Completely remove old paint or just sand and paint?

[rick57]

I will repaint next year in January and February. I want to get a good coat that is the same color white all over. Any artwork will be vinyl over the new paint. Is it worth completely removing all the old paint, then priming and painting? Or is it better to sand it down for good adhesion and proceed with new paint over the old?

 

[Mel]

In my opinion, YES, it IS worth it to remove the current paint.

In our kind of aircraft weight is everything; even though with all the auto-pilots, dual everything, back-up systems and leather interiors, it wouldn't appear so.

 

[lr172]

Clearly weight reduction is a benefit. The other issue is adhesion. If the bond of the original paint is only fair, you run the risk that it debonds and takes all the paint with it. Stripping addresses that. However, if the original paint used processes like alodine, an adhesion promoter, and the new paint won’t have that, you might be better off keeping that by sanding down to the primer only and recoating.

 

[rockyfatcat]

I had asked this same question. I bought a previously flying -7, and there were at least 3 different shades of white going on.

I was going to scuff and spray just the white. Long story short, I got talked into doing the FULL STRIP by another member here.

I later found out that there were 6 layers of paint. I have saved a slab of outer paint that is 0.071 thick, and of course there are 5 more layers underneath that.

The aircraft was stripped down to bare metal, sanded, prepped, painted with a coat of 2 part epoxy primer, painted with a coat of high build primer, every surface was then sanded as smooth as a baby's bottom.

When I started this project. Doing the full strip was not something I wanted to do. More correctly, it was the last thing I was interested in doing. Having done it. I can say that i have fixed or corrected all the details the original builder included in this build.

Right now the entire aircraft is apart and ready for the paint booth this Sunday.

 

[Mel]

If you decide to strip, I recommend that you weigh the airplane before stripping and after repaint. I think you will be happy with the results.

 

[Mike S]

Another thing to consider is color bleed from an old layer.

Fresh from bare metal will prevent that.

 

[rick57]

In my opinion, YES, it IS worth it to remove the current paint.

In our kind of aircraft weight is everything; even though with all the auto-pilots, dual everything, back-up systems and leather interiors, it wouldn't appear so.

What is best way to remove? Use paint stripper safe for aluminum and pressure wash to remove? Or is there something better?

 

[rick57]

I had asked this same question. I bought a previously flying -7, and there were at least 3 different shades of white going on.

I was going to scuff and spray just the white. Long story short, I got talked into doing the FULL STRIP by another member here.

I later found out that there were 6 layers of paint. I have saved a slab of outer paint that is 0.071 thick, and of course there are 5 more layers underneath that.

The aircraft was stripped down to bare metal, sanded, prepped, painted with a coat of 2 part epoxy primer, painted with a coat of high build primer, every surface was then sanded as smooth as a baby's bottom.

When I started this project. Doing the full strip was not something I wanted to do. More correctly, it was the last thing I was interested in doing. Having done it. I can say that i have fixed or corrected all the details the original builder included in this build.

Right now the entire aircraft is apart and ready for the paint booth this Sunday.


View attachment 99433


View attachment 99432

OK, I give up, how long is that going to take to get done?

 

[Aerodon]

I had a Seneca 'scratch and paint' once. Paint peeled off the leading edges in the first rain encounter. No fun paying for 2 paint jobs in a row.

Take it to a place that can do it properly, complete strip and paint. Save money by doing white with vinyl decals / stripes .

Aerodon

 

[Bandera]

If you decide to strip, I recommend that you weigh the airplane before stripping and after repaint. I think you will be happy with the results.

On average I have found that a single 3 color (base and two stripes) paint job weighs about 20-23 pounds.

I’ve told a bunch of customers over the years that if you want just a sand and paint, I can guarantee that my paint sticks to the old paint. I cannot guarantee that the old paint will stick to the airplane.

 

[Mel]

On average I have found that a single 3 color (base and two stripes) paint job weighs about 20-23 pounds.

I’ve told a bunch of customers over the years that if you want just a sand and paint, I can guarantee that my paint sticks to the old paint. I cannot guarantee that the old paint will stick to the airplane.

Maybe on average. BUT there is a very wide range. I've seen ranges from 18 lbs - 40 lbs.

Many years ago there were 2 identical RV-10s built in the same shop at the same time equipped identically with a weight differential of 20 lbs. and the ONLY difference between the airplanes was who painted them.

 

[Bandera]

Maybe on average. BUT there is a very wide range. I've seen ranges from 18 lbs - 40 lbs.

Many years ago there were 2 identical RV-10s built in the same shop at the same time equiped identically with a weight differential of 20 lbs. and the ONLY difference between the airplanes was who painted them.

I was thinking white base color. Most certainly the color or colors used plays a role in the final weight.

 

[rv6builder]

I'm in the "strip to bare metal" camp for sure. Painting is a big job and I dont want to take any chances. And the weight savings. I re- did mine last winter. Part way through I found a great paint stripper called "DeBond". Its biodegradable, no nasty fumes, and doesnt flash off so you can leave it on up to 24 hours if I remember correctly. Oh yeah, it was also half the price of the nasty stuff. I painted it on, and after 24 hours the paint was literally falling off on its own. It walked right through the epoxy primer that the Methylene Chloride stuff barely touched. Wish I had found it earlier in the project.

 

[Norman CYYJ]

I'm in the "strip to bare metal" camp for sure. Painting is a big job and I dont want to take any chances. And the weight savings.View attachment 99446View attachment 99447 I re- did mine last winter. Part way through I found a great paint stripper called "DeBond". Its biodegradable, no nasty fumes, and doesnt flash off so you can leave it on up to 24 hours if I remember correctly. Oh yeah, it was also half the price of the nasty stuff. I painted it on, and after 24 hours the paint was literally falling off on its own. It walked right through the epoxy primer that the Methylene Chloride stuff barely touched. Wish I had found it earlier in the project.

That looks like a really high drag paint job.

 

[rockyfatcat]

OK, I give up, how long is that going to take to get done?

I’m not sure what you are asking. I’m a retired A&P and this project has been pretty much my full time job for a while now. If you have any questions feel free to send a PM.

 

[lr172]

.

I later found out that there were 6 layers of paint. I have saved a slab of outer paint that is 0.071 thick, and of course there are 5 more layers underneath that.
.

So, 6 layers of paint at .070”. That is .420” or 7/16” of paint. Guessing there is maybe a decimal point error here.

 

[lr172]

Another thing to consider is color bleed from an old layer.

Fresh from bare metal will prevent that.

Two coats of quality sealer will create a fresh canvas. They are heavy on pigments and prevent bleed through with no opacity.

To be clear, i am not suggesting that sand and spray is better. However adhesion has a lot to do with experienced prep. If this is the op’s first attempt at painting, there is the possibility that what is currently there is better bonded than what he may do, especially if alodine was used. If the paint history is unknown, that probably pushes one towards a strip job.

 

[rockyfatcat]

So, 6 layers of paint at .070”. That is .420” or 7/16” of paint. Guessing there is maybe a decimal point error here.

Most of the layers were not as thick. 71 thousandths
.

 

[lr172]

View attachment 99452
Most of the layers were not as thick. 71 thousandths
.

That is crazy. How the heck does one get .07” of paint on a plane. Most individual coats are applied around a mil or so.

 

[justa6ereh]

The very best stripper I have found is Sunset Strip by Webbertek. It is non-methylene chloride...smells orange-ish...and works like nothing I have ever used before in 40 years in the aerospace business...spray it on...forget it for the day...and 90% will wash off next day...re-application and in most cases, it's extremely minor hand work after.

Webbertekllc.com I think and I have zero affiliation with them, but it truly is the best I have ever used.

 

[rick57]

That looks like a really high drag paint job.

Hope that's not contagious....

 

[rockyfatcat]

The very best stripper I have found is Sunset Strip by Webbertek. It is non-methylene chloride...smells orange-ish...and works like nothing I have ever used before in 40 years in the aerospace business...spray it on...forget it for the day...and 90% will wash off next day...re-application and in most cases, it's extremely minor hand work after.

Webbertekllc.com I think and I have zero affiliation with them, but it truly is the best I have ever used.

I used Sunset Strip @$100 per gallon. I was told that 10 gallons would strip a Cessna 182. I used 7 gallons stripping just the fiberglass. I then switched to Citri-Strip from Home Depot @$50 per gallon.

It seems to me to be the same product. The advantages of either seems to be the less lethal aspect and that unlike the methylene chloride it will not melt fiberglass.

The fuselage took 9 gallons to strip. 5 the first time and 4 the second. I stripped the wings twice with 4 gallons, with 2 gallons per.

Recently I saw an aluminum flight control stripped with Aircraft Ultra Paint Remover. About $100 a Gallon any auto parts store. It is methylene chloride based and it is both lethal and fatal for fiberglass, but did an amazing job.

After doing the full strip on my aircraft, I would use the Home Depot Citr-strip over Sunset Strip just for cost. Rent the biggest pressure washer you can get your hands on. I would buy some of the methylene chloride based Aircraft paint stripper for the aluminum bits that Citr-strip cannot get fully stripped.

 

[rick57]

The very best stripper I have found is Sunset Strip by Webbertek. It is non-methylene chloride...smells orange-ish...and works like nothing I have ever used before in 40 years in the aerospace business...spray it on...forget it for the day...and 90% will wash off next day...re-application and in most cases, it's extremely minor hand work after.

Webbertekllc.com I think and I have zero affiliation with them, but it truly is the best I have ever used.

Is there any concern with the hydrogen peroxide not playing well with aluminum or any other parts?

 

[rick57]

Two coats of quality sealer will create a fresh canvas. They are heavy on pigments and prevent bleed through with no opacity.

To be clear, i am not suggesting that sand and spray is better. However adhesion has a lot to do with experienced prep. If this is the op’s first attempt at painting, there is the possibility that what is currently there is better bonded than what he may do, especially if alodine was used. If the paint history is unknown, that probably pushes one towards a strip job.

First attempt at aircraft painting. But with strippers now available, I think I will do a complete strip. Get a really good all-over coat of the same white and use vinyl for any graphics. Thanks...

 

[justa6ereh]

I used Sunset Strip @$100 per gallon. I was told that 10 gallons would strip a Cessna 182. I used 7 gallons stripping just the fiberglass. I then switched to Citri-Strip from Home Depot @$50 per gallon.

It seems to me to be the same product. The advantages of either seems to be the less lethal aspect and that unlike the methylene chloride it will not melt fiberglass.

The fuselage took 9 gallons to strip. 5 the first time and 4 the second. I stripped the wings twice with 4 gallons, with 2 gallons per.

Recently I saw an aluminum flight control stripped with Aircraft Ultra Paint Remover. About $100 a Gallon any auto parts store. It is methylene chloride based and it is both lethal and fatal for fiberglass, but did an amazing job.

After doing the full strip on my aircraft, I would use the Home Depot Citr-strip over Sunset Strip just for cost. Rent the biggest pressure washer you can get your hands on. I would buy some of the methylene chloride based Aircraft paint stripper for the aluminum bits that Citr-strip cannot get fully stripped.

Not being argumentative un-necessarily..but my experience with the Sunset Strip is just the opposite of yours. If you strip your paint at the recommended 70 degree minimum...I took the paint off my helicopter which was factory original, covered by 3 coats of over-applied auto paints...after speaking with Scott Webber, I washed the surface with a water and Tide combination, and used a Maroon Scotch Brite pad...after drying for the day, I sprayed the Sunset Strip with a crappy Wagner Power painter and let it sit for two days in the hangar. I checked it several times and re-sprayed on the 2nd day and let it sit another day.

Almost all the paint literally had fallen off and onto the plastic tarp. I then re-applied one more coat on all problem areas and the next day pushed it outside and sprayed the whole airframe with my pressure washer.

99+% of the airframe was down to bare metal...the last tiny remaining bits were spot treated and then I completely scrubbed with a fresh scotch brite pad...

And then on to Aluma Prep and Alodine.

It does not work as fast as methylene Chloride, but is completely safe on aluminum AND YOUR SKIN...and won't even hurt your fiberglass...

I've done 4 aircraft and a car this way and the results are always the same. Amazing stuff and completely different than what you buy at Home Depot.

The cost is offset by the effort expended, in my humble opinion.

 

[rockyfatcat]

Not being argumentative un-necessarily..but my experience with the Sunset Strip is just the opposite of yours. If you strip your paint at the recommended 70 degree minimum...I took the paint off my helicopter which was factory original, covered by 3 coats of over-applied auto paints...after speaking with Scott Webber, I washed the surface with a water and Tide combination, and used a Maroon Scotch Brite pad...after drying for the day, I sprayed the Sunset Strip with a crappy Wagner Power painter and let it sit for two days in the hangar. I checked it several times and re-sprayed on the 2nd day and let it sit another day.

Almost all the paint literally had fallen off and onto the plastic tarp. I then re-applied one more coat on all problem areas and the next day pushed it outside and sprayed the whole airframe with my pressure washer.

99+% of the airframe was down to bare metal...the last tiny remaining bits were spot treated and then I completely scrubbed with a fresh scotch brite pad...

And then on to Aluma Prep and Alodine.

It does not work as fast as methylene Chloride, but is completely safe on aluminum AND YOUR SKIN...and won't even hurt your fiberglass...

I've done 4 aircraft and a car this way and the results are always the same. Amazing stuff and completely different than what you buy at Home Depot.

The cost is offset by the effort expended, in my humble opinion.

I’m glad you had great success. It was at least 90 degrees when I stripped for 24 hours each time.

The first strip tended to make the outer layer basically fall off. The other layrrs weren’t as much fun.

I used 7 gallons just stripping the fiberglass 3 times. 9 gallons on the fuselage, and 4 gallons on the wings.

I did the full pressure wash after each application of stripper. I used a textured ceiling applicator from Harbor Freight. I sprayed it thick enough that it would just start to sag.

The biggest, baddest pressure washer youcan get is a must.

 

[Bandera]

I use a stripper called AR15P. It’s hydrogen peroxide based. It’s slow acting but the paint does come off. I kinda miss the stuff we had back in the 90’s. It was an acid stripper. Everything came off. Including your skin.

Be careful putting any kind of stripper on fiberglass. It can cause it to delaminate.

 

[lr172]

Be careful putting any kind of stripper on fiberglass. It can cause it to delaminate.

curious how you deal with that. do you strip it mechanically?

I restored an old vette years ago and was steered away from chemicals, as well as soda blasting. ended up doing it with razor blades. Younger and stupider back then, but had lots of energy.

 

[Capt]

On a side note for entertainment purposes. Many years ago, like 45 years there was a guy I knew of who dismantled his C336 and took the shell to an industrial paint removal company who promptly sand blasted the entire airframe completely, that process took off the outer layer of the Alclad top surface entirely, destroyed the plane right there and then, worthless, looked very clean though

 

[plehrke]

On average I have found that a single 3 color (base and two stripes) paint job weighs about 20-23 pounds.

20-23 lbs is significant. It is 4 gallons of gas.

 

[Bandera]

curious how you deal with that. do you strip it mechanically?

I restored an old vette years ago and was steered away from chemicals, as well as soda blasting. ended up doing it with razor blades. Younger and stupider back then, but had lots of energy.

Anything fiberglass just gets a good sanding.

 

[rockyfatcat]

Anything fiberglass just gets a good sanding.

Sunset Strip is safe for fiberglass. Anything with methylene chloride in it will melt fiberglass.

 

[chaskuss]

I'm in the "strip to bare metal" camp for sure. Painting is a big job and I dont want to take any chances. And the weight savings.View attachment 99446View attachment 99447 I re- did mine last winter. Part way through I found a great paint stripper called "DeBond". Its biodegradable, no nasty fumes, and doesnt flash off so you can leave it on up to 24 hours if I remember correctly. Oh yeah, it was also half the price of the nasty stuff. I painted it on, and after 24 hours the paint was literally falling off on its own. It walked right through the epoxy primer that the Methylene Chloride stuff barely touched. Wish I had found it earlier in the project.

Alex, does DeBond easily remove Polyurathane paints like Imron, Jet Glow and PPG Delta? Do you have a link for this product?

 

[rv6builder]

Alex, does DeBond easily remove Polyurathane paints like Imron, Jet Glow and PPG Delta? Do you have a link for this product?

Can't say for sure with regards to other paints, but I used it on Nason urethane and it worked great. Just a guess but I bet it would work fine.

Here is a link:

DeBond Safe Paint Removal Coating

DeBOND™ / AiA™ uses proprietary, bond-breaking, encapsulation technology to penetrate through paint/coating layers, break the adhesion bond and safely detach the paint/coating from the underlying surface.

goindustrial.com

Now unfortunately we realized its only available in Canada... sorry guys. However based on descriptions, it could be similar to Stewart Systems stripper, but that would take further investigations.

Alex

 

[chaskuss]

Here is a link:

DeBond Safe Paint Removal Coating

DeBOND™ / AiA™ uses proprietary, bond-breaking, encapsulation technology to penetrate through paint/coating layers, break the adhesion bond and safely detach the paint/coating from the underlying surface.

goindustrial.com

Now unfortunately we realized its only available in Canada... sorry guys. However based on descriptions, it could be similar to Stewart Systems stripper, but that would take further investigations.

Alex

Nason urethane is modern car paint. It's nowhere near as difficult to remove as polyurethane paints like Imron, Jet Glow or PPG Delta. Based on other listers comments, it would be best to buy DeBond in the 5 gallon size, as it's a bit over $5 [Canadian] per gallon cheaper than buying individual gallons. I did a little research. I found the TDS for DeBond [and the heavy duty version called AiA] It appears that it's recommended for removing polyurethane paints.

DeBond/AiA TDS
Charlie

 

[chaskuss]

Sunset Strip is safe for fiberglass. Anything with methylene chloride in it will melt fiberglass.

It's also recommended for use in removal of polyurethane paints.

 

[rv6builder]

Here is a link:


Nason urethane is modern car paint. It's nowhere near as difficult to remove as polyurethane paints like Imron, Jet Glow or PPG Delta. Based on other listers comments, it would be best to buy DeBond in the 5 gallon size, as it's a bit over $5 [Canadian] per gallon cheaper than buying individual gallons. I did a little research. I found the TDS for DeBond [and the heavy duty version called AiA] It appears that it's recommended for removing polyurethane paints.

DeBond/AiA TDS
Charlie

Yeah, had I found it earlier in my project I certainly would have got it in the 5gal bucket

 

[rockyfatcat]

I had asked this same question. I bought a previously flying -7, and there were at least 3 different shades of white going on.

I was going to scuff and spray just the white. Long story short, I got talked into doing the FULL STRIP by another member here.

I later found out that there were 6 layers of paint. I have saved a slab of outer paint that is 0.071 thick, and of course there are 5 more layers underneath that.

The aircraft was stripped down to bare metal, sanded, prepped, painted with a coat of 2 part epoxy primer, painted with a coat of high build primer, every surface was then sanded as smooth as a baby's bottom.

When I started this project. Doing the full strip was not something I wanted to do. More correctly, it was the last thing I was interested in doing. Having done it. I can say that i have fixed or corrected all the details the original builder included in this build.

Right now the entire aircraft is apart and ready for the paint booth this Sunday.


View attachment 99433


View attachment 99432

FRESH PAINT!