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Sika question - remove powder coat?

jcarne

Well Known Member
Patron
Ok, I have read for what seems like days on Sika attaching the canopy and many threads mention something like "advantages and disadvantages on removing the powder coating have already been discussed". I have yet to find anyone talking about this so either it doesn't exist or I suck as searching.

So, I am going to attach my canopy with Sika to a slider frame. Did anyone remove the powder coat before applying the primer? What is the consensus on this? I would love to hear what you guys did as I'm trying to make the decision on whether I need two different primers or just one. Right now I personally would like to remove the powder coat and bond to steel but maybe there is someone that can help me make up my mind. Thanks!
 
I?ve done both

Jereme,

I have installed/applied Sika to two RV8 canopies:
The first canopy frame I removed the powder coating, the second frame I simply scuffed the powder coating with 220 grit...., both methods resulted in equal success.

However, be certain you use the appropriate Sika primer:
*Use Sika 209 G+P for bare metal (powder coat removed)
*Use Sika 209 D primer if mechanically scuffing the powder coating

The above info was provided to me by a SikaFlex Tech Support engineer. If you read the Sika Tech Data info, the 209 D primer is not designed to be applied directly to “bare” metal. If you choose to remove the powder coating you’ll have better adhesion success using the 209 G+P primer, as the 209 G+P is for bare metal application.

Best of luck and have fun with you project!

Mike
 
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Thanks for the replies everyone! Any more out there?

Jereme,

I have installed/applied Sika to two RV8 canopies:
The first canopy frame I removed the powder coating, the second frame I simply scuffed the powder coating with 220 grit...., both methods resulted in equal success.

However, be certain you use the appropriate Sika primer:
*Use Sika 209 G+P for bare metal (powder coat removed)
*Use Sika 209 D primer if mechanically scuffing the powder coating

The above info was provided to me by a SikaFlex Tech Support engineer. If you read the Sika Tech Data info, the 209 D primer is not designed to be applied directly to ?bare? metal. If you choose to remove the powder coating you?ll have better adhesion success using the 209 G+P primer, as the 209 G+P is for bare metal application.

Best of luck and have fun with you project!

Mike

Thanks for the info Mike, this is exactly why I'm trying to decide to remove powder coating or not. I'm just not sure if spending another 50 bucks on another primer is worth it if everyone seems to have good luck with just going to the powder coat.
 
9 years. 780 hours. RV-7 slider. Only scuffed powder coat. Bonded canopy and windscreen, no rivets or screws into plexi anywhere. Used 209D primer on all surfaces including bare aluminum. Zero issues, lives in hangar subject to 100 degree thermal cycles, all sorts of weather. Have done 4 others on local RVs with same results. Difference between primer and not primer is vast (as in, doesn't adhere or adheres); differences between primers is relatively small. Did coupon tests years ago to test that. Also note that Sika primer (any of them meant for acrylic) vastly improves adhesion of epoxy.
 
You can add me to the list of those who applied sika directly to the powder coat. I do my best to break my RV every time I fly and I fail every time! :rolleyes:
 
Add another data point for using Sika with only "scuffing" the powder coat, 780 hours, no issues. Sika has very tough adhesion and is very peel resistant.
 
I removed the powder coating only because I had several spots where rust was starting to form. Otherwise, I would have left it in place.
 
Thanks for all the feedback guys. I just ordered 209D primer so looks like I will bond straight to powder coat like many before me.
 
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