Ground strap on a powdercoated frame?

[Gene]

How do I go about getting bare metal on a powdercoated frame without causing damage to the finish? Do I just grind enough off in the spots where the strap will be located? Or am I missing something?

[71tahoe]

If it is a through bolt fastened by a nut then you will have to find bare metal. I might get flamed for this but if it is a screw that cuts threads into the metal there is no need to expose the frame surface. The threads will make solid contact with the frame and the back of the screw head will make the contact with the strap.

[Gene]

I have no bare metal, the entire frame was powdercoated. I was just wondering if I grind a small spot under the strap would that somehow damage the powdercoating?

[passthebuck]

A better way Gene might be to run a tap through the hole you are going to use to bolt the ground strap the frame. As long as it is bare metal under the bolt head, the current should be able to flow through the bolt & into the frame via the tapped bare threads. If you're concerned with corrosion, a dab of grease or antiseize should keep that at bay.

[Gene]

Originally Posted by passthebuck

A better way Gene might be to run a tap through the hole you are going to use to bolt the ground strap the frame. As long as it is bare metal under the bolt head, the current should be able to flow through the bolt & into the frame via the tapped bare threads. If you're concerned with corrosion, a dab of grease or antiseize should keep that at bay.

That sounds like a plan, I was going to use a bolt and nut but I don't see any problem with using just a bolt? Thanks!

[suville]

You might also consider a "star" or external tooth washer they are generally used just for electrical ground connections as it should bite into the PC or should I say through the PC and into base metal, aside from that I would thread a hole for a bolt to thread into and that should be sufficient for a ground and I would still use the external tooth washer under the ground strap tab.

[68gmsee]

Here's what I would do.

I would use one of the small grinding stones similar to the ones below and grind a small area around the hole like you mentioned. Then after the ground strap is bolted in, give it a shot with rustoleum or other rust preventative paint to seal it.

[cparman]

I agree, This is what I have done in the past.

Originally Posted by 68gmsee

Here's what I would do.

I would use one of the small grinding stones similar to the ones below and grind a small area around the hole like you mentioned. Then after the ground strap is bolted in, give it a shot with rustoleum or other rust preventative paint to seal it.

[OldCreek]

Do your grinding on the inside portion of the frame. The connection from the nut/bolt will ground on that side and you can keep the ground wire on the outside. The wire will ground through its connection to the bolt head.

[C20-67_N_MO]

I would do what the guys are saying above...PLUS once you insert your bolt thru the frame also get a good flat washer and sandwich your ground strap to that then tighten everything down. Then apply a little grease to seal it off.

Good luck.

[aps kustums]

I agree with the grinding on the bottom side of the frame. I rhino lined my frame and had to do the same

[CTENTA1]

Originally Posted by cparman

I agree, This is what I have done in the past.

Plus the cable and or washer will cover the grinding. You wont be able to see it unless you take it off. This was what I did.

[gkesseru]

From my previous electrical engineering career: In electronic enclosures, ground straps MUST have a star washer in order to make good electrical contact.

[Tom Vogel]

Originally Posted by gkesseru

From my previous electrical engineering career: In electronic enclosures, ground straps MUST have a star washer in order to make good electrical contact.

OK... but do you think the star washer will really cut through powder coat? I dunno...

[cdowns]

i've never went out of my way to use star washers for at least 45years and have had no grounding issues// actually a star washer i doubt would put a good scratch in powdercoating much less establish a ground

[Zeke]

Might try a piloted bonding brush, kinda pricey but will put a nice 1/2 round spot where you want to ground. type in bonding brush in the search block.

http://www.yardstore.com/

[Zoomin]

Originally Posted by cdowns

i've never went out of my way to use star washers for at least 45years and have had no grounding issues// actually a star washer i doubt would put a good scratch in powdercoating much less establish a ground

Oh, it will.