# Bolting Lugs to Transformer



## Cletis (Aug 20, 2010)

What's the best items to use and method to make the best connection of lugs to 
transformer plates?? 

Stainless, Galvanized, split washer, washer, no washer, locktite, no loctite, torque pounds, no torque, 2 nuts, 1 nut, brush grind surfaces, waste of time, whatever holds it, spray on plates, etc...


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## piperunner (Aug 22, 2009)

Cletis said:


> What's the best items to use and method to make the best connection of lugs to
> transformer plates??
> 
> Stainless, Galvanized, split washer, washer, no washer, locktite, no loctite, torque pounds, no torque, 2 nuts, 1 nut, brush grind surfaces, waste of time, whatever holds it, spray on plates, etc...



Never use stainless steel on lugs . split washer or lock nut on the nut side bolts case hard grade 5 and washer . 

have about three or four threads out past the nut meaning just what you need in length . 

If its a large trans we put conductive grease on when plates go on .


Stainless and heat not good plus stainless will not come off later on they break .

You dont grind or brush clean it install it lug to plate surface of transformer plate i prefer two hole lugs but use what the transformer has one hole one hole .

We never tamper with transformer bus plates no drilling or cutting grinding or brushing just clean it off and bolt on .

Only thing you brush or grind is the case lug to ground your taking the paint off for a good clean connection to case .


We buy lug kits from GE or SQ D thats what they supply from factory .


Biggest issue is paralleled lugs you cant get them from the factory you buy them separate from supply house .


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## Cletis (Aug 20, 2010)

*Brass*

What about brass?


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## MDShunk (Jan 7, 2007)

I use phos bronze bolts with Belleville washers, a nut, and a lockwasher.


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## Cletis (Aug 20, 2010)

*Brass*

Ahh. A little haughty today eh? I meant for the same reason as these components http://grounding-clamps.electrical-brass-components.com/


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## Cletis (Aug 20, 2010)

*more*

To be more clear to others. Places where they would be subject to extra moisture and chemicals possibly. 

Like these fine brass bolts

http://www.shivombrass.com/brass_bolts.htm


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## BBQ (Nov 16, 2010)

MDShunk said:


> I use phos bronze bolts with Belleville washers, a nut, and a lockwasher.


We only do that when the power company specs it.

I usually use plain old Grade 5 hardware.


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## BBQ (Nov 16, 2010)

Cletis said:


> To be more clear to others. Places where they would be subject to extra moisture and chemicals possibly.
> 
> Like these fine brass bolts
> 
> http://www.shivombrass.com/brass_bolts.htm



If moisture and chemicals are that much of an issue that you need brass hardware it may not be the right spot to place a transformer. :no:


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## Cletis (Aug 20, 2010)

*Trans*

Havent you ever installed a 3r transformer in a marina? what about a chemical plant? or places of that nature


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## Cletis (Aug 20, 2010)

*3R*

Like the applications for this Acme transformer

APPLICATIONS

Harsh industrial locations
Corrosive chemical exposure
Waste water treatment facilities
Coastal or marine applications with high salt mist
Any application where painted cold roll steel is not adequate


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## BBQ (Nov 16, 2010)

Cletis said:


> Havent you ever installed a 3r transformer in a marina? what about a chemical plant? or places of that nature


Yes transformers are installed in those locations, and so is common hardware. But neither of those facts mean it is a good choice.

If you need better than zinc hardware it is not a place for standard dry type ventilated transformer.





> 3R
> Like the applications for this Acme transformer
> 
> APPLICATIONS
> ...


Is that a ventilated transformer or an encapsulated one?

Encapsulated transformers do not use lugs (usually)


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## piperunner (Aug 22, 2009)

Cletis said:


> Like the applications for this Acme transformer
> 
> APPLICATIONS
> 
> ...


Well you may not be able to get this but the best cover or protection for anything like salt water or corrosive stuff is grade 5 spray .

But you can only get that in the Navy sorry .

Were do you get it i dont know we used it on ship board .

But yes you can use brass if you want but there soft bolts so think about lose over time and temp .

If your install lugs in a area of high corrosive stuff spray with a clear coat of polyurethane spray apply in thin coats let it dry 24 hours your done .

We used that also in the navy on 400 cycle stuff not only for salt and water and such but for close contact with other connections which were not tape or could bleed over like 1000 volt 400 cycle stuff .

Polyurethane is one of the best insulators for high voltage .

You can buy it at the local hardware store .

It will last for 100 years trust me on this one .


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## Big John (May 23, 2010)

piperunner said:


> ...Polyurethane is one of the best insulators for high voltage .
> 
> You can buy it at the local hardware store .
> 
> It will last for 100 years trust me on this one .


 I'd never seen it before I started dam work, but this was actually a common practice here. They coated the interiors of panels with urethane. 

It's definitely not my first choice, but I will say the panels where it's done are completely rust-free while everything around them disintegrates away.

-John


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## piperunner (Aug 22, 2009)

Big John said:


> I'd never seen it before I started dam work, but this was actually a common practice here. They coated the interiors of panels with urethane.
> 
> It's definitely not my first choice, but I will say the panels where it's done are completely rust-free while everything around them disintegrates away.
> 
> -John


Its a very good insulator for high voltage have you ever seen magnet wire its used to rewind motor windings make or repair coils .

magnet wire is poly coated on top .

It has a rating in mils per thousands of volts .

We use mineral oil also on electrical parts to protect them but just for a covering not a connection or contact point . 

Meaning after install spray it or wipe it on the best thing ever .


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## MDShunk (Jan 7, 2007)

piperunner said:


> Its a very good insulator for high voltage have you ever seen magnet wire its used to rewind motor windings make or repair coils .
> 
> magnet wire is poly coated on top .
> 
> ...


That's a pretty common spec in food. Spray panel and MCC interiors with USP mineral oil from a pump garden sprayer.


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## piperunner (Aug 22, 2009)

You can basically drain a liquid filled transformer and fill it with mineral oil now that said i would not do that if it ever shorted out down the road . Iam sure the factory would say oh you used mineral oil .

They want you to buy there products .


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## Jlarson (Jun 28, 2009)

Stainless usually, along with the properly sized 1 hole or 2 hole crimp on lug or mechanical lug.


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## Cletis (Aug 20, 2010)

Jlarson said:


> Stainless usually, along with the properly sized 1 hole or 2 hole crimp on lug or mechanical lug.


Better refer to post 2


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## airfieldsparky (Jun 10, 2011)

Never heard of using polurethane spray and I do work every now and then in corrosive environments is it safe to spray on live equipment?


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## Jlarson (Jun 28, 2009)

Cletis said:


> Better refer to post 2


I'll refer to my ability to use fasteners properly.


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## piperunner (Aug 22, 2009)

airfieldsparky said:


> Never heard of using polurethane spray and I do work every now and then in corrosive environments is it safe to spray on live equipment?




NO do not spray it on something hot dont do that .


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## JM2 (Aug 5, 2011)

Many sprays are of variable dielectric value - and some of the propellants these days are still flammable - so be careful spraying around live gear. Like one post said, "wait 24hrs" before energizing. I too don't like the galling that SS does to itself - they're a one-shot when torqued-down. Poor conductors on a relative scale too...


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## piperunner (Aug 22, 2009)

JM2 said:


> Many sprays are of variable dielectric value - and some of the propellants these days are still flammable - so be careful spraying around live gear. Like one post said, "wait 24hrs" before energizing. I too don't like the galling that SS does to itself - they're a one-shot when torqued-down. Poor conductors on a relative scale too...



Thanks for your input i need all the help i can get some times .

I have sheared off stainless steel bolts during tightening and taking them off old gear . I was told by a florida power engineer once they do not use stainless bolts because of the temp rating of that to the standard lug and they break . 

So i asked why 

He said the heat generated by the transformer buss connection increases the oxide coating on the SS bolts . We all think stainless is strong yes it is but not with electrical and magnetic effects thats more info i will not try to explain .

I learned something form him that day .

It basically locks the threads like cold welding he said galling is 10 times increased and partly do to current flow in the stainless and the heat transfer between different metals of a electrical connection .

That the surface film of oxide is broken down seizing galling locking itself like welding and in some cases this increases the tighting of the bolt itself which can break apart crack .

As it increases the physical size of the bolt to the nut its on and cracks .

Not a good thing so power company does not use stainless steel bolts ever.


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## Jlarson (Jun 28, 2009)

I'll be sticking to stainless since we never see any of these problems. Proper anti seize and bolt and lug sizing works for us.


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## brian john (Mar 11, 2007)

piperunner said:


> Never use stainless steel on lugs .


Not saying you are right or wrong, just curious, do you have a link or information to back this statement up?


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## brian john (Mar 11, 2007)

In use at the terminals in a transformer should not see that great of a temperature rise. I can post averages (IF I REMEMBER)


From the following link 


http://www.ssina.com/download_a_file/fasteners.pdf

STAINLESS
STEEL
FASTENERS
A SYSTEMATIC APPROACH TO THEIR SELECTION

HIGH TEMPERATURE SERVICE The selection of stainless steel fasteners for high-temperature service is complex because of the many factors involved. Mechanical and physical properties have to be considered together with corrosion resistance.

Chromium also plays an important part in the high temperature resistance characteristics for stainless steels. Figure 6 on page 14 shows this effect on the scaling resistance of chromium-iron alloys. Consequently, stainless steel Types 309, 310, 314, 442 and 446 would provide suitable performance in many of these environments, while grades with titanium, columbium and tantalum such as type 321, 347 and 348 can also be considered for elevated temperature service.

In all bolted joints, the fasteners are tightened to some initial elastic stress and corresponding strain. At elevated temper- atures, creep occurs in which some of the elastic strain is transformed to plastic strain with a corresponding reduction in stress. This behavior is termed relaxation. When bolts relax they no longer maintain a tight joint. Resistance to creep, or relaxation, is an important consideration for fastener systems at elevated temperature. Table 8 shows creep values for several widely used stainless steels, some of which are readily available as “off-the-shelf” fasteners.
Other considerations for elevated- temperature service include thermal expansion characteristics and oxidation resistance.
The thermal expansion of a fastener should match the expansion characteris- tics of the materials being fastened (Table 9), with a logical conclusion that stainless steel fasteners are best for stainless steel...For the rest read page 14 and on in tha attached link.


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## piperunner (Aug 22, 2009)

brian john said:


> Not saying you are right or wrong, just curious, do you have a link or information to back this statement up?



No just what i was told after asking the florida power engineer why it was a problem once when we actually had install stainless steel bolts on there transformers .

We had to take them out and replace with case hard grade 5 bolts & nuts. 

Which was not cheap in labor or cost so we asked why .

I know they break easy when we were taking them out this is 308 SS bolts already installed 7 bolts spilt or sheared off and they were new one week old .


I guess when your working at night at 2.30 am and half of orlando is down and you cant get a bolt to turn its a minor problem.

And no supply house open fun.

But who knows maybe that engineer didnt know anything .


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## JD_ (Jul 8, 2011)

We're doing a shutdown in a bit, now I need to decided if I should postpone and get steel or bronze bolts cause some contruction electrician and a POCO "engineer" said stainless bolts are bad. :lol:


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## Jlarson (Jun 28, 2009)

JD_ said:


> I need to decided if I should postpone


I'll make the decision easy. Do you want to get paid, and do you want me to yell at you? See, it's an easy decision. :laughing:


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## brian john (Mar 11, 2007)

brian john said:


> No just what i was told after asking the florida power engineer why it was a problem once when we actually had install stainless steel bolts on there transformers .


Once again an engineer inserting his opinion in lieu of hard facts?



> But who knows maybe that engineer didnt know anything.


I run into this more with engineers than electricians. They feel they have to be smarter than us (IN SOME CASES). I work with many excellent engineers, know how I know they are excellent? They ask questions and do not pretend to know it all.


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## piperunner (Aug 22, 2009)

JD_ said:


> We're doing a shutdown in a bit, now I need to decided if I should postpone and get steel or bronze bolts cause some contruction electrician and a POCO "engineer" said stainless bolts are bad. :lol:


Well use what you think is best you must be a service electrician and we know you guys are smarter then us construction guys.

We only build projects but we dont know anything about electrical work or how to trouble shoot.


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## piperunner (Aug 22, 2009)

brian john said:


> Once again an engineer inserting his opinion in lieu of hard facts?
> 
> 
> 
> I run into this more with engineers than electricians. They feel they have to be smarter than us (IN SOME CASES). I work with many excellent engineers, know how I know they are excellent? They ask questions and do not pretend to know it all.



Iam just the opposite if a engineer is asking questions seems to me his lost.


You seem to have a hard time with electrical engineers or are you talking about some that work in a plant that have the title but actually never went to school.

Florida power engineer humm on this job we were on its hard to think he was wrong but its about everyones own thinking just a thought 
personally i will take his advice over someone on this forum who i dont know . Most Google info or just know the code by memory on here.

Its was Turkey point i know you know were .



And thats what i get alot from these post who knows what one knows or really does on this forum .

I know you do testing Brain and i know you have a company were not putting you into this group ive seen your post and on MH .

Plus your a mod so iam being nice.

Iam talking about the ones that post and google but never actually work in the field or just because its a code rule they think they know every thing about electric.

It takes years to find problems that happen over time do ya think florida power might have a reason for not using SS bolts i kinda do .


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## Jlarson (Jun 28, 2009)

JD_ said:


> We're doing a shutdown in a bit, now I need to decided if I should postpone and get steel or bronze bolts cause some contruction electrician and a POCO "engineer" said stainless bolts are bad. :lol:


Why don't I go in to a little more detail on how we prevent galling with stainless stuff, this is stuff based on fact.

Stainless really can gall, cold weld, whatever you want to call it. Saw that all the time when I was an instrument/process pipe guy. 

First line of defense is anti seize, cheap and simple. 

Second is not running the nuts on super quick (especially important if you're using nylon insert nuts), if you are heating the hardware up you have ****ed up. Same with when you are backing it off, if you ever are taking a nut off a bolt and it seizes up along the way you were probably going too fast. 

If you are really having problems try using two different grades of stainless for the nut and bolt. 

Some are probably thinking isn't that a lot of work, wouldn't using a different fastener material be cheaper? For some yeah maybe, for us we buy so much stainless stuff it's cheaper for us to use stainless for everything pretty much, plus it's less inventory headaches, we don't need to worry about steel stuff getting into the stainless bins. 


Also expanding on something I said earlier, use the right size bolt, if the terminals have 1/2" holes and you have a lug bolted on with like a 5/16 bolt and have fender washers on there you've screwed up.


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## MDShunk (Jan 7, 2007)

I have a can of anti-seize specially for stainless. It's a white paste, as opposed to the grey stuff that gets all over everything. I have no idea what the difference is.


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## Jlarson (Jun 28, 2009)

MDShunk said:


> It's a white paste


Only white anti seize I ever used was loctite's high temp stuff. I think it's mostly mineral oil.


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## MDShunk (Jan 7, 2007)

Jlarson said:


> Only white anti seize I ever used was loctite's high temp stuff. I think it's mostly mineral oil.


I forget who makes the stuff I have. I got it when changing stainless c-face motors, for the bolts, shaft, and face flange.


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## piperunner (Aug 22, 2009)

Jlarson said:


> Why don't I go in to a little more detail on how we prevent galling with stainless stuff, this is stuff based on fact.
> 
> Stainless really can gall, cold weld, whatever you want to call it. Saw that all the time when I was an instrument/process pipe guy.
> 
> ...


We always use the size thats for that hole size of lug or terminals when we purchase these .

When we release our gear package we include lug kits for all transformers.

Have you seen factory lug kits for transformers now dont blow a gasket and get all worked up but they are not the size of the holes of trans or lugs not ever .

In fact there lose a gap by 1/8 of a inch so is this just stainless bolts your talking about or any bolt like grade 5 gear bolts we use .

Average lug kit from SQ-D or GE or SEIMENS typically all .

Plus they never give enough grounding lugs !


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## MDShunk (Jan 7, 2007)

piperunner said:


> We always use the size thats for that hole size of lug or terminals when we purchase these .
> 
> When we release our gear package we include lug kits for all transformers.
> 
> ...


Sometimes you need that wiggle room to get the bus bars holes to (somewhat) line up, especially when adding a new section onto old gear. Nobody I know has ever run a drill through bus bar holes. :whistling2:


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## Cletis (Aug 20, 2010)

*Nasa*

Here are are a few excerpts from an official NASA document about nuts, bolts, compounds, etc.... I just posted a few items. Really go need to look at whole document. Can be seen here. Really good stuff

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19900009424_1990009424.pdf

Fastener Materials
Bolts can be made from many materials, but most bolts are
made of carbon steel, alloy steel, or stainless steel. Stainless
steels include both iron- and nickel-based chromium alloys.
Titanium and aluminum bolts have limited usage, primarily
in the aerospace industry.
Carbon steel is the cheapest and most common bolt material.
Most hardware stores sell carbon steel bolts, which are usually
zinc plated to resist corrosion. The typical ultimate strength
of this bolt material is 55 ksi.
An alloy steel is a high-strength carbon steel that can be heat
treated up to 300 ksi. However, it is not corrosion resistant
and must therefore have some type of coating to protect it from
corrosion. Aerospace alloy steel fasteners are usually cadmium
plated for corrosion protection.
Bolts of stainless steel (CRES)are available in a variety of
alloys with ultimate strengths from 70 to 220 ksi. The major
advantage of using CRES is that it normally requires no
protective coating and has a wider service temperature range
than plain carbon or alloy steels.
A partial listing of bolt materials is given in table

Bolts of stainless steel (CRES)are available in a variety of
alloys with ultimate strengths from 70 to 220 ksi. The major
advantage of using CRES is that it normally requires no
protective coating and has a wider service temperature range
than plain carbon or alloy steels.
A partial listing of bolt materials is given in table I. The
following precautions are to be noted:
(1) The bolt plating material is usually the limiting factor
on maximum service temperature.
(2) Carbon steel and alloy steel are unsatisfactory (become
brittle) at temperatures below –65 “F.
(3) Hydrogen embrittlement is a problem with most
common methods of plating, unless special procedures are
used. (This subject is covered more fully in the corrosion
section.)
(4) Series 400 CREScontains only 12 percent chromium and
thus will corrode in some environments.
(5) The contact of dissimilar materials can create galvanic
corrosion, which can become a major problem. (Galvanic
corrosion is covered in a subsequent section of this manual


Zinc is also a common type of plating. The hot-dip method
of zinc plating is known commercially as galvanizing. Zinc
can also be electrodeposited. Because zinc plating has a dull
finish, it is less pleasing in appearance than cadmium.
However, zinc is a sacrificial material. It will migrate to
uncoated areas that have had their plating scratched off, thus
continuing to provide corrosion resistance. Zinc may also be
applied cold as a zinc-rich paint. Zinc melts at 785 “F but has
a useful service temperature limit of 250 0F. (Its corrosioninhibiting
qualities degrade above 140 “F. )


Nickel Plating
Nickel plating, with or without a copper strike (thin plating),
is one of the oldest methods of preventing corrosion and
improving the appearance of steel and brass. Nickel plating
will tarnish unless it is followed by chromium plating. Nickel
plating is a more expensive process than cadmium or zinc
plating and also must be baked the same as cadmium after
plating to prevent hydrogen embrittlement. Nickel plating is
good to an operating temperature of 1100 “F, but is still not
frequently used for plating fasteners because of its cost

Thread Lubricants
Although there are many thread lubricants from which to
choose, only a few common ones are covered here. The most
common are oil, grease or wax, graphite, and molybdenum
disultide. There are also several proprietary lubricants such
as Never-Seez and Synergistic Coatings. Some thread-locking
compounds such as Loctite can also be used as lubricants for
a bolted assembly, particularly the compounds that allow the
bolts to be removed. A summary of thread lubricants is given

Oil and Grease
Although oil and grease are the most common types of thread
lubricants, they are limited to an operating temperature not
much greater than 250 “F. (Above this temperature the oil
or grease will melt or boil off.) In addition, oil cannot be used
in a vacuum environment. However, oil and grease are good
for both lubrication and corrosion prevention as long as these
precautions are observed.

Synergistic Coatings (ANTISEIZE)
These proprietary coatings4 are a type of fluorocarbon
injected and baked into a porous metal-matrix coating to give
both corrosion prevention and lubrication. However, the
maximum operating temperature given in their sales literature
is 500 “F. Synergistic Coatings will also operate in a vacuum
environment.

Neverseez
This proprietary compound5 is a petroleum-base lubricant
and anticorrodent that is satisfactory as a one-time lubricant
4General Magnaplate Corporation, Ventura, California.
sBo~ti~ Emhart, Broadview, Illinois.
4
up to 2200 “F, according to the manufacturer. The oil boils
off, but tie compound leaves nongalling oxides of nickel,
copper, and zinc between the threads. This allows the fastener
to be removed, but a new application is required each time
the fastener is installed. NASALewis personnel tested this
compound and found it to be satisfactory.

Thread-bcking Compounds
Some of the removable thread-locking compounds (such as
Loctite) also serve as antigalling and lubricating substances.
However, they are epoxies, which have a maximum operating
temperature of approximately 275 “F.

Etc...Etc...


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## Jefro (Jul 28, 2009)

MDShunk said:


> I forget who makes the stuff I have. I got it when changing stainless c-face motors, for the bolts, shaft, and face flange.


I got copper anti-seize for that type of stuff, it is the best that I've tried. I think it's made by permatex.


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