home anodizing

[Bret888]

I was not at this seminar, and I am not sure which OPE manufacturer held it. They have been a Jonsereds dealer since the early 70's, but have several other lines of equipment. How do you recommend tuning? Lean to keep temps down, at the risk of insufficient lubrication?

 

[stipes]

Stihl saws are power coated, then as required, machined. That's one of the drawback with home powercoating the crankcases... "masking" isn't generally good enough, and powdercoat is BI?CH to get off...

Only way I found is to blast bead it off..I would love to have one of my old Mcc's powder coated,,but I asked Dennis about it and it's alot of trouble to go tru...Complete strip down...As Lakeside53 added too..To do the crankcase would be alot of trouble also...Get it in the cly. area,,your in it deep...Would be a good finish for outside parts,,hard as heck...The other thing about powder coating,,if it's got flex,,the coating will crack too....

 

[Lakeside53]

?????

Lean raises temperatures. You richen to lower...

 

[stipes]

I just wanted to add too if your gonna paint it...If you use Imorn wear a good resperator,,keep all parts of your skin protected...That stuff will poison you...

 

[Bret888]

My mistake. I know very little about small 2 strokes Diesels are the only thing I have measured exhaust gas temps on, so I assumed more fuel = more heat in saws as well?

 

[belgian]

anyways... it will not work!

aluminum to be anodized has to be of high quality. some aluminum are made with other base metals. especially cast aluminum have composition of copper, etc... those other base metals will desolve in the sulfuric acid part is anodized in. also the nitric acids, parts are dipped in to prep part will attack certain metals.

say you try to anodize a stihl side cover, after stripping off paints. what will come out of anodize tanks will be severely eaten away.

power coat is always the toughest... wonder if the exact color power coat is available?

I have been working as a sales manager for a continuous anodiser for the last five years and am supposed to be a product specialist.

Anodising = creating a controlled anodic (aluminiumoxide) layer on the aluminium surface, layer thicknesses (commercially) are ranging from 5 up to 25 µm. The purpose of anodising is usually to obtain increased corrosion resistance for outside use applications. Hard anodising (layers up to 50-60 micron) are used for increasing abrasion and wear resistance of aluminium (parts) alloys.

The most commonly known process is the sulfuric anodising (other = fosforic anodising, used in the aircraft industry), which includes the following steps :

- chemical etching (NaOH), to remove metal oxides and impurities.
- neutralising
- sulfuric anodising (galvanic process, using DC current)
- Coloring (if applicable)
- sealing (to ensure the corrosion resistance) in hot water.

All parameters in the process, such as chemical concentration, temperatures, current amps,etc. are closely monitored to ensure a homogenous and consistant anodic layer.

Anodised aluminium is highly corrosion resistant and outperforms all PE, PU, PVDF coatings on this aspect. Natural color anodised aluminium is also totally UV resistant. Colored anodised aluminium is guaranteed UV resistant with fully saturated layers, AND with a layer thickness of min 25 microns. This varies however in function of the dyes used (organic or inorganic). This is quite a complicated matter.

For obtaining a nice decorative finish, it is of supreme importance to use a "anodic quality" aluminium alloy substrate, generally a EN 5005 or EN5754 alloy. 1000 or 3000 series can be used also, but generate more risk as to surface quality. Like someone mentioned, aluminium alloys contain Mg, Mn, Si, etc. with rather large tolerances, and this causes a big concern to anodisers to guarantee a smooth, reproduceable anodic surface !!! That's why decorative parts that form one lot (façade, window profiles, etc.for a particular project) should be anodised in one batch, and preferably using an alloy from the same cast...)

Cast alumiminium gives very bad results regarding a decorative surface (continuous cast flat rolled products look horrible after anodising)...

This may be the mean reason why saw parts are not anodised. The process also is quite expensive (handling), and colors are limited.

So my opinion is that anodising is not a solution for saw covers.

 

[Taxmantoo]

Those thinking about companies like Jet-Hot might want to look here:
http://www.techlinecoatings.com/Exhaust.htm

 

[mtfallsmikey]

How about just rubbing a 361 against it?

 

[Nailgunner]

Anodising isn't difficult, for small parts a car battery charger will do the necessaries.

Another point is that the nasty finish it gives on castings may look terrible but it will do as a pretreatment for paint. Just omit the hot water sealing stage, leaving the surface porous so that the paint soaks in and sticks.

Disposal of the sulphuric acid afterwards will be a problem. Neutralise with washing soda to form a fizzy sodium sulphate solution? less harmful than dumping acid. Or bottle it up and keep for next time.

 

[belgian]

Another point is that the nasty finish it gives on castings may look terrible but it will do as a pretreatment for paint. Just omit the hot water sealing stage, leaving the surface porous so that the paint soaks in and sticks.

Unsealed anodising is indeed used as a pretreatment for subsequent coating, especially in continuous coating lines (fosphoric is much better than sulfuric anodising for this purpose, but very "ungreen")

Beware however that unsealed surfaces are unstable in time and subject to "autosealing" due to moisture in the air. I've experienced many claims resulting of bad adhesion, both in coating and bonding applications.

Most industries use Cr6 primers or other new developed primers as pretreatment for coating. Much more reliable and cost effective.

 

[Nailgunner]

^^ Also true. Alocrom 1200 works wonders under epoxy. It has a use-by date too, a number of aircraft specs seem to call for no more than 72 hours between treatment and painting. Not a lot of people seem to realise this and I used to be plagued with stuff that had been treated weeks ago, handled with bare hands, etc.

How are you finding less-toxic Cr6 replacements for aluminium work, ie Cr3, zirconium or polymer? We tried a zirconium treatment and in corrosion tests it was about half as good as Alocrom 1200, but a long way better than nothing.

 

[peterc38]

it's amazing that's there's 3 people in this thread that's got metal finishing experience....

yup totally agree with below of course.... there's a few unintentional results of having vats of acid laying around. unless they are completely sealed, you will get acid etch from gases released. this will effect ALL metals it touches. go to any plating shop and there will be a film of rust all over the building.

regulations for disposing chemicals have gotten tighter and tighter. don't know about you, but I'd wouldn't want the EPA to be snooping around.

used to be plating shops would simply flush all sorts of chemicals down the drain. those days are hopefully gone.

don't have as much experience as you do, but also have done almost every variation of metal finishing. from gold plating to rhodium, cadmium, electroless nickel, hard chrome, hard anodize, powder coating, etc.. etc..

Sometimes working in the metal finishing business has it's benefits. I needed a short piece of logging chain, so I bought a section of unplated G43 chain with hooks from a surplus store for 1/2 the price of what the plated stuff cost. Brought it in to work and plated it. This coating is a zinc-nickel alloy w/ yellow chromate topcoat. Its about 87% zinc which gives it excellent corrosion resistance and 13% nickel which gives it some wear resistance. Far better than any plated finish you would buy of the shelf. We primarliy use it for plating of outer races on aircraft bearing assemblies. Neat stuff, it will pass over 500 hours in a salt spray test.

 

[LAndrews]

Bret: No worries dude. I'm not busting your chops as much as trying not to let things get out of hand. It always amazes me how often someone tells me 'I read this on the internet' when what they're saying ain't quite right.

Diesels and turbines are their own ball of wax - stuff that runs on heavy oil just don't make sense to petrol-heads, and vice-versa. At first, at least... I do miss my old GMC 6.2, that thing was slow as anything but always ran great.

Belgian: Great writeups! Any way I can get you to tell me how much Kasteel Tripel costs for a 750ml bottle there? It's about $9 here. Deelish.

 

[belgian]

Belgian: Great writeups! Any way I can get you to tell me how much Kasteel Tripel costs for a 750ml bottle there? It's about $9 here. Deelish.

Thanks ! A Kasteelbeer triple comes mostly in 33 cl bottle over here and costs about 1,20 euro or 1,50 $. I have to check on a 750 ml bottle though, since they are not so popular...you have to be 2 persons to finish one without getting drunk

This beer is a little too heavy to my liking. I prefer triple blonds at 8 to 9 ° :love1:

 

[belgian]

How are you finding less-toxic Cr6 replacements for aluminium work, ie Cr3, zirconium or polymer? We tried a zirconium treatment and in corrosion tests it was about half as good as Alocrom 1200, but a long way better than nothing.

If I knew the perfect answer to that question, I'd be rich by now and own at least a 1000 collector saws...:hmm3grin2orange::hmm3grin2orange:

Many industries are seeking to find a suitable replacement for the toxic Cr6 and invest a lot of money in R&D. Most primers work well for one application but not so good for another. Each application seems to call for a particular primer, so testing is the only answer...

 

[LAndrews]

Thanks ! A Kasteelbeer triple comes mostly in 33 cl bottle over here and costs about 1,20 euro or 1,50 $. I have to check on a 750 ml bottle though, since they are not so popular...you have to be 2 persons to finish one without getting drunk

This beer is a little too heavy to my liking. I prefer triple blonds at 8 to 9 ° :love1:

Wow. That same bottle is $5 here, so ~3.2euro. Eeek... You're right though, it's pretty powerful. I don't drink it very often but when I do!