VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics

  #1  
Old 02-07-2019, 06:37 PM
escalantea escalantea is offline
 
Join Date: Dec 2018
Location: PARKLAND
Posts: 8
Default Primer testing and selection

This is not about "should I Prime or not". More about selecting a Primer.
I wanted to use a "shake can" primer (convenient), so I tested 8 different ones.

I sprayed on a clean piece of AL skin (no special treatment or scrubbing, just remove the blue vinyl), let it sit for 3 minutes and did a touch test, so see if it was quick to dry.

After ~10 minutes I did the "fingernail scratch" test, 24 hours later I repeated the scratch test.
The winners are the ones that dried quickly and resisted the fingernail scratch test completely, no scratch.
  • The clear winner is SEM PRIMER SELF ETCHING PRIMER (~$20 per can)
  • Followed [very] closely by Rust-OLEUM Professional Aluminum Primer (lowest cost)
  • Then Majic Fast DRY SELF-ETCHING Primer

All the others (5) did not get close. The winners dried very quickly and resisted the scratch test, no matter how hard I tried!

If someone wants the image of all 8 test candidates, please email me, I will send back.

I hope this helps.
Reply With Quote
  #2  
Old 02-07-2019, 06:48 PM
Mike S's Avatar
Mike S Mike S is offline
Senior Curmudgeon
 
Join Date: Sep 2005
Location: Dayton Airpark, NV A34
Posts: 14,523
Default

Quote:
Originally Posted by escalantea View Post
  • The clear winner is SEM PRIMER SELF ETCHING PRIMER (~$20 per can)
  • Followed [very] closely by Rust-OLEUM Professional Aluminum Primer (lowest cost)
  • Then Majic Fast DRY SELF-ETCHING Primer
Is this the Rust-Oleum product you tested??

__________________
Mike Starkey
VAF 909

Rv-10, N210LM.

Flying as of 12/4/2010

Phase 1 done, 2/4/2011

Sold after 240+ wonderful hours of flight.

"Flying the airplane is more important than radioing your plight to a person on the ground incapable of understanding or doing anything about it."
Reply With Quote
  #3  
Old 02-07-2019, 06:54 PM
wirejock's Avatar
wirejock wirejock is offline
 
Join Date: Oct 2005
Location: Estes Park, CO
Posts: 3,115
Default Gorilla tape test

Now rub a piece of Gorilla tape on each. Leave it over night and rip it off.
The Aluminum Oxide is still there and primer could still flake off later.
Surface prep matters.
__________________
Larry Larson
Estes Park, CO
http://wirejockrv7a.blogspot.com
wirejock at yahoo dot com
Donated 12/27/2018. Plus a little extra.
RV-7A #73391, N511RV reserved (2,000+ hours)
HS SB, empennage, tanks, wings, fuse, working finishing kit
Disclaimer
I cannot be, nor will I be, held responsible if you try to do the same things I do and it does not work and/or causes you loss, injury, or even death in the process.
Reply With Quote
  #4  
Old 02-07-2019, 06:55 PM
escalantea escalantea is offline
 
Join Date: Dec 2018
Location: PARKLAND
Posts: 8
Default

Looks very close, Maybe the can I have is newer.

It was as good as the winner, but since it did not say "Self Etching" I selected the SEM, just to be safe.

How can I easily insert a picture in the Post? (vs a link)
Reply With Quote
  #5  
Old 02-07-2019, 07:07 PM
Mike S's Avatar
Mike S Mike S is offline
Senior Curmudgeon
 
Join Date: Sep 2005
Location: Dayton Airpark, NV A34
Posts: 14,523
Default

Quote:
Originally Posted by escalantea View Post
How can I easily insert a picture in the Post? (vs a link)
http://www.vansairforce.net/articles...ums/images.htm

Understand that you are not "inserting" a photo, you are inserting the link to the website where the image is hosted.

The image must be online first, then linked to VAF.
__________________
Mike Starkey
VAF 909

Rv-10, N210LM.

Flying as of 12/4/2010

Phase 1 done, 2/4/2011

Sold after 240+ wonderful hours of flight.

"Flying the airplane is more important than radioing your plight to a person on the ground incapable of understanding or doing anything about it."
Reply With Quote
  #6  
Old 02-07-2019, 07:21 PM
escalantea escalantea is offline
 
Join Date: Dec 2018
Location: PARKLAND
Posts: 8
Default

Of course surface pre is important, fully agree.
My intention was to select a primer, not to protect a surface.
I assume that my winner will be even better on a properly prepped surface.

BTW, the aluminum sheets I used for the testing was ~16 years old practice sheet that came with a Box example and a wing element that Vans still sells. The vinyl was still on, I bet the surface had AL oxide.

OTOH, I also believe that any priming, even w/o proper prepping is better than no priming at all. On my build, (all new clean surfaces) I only prime the contact surfaces (both sides), I do no surface prepping.

A
Reply With Quote
  #7  
Old 02-07-2019, 07:52 PM
wirejock's Avatar
wirejock wirejock is offline
 
Join Date: Oct 2005
Location: Estes Park, CO
Posts: 3,115
Default SEM

Quote:
Originally Posted by escalantea View Post
Of course surface pre is important, fully agree.
My intention was to select a primer, not to protect a surface.
I assume that my winner will be even better on a properly prepped surface.

BTW, the aluminum sheets I used for the testing was ~16 years old practice sheet that came with a Box example and a wing element that Vans still sells. The vinyl was still on, I bet the surface had AL oxide.

OTOH, I also believe that any priming, even w/o proper prepping is better than no priming at all. On my build, (all new clean surfaces) I only prime the contact surfaces (both sides), I do no surface prepping.

A
My apologies Armando. My grandson's name.
I should not have jumped in with a comment about surface prep. You are correct. SEM is a superior product. NAPA 7220 is also good.
Aluminium prep is a subject dear to my heart. Build on.
__________________
Larry Larson
Estes Park, CO
http://wirejockrv7a.blogspot.com
wirejock at yahoo dot com
Donated 12/27/2018. Plus a little extra.
RV-7A #73391, N511RV reserved (2,000+ hours)
HS SB, empennage, tanks, wings, fuse, working finishing kit
Disclaimer
I cannot be, nor will I be, held responsible if you try to do the same things I do and it does not work and/or causes you loss, injury, or even death in the process.
Reply With Quote
  #8  
Old 02-07-2019, 07:59 PM
echozulu echozulu is offline
 
Join Date: Mar 2018
Location: Ocean City, MD
Posts: 43
Default

I use SEM products also, but I have switched from self etching primer to their EZ-Coat system. In conversations with their tech support team they stated that the primer needs a top coat, by itself it does not protect against corrosion. The EZ-Coat however does. Bit longer drying time and it goes on a bit thicker, but still a rattle can system.

I follow their directions, spray down with SEM surface prep, then about 2 coats of EZ-Coat.
__________________
RV-10 - Empennage started
www.wheelswelded.com
Ocean City, MD
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 10:17 PM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.