1/8" aluminium washers
 

I'd like to back the pop rivets holding the fibreglass tips on the empennage. I don't like the idea of a pop rivet on the thin (countersunk) fibreglass. On the HS I used a thin strip of 020 aluminium bonded to the fibreglass, but I think this may add unnecessary weight, since most of the material is 'wasted' in the gap between the rivets. So I thought an aluminium washer might be another idea. Except I can't find any. I'm thinking 1/8" ID, 7/16" or 1/2" OD and 1/16" thick or close too, and bond it in place on each hole. Anyone know if Al washers like this are available? If so, who from? I haven't found any in NZ yet. Of course, it doesn't help being Xmas with so many shops and suppliers closed :D
Cheers

Can't help with the washers, but I used a unibit to drill lightening holes in between the rivet holes and it worked real well.

I used washers
 

I had a quick look at wicks but didn't see Al washers. If you could let me know what you used, that would be great, thanks...

1/8" aluminium washers
 

Try your local Ace Hardware store, or Acehardware.com. Item#2014215.
The price on Acehardware.com is for 10pkgs of 30. They are about 3/8 OD and have a 1/8in hole. If you need a pkg and can't find it locally, send me your address and I'll mail them to you. I own an Ace Hardware store and it comes in very handy.

I used steel washers
 

For the inside of my tips, I just used regular 1/8" inside diameter steel washers and a little white glue to hold them in place until the rivets were set. (use a cleco to hold them while the glue dries)

Thanks Steve. I went on the website, but I'm not sure if they'll ship to NZ. I entered a question via the contact form. If they do not, then I'll take up your offer. I only just noticed that you own a store!! Thanks,

Just ordered some of these washers for backing up -4 rivets on my baffle material:

http://www.aircraftspruce.com/catalo...latwashers.php

Go near bottom of page for aluminum and you'll find the -4 washers.

Thanks Ned. Somehow I missed those. I notice that the OD is only [approx] 5/16" though, and I was hoping for something a little larger. I tend to work in metric so imperial sizes are sometimes a little more difficult for me to visualize. What were these like? In your opinion, plenty of meat around the hole to provide a bearing surface?

aluminum washers
 

Perhaps I'm stating the obvious, but can't you just cut little round washers out of 0.020" aluminum? They won't be perfectly round, but even if they are square, what's the difference? They'll never be seen, and will work great.

Another suggestion - just wait until later in your project to do the tips. By then you'll probably see that agonizing over this is really not worth the trouble.