[rebel-builders] tank rivets--mandrels breaking

[Ted Waltman]

You are living right Ken. I'm sure there is a sweet spot that I simply
haven't found with tank rivets. I don't recall ever having a standard
Avdel/Avex rivet stem breaking prematurely. I sure seem to be at maybe 5%
or 10% rate of having tank rivet mandrels break on me though.

Ted

-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of Ken
Sent: Friday, October 09, 2009 1:23 PM
To: rebel-builders@dcsol.com
Subject: Re: [rebel-builders] tank rivets

Might or might not mean anything but I use a regulator to drop air
pressure to minimum and have never had a 6402 or 6403 mandrel break off.
0 out of 22,000 is good odds. I have had a couple of the longer 6406
ones break off.
Ken

Garry Wright wrote:

Thanks Ray. I've never had a problem with mandrels breaking off ---
yet.... The broken off ones were done by others and I suspect,
because of the awkwardness of the typical location that it might be side
loading on the puller. A straight pull doesn't seem to generate that
problem.

Garry

ray.mason@dcsol.com wrote:

Mattic is very good to deal with. I have used them the last couple of

months.

The tank rivets are not AVEX as AVEX doesn't make a closed rivet and I am

not sure who makes them for Mattic. I also have had problems with the
mandrels breaking. I think the main problem for this is that the hole is

to

tight. I found if you pull them manually they don't break as much, but

the

best way would probably re drill the hole if the rivit is hard to get in.

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[Ken]

OK I've been thinking about this.
I've never changed the jaws on my puller and it is likely worn somewhat
from building 119R before I got into all the tank rivets on my floats.
Since the mandrels would be breaking at the first dent from the jaws it
might be worth grinding the first (or all) the gripping ridges on the
jaws a wee bit so they don't dig into the mandrel as deeply and cause it
to fail at the wrong place. Replacement jaws are available for a couple
of dollars from places like Princess Auto if the experiment goes badly ;(

Low air pressure may help but mostly I started doing that to give the
sealant more of a chance to spread around.

Ken

Ted Waltman wrote:

You are living right Ken. I'm sure there is a sweet spot that I simply
haven't found with tank rivets. I don't recall ever having a standard
Avdel/Avex rivet stem breaking prematurely. I sure seem to be at maybe 5%
or 10% rate of having tank rivet mandrels break on me though.

Ted

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[wright.garry30]

Interesting. R ur floats done and ready 4 nxt summer?
Sent on the TELUS Mobility network with BlackBerry

-----Original Message-----
From: Ken <klehman@albedo.net>
Date: Fri, 09 Oct 2009 18:27:54
To: <rebel-builders@dcsol.com>
Subject: Re: [rebel-builders] tank rivets--mandrels breaking

OK I've been thinking about this.
I've never changed the jaws on my puller and it is likely worn somewhat
from building 119R before I got into all the tank rivets on my floats.
Since the mandrels would be breaking at the first dent from the jaws it
might be worth grinding the first (or all) the gripping ridges on the
jaws a wee bit so they don't dig into the mandrel as deeply and cause it
to fail at the wrong place. Replacement jaws are available for a couple
of dollars from places like Princess Auto if the experiment goes badly ;(

Low air pressure may help but mostly I started doing that to give the
sealant more of a chance to spread around.

Ken

Ted Waltman wrote:

You are living right Ken. I'm sure there is a sweet spot that I simply
haven't found with tank rivets. I don't recall ever having a standard
Avdel/Avex rivet stem breaking prematurely. I sure seem to be at maybe 5%
or 10% rate of having tank rivet mandrels break on me though.

Ted

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[Ken]

Garry

Yes the floats are water tight and mated together. Might even get a bit
of paint on them if we get a few warm days!

Am wrestling with modifying the front vertical struts as the cross wires
want to go right through my radiator ;( The front struts slope forward
more than I expected. Easiest plan seems to be to attach the top of the
wires to the struts a few inches down from the fuselage. Of course that
means reinforcing the struts to take the side load without buckling and
new top fittings.

I think some guys attach the bottom rear cross wires to the bottom bolt
on the strut instead of directly to the float but that puts relatively
minor side loads on the strut compared to what I'm planning on the front
ones.

Ken

wright.garry30@gmail.com wrote:

Interesting. R ur floats done and ready 4 nxt summer?

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[Walter Klatt]

Does this mean you will be on floats for next summer? If you're coming again
on that Ramble, you should plan to spend a little time here, and could show
you around to some of out favorite lakes here. Maybe even Nimpo. And for the
rest of you guys on wheels coming on that Ramble, you should know that Nimpo
is also great for wheels, even pavement available for those that don't like
dirt strips.

Walter

-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of Ken
Sent: October 9, 2009 6:18 PM
To: rebel-builders@dcsol.com
Subject: Re: [rebel-builders] tank rivets--mandrels breaking

Garry

Yes the floats are water tight and mated together. Might even get a bit
of paint on them if we get a few warm days!

Am wrestling with modifying the front vertical struts as the cross wires
want to go right through my radiator ;( The front struts slope forward
more than I expected. Easiest plan seems to be to attach the top of the
wires to the struts a few inches down from the fuselage. Of course that
means reinforcing the struts to take the side load without buckling and
new top fittings.

I think some guys attach the bottom rear cross wires to the bottom bolt
on the strut instead of directly to the float but that puts relatively
minor side loads on the strut compared to what I'm planning on the front
ones.

Ken

wright.garry30@gmail.com wrote:

Interesting. R ur floats done and ready 4 nxt summer?

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[Garry Wright]

I had a look at a pic of RD from the Ramble07 and it does look like a
problem. I had not noticed how much that protrudes below the cowling.
Looks like it goes back aft of the firewall. If it stopped at the
firewall you could just attach at the back of the hardpoint bolt instead
of the front, but it does look tougher than that. My front and rear
bottom attachments are as you describe - at the lowest thrubolt on the
strut above the float attach point. Seems to work fine.

Using the outside vertical bolt on the front spreader as an attach point
might work out better. I don't think there is a serious mechanical
problem in that approach.

Side loads are normally pretty small but in a situation like a
waterloop, get well out of hand and do stretch the wires. That would
likely damage the struts as well as whatever else was happening. Classic
modification dilemma I guess.

Garry


Ken wrote:

Garry

Yes the floats are water tight and mated together. Might even get a bit
of paint on them if we get a few warm days!

Am wrestling with modifying the front vertical struts as the cross wires
want to go right through my radiator ;( The front struts slope forward
more than I expected. Easiest plan seems to be to attach the top of the
wires to the struts a few inches down from the fuselage. Of course that
means reinforcing the struts to take the side load without buckling and
new top fittings.

I think some guys attach the bottom rear cross wires to the bottom bolt
on the strut instead of directly to the float but that puts relatively
minor side loads on the strut compared to what I'm planning on the front
ones.

Ken

wright.garry30@gmail.com wrote:

Interesting. R ur floats done and ready 4 nxt summer?

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