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Scuff prior to self-etching primer?

Av8torTom

Av8torTom

Well Known Member
Are people scuffing surfaces prior to using self-etch primer, and if so, what are you using to scuff.

Thanks,

Tom
 
yes

I scuff and clean the part with a maroon Scotch-Brite pad and denatured alcohol.

Dry.
Spray.
Done.
 
Kinda same

Closest piece of scotchbrite (or right angle grinder and roloc pad ;)) and any paint prep solvent like mineral spirits, prepsol or laquer thinner. I'm using variprime.

BTW, a little heat during cure really hardens the finish on the little parts.
 
Im using the sherwin williams wash primer vans recommends, I scuff with maroon scotch bright and then clean with ipa (isopropal alcohol). On some part's I've even skipped cleaning and am seeing not much difference, but ipa's cheap so I'll continue on doing what im doing.
 
I did a wash down with dish soap and a maroon scotchbrite pad followed by a wipe down with laquer thinner before shooting the SW self etch primer.
DSCN1175.jpg
 
^^^But did you win that race you were running in? From the looks of it... ;)

I scuff, wipe with MEK or DA, then spray.

I am using Duplicolors' Self Etch and it sticks.
 
Last edited:
Ditto

I scuff with Maroon Sctochbrite pad, clean with some soap and water, let dry in the Houston sun, then use SW GBP self etch out of the rattle can.
 
Mr Dye,

Do you clean the scuffed parts after you have scuffed them or do you go right from scuffing to using Duplicolor primer? I just bought 2 cans of Duplicolor (all they had left) but haven't used any yet. It;s on sale right now 2 for 1 :) Think I'll buy a case of it!

Cheers

Chris
 
CDBridgesRV7A said:
Mr Dye,

Do you clean the scuffed parts after you have scuffed them or do you go right from scuffing to using Duplicolor primer? I just bought 2 cans of Duplicolor (all they had left) but haven't used any yet. It;s on sale right now 2 for 1 :) Think I'll buy a case of it!

Cheers

Chris
Click to expand...

If I felt that it had grease, oil, wax, adhesive, or something else that migt be chemical in nature, I'll clean it with whatever seems appropriate. For clean material, I just wipe off th edust from scuffing and shoot.

Paul
 
The photo of Jim Wright on his hands and knees made me think of this.

A very handy way to scuff larger areas, say if you're painting your own skins, etc. is to put the scotchbrite pad in an orbital sander and just go at it.

You can even put a coarse piece of sandpaper in the sander, or just leave in whatever is in it, place the scotchbrite between the orbital sander and the aluminum and go at it. The sandpaper typically holds the scotchbrite just fine.

No, the scotchbrite isn't going to hurt the alclad... but water, sweat, and corrosion will!!! Much better to have GOOD paint adhesion than not.... aluminum is hard enough to bond to so scotchbrite is a definite help.

Then clean and paint with your choice of paint system.
 
I do not scuff before priming with a self-etching primer. I went back and forth with this but ultimately the self-etching primer I use (Napa 7220) is not a real solid barrier against moisture unless it is sealed with paint. So I figured (my figuring is not academically related...just putting together the info I have and arriving at a conclusion) that the alclad would be an additional barrier in preventing corrosion and decided to leave it as it is. The self-etching primer, if sprayed and allowed to set (for a week) should etch the surface for a "good enough" bond. Since the primer is not a moisture barrier the alclad is still underneath to provide an added measure of protection.
I have scuffed scrap pieces of aluminum and taken non-scuffed alclad aluminum and sprayed them. To me, the bond durability seems to be about the same.
Not trying to start a war...these are my experiences and my thoughts and the process I used.
 
I second Aaron. I have tried spraying DuplicColor self etching primer on scuffed and non-scuffed alclad sheet, if allowing it to cue for a couple of days, the bonding on them seems the same. A finger nail won't be able scratch to through the primer on both of them, just leave a mark. And an unburred sheet aluminum will scratch through both of them. So, I just clean and spray without scuffing the parts covered with blue plastic. For ribs, I will scuff them all before cleaning and spraying because they came uncovered and there normally are some scratches to be smoothed anyway.

Shawn
 
I appreciate

everyone's input. My reason for asking was related to the alclad layer. I know it's VERY thin, and I know it's possible to scuff off or through. I also have to believe that paint adhesion to a scuffed surface will be better. So far I have just cleaned and primed with NAPA 7220.

I would be great to hear from someone who has some real expertise in all this

To scuff or not to scuff... that is the question.
 
I just wash with simple green aviation cleaner that's made for aluminum, then rinse, followed by air dry. I then hit it with Sherwin Williams 988 without scuffing the part up. It seems to make no difference whether or not the part was scuffed up prior to priming. The final product produces the same results. So, I don't scuff to save a little time. YMMV

Cheers
 
Av8torTom said:
everyone's input. My reason for asking was related to the alclad layer. I know it's VERY thin, and I know it's possible to scuff off or through. I also have to believe that paint adhesion to a scuffed surface will be better. So far I have just cleaned and primed with NAPA 7220.

I would be great to hear from someone who has some real expertise in all this

To scuff or not to scuff... that is the question.
Click to expand...

The Alclad layer has a nominal thinckness of 5% for 0.062 and under.

0.0015 for .025 sheet - red scotchbrite should be OK, but the coarser sandpaper grades sometimes mentioned would go through the layer.

Try using some coarser scotchbrite (brown) on a scrap piece. After a short while rubbing you can see the base metal sort of change color as the Alclad is removed.

Stick with the red stuff by hand and you should be OK....:)

All you ever wanted to know about 2024 is here...:)

http://www.alcoa.com/mill_products/catalog/pdf/alloy2024techsheet.pdf
 
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