Alclad Aluminum

mhorowit wrote:
jls wrote:


Where are you using it?


The leading edge of the ailerons is thin alluminum sheet. I put a lot
of effort into physically removing corrosion on the left aileron and if
the right was in the same shape, I was thinking it would be easier to
simply make new parts. Someone pointed out that alodining chemicals
could be brushed on (rather than having to build tanks) and cost was
very reasonable, so I think I'll stick with my original approach. The
sheetmetal will be covered by fabric.

You don't need tanks for alodining. You brush it on, let it sit
awhile, then wash it off. Use phosphoric acid solution first, then
wash off, then chromic acid solution. Then wash off, leaving a little
tannish, bluish color behind on the aluminum surface.

You can use a little scotchbrite to get off the oxide powder before
using phosphoric acid.

I have restored several sets of ailerons on Taylorcrafts from the 40's
and the aluminum in most cases is restorable. After you've alodined
you can prime with Polyfiber's proprietary primer which won't dissolve
when you glue on the fabric to the leading edge.

By the way... There is a metal prep that is used for cleaning prior to
alodining. It is a phosphoric solution. Is that also used for
chemically removing corrosion, or simply preping the surface for the
chromic coating? - Mike

The phosphoric acid prepares for chromic acid coating,as well as
removing some corrosion. Use scotchbrite if the corrosion is thick and
powdery.

mhorowit wrote:
jls wrote:


Where are you using it?


The leading edge of the ailerons is thin alluminum sheet. I put a lot
of effort into physically removing corrosion on the left aileron and if
the right was in the same shape, I was thinking it would be easier to
simply make new parts. Someone pointed out that alodining chemicals
could be brushed on (rather than having to build tanks) and cost was
very reasonable, so I think I'll stick with my original approach. The
sheetmetal will be covered by fabric.

You don't need tanks for alodining. You brush it on, let it sit
awhile, then wash it off. Use phosphoric acid solution first, then
wash off, then chromic acid solution. Then wash off, leaving a little
tannish, bluish color behind on the aluminum surface.

You can use a little scotchbrite to get off the oxide powder before
using phosphoric acid.

I have restored several sets of ailerons on Taylorcrafts from the 40's
and the aluminum in most cases is restorable. After you've alodined
you can prime with Polyfiber's proprietary primer which won't dissolve
when you glue on the fabric to the leading edge.

By the way... There is a metal prep that is used for cleaning prior to
alodining. It is a phosphoric solution. Is that also used for
chemically removing corrosion, or simply preping the surface for the
chromic coating? - Mike

The phosphoric acid prepares for chromic acid coating,as well as
removing some corrosion. Use scotchbrite if the corrosion is thick and
powdery.