Number plate nuts

[wiltsandy]

On further reflection, I wonder if the black plastic spacer (see picture) is supposed to do what the nut in your example is to do. Do you think that is possible, or would plastic be too soft?

I can't see what purpose the plastic piece in the picture serves to be honest. Could it be a spacer, fitted behind the number plate once the rivnut is in place. It's difficult to tell from the picture how it could fit in conjunction with the rivnut, especially as it appears to have two lugs on one side.

I haven't looked at the link to the rivnut site but it's still probably worth giving my method of inserting the rivnut a go rather than forking out for a special tool that you won't use again. The rivnut material should be soft enough that it will pull up.

 

[wiltsandy]

So even if I find the correct way to put these in, are you saying it's better not to because of the risk of corrosion arising from the three different metals in the bolt, nut and panel?

You can grease the bolt threads to help against dissimilar metal corrosion and I would've thought that as long as the paint around the hole is good it will go someway towards helping too.

The only real way to protect against dissimilar metal corrosion though is to use a proper jointing compound.

 

[White230CE]

I can't see what purpose the plastic piece in the picture serves to be honest. Could it be a spacer, fitted behind the number plate once the rivnut is in place. It's difficult to tell from the picture how it could fit in conjunction with the rivnut, especially as it appears to have two lugs on one side.

I haven't looked at the link to the rivnut site but it's still probably worth giving my method of inserting the rivnut a go rather than forking out for a special tool that you won't use again. The rivnut material should be soft enough that it will pull up.

Thanks Andy. I am definitely going to give your method a try. I just wanted to find out what the tool was all about. Certainly have no intention of buying it, unless absolutely no option. Bolide suggested I mastic up the holes and use double-sided adhesive tape, and given Malcolm's views on the different metals reacting, I may well end up doing that.

 

[White230CE]

Hi Andy,

Previous post crossed with yours about different metals. More food for thought about which option I go for eventually.

Thanks

 

[television]

So even if I find the correct way to put these in, are you saying it's better not to because of the risk of corrosion arising from the three different metals in the bolt, nut and panel?

You could use a plastic or alli screw, but they are not that strong, they are 6mm from memory.

Greasing or sealing will help a little but not by much

 

[wiltsandy]

Thanks Andy. I am definitely going to give your method a try. I just wanted to find out what the tool was all about. Certainly have no intention of buying it, unless absolutely no option. Bolide suggested I mastic up the holes and use double-sided adhesive tape, and given Malcolm's views on the different metals reacting, I may well end up doing that.

You're welcome!

The main thing with dissimilar corrosion is to make sure that the 'raw' metals don't come into contact with each other so in theory, anything that stops that would work to a greater or lesser degree.

On aircraft, a jointing compound known as 'yak s**t' is used extensively which is a thick yellow paste that stays flexible. But then on aircraft, not all panels are painted.

 

[White230CE]

I gotta get me some o dat yak sheeeeeet.

What do you call it in polite company?

 

[wiltsandy]

I gotta get me some o dat yak sheeeeeet.

What do you call it in polite company?

If I remember correctly it's called JC5A. It's a real sticky, yellow goo that gets everywhere and sticks like the proverbial to a blanket. I'm not sure if it's available commercially though but there must be similar products available.

 

[antijam]

JC5A is a zinc chromate corrosion inhibiting compound, used extensively in the aircraft industry; it's quite expensive and perhaps a more cost effective and easier to use material is Duralac, a similar compound which has been in almost universal use in aircraft manufacture for many years.

if you really want to try some, here is one supplier.

 

[White230CE]

One burning question: Why, out of all living creatures on God's earth, was the yak selected as the nominal producer?????

Next time I am at Whipsnade Zoo, I shall check out the yaks to see whether there is any sticky yellow goo that sticks like the proverbial....!

 

[wiltsandy]

One burning question: Why, out of all living creatures on God's earth, was the yak selected as the nominal producer?????

Next time I am at Whipsnade Zoo, I shall check out the yaks to see whether there is any sticky yellow goo that sticks like the proverbial....!

I have no idea to be honest! I remember when I was an apprentice we'd just ask the storeman for a tin of yak s**t and he'd know exactly what we wanted. I don't know if it was a nickname that was used just on the site where we were or whether it originated from within the RAF or Navy as we have a lot of ex services personnel here. It stuck though and as far as I know is still called that today.

 

[White230CE]

Reporting back on number plate nuts:

I bought a tube of Duralac from Ebay. I smeared it all over the aperture and inserted the rivnut into the aperture. Using the method suggested by Wiltsandy, I interposed a larger nut between the bolt and the rivnut and began to tighten. I felt the rivnut squeeze against the panel...then disaster. It began to turn in its hole. Luckily, the bolt had not been tightened too much, so I was able to undo it. Needed mole grips to pull the rivnut out of the aperture. Slight distortion of the aperture, but nothing too bad.

Picture attached showing the used rivnut against an unused one.

So the method does work, as the rivnut appears to have distorted uniformly, and the thread was still sound. However, I think the problem was the integrity of the aperture. It probably was not as perfectly hexagonal as it once was. So the extra force needed to distort the rivnut further was enough to turn the rivnut in the aperture. As this was one of the better holes, and one of the other holes is already half-round, I decided that honour and curiousity had been satisfied, and abandoned originality in favour of practicality.

Tried to fill the holes just with seam sealer, but clearly that was not going to work as I did not use a patch. Thought about what patch to use, then decided as I was going to use double-sided adhesive pads to stick the plate on, that I would use the same pads to seal up the holes. So that's what I did, after ensuring the hole edges were adequately painted. Made four patches out of number plate sticky pads, then stuck the number plate on with 3 further strips.

Plate looks great, but are the pads adequate as patches for the holes? Or can I expect water ingress?

BTW, if anyone needs some yak s**t, I've got a whole tube!

 

[television]

They should stop any water from getting in,,there is not that much that can get in

 

[Xtractorfan]

I have no idea to be honest! I remember when I was an apprentice we'd just ask the storeman for a tin of yak s**t and he'd know exactly what we wanted. I don't know if it was a nickname that was used just on the site where we were or whether it originated from within the RAF or Navy as we have a lot of ex services personnel here. It stuck though and as far as I know is still called that today.

This would be similar to what plumbers use to protect copper piping from cement erosion when laying pipes underfloor