- Thread starter john224
- Start date
How do you know when you need to change the oil ?
When you've saved enough money to pay for it.
brightspark
Member
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it depends on where its been kept and how often used lift the top off and look in if the oils clean and there isnt any corosion due to any water ingress on the transformer core lamination it will be ok 
ive never looked at mine in 35 years but its never been outside in the wet
ive never looked at mine in 35 years but its never been outside in the wet
brightspark
Member
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- 41,369
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- yarm stockton on tees
its just transformer oil expensive as well 
dont5 u know anyone that works for electricity board oh hv transformers have a look the oil might be ok in it .suck a bit out from the bottom of welder with a plastic tube into a glass bottle. oil floats on water if theres no water it will be ok and nothing will be rusty inside 
dont5 u know anyone that works for electricity board oh hv transformers have a look the oil might be ok in it .suck a bit out from the bottom of welder with a plastic tube into a glass bottle. oil floats on water if theres no water it will be ok and nothing will be rusty inside 
pedrobedro
Man at Matalan
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See if it welds then if it's working give it a coat of paint and carry on using it. The oil is unpleasant stuff and best left alone as it loses it's properties when exposed to atmosphere. Some from Morris lubricants not a bad price for 25 litres.
Water forms inside the metal case from condensation arising from the heat as well as general humidity in the air, I guess. The end result over years/decades is that the metal tank can rust quite badly in the areas not submerged in oil; notably the underside of the top plate. In addition, the condensation drips into the oil and falls to the bottom where it seems to start rusting the bottom plate. I'm not sure how this happens because you'd expect there to be a shortage of air for rusting, but it does. I doubt if there's much water 'in solution' in the oil which might conceivably start damaging the transformer. I would expect all water to fall to the bottom of the tank. You could filter the oil to remove particles of rust and dust but apart from that, I'm not convinced there's much of a case for oil replacement.
