We have an Older Model Doughboy D.E. Filter(model 1424) It seems that
parts are impossible to find and while in storage over the winter a
little mouse chewed holes in a couple of the fabric covers on the
"grids". Can it be repaired with any tight woven similiar fabric or is
there a special property to this covering?? I would like to understand
just what makes the D.E. Filter work...meaning why does the D.E.
adhere to the grids and make filtering possible.

Hello justme-ga,

I have divided your question into two parts:-


Q-1: I would like to understand just what makes the D.E. Filter
work..meaning why does the D.E. adhere to the grids and make filtering
possible?

D.E.(Diatomaceous Earth) is a white or cream-colored earth composed of
the skeletal remains of single-cell algae called diatoms used in
various industries as a filter, absorbent, clarifier and insulator
and, in the aquatics industry, as a filtration media.

The D.E. filter system consists of filter leaves, which are connected
to individual septa(a porous cloth), or main suction headers. These
header, which can be located at the top or bottom of the leaves, are
then joined together to lead out of the tank.

As with high-rate sand filters, there are pressure and vacuum D.E.
systems. The vacuum system is usually an open-topped concrete tank
located at the same level as the pool water level. Water drains by
gravity into the tank, filters through the large D.E. coated leaves
and is pulled by suction back into the pool.

The pressure system is typically a stainless steel cylindrical tank.
Instead of leaves, the filter elements are long, hollow filaments with
D.E. caked on the outside. Water is pumped into the lower section of
the cylinder, passes through the filter element and clean water is
drawn to a chamber at the top of the tank. Each of the filaments
terminates in this camber where the water is sent back to the pool.

In both systems, the D.E. material must be applied to the filter
leaves in a precoat or precast process. In this process, the filter
tank is closed off from the pool. D.E. is then introduced into the
tank and the water is recirculated to coat the leaves. The pressure
filters have a feature that occasionally "bumps" or dislodges the D.E.
from the filter elements, then recoats itself to provide a new filter
surface.

Diatomaceous earth filters are highly efficient, producing sparkling
clear pool water under the heaviest bather loads, but they are
certainly not perfect.

Source: 
http://www.chah20.com/publications/filtration.html
http://poolplaza.com/how-pool-filters-work.shtml
http://www.aquachem.com/PCFilter.shtm
http://www.tropixpools.com/repairs/filter/filterintro.htm

Q-2 Can it be repaired with any tight woven similiar fabric or is
there a special property to this covering?

Ans: It is covering of a sapta, a porus cloth. So, you can have any
tight woven similiar fabric to cover it or else can avail the special
material at :
http://www.patiostore.com/poo_de-fil-part.html  

Hope this helps. Please feel to ask if you have any clarification,
I'll be more than happy to answer you.

Regards
onlinexpert-ga

THANK YOU! all subjects address, and clearly answered. Speed was 
better than i could have hoped for as well. There are 5 teenagers
waiting for pool time that thank you as well!!