The weight of paint?

[GusBiz]

So a while ago someone told me "Gus, every idea weighs something??

I have a few gadgets I would like to add and I am knocking off the ones I think are just too heavy or too silly, (oddly they are often the same item)

So as I am adding all of this weight together it occurs to me that paint could be more weight than any of the other ?ideas? that I have thought of.

The surface area of the plane is not small and there is a wide range of paint jobs from a light coat to a custom show room finish.

I am looking more for the second one so I would be looking for the following (Welcome to the heavy and most likely stupid item)
So this is what would be involved I have been told;

1. Primer layer

2. Filler of surface imperfections
(or as we know it here in Australia, Bog?don?t even ask where that came from)

3. One to two coats of Base Colour

4. Three to four coats of clear that will be then cut and polished into a serious nice paint job

Now all of that may be too much and I know a lot will talk about flutter issues with the Emp, that Filler will be my biggest mass item, that I don?t need four coats of clear etc.

I would like to hear all of that. Bring it on guys; tell me how wrong I am because I might as well hear it now instead of regret not having heard it later.

Also please add the difference in weight that paint made to your aircrafts and please add what kind of paint job it was. A Base with one of clear or the overdone job I am intending on doing

PS. Does anyone know if certified aircraft is tested before its painted or after? I would assume after but I am interested in the whole "but what if you have to change something" discussion

 

[Walt]

From what I've seen, the average RV tends to gain about 20-25lbs for single stage 2-3 color paint job. I'm sure if you add more colors and lots of clear it's gonna gonna weight more.

 

[Mel]

The weight that paint adds has a lot to do with how it's applied. i.e. Auto paint shops typically use much more paint than a professional aircraft painter.
I once inspected two RV-10s that were built side by side with the exact same equipment. One was painted by the builder and the other was painted by an auto paint shop.
The one painted by the auto paint shop was 20 lbs. heavier than the one painted by the builder. Both paint jobs were beautifully done.
18-25 lbs. should be a good number for paint.

 

[rv8guy]

I weighed my -8 with the same scales before and after getting painted by Grady at 52F. I was at 1064 prior and 1096 after, with a small CG shift. The paint remains awesome and still draws a crowd after 5 years. That was Sherwin Williams material put on by a pro.

32 pounds for paint seemed about right to me, and I wouldn't change a thing. I fought many urges to add other stuff, and have the small battery, Grove Gear, and WW 200RV prop

 

[hydroguy2]

I didn't weigh mine before paint so don't actually know the paint additional number. But N155BK came in at 1095# after paint. 3 colors Base/clear coat sprayed by a Auto painter(that has shot 20 airplanes). I worked with Corky everyday for a month, he knew to keep it light and also knew I was going for a deep shine. We used thin coats, the yellow took 3 to get proper coverage, purple and green were only 2. Then for the clear I questioned the choice of only going with 2 clear, he said if we put it on correctly there will be no buffing, no filling in of the rivets and will be lighter.

I couldn't be happier.

 

[az_gila]

....
PS. Does anyone know if certified aircraft is tested before its painted or after? I would assume after but I am interested in the whole "but what if you have to change something" discussion

I visited the Piper Vero Beach factory at it's height in the 70's and one thing still I specifically remember is the line of unpainted planes outside, all with the same N-number rattle can painted on...

The Cherokees were definitely tested unpainted.

 

[Greg Arehart]

My Rv-9 gained ~30 lbs with a 3-color Imron paint job done by a professional. No clearcoat. I say about 30 because I made a few other mods between the time I first weighed it and then weighed it again after paint. Total weight is 1122.

Greg

 

[Bob Axsom]

Beauty is of course only part of the benefit

You already know the weight will increase 30 to 40 pounds with a beautiful paint job so you have the basic answer to your question I think. Perhaps surprisingly the weight is not that big a factor in cruise - maybe you know that. Dave Anders if a very famous RV-4 builder with extreme attention to detail including weight. He built his RV-4 with natural aluminum finish and red paint trim stripes and spinner. He flew it for years this way but now the aluminim is covered with white. The plane is described in a decades old Sport Aviation article - I can look it up if necessary - I still remember reading about him temperature controlling the rivets until installation in a dentist oven - detail!!! He set the RV Gold class record 240.58 mph in the AirVenture Cup race in 2010 painted.

When I worked at McDonnell Aircraft in St. Louis starting in 1958 the F-101 had a natural aluminum finish, The F-4 Phantom II was painted with epoyx, and the F-15 was painted with polyurethane. When I built our RV-6A I flew it for a year with no paint except for a thined epoxy resin brush on coat of the fiberglass cowl and fairings. I loved to fly it that way as it seemed very military utilitarian with no polish. I experienced no deterioration so either way works. I am sure in my own mind that the protection and appearance benefits of the weight are worth the sacrifice.

I know that is not directly responding to your original question but I think it is relevent to the bigger question.

Bob Axsom

P.S. The rule of thumb on the effect of weight on cruise speed is 1 kt per 100 lbs.

 

[GusBiz]

...snip...The one painted by the auto paint shop was 20 lbs heavier

Wow that is way more than I thought an over done paint job would have been, Thanks Mel.

...snip... I didn't weigh mine before paint so don't actually know the paint additional number. But N155BK came in at 1095# after paint

Brian, I am glad you replied. I have probably every photo of your aircraft saved to my hard drive, while my colours will be red black and white, I have decided that your scheme is the way to go. Consider your design stollen! . That is a really light weight by the way, considering with paint for both you and Marshall. Good job guys.

Gil,

Got it, I am now going to test before I paint.

Can I ask about rivet filling? I have seen some paint jobs where virtually EVERY rivet has been filled over to create what looks like a composite quality surface. When I saw that the thought I had was "That has GOT to weight a tonne...how could it not?!?"

Is that the case or is the real world amount you use to create a flat surface over a rivet minimal.

Thanks as well to Greg and Bob. Much appreciated

 

[Mel]

Filling rivets adds weight and lots of labor. I did it on one airplane. It really looks nice but I would never do it again.

 

[az_gila]

Filling rivets adds weight and lots of labor. I did it on one airplane. It really looks nice but I would never do it again.

I have a rivet filling Q for experienced painters too....

One builder mentioned not exactly filling rivets, but just adding one or two extra passes with a narrow spray fan along all of the lines of rivets during the primer application.

It seems this might somewhat fill the rivets but with little added weight or extra sanding work.

For the experienced painters, does this make sense?

 

[OneCharlieKilo]

16 lbs, red on white w/ black trim

Just another data point, but I weighed my RV-6A right before and after paint with same scales and result was 16 lbs for scheme in picture shown below. That was at T&P AeroRefinishers in Salinas and Juan pays a lot of attention to weight.
White coat went on everywhere, then black trim stripe added, then red. Clear coat on only the black and red areas.

paint data:

Base color: 570-535 Mattehorn white Jet Glo - Sherwin Williams
Red: RS911F Red - DuPont
Black: G9009S Black - DuPont
Clear coat (only applied to red and black): G2-7779S - DuPont

weight data:

Before: EW = 1,087 lbs, empty CG = 67.2"
After: EW = 1,103 lbs, empty CG = 68.1"

web page showing my paint process:

http://rv6aproject.ckhand.com/PaintJob/PaintJobPg1.htm

And prior thread I posted when I got it out of paint shop:

http://www.vansairforce.com/community/showthread.php?t=68189

Good luck, and post pics!

 

[bret]

You already know the weight will increase 30 to 40 pounds with a beautiful paint job so you have the basic answer to your question I think. Perhaps surprisingly the weight is not that big a factor in cruise - maybe you know that. Dave Anders if a very famous RV-4 builder with extreme attention to detail including weight. He built his RV-4 with natural aluminum finish and red paint trim stripes and spinner. He flew it for years this way but now the aluminim is covered with white. The plane is described in a decades old Sport Aviation article - I can look it up if necessary - I still remember reading about him temperature controlling the rivets until installation in a dentist oven - detail!!! He set the RV Gold class record 240.58 mph in the AirVenture Cup race in 2010 painted.

When I worked at McDonnell Aircraft in St. Louis starting in 1958 the F-101 had a natural aluminum finish, The F-4 Phantom II was painted with epoyx, and the F-15 was painted with polyurethane. When I built our RV-6A I flew it for a year with no paint except for a thined epoxy resin brush on coat of the fiberglass cowl and fairings. I loved to fly it that way as it seemed very military utilitarian with no polish. I experienced no deterioration so either way works. I am sure in my own mind that the protection and appearance benefits of the weight are worth the sacrifice.

I know that is not directly responding to your original question but I think it is relevent to the bigger question.

Bob Axsom

P.S. The rule of thumb on the effect of weight on cruise speed is 1 kt per 100 lbs.

OK OK, So....even if I am heavy on the paint I will only lose 1/2 a kt. I can live with that, I am 230 Lbs so I gues I can go on a diet if need be. I like painted.

 

[Mel]

One builder mentioned not exactly filling rivets, but just adding one or two extra passes with a narrow spray fan along all of the lines of rivets during the primer application.
It seems this might somewhat fill the rivets but with little added weight or extra sanding work.
For the experienced painters, does this make sense?

The problem that I've seen using this method is that some rivets will fill more than others and it will look "non-uniform".
I think it's better to either fill completely or leave them.

 

[RV6_flyer]

IF you want to go back 14-years, my RV-6 picked up 8 pounds after painting. Yes EIGHT pounds. It was weighed both before and after on CALIBRATED electronic scales that were used to weight other aircraft.

Paint used was DuPont ChromaOne Acrylic Urethane. It is an automotive paint and yes the airplane was primed with DuPont acid etching primer that was the big thing at the time. Aircraft was painted by a friend that had only painted a couple of airplanes before.

Paint does not weight that much after the liquid evaporates.

Looks like I am the only data point so far in this thread that did not pick up a substantial amount of weight.

 

[GusBiz]

That can't be right

So your saying Dry it was something like

Dry
2lbs = Primer
2lbs = Base COat
2lbs = Clear coat layer one
2lbs = Clear coat layer two

Lets say that its a mostly solvent solution so

Wet
10lbs = Primer
10lbs = Base Coat
10lbs = Clear coat layer one
10lbs = Clear coat layer two

I do not see 10lbs of wet anything covering a whole plane.

I think that you may have gone thin on some coats or just didn't include all of them.

 

[smokyray]

Gaining pounds

When I finally painted my RV4 in 1999 (after 4 years of flying) I very carefully weighed it on digital race car scales. I etched and alodined it, 1 coat grey primer 1 coat base color single stage PPG DGHS fleet cement truck paint. I chose to not paint stripes, rather paint control surfaces and cowling a different color, thus not having more than 1 coat.
End result was a 12 lb weight gain carefully checked on the exact same spot and scales. I know the paint is no longer used as it is considered hazmat. When we painted the X last year we repeated the process, exactly with a modern single stage sprayed with HVLP. Weight gain? 18 lbs.

For a unpainted RV in my neck of the woods, "rust never sleeps"...


FYI
Smokey

 

[videobobk]

This thread got me thinking--I went with vinyl for my second and third colors. I knew it was a big money savings, but what about weight? I just went down and weighed a square foot of Oracal 951 Premium Cast Vinyl in black. 951 is the best (IMHO) vinyl, and the only thing I put on airplanes. I weighed it on an accurate powder measure scale, and it weighed 158 grains. There are 7000 grains to the pound. That means that it would take a little over 44 square feet to equal one pound. I used about half that much on my 9A and I don't think I have added a pound to anything I have ever decorated; another argument for vinyl.

I would guess that using vinyl instead of paint on the average RV would increase the weight by about 1.476 ounces, give or take. CG shift would be exactly 0.0002" aft. I didn't figure it in knots

Bob

 

[Bob Axsom]

Lose Weight

OK OK, So....even if I am heavy on the paint I will only lose 1/2 a kt. I can live with that, I am 230 Lbs so I gues I can go on a diet if need be. I like painted.

That is what Dave Anders did for maximum performance - I don't remember the exact weight loss - but I think the greatest benefit was in the climb performance. Aside from aircraft performance the weight loss may have other benefits. I weighed 228 pounds in 1956 when I started conciously trying to get it down. I think I had it down to 197 by the time I left Korea. Yesterday morning I weighed 196.2 I think. I have had it as low as the high 170s and I made a new Year's resolution yesterday to get it back under 185 pounds in 2012 when I have my next third class medical coming up in November.

Bob Axsom