Scott A
FOUNDER
Park City, UT
Oh good.. was wondering the same.
New kid on the block - Smith Cub
- Thread starter Buzzcola777
- Start date
Buzzcola777
MEMBER
Montreal, Canada
Lost 1 year!!!
Yeap! 1 year down the drain…I learned the hard way about primer & paint!! As you may know, I covered my Cub using the Stewart System. I have followed all the steps up to the paint. After reading a bunch of reviews about painting with this system, people mentioned that it was difficult, and the application was different than enamel / epoxy / urethane since you need to use the fog/wet coat technique which is odd to all the gents that I’ve talked to.
I had seen interesting videos from Robbie Staton (Airtech Coating) about his paint system. I ask Robbie if I could use his primer and paint with the Stewart system. He was honest and he just did not know if I could apply it on. He suggested that I should make a frame, covered it, and follow all the steps up to where I am with the cub. So, I ask him to send me a quart of primer and paint to test it on the covered frame. Before applying the primer, the surface was sanded with 320 grit and cleaned. Primer & paint held strongly to the fabric. I have tried to sand it, peel off the paint with an X-Acto blade, scratch it, pour solvent on it…nothing I could do to remove it. I was happy about it and ordered primer from Airtech Coating and some Poly-Fiber paint from Aircraft Spruce since that there both polyurethane bases.
Primer and paint when on well and I were satisfied with the result except for one little paint run on the belly close to the landing gear location. Ann (wife) was giving me a hand with sanding between coats and we she saw that paint run she insisted to get rid of it by using a Nib file from Steck. So, she rubbed the run very carefully and after couple minutes, probably due to friction, a bubble appeared. I cut it open and noticed that the primer was not adhering to the Stewart System primer. I pulled the side of the bubble and the paint started to peel off!!!
I was horrified. What to do? I assessed another location, same result! Could I sand it down and repaint it? The primer & paint would stick very strongly to the tapes but not to other area. Now I tested the wings with the same problems. I could only visualize this aircraft with its new paint scheme sitting in the sun and bubbles popping up all over!
Well, after 3 sleepless nights, whichever way you look at it, the mishap was caught on time. I decided to remove all the fabric and glue and do it all over again! At this time, an unimaginable thing happened…Ann said that if I agreed to work only from 09:00 am to noon (6 days a week) she would team up with me to do whatever is necessary to recover the cub!! Well, she kept her words, and we did the job within a year.
This time, one system only! I choose Airtech Coating and using only their product. So far so good and Robbie has a great customer service.
Here is a comparison chart between the two covering jobs.
First covering job: August 19,2020 – Dec 18, 2021
Second covering job: May 01,2023 – April 23,2024
Getting ready for the next step: Primer & Paint!!
More to follow!
Dan
Yeap! 1 year down the drain…I learned the hard way about primer & paint!! As you may know, I covered my Cub using the Stewart System. I have followed all the steps up to the paint. After reading a bunch of reviews about painting with this system, people mentioned that it was difficult, and the application was different than enamel / epoxy / urethane since you need to use the fog/wet coat technique which is odd to all the gents that I’ve talked to.
I had seen interesting videos from Robbie Staton (Airtech Coating) about his paint system. I ask Robbie if I could use his primer and paint with the Stewart system. He was honest and he just did not know if I could apply it on. He suggested that I should make a frame, covered it, and follow all the steps up to where I am with the cub. So, I ask him to send me a quart of primer and paint to test it on the covered frame. Before applying the primer, the surface was sanded with 320 grit and cleaned. Primer & paint held strongly to the fabric. I have tried to sand it, peel off the paint with an X-Acto blade, scratch it, pour solvent on it…nothing I could do to remove it. I was happy about it and ordered primer from Airtech Coating and some Poly-Fiber paint from Aircraft Spruce since that there both polyurethane bases.
Primer and paint when on well and I were satisfied with the result except for one little paint run on the belly close to the landing gear location. Ann (wife) was giving me a hand with sanding between coats and we she saw that paint run she insisted to get rid of it by using a Nib file from Steck. So, she rubbed the run very carefully and after couple minutes, probably due to friction, a bubble appeared. I cut it open and noticed that the primer was not adhering to the Stewart System primer. I pulled the side of the bubble and the paint started to peel off!!!
I was horrified. What to do? I assessed another location, same result! Could I sand it down and repaint it? The primer & paint would stick very strongly to the tapes but not to other area. Now I tested the wings with the same problems. I could only visualize this aircraft with its new paint scheme sitting in the sun and bubbles popping up all over!
Well, after 3 sleepless nights, whichever way you look at it, the mishap was caught on time. I decided to remove all the fabric and glue and do it all over again! At this time, an unimaginable thing happened…Ann said that if I agreed to work only from 09:00 am to noon (6 days a week) she would team up with me to do whatever is necessary to recover the cub!! Well, she kept her words, and we did the job within a year.
This time, one system only! I choose Airtech Coating and using only their product. So far so good and Robbie has a great customer service.
Here is a comparison chart between the two covering jobs.
First covering job: August 19,2020 – Dec 18, 2021
Second covering job: May 01,2023 – April 23,2024
FABRIC | |||
Hours To Complete Controls | |||
| 2023 | 2020 | | |
| Elevators | 51.0 Hrs | 53.0 Hrs | |
| Stabilizers | 47.5 Hrs | 35.0 Hrs | |
| Rudder | 30.0 Hrs | 33.5 Hrs | |
| Gear Legs | 22.5 Hrs | 35.0 Hrs | |
| |||
Hours To Complete Fuselage | |||
| 2023 | 2021 | | |
| Fuselage | 150.0 Hrs | 139 Hrs | |
Hours To Complete Wings | |||
| 2024 | 2021 | | |
| Left Wing | 114.0 Hrs | 151.0 Hrs | |
| Right Wing | 153.0 Hrs | 173.0 Hrs | |
Hours To Complete Ailerons | |||
| 2024 | 2020 | | |
| Both Ailerons | 88.0 Hrs | 58.5.0 Hrs | |
Hours To Complete Flaps | |||
| 2024 | 2020 | | |
| Both Flaps | 49.5 Hrs | 63.0 Hrs | |
Total Hours To Complete Aircraft | |||
| 2024 | 2020 | | |
TOTAL HOURS | 705.5 Hrs | 741.0 Hrs |
Getting ready for the next step: Primer & Paint!!
More to follow!
Dan
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Buzzcola777
MEMBER
Montreal, Canada
Buzzcola777
MEMBER
Montreal, Canada
Olibuilt
MEMBER
Montreal, Canada
Dan, I hear your pain. Your wife and you make a good team. I'm sure it will look even better the second time.
I might hire you for my next covering job
How did you remove the blue Stewart glue before re-covering?
What are your thoughts about the the AirTech glue compare to the Stewart ?
I did mix products one time with good results: Endura polyurethane top coat over Stewart Ekofill-primer over bare fabric.
I might hire you for my next covering job
How did you remove the blue Stewart glue before re-covering?
What are your thoughts about the the AirTech glue compare to the Stewart ?
I did mix products one time with good results: Endura polyurethane top coat over Stewart Ekofill-primer over bare fabric.
Attachments
Buzzcola777
MEMBER
Montreal, Canada
Scott, once the decision is made and you make peace with it...You just go back to the ''Fun to build something'' mindset .
Buzzcola777
MEMBER
Montreal, Canada
Oli, Thanks!Dan, I hear your pain. Your wife and you make a good team. I'm sure it will look even better the second time.
I might hire you for my next covering job
How did you remove the blue Stewart glue before re-covering?
What are your thoughts about the the AirTech glue compare to the Stewart ?
I did mix products one time with good results: Endura polyurethane top coat over Stewart Ekofill-primer over bare fabric.
Concerning the Stewart Glue, we used a rod and wrapped it with masking tape backward on it really tight. It worked for large area. For the hard to get places, we used a rubber Belt Cleaning Stick by rubbing the glue off. Took about 150 hours to remove all the glue...Just don't want to do this again!!
Airtech Glue: First of all , once the glue is diluted with reducer, the smell almost dissepear. Mind you we worked in a fair size hangar, it helps! I really enjoy working with the Stewart System but I think that the Airtech glue sticks more strongly to the parts. I tested the glue on a sample before starting the job on the aircraft and I tell you it was hell to remove it! Stewart System glue is pretty well like rubber, that's why we could remove it with masking tape. you could not do that with Airtech...
Beautiful aircraft Oli you've got there. I'm glad that you did not run into my problems!! Also a nice series of pictures included, thanks!
Dan
Mountainman
MEMBER
Hello Dan!
My name is Alois Mayr. I am from Austria/Europe.
I have read the construction of your Smith Cub with attention and congratulate you on your wonderful aircraft!
Forgive me, for writing to you like this.
A friend and I, bought 2 Super Cub Kits from Nick Smith in Canada.
Unfortunately we didn't get any usable documents for the approval from Nick Smith.
Maybe you can help us.
The Canadian authority will probably require the same tests and documents for the certification of an experimental aircraft as the EASA in Europe.
We would of course pay for your trouble!
Our authority requires documents such as
Alois und Jozi
My name is Alois Mayr. I am from Austria/Europe.
I have read the construction of your Smith Cub with attention and congratulate you on your wonderful aircraft!
Forgive me, for writing to you like this.
A friend and I, bought 2 Super Cub Kits from Nick Smith in Canada.
Unfortunately we didn't get any usable documents for the approval from Nick Smith.
Maybe you can help us.
The Canadian authority will probably require the same tests and documents for the certification of an experimental aircraft as the EASA in Europe.
We would of course pay for your trouble!
Our authority requires documents such as
- "Strength verification for the main structure, wings and fuselage",
- "Rated weights and center of gravity positions",
- "Proof of stability",
- "Proof of flutter safety"
Alois und Jozi
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Bearhawk Builder
FRIEND
In the woods
Dan, I'm interested in your experience using another paint over Stewarts covering. I have two questions
Why do you think your test panel results were different from the final aircraft results?
You say that you sprayed Airtech primer and paint over Stewarts primer. Was this over their Ekoprime or did you go over their Ekofill with Airtech primer?
I don't know much about Airtech primer but it seems there is some incompatibility between it and the Ekofill/Ekoprime. Is it possible the Eko was not fully cured?, that all the water had not left the surface? Otherwise I'm not sure why another product would not stick.
Thanks for the honest write up.
Why do you think your test panel results were different from the final aircraft results?
You say that you sprayed Airtech primer and paint over Stewarts primer. Was this over their Ekoprime or did you go over their Ekofill with Airtech primer?
I don't know much about Airtech primer but it seems there is some incompatibility between it and the Ekofill/Ekoprime. Is it possible the Eko was not fully cured?, that all the water had not left the surface? Otherwise I'm not sure why another product would not stick.
Thanks for the honest write up.
skywagon8a
MEMBER
SE Mass MA6
Dave, This lighter yellow is Valspar ultra latex house paint over white Ekofill.
Bearhawk Builder
FRIEND
In the woods
Not bad
Must be white Ekoprime, Ekofill is charcoal only.
Must be white Ekoprime, Ekofill is charcoal only.
skywagon8a
MEMBER
SE Mass MA6
I used the wrong scrap of fabric when the paint was mixed which is why the tips don't match the wing.
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Bearhawk Builder
FRIEND
In the woods
Huh, white Ekofill. Thanks for that.
I've always used white Ekoprime over the Ekofill under light colors. It sands very nice.
I've always used white Ekoprime over the Ekofill under light colors. It sands very nice.
Buzzcola777
MEMBER
Montreal, Canada
Alois,
Nice to hear from pilots flying in Europe and buildings Cubs!
In Canada, unless I'm wrong, there are no requirements to provide documents concerning flutter, stability or the strength of a structure such as fuselage / wings etc...Except for the Weigh & Balance calculation. I would guess that for an aircraft to certify as airworthy, a flutter and stability test is carried out in a wind tunnel at max speed and disturbances are introduced to the airflow to see how the structure and controls withstand such vibrations before breaking. Not sure is any of the test were done to the PA-18...Interesthing points that you brought there. My youngest son is an Aeronautical Engineer, I will submit your points to him and see what king of calculations he can come up with. I'll get back to you... Dan
Buzzcola777
MEMBER
Montreal, Canada
Bearhawk,
I really don't know why it did work on the test panel and was a disaster on the fuselage...Let me tell you I really tried to figure out the problem. The fuselage was done exactly like the test panel, 1st coat of diluted glue followed by 3 coats of Ekofill (sanding between coats) THEN Airtech primer. Obviously, it is not about Airtech product but rather the compatibility between Polyurethane over waterborne base. It would be nice to know if we have any Cub drivers that have mixed a waterborne base coat with a polyurethane top coat??? To answer your question, the Ekofill had cured at least 3 weeks before applying Airtech primer. I can only conclude at this moment that when you start your project with one system, you stick to it 'till the end. Dan
