Alodine / Bonderite M-CR 1201 AERO with epoxy

E

erover82

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I'm using this product as directed (rinsing before dried), but am unsure if it's really ok to spray epoxy, which normally requires DA/blasting, directly over the treated aluminum. I'm getting a good gold color on the treated castings but they don't look or feel like the etch I'm used to before spray epoxy on steel.

I saw Barry this in another thread:
"Personally, all I have ever done on new or used transmissions is clean a couple of times with 700, no sanding, and epoxy."

It sounds like I'm good to go with proper cleaning with Bonderite C-IC 33 AERO, treatment with M-CR 1201, dry time, and then epoxy, but I want to make sure.
 
Spi epoxy has been used over the mentioned system 100s of times over the years.
A great system just follow their instructions to the letter.
 
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Thanks Barry. I'd become so used to the idea of "no chemical etch, DA/blasting only" with steel that it was hard to trust that these systems might work well together in the case of aluminum.
 
Just remember to work quickly after the aluminum has been prepped for epoxy.

Going from memory reading a thread here, you have about 24 hours after the aluminum has been prepped for epoxy so the aluminum doesn't start to oxidize.
 
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The TDS for 1201 states that it's a strong oxidizer (use caution), so is O2 in the air really going to make a difference after that?
 
MJM said:
Going from memory reading a thread here, you have about 24 hours after the aluminum has been prepped for epoxy so the aluminum doesn't start to oxidize.
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erover82 said:
The TDS for 1201 states that it's a strong oxidizer (use caution), so is O2 in the air really going to make a difference after that?
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I think 24 hours is the absolute maximum. When doing AL I always have tried to have it in primer in no more than 12 hours. Less if i could.

Irregardless of what you use to treat it, bare AL will start to oxidize immediately after it has been treated. No getting around that. The sooner you get the AL covered the better. If you wait too long you will need to do the process over. Consider 12 hours to be a safe working limit. 24 hours a max limit.

From the Bonderite TDS: "Paint soon after the work is dry in order to prevent soils or oxidation from recontaminating the prepared metal surface."
 
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I'm curious how this stuff works. The last few panels I did (by the book), the panel turned a light gold, but otherwise no texture emerged that I could see or feel. It must be very fine. Is it the profile of the texture that allows the epoxy to bond where normally 80 grit is recommended, or is there a chemical bond going on too?
 
erover82 said:
I'm curious how this stuff works. The last few panels I did (by the book), the panel turned a light gold, but otherwise no texture emerged that I could see or feel. It must be very fine. Is it the profile of the texture that allows the epoxy to bond where normally 80 grit is recommended, or is there a chemical bond going on too?
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It's all chemical bond that is why you must follow the alodine tech sheets as to the exact mins before applying epoxy, I don't know what the time frame is now as they have changed it a few times in last 20 or so years
 
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