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Sanchem Comments

Highflight

Well Known Member
I was contacted by Jon at Sanchem who felt that the Sanchem 6100 product is being a little misunderstood here on the RV forum. Based on his comments, he might be right so I thought I would pass on his notes here.

However, I'd like to start backwards and mention something that has been brought up before and something that I also have never been comfortable with when using the acid wash type systems (ex. Alodine).

Allow me to cut and paste from another message in this forum (from George Goff) that explains this issue:

gvgoff99 Join Date: Jan 2005
Location: Houston, TX
Posts: 44

Another consideration BEFORE you Alodine

I want to thank you Vern for an excellent and informative article. I also wanted to add the following that I found about the Alodine process. This is under the technical information at: http://www.alphametal.com/index.html
"Anodizing Aluminum assemblies
Aluminum parts that have been assembled together will anodize successfully. However the designer should be aware that lap joints such as spot welds and joints that are not completely watertight can become traps for cleaning agents and sulfuric acid. In some cases it is impossible to completely rinse all of the sulfuric acid from the joint. If this happens the joint then becomes a site of increased corrosion potential............. . However, as above, it is much better practice to consider this potential problem during the design phase of your product and plan to do the anodizing before assembly if at all possible. "

This information and Vern's information about the self-etching primers has saved me a lot of work. I found the above information as the result of a search that I did when I was wondering about the acid that almost for sure is held in by capillary action around the seams and rivets when doing the acid wash during the alodine process.
__________________
George Goff RV-6A (Houston, TX)


As George points out, it is possible that you can actually cause corrosion when prepping an assembled fuselage or wing because of wicking into lapped areas that cannot later be properly rinsed and neutralized.

So to better clarify this issue specifically with regard to Sanchem 6100, I asked John at Sanchem to explain the difference between the 6100 and other acid wash systems. I have cut and pasted my question and his answer below.

Jon,
When using the chemical wash treatments, I have never been comfortable with the idea that the acidic wash can wick into really tight areas (seems, etc.) where they can't be properly rinsed. That can actually CAUSE corrosion problems in the very areas that you are trying to protect.
So my question is; is the Sanchem 6100 similar where it could cause a problem in areas that can't be rinsed, or is the chemistry of the 6100 different where wicking isn't a problem?
I know that there's no problem when using 6100 on whole, unassembled panels, but many people buy "QuickBuild" kits where major areas of the aircraft are already riveted together. Should those people avoid using the 6100 in those circumstances?

Thanks,
Matt

Matt

Chemical wash treatments use a very strong acid that is designed to cut into the surface of the metal in order to “anchor” the coating to the metal’s surface. The acid used in “6100C, Mild Acid Cleaner” is a very mild acid that is not able to cut into the surface of the metal. It is only designed to loosen surface dirt so it can be rinsed off. In addition the “Safegard 6100” conversion coating, which is applied after cleaning the metal surface, will neutralize any acid it comes in contact with.

Jon[/I]


I thought this tidbit might be of interest to those who are thinking of using an acid wash pre-prep on their assembled aircraft.
 
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Now to Jon's points about things he feels are being misunderstood.

Here's a cut and paste of his comments:

Matt,

I looked at the Van's airforce website and I noticed some complaints about our company.

1. One person Claimed that we would not send a MSDS until he purchased the product. I do not know who he talked to but I send MSDS sheets out all the time. I believe that they told him that they send them out with every order.

2. Our labels have hand written lot numbers. That is because 1 gallon container line is not automated. Our products are sold primarily to manufacturing companies. Our new labels for these products have usage instructions on the label.

3. Another point someone made was that our process requires DI Water. Again these products are sold primarily to industrial manufacturing companies who usually have either DI or RO water available. Distilled water which can be bought at any grocery store can be used.

I would appreciate if you could inform people on your thread of this information.


I would like to make it clear that I am not a "rep" for Sanchem other than that I like the specs of the 6100 product in comparison to other acid wash systems.
It is likely that Jon contacted me personally about this because I'm the one who seems to have been asking the "deep" questions about the product and how to use it (6100).

For those unaware, "DI" is Distilled Water, and "RO" is Reverse Osmosis water.
Jon makes a good point that is universal to ALL acid wash products that use water as a rinse in that hard water can screw up any of the systems.
It doesn't take much water to rinse a panel, so spending a couple of bucks for a few gallons of Distilled Water would be easy enough to do. In my case, I have a Reverse Osmosis rig on my kitchen sink faucet so all I have to do is to catch a gallon or two when I need it.

The purpose of these notes is not to promote any particular product (unless someone wants to start paying me to :D ).
Accept the above as simply basic information in case it might be relevant to your particular situation.
 
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Sanchem 6100

Vern,

Thanks for the info. I think homebuilders are a new market for Sanchem and they are not used to dealing in such small quantities and with many individuals. Hopefully they will find this market useful to them and develop product packaging that meets our needs better. On that note I should point out that when I received my 6100 prodcut, it did not include an MSDS or usage instructions. Fortunately I had thoroughly discussed usage with them on the phone so that wasn't an issue, but I would still like the MSDS. On the other hand, I didn't specifically ask for the MSDS, I just assumed it would come with the product. I guess I'll call them at some pont and ask them to send it to me.

I do believe, however, that the requirement for DI or RO water is a limiting factor in using the product. I don't really think a couple of gallons of stoer bought distilled wter will last very long.

I have only done a brief test with the 6100 so far so I can't comment too much, but it does sound promising.
 
When I got my single gallons of 6100 material and saw that it was hand labeled (no, I mean REALLY hand labeled with a blank label on which was written the part numbers), I realized right there that Sanchem was geared up for commercial sales rather than small retail users.

Retail sales are a different game, however, so I guess time will tell if Sanchem thinks a market like ours is worth the packaging effort and all the hand-holding that comes with that. Jon can sell a pallet of 55-gallon drums to one company and have to deal with the questions of only one person, or, he can sell 220 gallons to 220 people and find himself on the phone 14 hours a day saying the same thing over and over to 220 people. Which one sounds like more fun? :)

The trick to making retail sales workable for Sanchem is to have labeling and literature that has been properly written by a Technical Writer (I did some of that at one time ;) ) where every word is parsed to ensure that the instructions are easily understandable by the intended customer market. Well documented instructions result in almost no follow-up inquiries about a product (which of course, is the objective).
If doing that is worth it to them, I don't know. Perhaps our (aluminum homebuilt aircraft) market isn't large enough to make that worthwhile for them. We'll see.

Regarding the clean water issue; I'll stand on my support of Sanchem's/Jon's comment on that. The only thing I would add is that Jon is throwing that info in a little early on so it looks like (to you) that DI or RO water is necessary.
What I would suggest is to use your regular tap water and simply see what happens. I'd bet that 98% of the time, people will get the "look" and performance as expected from the product. It's only in a minority of cases where someone does a rinse and wonders why it looks different from what they expected that it might be time to go with DI/RO water.

As a simple test, perhaps you might pick up just one gallon of DI water and experiment with it. Prep and rinse an area of aluminum with your tap water and prep and rinse an area using DI water. If the outcome looks the same, then your tap water is all you need.
If your tap water has lot's of mineral content in it, the resulting look of the rinse and how it looks when dried compared to the DI water rinsed part might indicate a problem with your tap water.

Understand that this applies to ALL of the acid wash systems and always has. It's just that you never hear about it because no one says anything until something DOES go bad. In those cases, whether it be Alodine or Sanchem, it's time to try some clean water.
 
Wrong Info!

Allow me to cut and paste from another message in this forum (from George Goff) that explains this issue:

gvgoff99 Join Date: Jan 2005
Location: Houston, TX
Posts: 44

Another consideration BEFORE you Alodine

I want to thank you Vern for an excellent and informative article. I also wanted to add the following that I found about the Alodine process. This is under the technical information at: http://www.alphametal.com/index.html
"Anodizing Aluminum assemblies
Aluminum parts that have been assembled together will anodize successfully. However the designer should be aware that lap joints such as spot welds and joints that are not completely watertight can become traps for cleaning agents and sulfuric acid. In some cases it is impossible to completely rinse all of the sulfuric acid from the joint. If this happens the joint then becomes a site of increased corrosion potential............. . However, as above, it is much better practice to consider this potential problem during the design phase of your product and plan to do the anodizing before assembly if at all possible. "

This information and Vern's information about the self-etching primers has saved me a lot of work. I found the above information as the result of a search that I did when I was wondering about the acid that almost for sure is held in by capillary action around the seams and rivets when doing the acid wash during the alodine process.
__________________
George Goff RV-6A (Houston, TX)


As George points out, it is possible that you can actually cause corrosion when prepping an assembled fuselage or wing because of wicking into lapped areas that cannot later be properly rinsed and neutralized.
=========================================================

Here's the deal...ANODIZING and ALODINING are two entirely DIFFERENT processes. To simply interchange the two is not only mis-informative, but now we've got people reading who have completely the WRONG impression about his whole process. Yes, Anodizing uses Sulphuric acid (in fact the parts are bathed in it), but Alondinging DOES NOT! One is a electro-mechanical process and the other is purely chemical.

Sorry for the rant, I just want to catch people before this gets to the "I read / heard" point where people think that alodining and anodizing are even remotely similar...they're NOT!

Regarding Sanchem, I'll wait and see who starts using it commercially in the aircraft business. "Tested by Boeing" and "Tested by the Military" don't mean a thing. When I see a white paper by either of them, or see it turn up at airlines or military depots, then I'll consider it. Before that, I'm hesitant to be a guinea pig myself.

Just my 2 cents!
Stein.
 
They are different processes, but they do share the common feature whereby a caustic chemical pre-treatment is used before the "final" step.
In either case, if the pre-cleaning caustic chemical isn't completely flushed and the hidden areas aren't covered by the final step, then corrosion can form in those hidden areas.

Now, "Alondinging" is a whole 'nuther process of which I am not very familiar :D
 
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