wrote:
wrote:

I use a stainless backing plate on anything that is boat thru, even on
the cleats.


I was asking why I definitely need a stainless steel backing plate if I
intend to re-attach the T-top frequently. I believe you have answered
my question. If I am going to re-attach the T-top very often, *the area
where the bolt gets through the desk will not likely to be very
water-tight, and will tend to rust the backing plate if the backing
plate is not stainless steel*. Thanks for giving me the hint to figure
this out.

Althought I am not planning to re-attach the T-top repeatedly, I will
still use a stainless steel backing plate -- This is kind of a "get it
done and don't want to re-visit" kind of task.

Jay Chan

Say what?
You don't want leaking around screws/plates. Use 3M 4200 bedding compound.

Gene Kearns wrote:
On Thu, 20 Apr 2006 15:56:31 GMT, Don White
wrote:


Here on the salt water we only use stainless steel or aluminum backing
plates. Why ask for trouble?


Good advice. Also, I *really* don't recommend aluminum and steel
combinations.... dissimilar metal corrosion will cause way more
trouble than you want to put up with.


Unless you have a way to isolate them from each other.
I've used 3M4200, liquid tape, gaskets made of plastic etc to make sure
the different metals don't touch each other. If you've ever drilled or
cut 1/8th thick ss plate, you know why I changed to 1/4" aluminum
backing plates.

"Don White" wrote in message
...
Gene Kearns wrote:
On Thu, 20 Apr 2006 15:56:31 GMT, Don White
wrote:


Here on the salt water we only use stainless steel or aluminum backing
plates. Why ask for trouble?


Good advice. Also, I *really* don't recommend aluminum and steel
combinations.... dissimilar metal corrosion will cause way more
trouble than you want to put up with.


Unless you have a way to isolate them from each other.
I've used 3M4200, liquid tape, gaskets made of plastic etc to make sure
the different metals don't touch each other. If you've ever drilled or
cut 1/8th thick ss plate, you know why I changed to 1/4" aluminum backing
plates.


And you want 5000 series aluminum. 5086 probably the best for most jobs
where salt water is contacted. 6061 is a tougher alloy. The 5000 is very
low copper content.

"Gene Kearns" wrote in message
...
On Fri, 21 Apr 2006 03:27:30 GMT, "Calif Bill"
wrote:




And you want 5000 series aluminum. 5086 probably the best for most jobs
where salt water is contacted. 6061 is a tougher alloy. The 5000 is very
low copper content.


More like no copper... the major alloying element in the 5000 series
being magnesium. 6061 is a tougher alloy because it can be heat
treated... the 5000 series cannot.

Heat treatables are 2000, 6000, and 7000 series.... Major alloy in
2000 is copper, 6000 is magnesium and silicon, and 7000 is zinc.

6000 series is acceptable in salt water service, but as you suggest,
5000 is probably a better choice if you don't need a hardened
alloy....

Problem with the 6000 is not very formable. You can not bend it to make a
radius bottom, without danger of it wanting to crack or crack in the future.
For flat plates, is good. All Aluminum will have some copper, just part of
the beast, but the alloys mentioned have very minute amounts.

I started using pieces of kitchen cutting boards as backing plates. The
ones that are about a 1/2 inch thick. They cut with regular saws and will
never rust.

"Don White" wrote in message
...
wrote:
wrote:

I use a stainless backing plate on anything that is boat thru, even on
the cleats.


I was asking why I definitely need a stainless steel backing plate if I
intend to re-attach the T-top frequently. I believe you have answered
my question. If I am going to re-attach the T-top very often, *the area
where the bolt gets through the desk will not likely to be very
water-tight, and will tend to rust the backing plate if the backing
plate is not stainless steel*. Thanks for giving me the hint to figure
this out.

Althought I am not planning to re-attach the T-top repeatedly, I will
still use a stainless steel backing plate -- This is kind of a "get it
done and don't want to re-visit" kind of task.

Jay Chan

Say what?
You don't want leaking around screws/plates. Use 3M 4200 bedding
compound.

I never thought about using HDPE as a backing plate, thats a great
idea. Thanks

I put my wake tower on with it. I've had two large tubes with as many as 6
teenagers on them attached to the top of the tower without a problem.

wrote in message
ups.com...
I never thought about using HDPE as a backing plate, thats a great
idea. Thanks