Epoxy Chromate Primer

[Spornrad]

Is anyone using Epoxy Chromate Primer for corrosion protection?
Is it still available or du you use something else?

[Spornrad]

Hi All,
how do you protect aluminium from corrosion ? What do you use? Thanks!

[Dave S]

Werner,

Pretty commonly, Polyfiber epoxy primer, is used for priming any metal surface including sloshing the insides of aluminum tubes.

Preparation and technique is as important as what a person uses to paint/prime. The surface must be degreased (solvent washed); and I like to do a wet sanding using dish detergent after that on sheet metal. The key to corrosion protection is creating a complete, moistureproof coating on the metal.

Our S7 kit was purchased with bare weldments, sandblasted, solvent washed, epoxy primed and topcoated with urethane (all polyfiber products). All metal parts epoxy primed inside and out.

I am not sure chromate primers can be commonly found anymore; for that matter, I don't think the chromate addition to paint does as much as good prep, complete priming and a topcoating with any system. The trick is to make the stuff stick through good preparation, and make sure the coatings used cover completely (no thin or missed spots). Epoxy is particularly good at sealing surfaces and being very tough.

The entire polyfiber manual which covers all of their products, uses, and procedures including the use on metals, is a free download from stits.com ( mother company of polyfiber products), or google up "polyfiber manual" to find it. An excellent resource for builders.

The kitfox manual also includes references to finding vulnerable places on the airframe and and blocking/protecting them from corrosion.

[alexM]

I use Bonderite products to etch (C-IC 33) and Alodine (M-CR 1201) aluminum parts, and use SprayMax 2K epoxy primer on top of that.

I see you're from Germany. Bonderite is made by Henkel and it's my understanding that SprayMax is also a German product.

[Spornrad]

Werner,

Pretty commonly, Polyfiber epoxy primer, is used for priming any metal surface including sloshing the insides of aluminum tubes.

.

Hello Dave S,
Do you mean the Polyfiber EV-400 epoxy varnish?

[Spornrad]

I use Bonderite products to etch (C-IC 33) and Alodine (M-CR 1201) aluminum parts, and use SprayMax 2K epoxy primer on top of that.

I see you're from Germany. Bonderite is made by Henkel and it's my understanding that SprayMax is also a German product.

Bonderite seems not to be produced in Germany and today you cannot get in Germany. Etch (C-IC 33) and Alodine (M-CR 1201) is not allowed here since 1 year.
SprayMax you can buy here. As it is a 2k product you have to use the whole can when you have activated it.

[Dave S]

Werner,

Regarding the polyfiber epoxy primer, I meant the product identified as EP-420. EV-400 varnish is normally used for finishing wood surfaces (like the wing ribs and floor panels) while the EP-420 is used for priming which may (or my not) recieve a top coat later.

The Epoxy varnish (EV-400) produces a gloss finish when dry while the epoxy primer (EV-420) leaves a semi-gloss or flat finish when dry. The two are chemically compatible but the surface texture when dry is different which is significant considering adhesion where a top coat would be used.

The Epoxy primer, EP-420, comes in white and green.

[Geek]

...........SprayMax you can buy here. As it is a 2k product you have to use the whole can when you have activated it.

According to the SprayMax can you have three days to use it after activation. I can attest to the fact that you don't want to go longer than that but within the three day window it's fine. But as Alex has previously stated, "it's pricey to use." Runs about $25 a can if you look hard and doesn't seem to go far. You just have to have a list of what you want to paint so that if you finish what you really wanted done, you have something else to paint too.

Gary