Metal wipes/etch

[fizzy]

I was taking to a mate who runs a premium sprayshop for cars.

I asked about etching aluminium and he said he uses wipes that etch and protect the metal before spraying. It also stops bare steel rusting.

Has anyone tried these miracle wipes? Any good for ali or steel before using epoxy paints?

He didnt mention a brand but maybe something like this?

http://www.henkel.co.uk/2838_UKE_HTML.htm?nodeid=8802694266881

http://www.vinnybyrne.com/body-shop/wiping-products/bonderite-1455-w-etch-primer-wipes.html

 

[graffian]

Has anyone tried these miracle wipes? Any good for ali or steel before using epoxy paints?

When I asked about zinc phosphate the bloke suggested I try Bonderite, but the zinc
phosphate cost me 17 quid and the bonderite was about 50 quid. I should have tried
Bonderite as the zinc phosphate was a pain setting up for spraying the stuff on and
rinsing.

I was told the best thing for ali pre-treatment before paint is Alodine. We used to hand
finish parts made for Bristows helicopters and someone who made parts for outboards, I
used to drop the parts off at a local anodisers to be Alodined and after they had dipped
them they were painted.

 

[500e]

We use it to repair touch up alloy parts prior to finishing, a lot of info if interested, not to difficult to do.
http://www.henkelna.com/industrial/alodine-electro-ceramic-coatings-process-7146.htm
http://www.aircraftspruce.com/catalog/cspages/alodine1201.php
http://www.northerncomposites.com/partners/henkel/henkel_surface_treatments/alodine_coatings

 

[MG David]

I have heard people use Alodine on alloy body Jags where they have blisters in the paint. They seem to remove the blistered paint and the white fuzz underneath it, treat with Alodine, then prime and paint as normal.

 

[fizzy]

I am surprised not many people on here use the wipes - they seem to be a bit of a revolution especially for car body shops etc.

They say "throw away your etch primer".

http://www.spraygunsdirect.co.uk/product.php?tid=194&products_id=7657

It is good for steel or ali etc.

 

[OllieG]

Looking for a bit of advice here…related to the etching topic prior to 2K epoxy-primering. I'm stripping my car back to bare metal with paint-stripper and wire cup brushes on a grinder. Then I've been cleaning up thoroughly with de-greaser and spraying the epoxy direct. On another forum I noticed a guy was using a phosphoric acid/ water-based etching solution on the bare steel before the epoxy primer… I figured that just scuffing the metal surface with the brush would give me a good enough mechanical bond with the epoxy..and no issues so far!

What would you guys recommend? These wipes you mention look good but they're pretty £££££!

Thx.

 

[ajlelectronics]

Using anything under epoxy primer will reduce the performance to that of the substrate.

 

[OllieG]

The acid is just a wipe-on treatment prior to epoxy priming…it's not a coating as such. My understanding is it's used to etch the surface of the bare metal so the epoxy primer can key more effectively to the bare metal. But my reckoning is wire-brushing on a grinder is probably sufficient to etch the metal surface…then a good clean with degreaser...

 

[richie00boy]

Depending on the particular epoxy primer, an acid etch can make things worse. Automotive epoxy primers such as HB Body and Lechler contain zinc phosphate, treating the surface with acid before using these coatings can mess up their chemistry and design, the zinc phosphate is there to give extra bite so you don't need an etch. Basic epoxy such as Jotun can benefit from a phosphoric etch.

I'n no longer a fan of wire brushes on grinders, I have found they polish the metal which possibly makes adhesion worse. The best method is polycarbide wheels, more expensive and don't last as long but the end result is better. I only use small wire brushes in a drill now where a wheel cannot get in to corners etc. Of course blasting would be the best, but it's not really an option much in a garage.

 

[OllieG]

Good advice, cheers. I'm using Lechler and haven't acid etched before and have had good results so I probably won't bother to in future. I've found the polycarbide wheels are good on large flattish surfaces; but for engine bays and the like, I've only managed decent results with a wire cup brush as it can 'distort' into tighter spaces… The P/C wheels as you say are sooo pricey!

 

[langy]

Looking for a bit of advice here…related to the etching topic prior to 2K epoxy-primering. I'm stripping my car back to bare metal with paint-stripper and wire cup brushes on a grinder. Then I've been cleaning up thoroughly with de-greaser and spraying the epoxy direct. On another forum I noticed a guy was using a phosphoric acid/ water-based etching solution on the bare steel before the epoxy primer… I figured that just scuffing the metal surface with the brush would give me a good enough mechanical bond with the epoxy..and no issues so far!

What would you guys recommend? These wipes you mention look good but they're pretty £££££!

Thx.

Bit pointless really Epoxy don't need anything under it, also those wire brushes tend to burnish the surface reducing adhesion.