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PostPosted: 13 Jul 2015, 21:59 
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Joined: 15 Nov 2013, 10:16
Posts: 234
Location: MB, Canada
So, I've got a new chassis on order, it's coming with no finish, it's just been brushed..

I've done a bit of research and I think I should probably finish it with something to prevent oxidation.. I don't want to spend too much on doing this, so my initial thought was just to go with a simple spray can clear coat.. Although I've read about clear coats yellowing over time. Though good modern clear coats shouldn't have this problem apparently.. I was thinking about possibly using this product http://www.canadiantire.ca/en/pdp/dupli-color-wheel-coating-clear-matte-finish-0477562p.html#.VaR6iUYldio

I've also read about using a chemical called alodine which apparently keeps the surface from oxidizing, although doesn't provide any protection against scratches. There seem to be a few types of alodine, the most common kind gives the metal a yellow color, but you can get it so that there's no tint after the process is done.

I can order Alodine 1001 here http://www.aircraftspruce.ca/pages/me/metalprep/alodine1001.php for no tint.
To prep the metal for the alodine solution, it's recommended to use this prep / cleaning agent http://www.aircraftspruce.ca/catalog/cspages/alumiprep.php

Anyways, just looking to see what people have done to finish aluminum.. I'd like to keep the aluminum look, so I don't want to paint it or anything. Has anyone used a clear coat? Any recommendations on specific products?
Has anyone done the Alodine process?


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PostPosted: 13 Jul 2015, 23:23 
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Joined: 08 Aug 2009, 03:11
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Location: Chilliwack, BC
If you know someone that can anodize, that's the best. Second best is powder coat.
If you want to keep the natural look of the brushed, use a clear-coat spray. IME, the cheaper brands actually work better, as they stay flexible and can expand and contract with heating cycles. The expensive stuff hardens like glass and will chip or crack in a few months.

Cheers!

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-= Gregg =-
* Ratings are for transistors - tubes have guidelines*
Home: GeeK ZonE
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PostPosted: 13 Jul 2015, 23:28 
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Joined: 15 Nov 2013, 10:16
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Location: MB, Canada
Geek wrote:
If you know someone that can anodize, that's the best. Second best is powder coat.
If you want to keep the natural look of the brushed, use a clear-coat spray. IME, the cheaper brands actually work better, as they stay flexible and can expand and contract with heating cycles. The expensive stuff hardens like glass and will chip or crack in a few months.

Cheers!


Everyone keeps saying anodize.. I live in a small town, and I really don't want to send the chassis away.. I figured there'd be some simple way to keep the chassis from oxidizing. I'm not concerned about giving the surface a protective layer from a getting bumped around point of view to be honest.

What do you think about that clear coat I linked?

Also, any thoughts about the alodine treatment? https://en.wikipedia.org/wiki/Chromate_conversion_coating

Maybe powder coating would be the way to go.. I'm sure there's an auto body shop in town that would do that..


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PostPosted: 13 Jul 2015, 23:44 
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Location: Chilliwack, BC
Oh, you're Canadian, right!
Go to Princess Auto and get "Power Fist" brand or el-cheapo "Rona" brand. Got chassis out in the wild for years with it.

Cheers!

_________________
-= Gregg =-
* Ratings are for transistors - tubes have guidelines*
Home: GeeK ZonE
Work: Classic Valve Design


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PostPosted: 13 Jul 2015, 23:47 
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Joined: 15 Nov 2013, 10:16
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Location: MB, Canada
Geek wrote:
Oh, you're Canadian, right!
Go to Princess Auto and get "Power Fist" brand or el-cheapo "Rona" brand. Got chassis out in the wild for years with it.

Cheers!


This guy right here? http://www.princessauto.com/en/detail/clear-all-purpose-enamel-spray-paint/A-p8057259e

I had someone else mention that the aluminum could oxidize underneath a clear coat.. I don't quite understand that.. I'd be pretty happy to just go with something like this power fist product.

I also don't like the idea of the finish yellowing over time.. Which I've heard can happen with clear coats. Any experience with that?


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PostPosted: 14 Jul 2015, 15:19 
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Location: Chilliwack, BC
Yes, that's the one! :D

Yes, the aluminum can oxidize underneath. A trick to that is:

1) clean with dish detergent to remove grease and finger prints. Handle with nitrile gloves from this point on.

2) Dry as best you can with non-fuzzy towel. The brown industrial or blue Shop Towels are good.

3) Hang and hit with heat gun for about 5 minutes. Let cool.

4) Apply coat.

What you're doing here is "oxidizing it out". The chemical reaction from the heatgun. atmospheric moisture and cooling means the aluminum will oxidize as far as it can go before you hit it with the coating.

As for yellowing, the Power Fist "patinas" - will get a tan colour similar to a sepia toned photograph, but very slightly. If the rest of your chassis is wood, it will age quite well and look better. If you're doing all aluminium, sorry, I have to go back to the anodizing suggestion :|

Also, use the semi-gloss, if they have it (Winnipeg is the HQ, so they better). The matte is good for covering paint, but makes for boring aluminium and gloss is too difficult to get perfect.

Cheers!

_________________
-= Gregg =-
* Ratings are for transistors - tubes have guidelines*
Home: GeeK ZonE
Work: Classic Valve Design


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PostPosted: 14 Jul 2015, 15:40 
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Joined: 15 Nov 2013, 10:16
Posts: 234
Location: MB, Canada
Geek wrote:
Yes, that's the one! :D

Yes, the aluminum can oxidize underneath. A trick to that is:

1) clean with dish detergent to remove grease and finger prints. Handle with nitrile gloves from this point on.

2) Dry as best you can with non-fuzzy towel. The brown industrial or blue Shop Towels are good.

3) Hang and hit with heat gun for about 5 minutes. Let cool.

4) Apply coat.

What you're doing here is "oxidizing it out". The chemical reaction from the heatgun. atmospheric moisture and cooling means the aluminum will oxidize as far as it can go before you hit it with the coating.

As for yellowing, the Power Fist "patinas" - will get a tan colour similar to a sepia toned photograph, but very slightly. If the rest of your chassis is wood, it will age quite well and look better. If you're doing all aluminium, sorry, I have to go back to the anodizing suggestion :|

Also, use the semi-gloss, if they have it (Winnipeg is the HQ, so they better). The matte is good for covering paint, but makes for boring aluminium and gloss is too difficult to get perfect.

Cheers!


Thanks for the tips! I did find a location in Winnipeg who will anodize for me though, so I'm currently investigating costs on that. They'll actually also do the alodine process if I would prefer.

What is a reasonable cost for chassis anodizing?


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PostPosted: 15 Jul 2015, 02:16 
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Location: Chilliwack, BC
It goes by the sq. inch. Competition is pretty fierce in Vancouver. Last time I had a ST-70 sized plate anodized, it was $30. The same piece on The Rock a mate had done was $120. Depends on how many places are in town.

_________________
-= Gregg =-
* Ratings are for transistors - tubes have guidelines*
Home: GeeK ZonE
Work: Classic Valve Design


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PostPosted: 15 Jul 2015, 08:04 
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Joined: 15 Nov 2013, 10:16
Posts: 234
Location: MB, Canada
Geek wrote:
It goes by the sq. inch. Competition is pretty fierce in Vancouver. Last time I had a ST-70 sized plate anodized, it was $30. The same piece on The Rock a mate had done was $120. Depends on how many places are in town.


Hm.. Well I'm still waiting to hear back on a quote.. They also do that alodining process, so I can compare the price for either option. I'm not really concerned about physical durability against scratches and so on, I'm really just concerned about oxidation.. So I'll see how the prices compare.

Someone suggest I tell the company I'm a hobbyist, and see if they can cut me a break by putting my chassis through with some other job or something.. So we'll see what they say about that.


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PostPosted: 15 Jul 2015, 17:21 
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Joined: 09 Oct 2012, 19:43
Posts: 297
Location: Vancouver Canada
Just to add to the confusion. Did you know that aluminum can be polished until it has a mirror finish?


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