Landracing Forum
Tech Information => Technical Discussion => Topic started by: Jack Gifford on April 19, 2020, 03:13:10 AM
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The finish on these bolts was a nice match to the satin black paint under the hood of my '59 GMC so I hadn't painted them. They looked fine for a couple of years, but as I recently got the truck out of winter storage- UGH! I don't remember the source of them, but I've usually had better experience with black oxide finish.
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Hey Jack that looks like a lot of the fasteners on the race car.... mine, not yours.... :lol:
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Jack, the black oxide doesn't provide much protection. It's the oil that the surface retains that does it, just like gun bluing.
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McMaster-Carr offers 18-8 Stainless Steel fasteners in black oxide. A nice satin finish. Price is not bad. A package of twenty five 1/4-20 allen bolts is about 8 bucks.
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Gus used black oxide allen buttonheads to attach his pickups wheel flairs (it was my idea).
A couple years later he needed to remove them to paint the truck and we had to use a sawzall but they did look nice. :-P
Don
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Jack, the black oxide doesn't provide much protection. It's the oil that the surface retains that does it, just like gun bluing.
Of all the "processing", black oxide provides the least corrosion protection. As Neil points out, it's the oil on the black oxide that "delays" corrosion. The "black" is for appearance.
"Plating", of various types offers somewhat better corrosion resistance, but even chrome plating can be corroded underneath. You might want to consult a chart of "salt exposure corrosion results for various materials, platings and coatings."
I suggest that racers choose a fastener based on suitability/cost/looks/corrosion resistance, not in any particular order. If my memory serves me correctly, 316 stainless has the best corrosion resistance of any readily available fastener. It is, of course, very expensive.
To quote the "Wisdom of Booger", (an old racing "acquaintance" . . . . . .)
"Yo pays yo money, and takes yo choice."
:dhorse:
F/b
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FB is correct. Black oxide is for oil retention and little else. Widely used on camshafts, lifters and other engine components needing oil retention.
I purchased stainless steel, 1/4-28, flat head hex drive bolts from eBay for around $12 per pack of 25. Not sure what grade stainless they are but have worked out well so far. You get your choice of length too.
John
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Hey John, faster than ebay.... Wichita Fasteners on Oak Street in Delano... and cheaper!
Stainless would look good on the truck Jack, just remember all stainless fasteners need anti-seize.
I have a lot of 1/4 and 5/16 fasteners on the race car... including stainless nyloc nuts... yep those get anti-seize as well.
I think the same as Gun Blue... a little wax protection can help... :cheers:
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Instead of anti-sieze I am using Loctite 567 thread sealant with a 25 percent reduction from the dry torque reading to account for the lubricity. Enough sealant is used for it to ooze out from under the bolt head, nut head, or washers when the fastener is tightened. The goop provides some locking capabilities and it seals the gaps between the fastener and the clamped pieces to prevent electrolytic corrosion. It seems to work OK. No problems experienced except for the cost of the stuff.
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... Stainless would look good on the truck Jack...
"Looks good" is in the eye of the beholder. My goal with this truck, generally, is to preserve the original '59 design. Bright bolt heads on the black inner fender panels would look garrish. So I just cleaned up the rust and painted them black.
Thanks for the comments. I did use plenty of stainless fasteners to put the truck together, mostly where they're out of sight.
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Jack... lots of stainless fasteners come in black....
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I didn't know that. Thanks, Robert.
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Silicone spray is not only good for sealing moisture out of electrical connections but will prevent corrosion forming on bare metal parts like bolts & nuts. I've even had safe sex with it! aktion086 Ok, that was a lie but it got your attention didn't it!
Sid.
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Silicone spray I've even had safe sex with it!
Sid.
Sid, none of my business but I'm curious, was someone/something else involved or just you and the silicone? :?
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I should comment on silicone spray and.....anything to do with a vehicle. That silicone was a nightmare for us in the auto industry. Much of the "shine up the interior" stuff has silicone in it. We saw many failures with Cruise Control and brake electric circuits because it found its way into switches. Silicone spray used under the hood to "spiff up" a used car gave us EFI problems, ABS failures (repeat trouble codes until you just threw away everything and started over).
Unbelievable how many crazy problems were caused by "auto detailer" services. Especially the ones that come to your home or office and "detail" your car. We spent years teaching the dealers how to avoid ruining a perfectly good car/truck....and then the customer clips a coupon out of the paper and orders up a boat-load of trouble.
The worst place to have silicone spray is around anything painted. It is an amazing molecule that figures out how to creep under paint and start peeling it off. All it takes in one little pit or scratch and away it goes.
We went to BIG extremes of control in our factories to prevent bad paint jobs. Employees are not even allowed to use deodorant or hair products, because there is a little silicone there and it can get into the air and make fish-eyes in the paint. We even had to carefully cover our shoes before entering the finish booths, because many shoes have traces of silicone that was used in the molding or assembly/stitching processes.
We finally forbid our dealers to have any silicone sprays in the parts or service departments. What a nightmare....the stuff was like a virus.....it could get places we couldn't imagine and was nearly impossible to clean up.
I still hate that stuff. :x :x
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Silicone spray I've even had safe sex with it!
Sid.
Sid, none of my business but I'm curious, was someone/something else involved or just you and the silicone? :?
LOL. :cheers:
Sid.
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JimL
I've been using it for electrical moisture protection on trucks, equipment, marine & all my own stuff for a good 40 years & never had an issue with it. The stuff dries up so I don't see how it can migrate anymore than the stuff in a tube. I've been working on Utah trucks for more than 20 years that have the growing green wiring problem from the salted roads & it gives them a permanent fix. Clean it out with battery cleaner, wash it out with either, shoot it full of white grease & plug it back in, wash it down with either then silicone spray it. It even works in the middle of winter when it's -30 something out here.
Sid.
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Someone who has already lived 168 years should be allowed any sort of safe sex he desires... :lol:
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Safe Sex is good if you have the combination.... aktion086
Yea Jerry I know... it's Saturday....
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Safe Sex is good if you have the combination.... aktion086
Yea Jerry I know... it's Saturday....
Stainless, all you need if a "safe word" not a combination. 8-)
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Sid, I tend to view this from the recent technology point of view, which is why I speak strongly against the product. For example: 4-channel ABS computer performs self-check each time a car is started. One of the things it does is put about 40 milli-amps down the switching circuits to check continuity. Silicon in that switch will easily block that little 40 milli-amp current flow. ABS light stays "ON" and customer goes to the dealer for help.
There is no solvent that will clear those molecules and the ABS actuator is scrap, as may be the entire wire harness that was connected to it. I had a dealer go through 3 ABS actuators in a row before he called me. I told him to replace the wire harness, complete. One car, multiple warranty claims, almost $14,000 down the drain.....because it got a nice detail job by the lot men.
There are many circuits that perform self-testing at extreme low milli-amp and often does that at only 5-volts. I saw problems in some transmission external connectors where techs had sprayed a little silicone spray into the "weather pack" to allow easier connection of the connectors. It really sucks to have to replace a $4000 transmission because that connector got sprayed (a connector that is built in to the case....not available as a replacement part).
One thing we learned was that the carrier agent (in the spray can) dries away quickly, but the silicone molecule stays and never stops spreading. Silicone that is spread so thin it feels dry, will still ruin a paint job and shut down an entire production line.
I remember my early years as a line tech, when we used silicone spray for many things. There weren't any computers in those cars, no electronic controlled transmissions, no on-board diagnostics. I was working on new cars that still had generators, and points and condensers back then (I did give away my growler about 10 years ago....finally).
I hope folks understand that we are talking about two different situations. Anyone using silicone lubricants needs to know where it can migrate to.....because it never stops spreading. Amazing stuff, from the chemistry point of view. But.....it ain't no friend of mine these days!
Jim
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Jim that was very informative about your experience with silicone spray. Thanks for letting us know.
What about the electrical grease that is used for waterproofing connectors? I use that in my Bonneville wiring harnesses. Does that have silicone in it or cause problems by itself?
Don
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If you're talking dielectric grease, that's silicone based.
Sid.
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There are lots of things that can cause problems like this. One basic cause is the connector pin itself. Low voltage, low current connections are particular problems whether they be in connectors, switch or relay contacts. These are called "dry circuit contacts" and are subject to thin surface oxide or corrosion on the surfaces of the contacts or pins. even an extremely thin layer will cause an open circuit and silicone acts in the same way.
Higher voltage and current circuits don't have this problem. The voltage between the pins or contacts punches through the thin oxide layer and each time the connector is mated or the switch or relay is activated with power applied, there is slight arcing which burns off the oxide or silicone coating. In addition, a well-designed switch or relay very slightly
slides or wipes the contacts together, cleaning them each time it is actuated.
To promote conductivity, connector pins are frequently silver plated and switch or relay contacts are solid silver or a silver alloy. This is great for power applications but very poor in dry-circuit applications as silver tarnishes rather rapidly and creates the thin insulating layer. For low-level circuits, the best approach is to use gold-plated pins or contacts since gold does not oxidize. This is expensive so unless it is in a military or aerospace application the gold may be absent.
If gold-plated contacts are used for power, after a few cycles the gold is burned off and then it is not suitable for dry-circuit applications.
After many years, even high quality stereo equipment develops intermittent switches and scratchy pots but the popular solution to this problem is to spray the switch contacts and pots with "De-Oxit" contact cleaner and cycle them repeatedly. It seems to be the best way of restoring low level electrical contacts.
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Thanks for the advice on this Neal. Triumph has some grease on all of their electrical connector plugs. Do you have any recommendations about what to use for that? I have been using Sta-Lube dialectric grease. Is there anything that works better?
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WW, back in my Army missile days in Germany we used Dow DC4 silicone dielectric grease as a weatherproofing compound for the cable connectors between the radar, Doppler, and computer vans. We never experienced any problems with it.
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Silicone dielectric grease is a different molecule than the canned spray. Silicone has 4 available electron potentials in its 3p valence. When put together in the right compound, the silicone atoms stayed bonded to their condition. We found the sprays were leaving free silocone to migrate, after the carrier evaporates in the precense of oxygen.
The only problem we learned of with dielectric grease was gradual water absorption. This gave us trouble on 4-wire O2 sensors where the 12v heater circuit would temporarily cross feed into the sensor side 0-.9 volt circuit. During warm up, we would see up to 7 volts on the O2 circuit which drove the efi so lean the car would fall on its face. As the exhaust pipe temps got high enough, the "humidity" would be driven from the metal connector pins. Performance returned to normal until the next cold start drive cycle. I never did learn the physics of that; we were told to teach the techs to clean the connector, dry it, and regrease.
When a fellow doesn't speak their engineers language.....well, you just get left with "do what you're told and don't ask questions."
Strangely, we had struggled with this for a couple years when I was sent to Temecula to look at a pickup with the problem. I decided to watch the O2 sensor with my portable digital osclliscope. I was taking pictures of the screen when it suddenly went high voltage. On the follow-up visit with the factory engineers, they couldn't understand what made me try that process. I told them I "just took a flyer". It was their turn to look confused. :wink:
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I have no experience at Bonneville, but in other applications I have found that a little bit of Gibbs Oil applied to black oxide steel after cleaning helps keep the rust away.
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I am with Joel, Gibbs Oil is one of the best ways to slow down rust corrosion on steel. I like to collect old tools like dividers, calipers double screw clams etc. I usually find them in some state of rusting, I clean them down to bare metal and then soak them in Gibbs Oil for a couple of weeks then hang them on my peg board. I hardly ever use them but I have many that I have had for 5-10 years and they have no rust. Gibbs Oil is great!
Rex
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Amazing discussion about errant electrical difficulties. THANKS!
Back to the original discussion (remember the one about the bolts) my standard for salty LSR work is Zinc-Aluminum coated grade 8 bolts and stainless nylox nuts. Super strong, no discernible corrosion (ever) and no galling. FWIW I never noticed any difference between 18-8 stainless and 316 stainless Nylox. Your mileage may vary.
https://www.mcmaster.com/screws/hex-head-screws/high-strength-grade-8-steel-hex-head-screws/finish~zinc-aluminum-coated/
And as long as we're on the subject of bolts let me put in a good word for Torx-Plus fasteners.
https://www.mcmaster.com/torx-bits
I run a lot of stainless fasteners, many with allen (hex) sockets (because they don't make Z-A coated bolts in the sizes I need). I got tired of drilling out the bolts after the soft metal socket in the head had rounded off.
So I did a little research, found out about Torx and, more importantly, Torx-Plus. To satisfy my curiosity, I did an experiment. Got a brand new 10-32 Allen bolt, plus a brand new Snap-On Allen wrench. Put an inch/lb torque wrench on the setup and pulled until I twisted the wrench inside the bolt head at about 138 In/lbs.
Did the same with the Torx setup. Made it to about 155 In/lbs.
Moved on to the Torx-Plus setup and snapped the head off the bolt.
Now, instead of tippy toeing down a row of bolts, hoping each will cooperate, I experience the joy of going down that same row, now with Torx-Plus bolts, with a battery impact and just spinning them on or off without worry.
Back to you, Chet.
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Every once in a while you come across a gem! You just gave us one. Thanks Jim!!! :clap :clap :clap
Pete