Unique striping and prep questions

S

silflexer

I am getting ready to paint an old aluminum airplane that will be SPI red and polished aluminum. Here is my plan, followed by a few questions/looking for your feedback.
1. Prep aluminum/mask/epoxy at my house. Epoxy must be applied within 24hours of the metal prep and the masking will take me some time.
2. Sand epoxy with 400 or 600 as needed to remove trash and fix any problems.
3. 24 hours later take airplane to booth and clean with W&G and then mask using 3M green fineline/Nason white paper/3m plastic.
4. Shoot a 1:1:1 reduced epoxy coat of epoxy
5. Wait two hours, maybe less and shoot SPI red base
6. Next morning shoot universal clear and demask.

Questions: does my timeline and process make sense to you? Should I spray the sealer coat of epoxy and then base and pull the masking tapes or do I use the same masking for the whole job? Pictures of a completed airplane so that you know what I am facing with the color right on the polished aluminum.
Thank you!
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That looks like A LOT of masking. Fairly complicated too. Me, I'm a slow masker and with that type of detail would take me even longer. Are you only applying metal prep to the painted areas? Or the whole thing and polish out later? If it was me I would do the metal prep as you planned, then tape it out and if I went over the 24 hours (I would) simply hand sand with 180 all the areas receiving epoxy after I masked it. Perfectly acceptable to do that. Barry or Jim C could give you a definitive answer (about using scotchbrite) but you could even use red scotchbrite in place of the 180 and give it a hard scuff, which would be easier and go quicker than the hand sand. Blow it off, wipe it down and then epoxy. Main thing is to do it fairly quickly after the scuff or sand, just like with the metal prep.

Would be more realistic and easier on you. Rest of your plan sounds good.
 
How are you prepping the bare aluminum before epoxy? Alodine? just sanding?
I would do as Chris stated: polish whole plane then mask areas for paint then sand with 180 clean and go strait to epoxy sealer.
I have painted a lot of aircraft parts and for durability it's always a single stage color. I would look into that verses a B\C paint job.
 
I have another possibility here. Haven't personally used the product yet, but Cerakote mc160 is a 1 part air dry ceramic clear that can be used on polished aluminum & sprayed with a normal quality spray gun with .8 tip to a less than 1 mill thickness. There is also a #5100 now meant specifically for aluminum. Tough enough for gun community including military and some long term positive comments on it from people on pro-touring.com on aluminum parts & wheels that had it applied. Aluminum won't be as shiny as freshly polished, but will stay clean without all the hard maintenance. Could polish all main areas plus margin needed, coat, then tape , scuff, epoxy, & paint red parts.

Like I said, never personally tried product yet, but heard enough good comments on it. I'm sure spi epoxy would bond fine to it. Could call them & get their take on project & do a sample project run. Sounds better than trying to polish aluminum next to paint for maintenance. My possible suggestion here would make the highly detailed taping job more like painting over clearcoat & less time sensitive.
I'd also say do SPI single stage red.
 
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I would use single stage instead of base clear. I think it will be a tougher finish. Less time too.

Don
 
I have another possibility here. Haven't personally used the product yet, but Cerakote mc160 is a 1 part air dry ceramic clear that can be used on polished aluminum & sprayed with a normal quality spray gun with .8 tip to a less than 1 mill thickness. There is also a #5100 now meant specifically for aluminum. Tough enough for gun community including military and some long term positive comments on it from people on pro-touring.com on aluminum parts & wheels that had it applied. Aluminum won't be as shiny as freshly polished, but will stay clean without all the hard maintenance. Could polish all main areas plus margin needed, coat, then tape , scuff, epoxy, & paint red parts.

Like I said, never personally tried product yet, but heard enough good comments on it. I'm sure spi epoxy would bond fine to it. Could call them & get their take on project & do a sample project run. Sounds better than trying to polish aluminum next to paint for maintenance. My possible suggestion here would make the highly detailed taping job more like painting over clearcoat & less time sensitive.
I'd also say do SPI single stage red.
I have used the Cerakote MC160 on polished bronze and aluminum with good results so far. I haven't tried the aluminum specific formula yet.
I agree with your concept but would also have concerns about any other materials adhering to the MC160. I did a similar process on some aluminum MC wheels with a polished the rim edge and painted the rest. I was concerned about the adhesion over the MC160 so I hard taped the edges. IE: taped with the rim exposed, applied the clear then hard taped the clear rim with a slight over lap and then painted the rest. The only problem I encountered was after the MC160 was taped with 3M blue I had a small leak with the acid prep (Aero 33 - phosphoric) under the painted part and it left some small white streaks on the clear. Burned it I assume. In hind sight I could have avoided that by taping of the polished part, then prepping and painting the paint part. that way I could have polished out any streaks prior to applying the clear. There was no fixing the MC160 with any compound at all.
 
The aluminum is already polished and will be sanded in the areas to be painted before metal prep. The Prekote metal prep will be applied with a red scotchbrite and then I will rinse with water and demask. Once the metal prep is on, it does not allow the metal to be touched, even with a tack rag so I will mask, blow off, and epoxy. I already own the SPI red and clear (only goes on the side of the airplane not the leading edges) so I will probably not be buying a single stage. I am concerned about leaving the mask on for the entire process, would you remask the whole thing between base and clear? The good news is that the remasking should go pretty quickly since the edges of polished and painted will be well defined and I will not have to guess about where to place tape.
 
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The aluminum is already polished and will be sanded in the areas to be painted before metal prep. The Prekote metal prep will be applied with a red scotchbrite and then I will rinse with water and demask. Once the metal prep is on, it does not allow the metal to be touched, even with a tack rag so I will mask, blow off, and epoxy. I already own the SPI red and clear (only goes on the side of the airplane not the leading edges) so I will probably not be buying a single stage. I am concerned about leaving the mask on for the entire process, would you remask the whole thing between base and clear? The good news is that the remasking should go pretty quickly since the edges of polished and painted will be well defined and I will not have to guess about where to place tape.

Couple of questions and things to consider, you are going to have a sharp break between polished and treated metal. How are you going to be able to follow that closely? Unless you pretape all the edges you are going to bleed over. That is complex masking, unless all you ever do is mask, it will take much longer than you think. Not going to be just a few hours. Your are talking all day masking it if you are lucky. Not being able to tack it off? That sounds nuts to me.
I know what the metal treatment manufacturer says, but have you checked with Barry about the compatibility of SPI epoxy over that Pre-Kote stuff? I would want to hear it from him that it's OK. Only way I would even consider using it. I don't care what the metal prep manufacturer says. It is an alkaline so if that isn't neutralized in the process it would be similar to coating something soda blasted that hasn't been neutralized.
Personally I would do as has been suggested and mask, then hand sand with 180. It is just as good as using the metal treatment. SPI Epoxy will give you all the corrosion protection you will need, and your adhesion will be as good, most likely better than using that stuff.
As for remasking, NO you would not want to remask between base and clear. That would be a big mistake. It's never done, plus think about the issue you would have trying to follow and retape all those edges between paint and polished surfaces. Trust me you do not want to have to do that. Leave it masked. One thing you should do is use a high quality fine line tape on all the edges and when you untape it, pull the tape back on itself. Meaning straight up then backwards. That will help ensure you have clean lines. If you don't you will get some ragged edges. When not pulling it straight back, sometimes the base that is on the tape will slide off the tape and you have to take a exacto knife and try to cut it away. So make sure you pull the tape off correctly.
 
Thanks Chris, I appreciate the response. Prekote is used everyday with almost every brand of epoxy. Aluminum certainly presents a unique adhesion and prep challenge which is why chemical treatment is preferred for long term corrosion prevention and paint adhesion. I will mask, sand, prekote and the unmask. Then take to booth, mask, shoot sealer, base/clear and then pull tapes like you described.

Josh
 
Thanks Chris, I appreciate the response. Prekote is used everyday with almost every brand of epoxy. Aluminum certainly presents a unique adhesion and prep challenge which is why chemical treatment is preferred for long term corrosion prevention and paint adhesion. I will mask, sand, prekote and the unmask. Then take to booth, mask, shoot sealer, base/clear and then pull tapes like you described.

Josh

Sounds like you are the marketing guy for the company.:) I know that's what they say, but not all epoxies are the same and Barry has said some very specific things about metal treatments and SPI Epoxy in the past. Would not want you to have an expensive re-do. I still would check with Barry. Please take a few moments. Text him @ 404-307-9740. You can take what he tells you to the bank. No marketing BS.

FYI in case you didn't know Barry is the Owner of SPI.
 
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Thanks Chris, I have spoken to Barry a few times over the past ten years. I am just a dude with a hobby that does not desire to poison my own well with chromates. Just really want to make sure that my mask will still pull correctly after having a base dry and then clear over the top.

Josh
 
Thought I would update this thread after I actually did something. Here is what I ended up doing, all of it by myself.
1. Wed night- dawn dish soap and maroon scotchbrite entire area to be painted, load onto a trailer
2. Thursday early am, drive 1.5 hrs to place with booth- go to carwash and use the metal prep (prekote) and maroon scotchbrite on area to be painted. Unload at booth, dry with air and mask airplane. Masking took 5 hours
3. Friday- booth opened at noon and I had a little more masking to finish. Finished at 2pm which was about 25hrs after I had metal prepped. Product instructions say the window is 24hrs. I had bought a can of their wipes and they say to wipe and then paint with no other steps so I elected to do that. Turned out to be a good idea since I had not wiped the thing down per their instructions.
4. Made sure that the wipes had dried and sprayed 3 coats of epoxy. Some peel and trash present, the booth was definitely dirty
5. Saturday- sprayed 3 coats of spi red base with 30 minutes of flash time between followed by 2 hours of rest and then 3 coats of spi universal clear. Pulled tapes 30 minutes after last coat of clear
Results- “factory” amount of peel and overall I am happy. I am still nee at painting and my masking was below average on several spots. Need to figure out to clean up some of the mask lines and rivets where there is paint on what is supposed to be polished aluminum. I also peeled some base off of the epoxy and will need to find ways to fix that. For a beginner, I am happy enough. Love that spi red
 

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