The **** Undercast

[maniago]

So I'm heavily into polishing for the first time. But I'm stuck trying to get the undercase (or clouds) out of the finish. You can only see them when viewed directly from directly above.

Here's my procedure for raw AL to shiny...(note: on each application, all the polish has all been taken up/disappeared)

3 applications compound F9 (two passes: one horizontal, one vert)
3 apps compound F7 (2 passes each)
2 apps comp C (2 passes each)
2 apps cyclo S (2 passes each)
1 pass cyclo dry cloth (removes vague "black clouds" that the cyclo C seems to leave after the polish has been all taken up)

This leaves me with a nice shiny finish, save for the white clouds.

Ive tried a few things to quit the clouds...

Compound with S, then cyclo with S (no change)
Cyclo with C, cyclo with S (no change)
Compound with G6, cyclo with S (slight change after 3 applications) - this is the perfect polish site recommendation for clouds

I've been all over the Perfectpolish site and any other google source possible but to no avail.

Short of acid wash, which I'm a bit loathed to try (I'm still building and dont know how long it'll be before I fly and get all that liquid out of the seams).

Anyone got any magic polishing solution to the white clouds? (they dont show up on pictures). I didnt get any hits on search here, or any threads Ive read so far.

Thanks.

[odens_14]

Push it in the hangar so the clouds stop reflecting??

while my plane is "polished", I've never gotten even close to a perfect mirror like it sounds like you're striving for so I can't offer any real help. Just to offer my 2c that if you have to look really close, from just a certain angle, you're probably better polished than 99% of "polished" airplanes.

For reference, I still get positive comments pretty often and all i did was 2 or 3 compound f7, cyclo f7, cyclo c, cyclo s 10 years ago and cyclo s once a year since then. for a quick clean I use about 2 cups distilled water and about a tablespoon of nuvite S in a spray bottle.

[maniago]

Originally Posted by odens_14

Push it in the hangar so the clouds stop reflecting??

while my plane is "polished", I've never gotten even close to a perfect mirror like it sounds like you're striving for so I can't offer any real help. Just to offer my 2c that if you have to look really close, from just a certain angle, you're probably better polished than 99% of "polished" airplanes.

For reference, I still get positive comments pretty often and all i did was 2 or 3 compound f7, cyclo f7, cyclo c, cyclo s 10 years ago and cyclo s once a year since then. for a quick clean I use about 2 cups distilled water and about a tablespoon of nuvite S in a spray bottle.

You maybe right, I may be overkilling it. I have a boat load of fluorescent lights over head, and I can read the "Sears" on the door openner...thru the clouds.

However, I was just looking at the wing, and I came across a panel I did originally that has no clouds. Eh? I said "Ok, I did something right, but what was it?" Dunno. So I hit the panel next to it that has clouds with compound F9, F7, G6, Cyclo S, Cyclo dry. It came out better than any other clouded areas I've experimented on, so it may be that despite 3 "wet" F9 passes originally, theres still some cutting that needs to be done. I'll keep fooling with it. Maybe its just extra hard 2024, dunno.

[OKAV8r]

Try wiping it down with lacquer thinner, then do another cyclo/ S pass, then dry cyclo....

[maniago]

Originally Posted by OKAV8r

Try wiping it down with lacquer thinner, then do another cyclo/ S pass, then dry cyclo....

Ive hit it with acetone to no avail. Its not my impression that its a residual oils issue, but I'll give it a shot cause I'm low on solutions. Maybe the slower evap rate of the toluene in it will make a difference I dunno. Thanks.

[maniago]

No joy on removing the clouds with lacquer.

Has anyone tried Alumiprep33 acid wash?

[BillL]

Originally Posted by maniago

No joy on removing the clouds with lacquer.

Has anyone tried Alumiprep33 acid wash?

That is going the wrong direction.

A finer polish gets it out if it is a surface finish related issue. Cotton polishing cloth and it can not be contaminated with coarse grit material.

A light pure water spray and buffing with a clean, soft cotton cloth should get the haze out - like cleaning a mirror. Then determine if it is haze or in the metal. If metal see above.

Sorry, I am not familiar with the specific abrasives and pads you are using, just the result. Some products contain super fine waxes that polish and shine for that last coat.

[maniago]

Originally Posted by BillL

That is going the wrong direction.

A finer polish gets it out if it is a surface finish related issue. Cotton polishing cloth and it can not be contaminated with coarse grit material.

A light pure water spray and buffing with a clean, soft cotton cloth should get the haze out - like cleaning a mirror. Then determine if it is haze or in the metal. If metal see above.

Sorry, I am not familiar with the specific abrasives and pads you are using, just the result. Some products contain super fine waxes that polish and shine for that last coat.

Not familiar with Nuvite? What polishing system do you use for aircraft skins?

[BruceW]

White clouds I get (with nuvite) is from over working an area and getting it either too hot or too much grind, particularly with the rotary. I cant get it out until I polish again the next year. Used to bug me, now I just accept it.

[Deven]

Too hot...