Remove paint from aluminium aircraft

[Adrian Lewer]

Hi guys I have decided to replace some paneling on the CH601 and would like to know the best way to remove the old paint from the remaining surfaces in preperation for a colour change.

 

 

[Guest ozzie]

Boy are you in for a lot of fun.

 

paint stripper, MEK and scotchbright.

 

 

[Gibbo]

Oven cleaner and a scourer works a treat on alloy. Penetrol afterwards.

 

G

 

 

[Guest ozzie]

Adrian what is the paint system on it now? two pak?

 

 

[planedriver]

Hi guys I have decided to replace some paneling on the CH601 and would like to know the best way to remove the old paint from the remaining surfaces in preperation for a colour change.

Hi Adrian,

 

If you look through your local paper you'll probably find ad's for local strippers, that may help.

 

Just a thought, trying to be helpful.;)

 

Kind Regards

 

Planey

 

 

[Tomo]

I've scrubbed a far bit off a C182 once... but I honestly couldn't tell you what we used, it was green, and we let it soak over night raped up in plastic to keep it moist. I think it was some sort of paint stripper. That gets the paint off, then you have to polish the Alloy with something else.

 

Gee's I'm not much help am I?!

 

 

[Adrian Lewer]

Jeezz what a great help you lot are ;)

 

What sort of paint stripper can I use ? any old MOTOSPRAY crap from autobarn ?

 

Is it simple, just like a car ? apply let it sit and scotchbright it off and wash with water ?

 

 

[farri]

G`Day Adrian,

 

I completely stripped the old paint off my Drifter,tried scrubing,wasn`t an option,too difficult and not a good enough result.

 

I used commercial paint stripper then immediately washed the blistered paint off with a 1500 PSI gurney,made the job easy and the result was excellent.

 

Cheers,

 

Frank.

 

 

[Adrian Lewer]

Thanks Frank, but wont the water affect the Aluminum ?

 

 

[planedriver]

I've scrubbed a far bit off a C182 once... but I honestly couldn't tell you what we used, it was green, and we let it soak over night raped up in plastic to keep it moist. I think it was some sort of paint stripper. That gets the paint off, then you have to polish the Alloy with something else.Gee's I'm not much help am I?!

Of course you are Tomo,

 

I Use Autosol from Supercheap for polishing metal, and it's brilliant stuff for polishing wedding rings to many things larger. It's also great for for cutting back freshly painted surfaces to give it a mirror finish. I recently resprayed my sons boat and hand finished it with Autosol and it looks like glass.

 

I'd be looking at using a power-buff wetted with a little water just to keep it the mop damp, which is important, and a good squirt of Autosol, and with a bit of effort it should polish up a treat. It's only a fine abrasive, but when polishing and the cloth, or buff, starts to turn black, you know it's doing it's job, and cutting slowly into the metal. If you finish it by hand, you'll wind up with something that you'd be really proud of.

 

Regards

 

Planey

 

 

[Guest ozzie]

Ok go and buy a large roll of black plastic and cover the floor in it. tape the overlapped joins. research the stripper. It has been almost 15 years since i've done this so things change. main point is make sure it will not damage the aluminium. buy a roll of aluminium tape 1/2 inch wide. the thickness should be so it does not rip easily but needs to be cut. run the tape where two pieces of metal overlap so the stripper cannot find it's way between the skins. remove the control sufaces. tape any entry were the stripper can find it's way inside. control surfaces: paint on the stripper and cover with plastic. this will help the stripper do it's job. when it has bubbled off the paint use plastic scrapers to remover the paint. depending on how and what it was painted in you may find that the stripper will not move the primer. wash the component with soap and water. To remove the chromate primer you will need MEK and scotchbrite. different colours of scotchbrite are different ratings of fine to rough. green to lightt brown is good. you can get these as round discs that fit in a drill and are perfect for removing the last bits of paint around rivet heads. sheete of scotchbrite can be torn to size and used by hand on flat panels in between the rivets. again when done wash completly with soap and water. remove the tape and carefully do these sections by hand. when using MEK and the discs use a AIR DRILL. NO SPARKY STUFF. plenty of fresh air and mask, gloves eye coverand coveralls. have plenty of fresh water and soap.on hand to wash the stripper off your skin. do not put rag with mek on it in your back pocket. when done use a chem wash to clean the metal and then treat with dealodine (spelling). treat any corrosion before you do the chem wash. how well you do the strip job will show when you put the new colour on it..

 

this should get you going. have fun

 

 

[Adrian Lewer]

Thanks for that OZZIE. A big job ahead of me Me thinks......

 

What happens if water finds its way into the airframe ? this is my biggest concern.

 

What is MEK ?

 

When I have done the above and sprayed with etch primer (the green stuff) what do I do ?

 

Just give a light scuff and paint the 2K ?

 

 

[Guest ozzie]

METHEYL ETHYL KETONE used in the fibreglass industry. should be able to buy 4 lts of it in supercheap. expensive keep the lid on it fully evaporates really fast.

 

water in the fuse? what happens when it rains? make sure the drain holes are clean. if it gets to carried away use a wet vac. rinse don't drown. i'd give the water blaster a miss.

 

 

[Adrian Lewer]

So its like prepsol ? used to clean the surface ?

 

 

[Guest ozzie]

No. prepsol is a wax and grease remover used to clean the surface before the paint application. prepsol should not remove paint. MEK will break thru just about any chemical barrier. prepsol can be used over bare metal and primer before final colour goes down.

 

other tips, use white cotton rags, nappies are great. do not mix up rags keep MEK rags away from anything painted, dyed or glued. house keeping is very important. No dust. place used rags and plastic sheet and removed paint into a METAL bin with a lid. put some water in it. place it outside the workshop. spontanious combustion has been known to occer with this stuff due to self generated heat. take the obvious precautions.

 

 

[Ultralights]

its no problem if water gets into the airframe, it will evaporate away, but dont get any stripper in there as it will start severe corrosion.

 

In the airline/military game, most aircraft requiring a repaint are just lightly sanded, prepped, and then repainted over the old sanded paint. this preserves the protective qualities of the paint, and minimises chances of exposing bare aluminium and damaging its surface.

 

PAint strippers are very bad news for fibreglass parts as the solvents in the strippers will dissolve parts of the resin structure and destroy the resin bonds. Not good.

 

I have spent many hours hand sanding 747s for repaints, its not uncommon to repair an aircraft and find 10 or more layers of paint! even the NAVY Sea King helicopters still have the Light brown colour under many layers of grey,as they were bought second hand from Israel.

 

Dont sand rivet heads as you can grind half the head away and reduce the rivet strength. scuff rivets with scotchbrite.

 

personally if i was to repaint a metal aircraft and strip it back to bare, i would remove and strip each skin and piece from the aircraft and strip it

 

separately. Residual stripper hiding under skin joins and fasteners etc can be a real pain in the butt and cause problems long after the paining is done.

 

Dont forget MEK is a known carcinogen.(in california only apparently) when we use MEK in the hanger, we clear the hangar of all unnecessary personnel, wear full protective clothing and supplied breathing air.

 

 

[Adrian Lewer]

Health warning !!!!

 

Flying in the state of california may cause cancer

 

 

[Guest ozzie]

Military paints. i stripped down and painted Bell 47 that came from Thailand in military paint. i gave up trying to get it off after two 4 ltr tins of stripper did zip to the paint. got the chemical companies out to have a go and they thru all sorts of stuff at it. took a while but they got it off.

 

Painting over old paint. one word... weight. you will really have to work sanding around the rivet heads ect to get a good 'mechanical keying' (getting the new to stick to old) especially if the old is a urathane two pak..

 

The control surfaces should be checked for balance when finished.

 

As ultralights mentioned above with glass parts mek will screw them up as well just sand and paint.

 

If you have no drain holes in the fuse now may be the time to do them.

 

If the aircraft is in one piece i hope you like long periods flat on your back

 

 

[Bill Hamilton]

Folks,

 

Look carefully at what Ozzie has said.

 

Many auto type paint strippers can do really horrible things to aluminium. You are only starting with 24, 26 guage sheet, not like it is the aluminium side of a tipper truck.

 

A really good reason to strip an aircraft completely, is to check for corrosion under the paint. There are some really good two pack anti-corrosion primers these days.

 

Caustic stripper in lap joints and other hard to get at spots can write an aeroplane off, I have seen it with a C-172. Some little time ago, a well known commercial aircraft re-finisher got into all sorts of CASA and commercial trouble for using an unapproved and very caustic automotive paint stripper.

 

Please do your homework, and make certain the stripper you use is "aviation approved".

 

Be very careful with control surfaces, and they WILL have to be rebalanced after whatever you do to them, and an aircraft will have to be reweighed after painting --- you would be surprised how much paint weighs ---- and make certain it is all supervised by a LAME if it is VH- and not an experimental where you can do the maintenance. For a VH- standard cat. GA aircraft, paint stripping and painting is NOT pilot maintenance.

 

Regards,

 

 

[Adrian Lewer]

Where do you go to find things like "Aviation Approved" paint stripper ?

 

Is there a shop ETC like skylines at moorabbin airport where you can buy maintenance stuff ?

 

To be honest I might remove most skins on the entire A/C and inspect it all anyway as I am not happy with the way the A/C has been maintained.

 

I will strip most Fuzz sheets (most need replacing due to dents ETC) most wing sheets as well as the Horizontal Stab. the rudder will be a new kit so I will strip the paint with the sheeting off the A/C to avoid any contamination of hidden orifices.

 

Why go to all that trouble you ask ? well most of the fuzz sheeting will need to be replaced, the ailerons need to be re sheeted, Rudder is new kit anyway, and the rest I would like to inspect as I said the build/maintenance quality is not to flash

 

 

[Guest ozzie]

EAA's Online Store - Publications - Technical & How-To

 

scroll down the page and find the book how to paint your own plane.

 

i have not read it but it would be a good place to get some worthwhile tips. cheap to at <20 dollars us.

 

Isn't there a well known aircraft paint shop around your area? if so go check what they use. The bin is a good place for industrial spying.

 

had a bit of trouble working out what a 'fuzz' was. you mean 'fuse', you a kiwi?

 

 

[Adrian Lewer]

LOL... Fuzz is just slang.

 

Not sure if there is a aero paint shop around. was going to go to the local panel shop and get paint from them. 2K...

 

So you suggest a bit of espionage ?

 

 

[Bill Hamilton]

Adrian,

 

Try the Aviall web site. Indeed, an Aviall catalog ( about the size of a telephone book) is a very useful reference on many item, they are not free, but well worth the money.

 

There is an Aviall in Melbourne.

 

Regards,

 

 

[Guest ozzie]

when it is ready for paint if you can get it into a booth at a panel shop it will turn out heaps better than in your shed or backyard. some colours like yellow seem to attract every bug for miles. maybe even get a pro to shoot the paint.

 

if you want a smooth high gloss finish you can dive into use Almigrip paint system. it has a non sand primer and good covering colour. Avoid if you can auto paints they do not have the flexibility to handle the extreme temp changes that your aircraft will give it.

 

Unlees they have closed i am pretty sure there was a paint shop at ballerat

 

ozzie

 

 

[Guest Wigg]

Adrian,

 

We are in the process of repairing the skyfox. We found a product in Bunnings that isn't expensive, but removed each layer of paint one at the time. I am not sure of the name of it,but is in a yellow tin. I am off to Bunnings soon to find out the name of it. (any excuse to go to Bunnings). To clean it off the residue we used a spray bottle with metho in & a green scourer. John