Self Etching Primer

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ridekorn
Posts: 9
Joined: Tue Nov 26, 2019 9:34 am
Location: CA

Self Etching Primer

Post by ridekorn »

I have decided that I am going to prime my build. I went a workshop and the guy there recommended using automotive self etching primer. However There are a ton out there and knowing nothing about them, I was wondering which one other people were using or if it even matters and all of them are pretty much the same? The one I was looking at was this https://www.autozone.com/paint-and-body ... 246429_0_0. Thanks ahead of time.
ebrunye
Posts: 51
Joined: Mon Nov 25, 2019 9:33 am
Location: San Diego

Re: Self Etching Primer

Post by ebrunye »

I used this one on my empennage, and this is the one that builders who use rattle can self etching primers typically use. That being said, its total junk in my opinion. It scratches off easily, which kind of defeats the point.

I know a lot of people have their opinions on this issue, and really all the viewpoints are correct in their own way. I pretty strongly believe if you are going through the effort to prep and prime the parts, do it with good epoxy primer. The prep work for priming is the hard part consuming all the time, not the actual priming.

The aluminum Sling uses is almost completely corrosion resistant without any treatment though, so I chose to stop priming altogether. I wrote a more in depth post about the aluminum on this forum somewhere already, I think it's in this priming/painting section.
ridekorn
Posts: 9
Joined: Tue Nov 26, 2019 9:34 am
Location: CA

Re: Self Etching Primer

Post by ridekorn »

Thanks. I saw the other post but was never sure on the actual can that others used. I appreciate the info, just trying to do as much research as I can while I wait for my kit to get here :)
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PhilipRueker
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Re: Self Etching Primer

Post by PhilipRueker »

Yes the Rustoleum Self Etching Primer is what most of us use. I'm using it on mating surfaces.

Matthew did an experiment when he started his build with a few of different primers - https://sling4tsibuilder.wordpress.com/ ... nt-update/

A lot of it comes down to good prep, but as Evan said, it ultimately comes down to personal preference.
Building a Sling TSi in my Garage.
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wiseguy59
Posts: 3
Joined: Wed Jan 15, 2020 8:33 am
Location: MD/KDMW

Re: Self Etching Primer

Post by wiseguy59 »

I'm a little late to the game here, but I thought I'd add my recent experience.
I used SEM green on the vertical stabilizer structure and the inside of the skin. It applies well, and SEM makes good products. No flaking of the primer.
After I ran out of SEM, I was unable to find it in green. Evidently, the green pigment is difficult to get at this time.

I then tried to find another green primer, and found TranStar. It is a two-part, whereas SEM is one part.
You mix the two together and can spray right away, no induction is necessary. Again, it applies well and does not flake.

When it came time to prime the remaining empenagge skins, I used UPOL self-etching primer in grey.
It sprays very well and provides good coverage. It is a one part primer, agitate and shoot. No flaking.
The best part about the grey color, is that it won't take heavy coats to cover it up, as the green does. This will help when it's time to shoot the epoxy.

All surfaces were prepped by using a red Scotchbrite pad and rubbing in different directions to make sure all areas were scuffed.
The panels were then wiped with a clean cloth, in one direction only, no back and forth. You're trying to remove the dirt, not move it around.
Next step was to use SPI(Southern Polyurethane Inc) Grease and Wax remover. Again, wipe in one direction only until the towel is clean.
All primers were sprayed at 25 psi (at the gun).
The towels used were lintless prep towels for painting cars. You could use any quality paper towel, as dust in the primer is not that bid of a deal.

If you don't have the means to spray it, aerosol cans will work fine. Just do the proper prep and you are 90% of the way to a good job.
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lutorm
Posts: 19
Joined: Fri Jan 28, 2022 11:00 pm
Location: USA

Re: Self Etching Primer

Post by lutorm »

I'm curious, what's the weight penalty on priming everything? It seems one of the advantages of Alodining is that you're not adding a bunch of weight. Of course, there's the nasty chemical disadvantage instead...
Blog of various projects: https://blog.familjenjonsson.org/blog/
Cyrus
Posts: 21
Joined: Sun Dec 08, 2019 11:38 am
Location: KTIX, Cocoa, FL

Re: Self Etching Primer

Post by Cyrus »

lutorm wrote: Wed Aug 24, 2022 5:35 pm I'm curious, what's the weight penalty on priming everything? It seems one of the advantages of Alodining is that you're not adding a bunch of weight. Of course, there's the nasty chemical disadvantage instead...
I will be able to tell you this in a few weeks, as I'll be disassembling the VS, priming and reassembling it. For the rest of the plane outside of the Empennage, I've gone through 24 cans of SEM self-etching primer.
Cyrus
Sling TSi in progress.
Cyrus
Posts: 21
Joined: Sun Dec 08, 2019 11:38 am
Location: KTIX, Cocoa, FL

Re: Self Etching Primer

Post by Cyrus »

wiseguy59 wrote: Tue Aug 23, 2022 11:20 am I'm a little late to the game here, but I thought I'd add my recent experience.
I used SEM green on the vertical stabilizer structure and the inside of the skin. It applies well, and SEM makes good products. No flaking of the primer.
After I ran out of SEM, I was unable to find it in green. Evidently, the green pigment is difficult to get at this time.

I then tried to find another green primer, and found TranStar. It is a two-part, whereas SEM is one part.
You mix the two together and can spray right away, no induction is necessary. Again, it applies well and does not flake.

When it came time to prime the remaining empenagge skins, I used UPOL self-etching primer in grey.
It sprays very well and provides good coverage. It is a one part primer, agitate and shoot. No flaking.
The best part about the grey color, is that it won't take heavy coats to cover it up, as the green does. This will help when it's time to shoot the epoxy.

All surfaces were prepped by using a red Scotchbrite pad and rubbing in different directions to make sure all areas were scuffed.
The panels were then wiped with a clean cloth, in one direction only, no back and forth. You're trying to remove the dirt, not move it around.
Next step was to use SPI(Southern Polyurethane Inc) Grease and Wax remover. Again, wipe in one direction only until the towel is clean.
All primers were sprayed at 25 psi (at the gun).
The towels used were lintless prep towels for painting cars. You could use any quality paper towel, as dust in the primer is not that bid of a deal.

If you don't have the means to spray it, aerosol cans will work fine. Just do the proper prep and you are 90% of the way to a good job.
Try R&E Paint Supply online and in Arkansas. I was able to order green from them with no issues as recently as 2 weeks ago.
Cyrus
Sling TSi in progress.
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