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Building a Javron Cub

Bill, I thought you were going with an EFIS? Which one or are you just going with the 796? No knobs there - and that's where you will spend most of your time controlling the radios, right? Sorry, I've not played w/ the 796 - not sure how easy it is to change frequencies to the radio - though I know they can talk.

What transponder are you going with? There's another pound or more to be saved over a garmin by going with the new Trig mode s - with a built in encoder. Maybe save you some sanding? ;-) sorry j/k

Thanks for all the info - luv this thread. Very educational.
 
Dougsapplic - sorry, I forgot to respond. I don't think you could do it in much less than 4 Gal. I am actually going on pretty light, using an HVLP gun, and I anticipate about 4 gallons. If you used what they recommend, 2 to 3 coats you would probably be closer to 6. If you just used 1 cross coat you might get it down to 3 gallons but you will not have much sanding room before you went right down into the fabric. Just my opinion.

Bill
 
P1020517.jpg

I love the "See I built it" pictures!

Looks great Bill, cant wait to see it in person at NH next year. You almost got me 2:1.
 
Hmmm, I guess that is Bill. I've been trying to figure out if it was a Martian or if he got one of those guys at Home Depot to paint it. In my defense, the space suit and paint gun clearly send mixed messages.
 
Hmmm, I guess that is Bill. I've been trying to figure out if it was a Martian or if he got one of those guys at Home Depot to paint it. In my defense, the space suit and paint gun clearly send mixed messages.
Mixed message only if you don't value a long and healthy life
 
I did not consider the MGL, Micro, Becker, etc. I don't care for the small knobs, switches, display etc. If I were building a LSA or ultra-light I would have looked more closely at the "micro" radios. The technology certainly seems to be headed in that direction.


IMG_14781.jpg

Hopefully this will do all that remains. Obviously not all of this will will end up on the plane. Just thought it was interesting.


P1020517.jpg

New gun much better. Used about the same amount, (maybe a half cup less) of primer on the second (right) wing. I'll weigh it tomorrow. One crosscoat and one more pass.......so 1.5 coats. This wing went MUCH better than the left. I got some pin holes/pock marks in the left wing. I cleaned the left wing prior to paint with a light rub down of acetone. I think it softened the glue a little and I did not give it sufficient time to flash off prior to painting so it created a pock mark in some places. I will have to sand and reprime those areas. On the right wing I did the final cleaning more carefully and used Alcohol, rather than acetone, and gave it several hours to dry before primer. No pin holes or pock marks. The left wing is fixable it will just take a little more time.

Hope this helps

Bill
Bill tell me that's not quartz lighting in your booth...
 
Hmmm, I guess that is Bill. I've been trying to figure out if it was a Martian or if he got one of those guys at Home Depot to paint it. In my defense, the space suit and paint gun clearly send mixed messages.


Sorry oldcrow, it was just a feeble attempt at humor. Other thoughts were papa smurf or an Ebola doctor were doing his painting. Perhaps I should have just kept my trap shut, but instead of a pool on how much the final cost of his build is, his central/southern okie friends have a pool on how many supercub.org pages it takes to build a Javron cub.
 
Sorry oldcrow, it was just a feeble attempt at humor. Other thoughts were papa smurf or an Ebola doctor were doing his painting. Perhaps I should have just kept my trap shut, but instead of a pool on how much the final cost of his build is, his central/southern okie friends have a pool on how many supercub.org pages it takes to build a Javron cub.
My bad, in a past life I worked in the water storage tank industry and I've seen the effects of not being careful with solvents.
 
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Folks

P1020519.jpg

All 5 tail surfaces are in white.
Thoughts......You will note that when I shot primer I had all 5 surfaces in the booth at one time. It was pretty crowded. Easy to drag a hose into a part, or brush into it when moving around. Not all that big of a deal because we will sand them anyway. When doing the final paint, it was not worth the risk. So I did it in two parts. Stabs, then the elevators and rudder.
Lets talk a little about final coats. When putting the topcoat on the primer, it melts down into the primer and it will lose a little of its gloss and also it will pick up a little of the primer color. If you use different colors for your primer your topcoat will be different shades as well. The trick is to shoot a thin color coat and then let it completely cure. 7 to 10 days for most two part polyurethanes. Then that topcoat is wet sanded with 400 grit and repainted. Now there will be no melting into the previous coat. It will sit on top and this then gives the best gloss and tint/hue. This is called "color holdout". If you want a show winning paint job this is how to do it. You want that final coat to sit on top of the undercoats NOT blend down into it.
Another thought - paint sticks to paint two ways. Chemical and mechanical. You have probably seen the warning that says "Recoat within 72 hours. If not you must sand for best results". If you put a topcoat on primer within X amount of time (it varies but usually from 2 to 7 days) then the undercoat is still not fully cured and additional coats will "chemically" blend in. In the process you may get some softening of the gloss and also color. Thus no color holdout. If you repaint after the specified time period, you must sand the surface in order to get a mechanical bond because the primer is fully cured and you will not have a chemical bond. If you sand and paint within the time period you will get both a chemical and a mechanical bond. Still with me?
So you now know how to get the very best finish. But we also know that sanding does not reduce the weight, or material much at all. So..... to do the "top job" paint we have to use at least 2 coats and that adds weight, and it also makes the final paint thicker, and the thicker the paint the more likely you are to have problems in the future like cracks, ringworm, flaking, etc. Thick paint may look nice but it does not usually hold up very well. Be sure to get your Oshkosh award the first year because you may not be able to win after the second year.
So there-in lies the dilemma. Do we go with thin paint that may not look the "best", or go for the highest gloss? If you were careful to only put on one pass the first time, (ie not a cross coat, just one direction). Then sanded and put a cross coat on you would only have 1.5 coats. With the polyurethanes you almost always have to do a cross coat for the top coat. The first half of that cross coat is just a tack coat, its main purpose is to get "tacky" so that when you put the next half of the cross coat on, that "wet" topcoat has something to stick to so you can get it on thick enough to flow out but not get any runs. Without that tacky substrate if you put it on thick enough to flow out you WILL get runs. So, the bottom line is.... if you are going for the "high gloss look" the very minimum paint you could apply would be 1.5 coats.
But if we accept a little less than "show" quality we can do one cross coat, (remember we need the tack pass, then the wet topcoat).
Doing it this way also saves time. Remember, for the "show" finish we need to paint, wait about a week for it to fully cure, sand it all down (this is many hours on something the size of a wing) then we get to paint it again. Takes a lot of time and also LOTS of sanding, but it is noticable. It produces a very high gloss, beautiful finish.
I elected to just put one cross coat on for the topcoat. I don't want thick paint, nor am I trying to win at Oshkosh, nor do I want to spend the next three months sanding. I painted the stabs first, and my tack coat was a little too thin. Still worked just fine but I went just a little heavier on the elevators and rudder and I think they came out better. Now that I have told you this you might be able to see the difference. Had I not told you this I doubt many people would ever notice. But for those trying to learn about painting and getting ready to paint your own I offer this so you might learn.
I mentioned that I got a new paint spray gun. When shooting primer, the gun quality difference was not all that noticable. Primer goes on pretty crude and it is not uncommon for even the very best hot rod body shops to use a cheap gun for primer. When shooting the top coat it made a HUGE difference. The gun was/is worth it. I got a SATA 4000B digital HVLP with a 1.4 tip set. The fan, and atomization, are just worlds different. On my last Cub, I used a Sharpe T1 syphon feed gun. I am serious when I say there was only one part of that entire airplane that I was reasonably happy with. The rudder was OK. Every other part, both wings, fuselage, elevators, stabs, cowling, flaps, ailerons, etc etc was repainted at least twice as the quality was sooo bad it was embarrassing. I had runs on every part, or orange peel, or both. Some runs were REALLY bad. It was very frustrating and took a lot of the fun out of the build. It is not very rewarding when your workmanship looks like crap.
Although not perfect by any means, all five tail surfaces are better than my best part on the last build. I attribute it to having a really good gun. I am not any better as a painter than my last build. I have not painted anything since (other than the BD-5 and that was kinda a quicky with my old gun) so my skills have not gotten better via practice. Having a good quality gun and watching lots of Youtube videos helped immensely. It is amazing what you can find and learn from Youtube. How to clean your gun, how to set up your gun, how to build a paint booth, etc etc. Tons of great info there.
This guy is especially good and has LOTS of excellent how to paint videos

http://www.youtube.com/watch?v=P_9WQmicyJU

The bottom line is you CAN do this. It's not rocket science. Get a good quality gun, spend some time learning on youtube, and go for it. I know the pro's can take a Harbor Freight 39.95 gun and do better than I can with the best gun on the market. With the best I can get an "OK" job. With lesser quality tools I can get very frustrated, (takes the fun right out of it) and do a really crappy job. It still won't be perfect, but I'm reasonably happy, and at this point the cost of the gun was worth it. Lets hope it continues to work out.

P1020520.jpg

Both wings are in primer. 1.5 coats. I will have to do some sanding. I might be able to get the fuselage in primer tomorrow.

Sorry for the long post.......Hope this helps

Bill

PS - Mike, there was about 1/10 of ounce difference in weight after a flood washing and three additional days of off gassing. Not much.

PSS - I will weigh the parts to get the paint weight after they have time to fully cure. Might be a day or two.
 
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Ok

Weighed the tail surfaces after paint. Added the weights to post 1158 for those who want to see the raw data. Here are some summary thoughts on this little experiment.

The tail feathers referred to include the rudder, both Horiz stabs, and both elevators, so 5 pieces.
Total fabric including glue, stitching, tapes etc = 3.29oz
Primer before sanding = 1.5 coats = 88.33oz (5p8.33oz)
Primer after sanding = 76.9 (about 13% sanded off, with pretty aggressive sanding)
Paint = 1 crosscoat = 13.71

notes:
The primer added 88.33oz (76.9 ounces after sanding) and the paint added 13.71. Even if you account for the difference in 1.5 coats primer Vs 1 coat of paint the weight is in the primer NOT in the paint. (with this system - Air Tech). The stabs and elevators turned in very close numbers so I was using about the same amount of paint and primer and sanding them about the same as well. The differences were in the 10th of an ounce and perhaps that is lost in the noise. If we assume the stabs and the elevators have about the same area, I used about 2.5oz of paint on the stabs (remember I mentioned a pretty thin tack coat on those) and I used close to 3 oz on the elevators. Thus the little extra paint in the tack coat was about 1/2 oz. Not much, and again we may be in the noise.

If we were to color sand these I doubt we would get much weight off, less than 10%, but we also know another coat of paint would only add about 13oz for all five surfaces, so the weight gain for the "color holdout" paint job would not be excessive, but another coat of primer would be a bunch of weight, probably in the vicinity of 55oz.

Lots of folks have said "the weight is all in the topcoat, yes siree, thats where all the weight is" At least with Air-Tech we can safely say at this point, most of the weight is in the primer, and sanding does not take all that much weight off.

Hope this helps

Bill
 
Fuselage is in primer. Unfortunately I forgot to weigh the fuselage before I got it all set up in the rotisserie, and tapped off. I used 5.1/2 cups of primer just exactly as on the wings so I should be able to estimate pretty closely the primer weight.


P10205211.jpg

This is how I mounted the fuselage in the rotisserie. This is a Wag Aero wing rotator. I got it here

http://store.wagaero.com/product_info.php?products_id=12693

Man, it has gone up in price!! But at the same time I can't hardly imagine doing this without some type of rotator mechanism. Build it or buy it but your gonna need it.

P1020523.jpg


P1020522.jpg

This is how I did the tail. The rudder hinge points are not really all that strong, (and furthermore they are at a angle, unless the tail is 5 feet up) so I drilled a couple of holes in the rotator and bolted it to the tailwheel attach bracket. Works great. As noted previously the rotator is bolted to the floor. You HAVE to do this or it will walk and fall over (according to Murphy - right after you just sprayed your nice perfect wet topcoat). Another thought - drilling these holes through this steel square tube would have been darn near impossible with a hand drill, but it is like butter with a drill press. I don't really understand why drilling a hole is sooooo much easier with a drill press than it is by hand, but it is. Another tool that is worth every penny.

P1020524.jpg

Fuselage in primer. Lesson learned. I am doing a fabric headliner, so it needs primer and paint. I did the outside and the inside all at once. Not a good idea. One) The complexity of taping off everything for the dual painting was arduous. It took close to 8 hours just to mask it off. Two) it was a total of almost 4 hours in the paint booth. Too hot, too long breathing from the fresh air respirator, too tiring physically. Three) Difficult to spray the inside and not touch the outside, or mess up the inside while doing the outside. Four) Lots of bounce back and blow back with your head and shoulders crammed in there. The paint and mist bounces off the fabric right back in your face (like washing out a garbage can with a garden hose sprayer. Five) The full size gun and paint cup did not fit in the headliner area. I bumped the wet paint several times with either the hose or the cup. Fortunately the Air-Tech primer sands super well so I will be able to sand it all out and it will come out perfect for the top coat. But I will have to get a jamb gun, or at the least a much smaller cup for the final interior paint. I will do the topcoat in two parts. Interior, then allow it to dry, then tape it off and do the exterior in a separate session.

Hope this helps

Bill

PS - just had another thought. The interior fabric, headliner, or side panels, or baggage compartment, etc. might be an excellent application for Oratex. Then you would not have to try to get in there to sand and paint which is a real pain in the arse. Hmmmm, I'm thinking that might work really well.
 
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Bill,

If you were starting over with the fabric painting, and aside from using Oratec for the fabric headliner, would you install the headliner and paint it first, and then cover the fuselage and paint it seperately?

Also, your fuselage appears to be stripped of almost everything. What remains attached to the fuselage during your paint process... control cables, jack screw, trim cables?

Thank you,
Jasperfield
 
Jasperfield

I had not considered painting the headliner before covering the rest of the fuselage but that might make things a little easier. I can't see why it would not work.

My fuselage covered and going into the paint booth included.....

Rudder and elevator cables with the tangs on the ends
Cargo floor boards, both upper and lower.
Rear cockpit floorboard (only the front floorboard is not in)
Rear wall of both the upper and lower cargo compartments
ELT mount, antenna, and cable to front
Electric trim and taillight wires
Electric trim motor, travel limiting micro switches
Jackscrew, Yoke and Carry through Tube that bolts to the yoke
Elevator balance cable and spring that attach to the yoke and the elevator horn
Fuel lines and selector valve
Rear seat rudder pedals and associated hardware and springs

After primer, in this configuration, it weighed exactly 141 pounds. Fuselage fabric estimated at 5 to 6 pounds and primer estimated at 5.5 pounds. (So all this stuff above weighs about 25 pounds)

I used about 5.5 paint cups (28oz Vs 32oz in a qt) on the tail, and each wing also took 5.5 cups as did the fuselage. 5.5 paint cups seems to add an amazingly consistent 5.5 pounds. So, even though I did not weigh the fuselage prior to primer I am very confident that the primer added right around 5.5 pounds within just a few ounces. (Hmmmmm - interesting thought - I used a little less than 1 cup of white paint on the tail surfaces and that weighed 13 ounces - I'm starting to think 1 cup of paint/primer is going to add about 1 pound. Certainly seems pretty consistent so far)

I still have to do flaps, ailerons and the door. If those parts also add 5 pounds then I will have used 25 pounds in primer (before sanding). We know primer is heavier than paint in a big way so an early guesstimate will be about 33 to 38 pounds in primer and paint on the fabric parts.

Hope this helps

Bill
 
Paint weights. while this topic is being discussed, check out the type certificate data for the Waco DGC-7.
http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/bf98e6d0fae5df048525673f005d1696/$FILE/ATT9HHTW/ATC639.pdf
Look at item 309. The weights of different colors are listed. Notice that the darker the color the heavier the paint weighs as much as 51 lbs extra for French grey. Blue is only 7 lbs extra. This should be an eye opener for the weight conscious builder.
 
PS - just had another thought. The interior fabric, headliner, or side panels, or baggage compartment, etc. might be an excellent application for Oratex. Then you would not have to try to get in there to sand and paint which is a real pain in the arse. Hmmmm, I'm thinking that might work really well.


You would not be the first one to DO THAT. It works great and is nearly Bullet or Moose-Antler-Proof.
Regards,
Lars
 
Folks

Not really much to offer at this time. I have been sanding and painting. I am using the Air Tech system. I am using 220 grit wet on the open bay areas and then following with 320 and maroon scotch brite. The paint fills the 320 grit scratches so there is no need to go to 400 grit. That helps a little.

Important Note - Ibuprofen (Advil or Motrin) and Acetaminophen (Tylenol) are different drugs. You can alternate. They both say take every 6 to 8 hours. So you can take Tylenol at 10AM, then Advil at 1300, then Tylenol at 1600, Advil at 1900 etc. This will mask a LOT of pain from sanding. You might be really sore the next day but it can help make a productive weekend - then recuperate later. Important stuff to know.


P1020536.jpg

I extended the red stripe back to the spar. This dark color on the Leading Edge helps melt the frost off more quickly.



P1020537.jpg

You don't usually get frost on the underside of the wing so I used a little less red here. Personal preference.



P1020538.jpg

Drying rack. Even though the paint is dry it remains "soft" for several days or even a couple of weeks. If you lay a wing on saw horses you are likely to put a crease in the paint, thus I hang everything in the drying rack for a while until I am ready to assemble things.



P1020539.jpg

More of the same.



P1020540.jpg

Fuselage in the booth. No weights yet. I want to make sure everything is dry before I weigh things just to make sure I don't mark the paint before it if fully cured.



May not be much to post for another stretch while I paint the fuselage, flaps, ailerons, wing struts, etc.

Bill
 
Bill, that is sooo awesome. What's your ETA @ Nimpo (if you keep your pants dry this time)? :)
 
Looking good Bill! I'd be interested in how you set up your paint booth. Have you shared how you set it up in any of your threads? For example what did you use for the walls and how did you setup the airflow and filters? I've done several small temporary booths in the garage but I'm sure I could learn something; knowing your attention to detail.
 
TO ALL - A couple of years ago some dirtbag spammer harvested my email list and now every few months my list of email contacts comes to the top of their dirtbag rolladex and all my contacts get spam addressed from me. I am sorry for the trouble. Unfortunately nothing I can do about it. If it is not about flying, camping, fishing, or the Lord, it is probably not from me. I will never send out just a link with no other explanation, verbiage, etc. Sorry for the trouble folks.


Logan - Next summer - Lord willing. :smile:


Sophistical

Here is a little info on the booth.........

http://www.supercub.org/forum/showt...g-a-Javron-Cub&p=597132&viewfull=1#post597132 (scroll down a little)

One of the better parts of the booth is the exhaust fan set up. I have a window in the hangar (several actually) and I used one to exhaust the booth. Cut a hole in the booth wall to access the window, built a sheet metal box to hold a fan, open the window, slide the box in. No it is NOT OSHA approved. That would cost about 5000 bucks. Has not blown up yet. Looks like this.....


P1020542.jpg

You will need lots of inlet filter area otherwise the fan will suck air from the floor cracks etc. I have 4 filters and need about 4 more


P1020545.jpg

The box has a couple of "L" brackets for the fan to butt up against. A little foam fills the gaps


P10205461.jpg

Fan in the window......


P1020548.jpg

From outside. The box needs to extend out a little so you don't paint your outside wall.


It is not great but its better than plastic and it keeps the paint from getting outside the booth (ie all over everything in the hangar). It can be easily disassembled, stacked, or shrunk. I usually leave the last 12x8 panels up so I have a 12x8 booth which works great for everything except the big stuff.

Hope this helps

Bill
 
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Bill, You are really rolling. Thank you for all the time you spend letting us in on your project. It is great learning and inspiration. I look forward to your big day! Greg
 
Looks real good, Bill. I'm paying attention to the paint and fabricing as I am getting closer.

Did you color sand your wings?
 
Kevin

Not yet and not intentionally. This is from a previous post..........

Lets talk a little about final coats. When putting the topcoat on the primer, it melts down into the primer and it will lose a little of its gloss and also it will pick up a little of the primer color. If you use different colors for your primer your topcoat will be different shades as well. The trick is to shoot a thin color coat and then let it completely cure. 7 to 10 days for most two part polyurethanes. Then that topcoat is wet sanded with 400 grit and repainted. Now there will be no melting into the previous coat. It will sit on top and this then gives the best gloss and tint/hue. This is called "color holdout". If you want a show winning paint job this is how to do it. You want that final coat to sit on top of the undercoats NOT blend down into it.
Another thought - paint sticks to paint two ways. Chemical and mechanical. You have probably seen the warning that says "Recoat within 72 hours. If not you must sand for best results". If you put a topcoat on primer within X amount of time (it varies but usually from 2 to 7 days) then the undercoat is still not fully cured and additional coats will "chemically" blend in. In the process you may get some softening of the gloss and also color. Thus no color holdout. If you repaint after the specified time period, you must sand the surface in order to get a mechanical bond because the primer is fully cured and you will not have a chemical bond. If you sand and paint within the time period you will get both a chemical and a mechanical bond. Still with me?
So you now know how to get the very best finish. But we also know that sanding does not reduce the weight, or material much at all. So..... to do the "top job" paint we have to use at least 2 coats and that adds weight, and it also makes the final paint thicker, and the thicker the paint the more likely you are to have problems in the future like cracks, ringworm, flaking, etc. Thick paint may look nice but it does not usually hold up very well. Be sure to get your Oshkosh award the first year because you may not be able to win after the second year.
So there-in lies the dilemma. Do we go with thin paint that may not look the "best", or go for the highest gloss? If you were careful to only put on one pass the first time, (ie not a cross coat, just one direction). Then sanded and put a cross coat on you would only have 1.5 coats. With the polyurethanes you almost always have to do a cross coat for the top coat. The first half of that cross coat is just a tack coat, its main purpose is to get "tacky" so that when you put the next half of the cross coat on, that "wet" topcoat has something to stick to so you can get it on thick enough to flow out but not get any runs. Without that tacky substrate if you put it on thick enough to flow out you WILL get runs. So, the bottom line is.... if you are going for the "high gloss look" the very minimum paint you could apply would be 1.5 coats.
But if we accept a little less than "show" quality we can do one cross coat, (remember we need the tack pass, then the wet topcoat).
Doing it this way also saves time. Remember, for the "show" finish we need to paint, wait about a week for it to fully cure, sand it all down (this is many hours on something the size of a wing) then we get to paint it again. Takes a lot of time and also LOTS of sanding, but it is noticable. It produces a very high gloss, beautiful finish.
I elected to just put one cross coat on for the topcoat. I don't want thick paint, nor am I trying to win at Oshkosh, nor do I want to spend the next three months sanding.
So, I shot 1 1/2 coats primer, sanded that VERY aggressively, then shot one crosscoat of topcoat.

The first wing I painted I got orange peel on the bottom (the top came out OK) and pin holes in the red stripe (did not allow enough flash off time for the final wipe) and so I will probably color sand those areas and respray them. The second wing was painted horizontally (Vs the first wing vertically) and that helped me to get the paint on with almost no orange peel and I waited much longer for the final wipe to flash off so the red stripe came out much better. So the bottom line is "no, I elected not to color sand" but I might end up doing a little anyway, to fix the first wing paint job, and it will be interesting to see how it comes out and to compare the color sanded area and the non color sanded parts. As you can imagine I will report my findings, good or bad.

Hope this helps

Bill
 
Folks

Another little update.

Fuselage is in white and I hope to put the red stripes on this coming weekend.

The left wing is the one that I used acetone as a final wipe before primer and then I did not wait long enough before shooting primer. The acetone finished evaporating through the primer and messed it up in a few places. So I had to sand that wing pretty hard and reprime. Then sand before final paint. So.......it looks like this......
Left wing ( with 1 aileron cable, tip light mount, light wires, pitot tubing, tank straps but no tank or lid, square tip,) weighed 73.85
After all fabric, stitching, tapes etc - 79.4
After 1.5 coats primer - 85.25
After sanding the primer on all of the top and about 10% of the bottom - 84.2
After top and part of bottom re-primed - 85.7
After sanding again - 85.05
After final paint (white with red LE) - 88.15

So what does all this mean? Once again I will state that you can sand a lot but it will not take all that much weight off. In this case I sanded very aggressively (can see the fabric in lots of places ie the primer is mostly sanded off) and it took off maybe 15% of the weight. So fabric (inc glue, stitching, tapes,) added about 5.5 pounds. This value is not dependent on system used. They all use basically the same fabric, tapes, stitching etc. Then the primer added about 5.8 pounds. I sanded off about a pounds worth then added back a pound and a half on the reprime, then took a half pound off sanding a second time. Then I shot about three cups of white final color coat and yes sports fans, it added about 3 pounds reiterating once again, a quart paint cup adds about a pound. Final wing weight came in at 88.15 pounds.

So fabric adds about 5.5 pounds
Primer and paint add about 9 pounds for a total of roughly 15 pounds for fabric and paint on a square tip Cub wing. Folks I am putting this stuff on about as thin as possible.
One Cross coat, plus 1 pass for 1.5 coats of primer, sanded to fabric, followed by one cross coat color.....looks like this in primer.....

P1020533.jpg

The tiger stripes is where the primer is sanded so thin you can clearly see the fabric, the white top coat completely covers this, so it does not hurt to sand it thin. The airplane will not be tied down outside year round so I am not worried about UV issues from sanding the primer too thin.


P10205321.jpg

It can be tough to see in the photos, so here is another shot....


P10205411.jpg

And again........part of the reason for the sanding is to get a nice smooth surface to put the topcoat on and also to try to keep the paint as thin as possible to improve flexibility and durability. The objective is to get the very best possible finish with the minimum paint thickness and the least weight.

The right wing primer came out better as I used alcohol as a final wipe and gave it plenty of time to evaporate. So we shot primer, sanded the primer, and painted the white topcoat. Unfortunately I did not do a very good of shooting the topcoat (lots of orange peel on the bottom, then once again I did not wait long enough after the final wipe and it pin holed the LE red stripe pretty bad - Doh - you would think I would learn). In a nut shell I was not happy with my workmanship. So we (MMR came over and helped) started sanding down the red stripe and the bottom of the right wing (the top came out OK) and I will repaint the bottom and red stripe.
Right wing before cover (as above) - 73.2
After covering - 78.9
After primer - 83.8
After sanding - 83.1
After paint - 85.8
I will weigh after color sanding the bottom and the red stripe on the LE, then again after final paint.

P10205711.jpg

Once again the stripes are where I have sanded the paint all the way down to primer. Trying to keep it thin. I expect to be able to re-coat the bottom here in basically one pass (so half a cross coat).

Lessons learned so far

1) use the system products all the way. If they have a reducer use that - don't substitute acetone, Lacquer thinner, or MEK
2) if they have a final wipe product - use it. Don't substitute alcohol even if their product smells just like it. Perhaps one of the reasons my final wipe with alcohol did not flash off quickly is that it was 91% alcohol and 9% water. Air-Tech final wash smells like alcohol but that last 9% might be acetone, or some other chemical. My thought is that the alcohol flashed off just fine but that last 9% water may have left almost microscopic water drops that did not have time to evaporate before I sprayed. At any rate what I am now doing is cleaning, final wipe with Air-Tech products, in the evening and spraying the next day. Giving it 8 to 10 hours to flash off. Excessive? Yes but I am tired of sanding so I don't want to take ANY chances. Those items I have sprayed after a long flash off have all come out pretty good. At this point I am happy with the tail feathers, left wing, and fuselage. The right wing will be good after a respray this weekend. Because of all the sanding I am not concerned about paint or primer build up for the two areas I have had to redo, one in primer and one in paint. I think it would be pretty easy to get a good finish if you did not worry about how much primer and paint you put on. It is much more challenging to get a really nice finish with minimum materials, and it takes a lot more time. Is it worth it? Beats me, that gets down to what your standards are and what is acceptable to you. Another aspect to that philosophy is the exponential curve issue. An average job takes 50 hours, a better job takes 100 hours and the best job takes 1000 hours. I don't really have an answer there. Furthermore, I might strive for that "best" job, invest a ton of time, and still come out with an average job. If and when I do this again it might be fun to try to crank out a Cub in record time and see what it comes out like, and not worry so much about every single speck of dirt in the paint, or use plywood for the floors instead of spending lots of time and money on composite floor boards. Things like that.
3) Extra reducer in the primer helped. Extra reducer in the paint equals runs.
4) You must replace the plastic floor and clean the booth thoroughly before each spray session. It is amazing how much dirt floats around. I am still fighting this issue.
5) Don't leave the masking tape on more than a couple of days. It will leave residue and gets much harder to remove after just a few days. I will do a post on taping this weekend.
6) While waiting the 20 to 30 minutes between the first pass and the second pass of the cross coat, I clean the gun and start with a fresh batch (cup) of paint. On my last build I had a couple of really bad spray experiences that I attribute to the paint starting to set up in the cup and also drying in the gun nozzle while waiting between coats. So now after the first pass, while waiting for it to tack up, I throw out the left over paint in the cup, clean the gun, and effectively start over. I mix a new batch (cup) of paint when ready to spray again. It has worked well so far in that I have not had the disasters I had the last time. The last Cub I built was a flying paint train wreck. I am still not all that good with all this paint stuff but feel I am at least getting better. Hopefully you can learn something from my mistakes, and when you get to see my Cub at gatherings you be able to look at the finish and see some of the things I have written about, and learn a little more.
7) Everyone says painting is all in the prep. Bunk. I can invest 50 hours and have awesome prep, and then I can ruin it all in 10 minutes in the paint booth. Painting is a perishable skill. About the time you get it all figured out and get pretty good at it you are done and don't do it again for several years, then you have to learn it all over again.
8) Painting takes help. You will need friends to help move parts in and out of the booth, flip wings over for sanding, etc. A lot of the build can be done solo but I find myself needing help more in this phase than any other. Many Many thanks to MMR, Cal, Glenn, Ken, Buck, Lytle, Jim and others for helping me weigh wings, fuselages, turn things over, sand, put plastic down, etc etc.

Hope all this helps

Bill
 
I knew a fellow who raked the tire tracks out of his white gravel drive after he parked his car in the garage. I wish I had your abilities and creativity re airplane building. Your posts on this forum have helped me a lot.
 
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