Epoxy Chromate?

[Andy Walker]

On Sonex plans page F10, the plans say to seal a bushing with "epoxy chromate," but I'm having trouble finding something with that name. Is that the same as zinc chromate? And if so, is there a brush-on version instead of the spray, since I know that inhaled zinc chromate particles are a known carcinogen?

Thanks!

[falvarez]

Hi Andy,

They are 2 different things and from my experience, Epoxy Chromate is much tougher and durable. When I've bought it in the past, it was a 2 part mix that you would thin to spray, so I guess you could just brush it on if desired. The only issue I had with it (other than it has the same health type risks as Zinc Chromate) is that it's rather expensive. Here's a link to what I used in the past, but there are many brands to choose from:

http://www.aircraftspruce.com/catalog/cspages/stitsepoxyprimerwhite.php

Frank
Sonex #800 - Scratch Building

[Mike53]

As was pointed out to me here before Vans Forums are a great source of information http://www.vansairforce.com/community/s ... d=13773418
If your up to a lot of reading :arrow: :idea: :?

[Andy Walker]

Hi Andy,

They are 2 different things and from my experience, Epoxy Chromate is much tougher and durable. When I've bought it in the past, it was a 2 part mix that you would thin to spray, so I guess you could just brush it on if desired. The only issue I had with it (other than it has the same health type risks as Zinc Chromate) is that it's rather expensive. Here's a link to what I used in the past, but there are many brands to choose from:

http://www.aircraftspruce.com/catalog/cspages/stitsepoxyprimerwhite.php

Frank
Sonex #800 - Scratch Building

$81 for a quart? How much for a teaspoon?!? :lol: Seriously though, I don't want to spend $80 to treat a $2 bushing...

[falvarez]

Yeah, I don't plan on buying any again. My plan is to see if anyone in my EAA chapter has some laying around, or going to a paint supplier in town to see what is comparable and cheap in a small quantity.

Frank
Sonex #800 - Scratch Building

[Andy Walker]

Well, I asked Sonex about it, and here is the gospel according to Kerry:

"No need to prime that part. It is a bearing surface so please polish it up and protect it with white lithium grease."

I wish they'd just say that in the plans!!! :lol:

[falvarez]

I'm getting close to working on this part myself so this is quite helpful and timely.

I believe there are 2 different bushings...the oilite ones and the ones we make from the 4130 stock. Was Kerry's response for both of these types of bushings? I agree that the inside of the 4130 steel won't rust if grease is used, but what about the outside?

Thanks,
Frank
Sonex #800 - Scratch Building

[Andy Walker]

I was asking about the ones made from stock, as that has a note in the plans...I didn't see a note for priming the other bushings, is there such a note?

[falvarez]

No, no need to prime the oilite bushings. I was confused by the note on the oilite bushings that that they need to be oiled vs what you were told Kerry. Wanted to confirm 1) That he wasn't also recommending the grease for the oilite bushings and 2) The greasing the 4130 would be sufficient to prevent rust.

Guess I'll just glob some grease on the outside of the 4130 to be sure ;-)

[Sonex1517]

in the wings, with similar notes, there was an update to the plans to replace the words about priming with words to the effect of lubricate with lithium grease....sounds like these must be the same parts. In my wing kit, they were part of the parts received...ai think I wrote a post about that two weeks or so back...


Robbie Culver
Sonex 1517
Chicagoland
Aerovee/taildragger
Starting on the wings
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