that after further thought, the've decided that they won't treat previously welded sumps because in their experience, the welds crack. Sorry for any confusion. I've edited my last post above to reflect this decision.
Since epoxy is a protective (as well as a sealing) material... if I were to overhaul/rebuild/repair my engine these days... even if the sump were in fine condition...I think I'd spend the $375 to have it treated anyway for preventive purposes.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention. An originality nut (mostly) for the right reasons.
I received my sump back from Okanagan, so I thought I would share the results. Total turn around time was about 2 weeks. Cost was $375.87 US ($500.00 Canadian) for the work, plus about $51.00 US to ship the sump to Okanagan via USPS, plus $37.50 US for them to ship it back to me via Canadian post, plus about $5.00 credit card currency conversion fees = $469.37 total cost/outlay. Not too bad.
Here's a "before" photo of the inside of the sump at the critical area where most corrosion occurs:
IMG_1912.JPG
And here are "after" photos showing the sump now, including the same area shown in the photo above:
IMG_1948.JPG
IMG_1945.JPG
IMG_1947.JPG
IMG_1946.JPG
They did a nice job.
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