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  #1  
Old 09-02-2022, 01:01 PM
Mistfarer Mistfarer is offline
 
Join Date: Oct 2021
Location: West Midlands, United Kingdom
Posts: 30
Default EkoPrime: Close-up picture of scuffed aluminum?

Hi all

I understand the process to use EkoPrime involves scuffing the surface with Ekoetch and maroon scotch brite.

I am going to give this a go on a practice kit in the coming week, and was wondering if anyone could share a high-definition, close-up picture of what a part should look like after that particular step? Just to get a sense about how much scuffing is "just right".

Thanks in advance for your support.
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Van's RV-8 "Mist" #84063
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  #2  
Old 09-02-2022, 02:49 PM
rapid_ascent rapid_ascent is offline
 
Join Date: Mar 2008
Location: Dublin, CA
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Default

Patrick, I originally started with Eko-Prime and I didn't really like it so I moved on to Akzo which is much more durable. However, I still use their etching process. I don't have any pictures but I can provide some guidance. Most of the aluminum parts we receive have a slight shine to them. The etching and sanding with the maroon scotchbrite will create a matte finish. You will know when you are at the right point. If there are still areas which are still somewhat shiny then continue the process until that is not the case. The skins are alcad which is softer than some of the angle pieces so they etch faster. I don't think its all that critical that you get the perfect surface finish to get good primer adhesion so I wouldn't worry about it too much. Once you do it a few hundred times you'll know what you are looking for. Seriously I think you'll get the idea pretty quickly.
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RV-7 Fuselage in progress
* Cabin Interior - In progress
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  #3  
Old 09-02-2022, 05:55 PM
Mistfarer Mistfarer is offline
 
Join Date: Oct 2021
Location: West Midlands, United Kingdom
Posts: 30
Default

Quote:
Originally Posted by rapid_ascent View Post
Patrick, I originally started with Eko-Prime and I didn't really like it so I moved on to Akzo which is much more durable. However, I still use their etching process. I don't have any pictures but I can provide some guidance. Most of the aluminum parts we receive have a slight shine to them. The etching and sanding with the maroon scotchbrite will create a matte finish. You will know when you are at the right point. If there are still areas which are still somewhat shiny then continue the process until that is not the case. The skins are alcad which is softer than some of the angle pieces so they etch faster. I don't think its all that critical that you get the perfect surface finish to get good primer adhesion so I wouldn't worry about it too much. Once you do it a few hundred times you'll know what you are looking for. Seriously I think you'll get the idea pretty quickly.
So the process does not leave any scratch? In any case, you are right, I'm probably overthinking it. I'll go through the process on scraps and see what happens.
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  #4  
Old 09-02-2022, 06:19 PM
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PaulvS PaulvS is offline
 
Join Date: Aug 2019
Location: Western Australia
Posts: 1,277
Default

Patrick, the scuffing process with maroon scotchbrite does scratch the surface microscopically. You can sort of tell by looking whether it is scuffed enough but a better test is to scuff using a bucket of water and a few drops of mild dish detergent. When the water sheets off without beading this indicates that the oxide layer has been removed, which is the intent. Primer must then be applied within 6 hours because the aluminium starts to re-oxidise immediately.
Cheers,
Paul.
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  #5  
Old 09-02-2022, 06:26 PM
wirejock's Avatar
wirejock wirejock is offline
 
Join Date: Oct 2005
Location: Estes Park, CO
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Default Scuffing

Quote:
Originally Posted by PaulvS View Post
Patrick, the scuffing process with maroon scotchbrite does scratch the surface microscopically. You can sort of tell by looking whether it is scuffed enough but a better test is to scuff using a bucket of water and a few drops of mild dish detergent. When the water sheets off without beading this indicates that the oxide layer has been removed, which is the intent. Primer must then be applied within 6 hours because the aluminium starts to re-oxidise immediately.
Cheers,
Paul.
Bingo! Give that man an adult beverage.
Easiest method I have used is Bon Ami cleaser and Maroon Scotchbrite. Scrub like washing a pan. Doesn't take much work. No harmful chems. No harm to the environment or you.
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  #6  
Old 09-12-2022, 04:36 AM
Mistfarer Mistfarer is offline
 
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Location: West Midlands, United Kingdom
Posts: 30
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Right! So I did a bit of experimenting. Here are pictures of my art. I have used 2 pieces of scrap metal. One is brand new (literally just removed the blue protective film), the other one was cleaned with EkoClean, then etched with EkoEtch.

https://www.mistfarer.com/media

Picture 1 (left): Cleaned with EkoClean (top) vs brand new (bottom)
The cleaning, using tack cloth, removed all marks and left a few scratches.

Picture 2 (right): Etched with EkoEtch (top) vs brand new (bottom)
The etching, using maroon scotch brite, made the aliminum look mat/dull, and left some more pronounced scratch marks. Water wasn't beading (as suggested by an above poster).

Does that look about right to you?

Thanks again for all the support.
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Last edited by Mistfarer : 09-12-2022 at 04:21 PM.
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  #7  
Old 09-12-2022, 07:53 PM
rapid_ascent rapid_ascent is offline
 
Join Date: Mar 2008
Location: Dublin, CA
Posts: 1,760
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Yes it seems about right. It doesn't need to be perfect for primer application.

One thing to watch out for is some areas are easier than others to scuff with the Scotch-brite. So you can see that you didn't do quite as good of a job on the lower edge. Sometimes you need to support the edges of the piece so you get even pressure. Also you mentioned the scratches. The Scotch-brite is similar to a medium - fine sandpaper so it won't remove larger scratches if you want to remove those you need to do it prior to scuffing with Scotch-brite. However, those scratches appear to be minor so I wouldn't worry about them. Once you start shooting the primer you will see what shows through the primer. If its a piece that isn't going to be seen then you probably don't care. If it is an interior piece then you may care.
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2022 Donation Paid
Titan IOX-370, Dual PMAGs, 9.6:1 Pistons, FM-150
Sensenich Composite 3 Blade Propeller
RV-7 Fuselage in progress
* Cabin Interior - In progress
RV-7 SB Wings
* Both Wings fully skinned
* Fuel Tanks Complete - No leaks finally
* Ailerons Complete
* Flaps Complete
RV-7 Empennage - Complete (a little fiberglass work left)
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RV-7 Preview Plans
Vans Training Kit #1 - Complete
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  #8  
Old 09-13-2022, 10:03 AM
wirejock's Avatar
wirejock wirejock is offline
 
Join Date: Oct 2005
Location: Estes Park, CO
Posts: 5,692
Default Cleanser

Looks like your in the UK. Humor me and try this.
I'm sure the grocery sells some sort of powdered cleanser. Bon Ami is best but any will work. Comet, Ajax, etc.
Scrub with maroon while washing with the cleanser. Just try and scrub the whole surface. No need to get crazy. Rinse well. Dry. Paint within a few hours. Cheap and no environmental issues.
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Estes Park, CO
E-mail: wirejock at yahoo dot com
Builder Blog: http://wirejockrv7a.blogspot.com
Donated 12/01/2021, plus a little extra.
RV-7A #73391, N511RV reserved
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.
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  #9  
Old 09-13-2022, 02:17 PM
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bjdecker bjdecker is offline
 
Join Date: Jun 2005
Location: Georgetown, TX
Posts: 1,355
Default

Quote:
Originally Posted by wirejock View Post
Looks like your in the UK. Humor me and try this.
I'm sure the grocery sells some sort of powdered cleanser. Bon Ami is best but any will work. Comet, Ajax, etc.
Scrub with maroon while washing with the cleanser. Just try and scrub the whole surface. No need to get crazy. Rinse well. Dry. Paint within a few hours. Cheap and no environmental issues.
Do not use COMET or AJAX, those product contain/may contain chlorine bleach which will cause corrosion of aluminum. There was a propellor failure a few years back attributed to corrosion caused by chlorine - details here : http://www.tsb.gc.ca/eng/rapports-re...7/a94q0037.pdf

Bon Ami is fine as it is only feldspar + soap.
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  #10  
Old 09-13-2022, 03:14 PM
wirejock's Avatar
wirejock wirejock is offline
 
Join Date: Oct 2005
Location: Estes Park, CO
Posts: 5,692
Default Comet & Ajax

Quote:
Originally Posted by bjdecker View Post
Do not use COMET or AJAX, those product contain/may contain chlorine bleach which will cause corrosion of aluminum. There was a propellor failure a few years back attributed to corrosion caused by chlorine - details here : http://www.tsb.gc.ca/eng/rapports-re...7/a94q0037.pdf

Bon Ami is fine as it is only feldspar + soap.
Hence the phrase "Rinse well". However, I don't want to be the cause of an airplane falling out of the sky so please don't use any cleaser with bleach.

I wonder if Bar Keepers Friend would work. Oxalic Acid.

Link didn't work for me. I'm curious how enough clorine got in there to cause a prop failure and if was Ajax or Comet.
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Larry Larson
Estes Park, CO
E-mail: wirejock at yahoo dot com
Builder Blog: http://wirejockrv7a.blogspot.com
Donated 12/01/2021, plus a little extra.
RV-7A #73391, N511RV reserved
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.

Last edited by wirejock : 09-13-2022 at 03:23 PM.
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