| Author |
Message |
raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21520
Location: Oklahoma City
|
 Posted: Sat Nov 11, 2017 2:45 pm Post subject: Type 4 cooling shroud alloy |
 |
|
I seem to remember more than a few conversations about this....but have never seen a definitive answer.
Has anyone figured out a definitive alloy for the type 4 main fan shroud?
I know SGKent did a bit of work on this.
I am cleaning one up for an engine I am building...and will probably do one of my spares for my upcoming engine in the spring.
So is it magnesium....aluminum....or an alloy of both?
I am looking at an Alodine 5700 treatment that Henkel says works on aluminum and magnesium. While that alone for street level use has a reasonable amount of corrosion resistance.....the problem with Alodine is that once the surface it covers starts to corrode....meaning oxygen has arrived on the scene.....it can slough off in sheets as white rust forms beneath it.
Its best use is as a primer layer for other coatings like powder coating. I am looking at using an epoxy e-coat (electrophoretic dip paint).
Ray |
|
| Back to top |
|
 |
busdaddy
Samba Member
Joined: February 12, 2004
Posts: 51153
Location: Surrey B.C. Canada, but thinking of Ukraine
|
| Posted: Sat Nov 11, 2017 3:19 pm Post subject: Re: Type 4 cooling shroud alloy |
|
|
I don't recall anyone actually having the alloy tested, but it's a mag/aluminum mix much like a type 1 case.
_________________
Rust NEVER sleeps and stock never goes out of style.
Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!
Слава Україні! |
|
| Back to top |
|
|
raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21520
Location: Oklahoma City
|
| Posted: Sat Nov 11, 2017 3:54 pm Post subject: Re: Type 4 cooling shroud alloy |
|
|
| busdaddy wrote: |
| I don't recall anyone actually having the alloy tested, but it's a mag/aluminum mix much like a type 1 case. |
Yep....I bleive so too. Looks and tastes like magnesium.....my oldest one is a dark gray with a "scritchy" sound.....so I will treat it like mag. Ray |
|
| Back to top |
|
|
lil-jinx
Samba Member
Joined: August 14, 2013
Posts: 1109
Location: New Brunswick,Canada
|
| Posted: Sat Nov 11, 2017 3:58 pm Post subject: Re: Type 4 cooling shroud alloy |
|
|
A scratch test may identify it for you,according to Tom Wilson's book,Magnesium will make harder,higher pitched screech then aluminum when scratched.
Or you could try setting an old one on fire.
_________________
https://www.thesamba.com/vw/forum/viewtopic.php?t=620186
https://www.thesamba.com/vw/forum/viewtopic.php?t=668799
1974 Bay Westfalia. she likes to be called Ethel.
1968 Dune Buggy
1974 parts bus
A smart man learns from his mistakes,a very smart man learns from other's mistakes. |
|
| Back to top |
|
|
SGKent 
Samba Member
Joined: October 30, 2007
Posts: 41031
Location: Citrus Heights CA (Near Sacramento)
|
| Posted: Sat Nov 11, 2017 4:41 pm Post subject: Re: Type 4 cooling shroud alloy |
|
|
ray - based on the color and weight it has a high % of mag in it. It is not pure mag because it is too heavy. Some folks powder coat, some paint. The sacrificial Dow process is still done by a guy in aviation in So Cal. Expensive. The process is sacrificial in that it burns off with time. It was designed to protect the mag and be painted over. Paint will eventually flake off non-treated mag. That said my shroud was painted aluminum in color in 2008, and it has lasted a long time. Some factory photos show the aluminum color with a silver-gold coating, and others show a gold coating. It is probably a personal preference thing.
best thread on it: https://www.thesamba.com/vw/forum/viewtopic.php?t=484928&highlight=shroud+gold
.
_________________
“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
|
| Back to top |
|
|
raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21520
Location: Oklahoma City
|
| Posted: Sat Nov 11, 2017 6:11 pm Post subject: Re: Type 4 cooling shroud alloy |
|
|
| SGKent wrote: |
ray - based on the color and weight it has a high % of mag in it. It is not pure mag because it is too heavy. Some folks powder coat, some paint. The sacrificial Dow process is still done by a guy in aviation in So Cal. Expensive. The process is sacrificial in that it burns off with time. It was designed to protect the mag and be painted over. Paint will eventually flake off non-treated mag. That said my shroud was painted aluminum in color in 2008, and it has lasted a long time. Some factory photos show the aluminum color with a silver-gold coating, and others show a gold coating. It is probably a personal preference thing.
best thread on it: https://www.thesamba.com/vw/forum/viewtopic.php?t=484928&highlight=shroud+gold
. |
Yes.....for magnesium mix you can actually do that yourself. That sacrifical coating....as you note is made to be painted or coated.
If the aluminum content is high enough I can do that with Alodine 1200.....but its finicky.....and nasty because it does have chrome in it and uses a nitric acid mix pre-pickle.
For aluminum, aluminum and mag or just mag.....I can do that with Alodine 5700. Much easier.
Especially if you are definitely not going to,screw around....and plan to coat it NOW....you van buy Alodine 5700 spray or wipes. Surface it....hook on a wire ....then go straight into the epoxy bath.
The Alodine seals the surface completely....but short term. To really keep it from corroding lime it naturally does for a long time.....it has to be painted, powder coated or e-coated.
I'm sure its the same process your guy in CA is doing......or it may be a different brand of the same stuff.....like Bonderite. I followed that thread....and had heard and seen Bonderite before and oddly had never heard of Alodine brand until that thread.
Ray |
|
| Back to top |
|
|
SGKent
Samba Member
Joined: October 30, 2007
Posts: 41031
Location: Citrus Heights CA (Near Sacramento)
|
| Posted: Sat Nov 11, 2017 10:05 pm Post subject: Re: Type 4 cooling shroud alloy |
|
|
the problem is that you can't get rid of the chemical once you use it as DIY. No one will take it and you can spend your life in prison if they find it dumped somewhere. Cameras are everywhere these days.
_________________
“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
|
| Back to top |
|
|
raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21520
Location: Oklahoma City
|
| Posted: Sat Nov 11, 2017 11:29 pm Post subject: Re: Type 4 cooling shroud alloy |
|
|
| SGKent wrote: |
| the problem is that you can't get rid of the chemical once you use it as DIY. No one will take it and you can spend your life in prison if they find it dumped somewhere. Cameras are everywhere these days. |
I dont live in CA. 
Alodine 5700 has no chromates. I can dispose of it in household trash in all 50 states. Or simply neutralize it at,home with no risk. The chromate stuff your guy is using is only necessary for uncoated metals. Its also old school. The industry has moved on.
Even if it did...I can dispose of anything short of plutonium in my county's dedicated haz-mst disposal center....for free.
Many counties in most states other than CA have this service.
As long as it is properly labled, properly contained and if its actually hazardous (meaning toxins, heavy metals etc.) and not just a class 3 flammable or irritant or other simple product....it has to come with an SDS sheet and with the original container ....which is not an issue
Under the Federal EPA homeowners exemption.....I have no issues with using either chemical type up to 50 gallons. Neither do you actually....but CA just has no options for you to buy it or dispose of it properly. Your tax dollars NOT at work I guess.
The local county haz-mat here..... is also not just some funky dumping ground. Its a highly professional, well staffed and properly logistically segregated for containment.
You forget....I do haz-mat for a living! 
Ray |
|
| Back to top |
|
|
richparker
Samba Member
Joined: November 24, 2011
Posts: 6983
Location: Durango, CO
|
|
| Back to top |
|
|
Hoody
Samba Member
Joined: November 28, 2007
Posts: 1948
|
| Posted: Sun Nov 12, 2017 9:19 am Post subject: Re: Type 4 cooling shroud alloy |
|
|
| I just polished mine after drememilg all of the burrs and scratches out with 2 different abrasive wheels and then coated it with Gibbs Brand. The mag patinas to a nice dull gray. Did the same with the tranny. No more corosion and only have to occasionally wipe on some some more Gibbs. I first cleaned the surface extremely well first. |
|
| Back to top |
|
|
raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21520
Location: Oklahoma City
|
| Posted: Sun Nov 12, 2017 9:37 am Post subject: Re: Type 4 cooling shroud alloy |
|
|
| richparker wrote: |
| Hey Ray, can you post some before and after pics for us? It will be interesting to see the difference. Thx. |
Yes.....as I get started on these parts......they will be posted in two ways.
1. I will do a how to for it posted in the 411/412 forum and link to it here.
2. As I am working on the engine build for the other person right now.....and I am in the cleaning and measuring stages right now with about 90% of the parts on hand....with a finished engine target of end of January....I am taking pictures and documenting to make a "build thread" for the owner......for if and when he wants to post one.
Just to answer the inevitable questions in my last response to Steve.....I want everyone to know that I was not being glib or snarky.
What Steve brought up is incredibly important. That is proper handling, saftey equipment....and above all disposal.
As part of what I do for a living I deal with a serious range of chemicals.
I also have 24 and 40 hour HAZWOPR (hazardous waste operations training) and have to renew it every year.
Along with this I have DOT transport documentation training, GHS training and am working on being a trainer for GHS....along with this I have....a lot of experience in waste management, do a lot of site inspection for customers for logistical chemical storage and seperation for compliance to solid waste disposal permits and air quality permits for state DNR.
The local hazardous material disposal facility I mentioned here.....is impressive. Not every state and city has one....but you find these fairly regularly in this region...and all the way down through the industrial belt through Texas in the center of the country. The industrial, petroleum, farming and rust belt.
This is NOT just some local fire department that takes in chemicals from homeowners on a 2-3 times a year basis like you find in many places.....though there is nothing NOT impressive about that type of operation.
This is a dedicated facility with staffing and proper storage and segregation, grounding and bonding and vapor control for all flammability classes from 1, 1A, 1B, 1C, 2, 3, 3A and 3B....containment and safety neutralization for a huge range of acids and bases and segrgation, control and disposal for toxic hazardous materials that range from heavy metals to pesticides.
The difference is that this facility if NOT here to serve large businesses that have....and are required to have....as businesses.... solid waste and air discharge permits and written procedures to use them.
How much you can bring in is limited.....and each time you bring it in you have to identify yourself.....and sign documents. They check these documents and make sure that you are NOT a company trying to get rid of material that you should be getting rid of at YOUR cost and with documentation.
They do this in this area because you CAN buy a huge range of chemicals and pesticides and this region.....the rust and farm belt.....which has lots of small agricultural and homeowners and hobbyists who use chemicals. And they do this because if they do not.....because of the exemptions for usage and volumes allowed to homeowners.....with no other disposal alternative.....lots of chemicals WOULD be at risk of being disposed of improperly.
Iowa and other states especially in this region....also have more facilities like this than some other places...precisely because in the past the state HAS done a poor job of disposal control....and also..... ....because in this EPA region....region 7....only a couple of states in the region have their own state EPA (not the same as the department of Natural resources...DNR)......and therefore stack the compliance and inspection duties on the back of the Federal EPA....which pisses them off....so there are compliance requirements here that are higher....and this waste management facility is one of those requirements.
California.....works in other ways. There is a huge range of chemicals that home owners and hobbyists are not allowed to buy or posses.....without permits. And there are correspondingly less places you can dispose of said chemicals without heavy $$$.
The chemical process that Steve was alluding to.....is better.....in the respect that it will on its own.....pass a 500 hour and even possibly upwards to 750 hour salt spray corrosion test....uncoated.
But...is also a more stringent process, and due to its pickling and cleaning stages in mixtures that are both more toxic and less PH and heat stable.....takes vats of specific material, much more critical temperature control.....and produces a waste product that in most places....not just California...you require site inspections, permits and a solid waste disposal plan. Thats costly.
The chemical process I am looking at is the same "type" of coating but does not use hexavalent chrome. It also uses a different level and type of non-oxiding acid for prep. To be fair.....on its own....uncoated....it will only survive at most a 75-100 hour salt spray corrosion test. But.....its designed to produce....just like the nastier process...to produce an oxygen sealed, electrolytic "seed" layer ....for proper coatings to stick to.
The object with this lesser version of these chemical treatments....is not to produce a bullet proof layer that can survive months on its own. Its designed to prevent ANY oxidization of the magnesium or aluminum....BEFORE it can be encapsulated by a paint, powder coating or plating.
In fact...all of these electrolytic aluminum and mag coatings (except for anodizing) are designed as primer and protection coats.
These are the same coatings you find on the original equipment ATE and FAG brake master cylinder kit pistons.....those sometimes yellowish or pinkish brown coatings. They are designed to be protected just long enough to get them fully submerged in brake fluid where there is no air.
In REALLY old brake kits....you can pull the pistons out and find them with looks like a complete sloughed off skin of....what most people think is some kind of cosmoline. Its not. Its the Alodine coating. Once the magnesium does its natural thing... which is to form a sacrifical white rust coating in response to oxygen and moisture.....it levers off the entire Alodine coating in one sheet.
Ray
Last edited by raygreenwood on Sun Nov 12, 2017 10:09 am; edited 1 time in total |
|
| Back to top |
|
|
raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21520
Location: Oklahoma City
|
| Posted: Sun Nov 12, 2017 9:50 am Post subject: Re: Type 4 cooling shroud alloy |
|
|
| Hoody wrote: |
| I just polished mine after drememilg all of the burrs and scratches out with 2 different abrasive wheels and then coated it with Gibbs Brand. The mag patinas to a nice dull gray. Did the same with the tranny. No more corosion and only have to occasionally wipe on some some more Gibbs. I first cleaned the surface extremely well first. |
The Gibbs product is really intdresting. I have been reading about it for a while. In reality its a penetrating oil. Its claim to fame....and method of operation....is that it uses heptane ad the carrier for its oils. Its designed to defeat surface tension and flow into pores as small a 1 micron.
That allows even a basic petroleum oil to coat a surface so thoroughly that it displace oxygen that can start the basic sacrifical corrosion process of magnesium.
So in a lot of reapects.....it does the same thing as an Alodine coating....but in a different way. Yes....you will have to reappy it occasionally.
In reality....what the acid pickling process does before you apply a coating like an Alodine....is to change the surface tension of the metal.....allowing liquid penetration into pores that are too small for the surface tension of water to get into.....1 micron and below 1 micron. This is called surface activation.
Ray |
|
| Back to top |
|
|
Lil Lulu
Samba Member
Joined: December 08, 2007
Posts: 1745
Location: Mouth of the Columbia
|
| Posted: Sun Nov 12, 2017 2:43 pm Post subject: Re: Type 4 cooling shroud alloy |
|
|
Man I love it when Ray goes all Hephaestus. 
_________________
'65 Beetle "Lil' Lulu"- Ruby Red
1600 stock from '71 bus
'72 Deluxe - Niagara Blue w/pastelwiess Camper Special 2L dual 40 Webers 002
'74 Hightop Weekender "Dixie" 1800 34 Del singles |
|
| Back to top |
|
|
raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21520
Location: Oklahoma City
|
| Posted: Sun Nov 12, 2017 3:36 pm Post subject: Re: Type 4 cooling shroud alloy |
|
|
| Lil' Lulu wrote: |
| Man I love it when Ray goes all Hephaestus. |
That fits!....got my hammer, anvil and tongs....hanging on my "Hello Kitty" tool belt!
Ray |
|
| Back to top |
|
|
|
