View Full Version : Lowers: teflon over anodizing vs. just anodized
SomeOtherGuy
12-22-10, 19:51
I did a couple searches and couldn't find an answer to this question, so here goes.
A few manufacturers of lower receivers advertise that they do class III anodizing and then apply teflon over it. The ones I know of are DPMS, CMMG, Charles Daly Defense, and DoubleStar. It appears that Spike's Tactical makes some but not all of its lowers this way also.
In addition, I've read comments about Mega lowers having this teflon coating, but have not seen it advertised by Mega or their distributers.
Virtually all the other manufacturers say only that they do class III anodizing (some of them will go further and say class III, type 2, military spec) without any mention of teflon coating. I am guessing that the military spec does not call for teflon and that manufacturers following it, such as the high quality Colt, DD, BCM etc. do not do teflon. But I'm only guessing.
Can someone tell me:
1) Is the teflon over anodizing only done by the listed few above? I ask partly because a post somewhere else said that the teflon was a standard post-anodizing treatment, which makes me wonder if it's done on most/all but only advertised by a few.
2) If teflon is not done by most, why not? It seems like it adds durability and corrosion resistance even beyond what you get from the hard anodizing. Does it create any issues with retaining rollpins in place?
3) I have a Charles Daly Defense lower and their finish looks different from the other companies advertising teflon (DPMS and CMMG in particular) and seems more durable than any other lower finish I've seen. And I've read comments from others to this effect. CDD is out of business and their lowers are basically off the market now. Does anyone else make a lower with the same finish?
4) If anyone knows, are the Mega-branded lowers teflon coated or not?
Wow, you're right. I bought a Charles Daly lower from Rainier Arms a few weeks ago but they don't seem to have any more. Beautiful lower and beautiful finish! I would say my S&W M&P-15 lower compares quite well with the CDD though.
My limited understanding of this was that the anodizing is always clear. The anodizing, which is nothing more than a layer of forced oxidation, has to be dyed to have color, in most cases black.
If you anodize a shiny part, your get shiny anodizing. Likewise, bead or media blasted parts have a dull, lusterless finish.
IIRC, the teflon coating came about as a way of color matching. Typically, there are slight varations in anodizing, due both to the process and the dye. I had a Larue SPR mount where the rings and the scope body where very slightly different shades of black.
The teflon coating eliminates this, as well as making things less likley to stick to the finish, making cleaning easy.
The down side to teflon coatings would be that it can flake off. No different than if you scratch a teflon coated skillet.
Purely conjecture, but I suspect that all of the manufactures that are using teflon coated parts are getting them from the same place. Or at least, the parts are being finished by the same company.
Can someone tell me:
1) Is the Teflon over anodizing only done by the listed few above? I ask partly because a post somewhere else said that the teflon was a standard post-anodizing treatment, which makes me wonder if it's done on most/all but only advertised by a few.
2) If Teflon is not done by most, why not? It seems like it adds durability and corrosion resistance even beyond what you get from the hard anodizing. Does it create any issues with retaining rollpins in place?
3) I have a Charles Daly Defense lower and their finish looks different from the other companies advertising Teflon (DPMS and CMMG in particular) and seems more durable than any other lower finish I've seen. And I've read comments from others to this effect. CDD is out of business and their lowers are basically off the market now. Does anyone else make a lower with the same finish?
4) If anyone knows, are the Mega-branded lowers Teflon coated or not?
1) Teflon is done by mostly the lower end guns, most likely to get a uniform & repeatable finish because "fit and finish" are a selling point to that segment.
2) Those that don't do the Teflon coating are building guns closer to the TDP which doesn't call for it. The receivers are aluminum, corrosion really isn't a problem, any type of surface coating can cause dimensional problems.
3) I don't know what coating they used but Teflon is a brand name for PTFE (http://en.wikipedia.org/wiki/Polytetrafluoroethylene) which can be made by many different companies with different properties, application methods ect and can be applied aftermarket with Duracoat, Gun Kote and the like.
4) No idea, call or email MEGA.
My .02c It's not really needed unless you want your gun some other color than black.
mkmckinley
12-23-10, 08:11
I dont think higher end brands use it because it's pretty much a marketing device. Makes cleaning easier? Ive neverhad a problem cleaning off the aliminum surface of a receiver. More durable? I've never had a receiver fail due to lack of teflon and corrosion is a non issue with aluminum. The teflon is just there to look pretty until it starts scratching off.
I only buy MEGA receivers for my builds. Their finish is something to behold. Makes cleaning super easy and it's a tough, durable finish. Very resistant to scuffs and scratches. I've got high-use receiver sets from MEGA from 4+ years ago and they still look brand new.
It isn't a "marketing device" and it doesn't "scratch off." MEGA doesn't even really market their finish.
I only buy MEGA receivers for my builds. Their finish is something to behold. Makes cleaning super easy and it's a tough, durable finish. Very resistant to scuffs and scratches. I've got high-use receiver sets from MEGA from 4+ years ago and they still look brand new.
It isn't a "marketing device" and it doesn't "scratch off." MEGA doesn't even really market their finish.
For some it's a marketing device, it's hardly necessary on aluminum and I assure you just about any coating can be scratched/worn off. Just because you haven't done it doesn't make it impossible.
Mega had a rep that posted on TOS that stated that they do not use Teflon coatings.
SomeOtherGuy
12-23-10, 10:01
Mega had a rep that posted on TOS that stated that they do not use Teflon coatings.
Good info, thanks.
I don't know if Daniel Defense use teflon or not (probably not), but my LMT sure is plain anodized, I can leave a mark with a fingernail on it, but a Daniel Defense upper I bought sure doesn't have the same finish as my LMT, the DD doesn't scratch, whatever they put on it it's not the same as my LMT, it's shinier too. I think BCM uses the same finish too.
mkmckinley
12-23-10, 21:40
If you can actually leave a mark in the anno with your fingernail then something is waaay outta spec. The anodized surface on an aluminum part is a lot harder than the aluminum itself. My guess is that the mark you're seeing is parts of your fingernail being scratched off onto the annodizing like a piece of chalk on chalkboard.
If you can actually leave a mark in the anno with your fingernail then something is waaay outta spec. The anodized surface on an aluminum part is a lot harder than the aluminum itself. My guess is that the mark you're seeing is parts of your fingernail being scratched off onto the annodizing like a piece of chalk on chalkboard.
Yes, I didn't mean to sound like I actually scratched the anodizing. :sarcastic:
But the anodizing on the DD is shinier and very smooth, doesn't leave a mark when I rub a fingernail.
How old is your DD receiver?
I bought mine a few months ago, and I've found it's a pretty flat black. I wonder if there is a difference in batches.
I don't know, I think it differs from mfg to mfg, the anodizing like I have on my LMT is more porous and holds oil, where the DD is smooth and doesn't hold oil. I just don't know what "kind" of anodizing they (and other top tier mfg) use.
Alpha Sierra
12-24-10, 10:59
I don't know, I think it differs from mfg to mfg, the anodizing like I have on my LMT is more porous and holds oil, where the DD is smooth and doesn't hold oil. I just don't know what "kind" of anodizing they (and other top tier mfg) use.
That textural difference isn't due to the anodizing process. It's due to the metal surface finish prior to anodization.
Anodizing is a surface conversion process. Half of the coating thickness goes into the surface and half of it "grows" the surface. Hard coat anodizing is full of millions of microscopic cracks. To get color it is dyed and the dye goes into the surface. For good corrosion protection it needs to sealed. IIRC the milspec calls for nickle acetate sealer - a fairly old technology.
A Teflon sealer, especially if applied as vacuum impregnated, is an excellent protective layer. If the surface is sealed this way it probably won't hold paint very well but it should be very corrosion resistant. The Teflon finish is used on high end marine hardware.
mkmckinley
12-25-10, 22:35
Under what conditions does one need to worry about aluminim corroding?
Bushmaster advertises that they apply a nickel acetate sealant over their finishes. Not really sure of the pros/cons of that particular application, but they advise not to rub down the exterior with any solvent that would affect nickel.
SomeOtherGuy
12-26-10, 12:46
DBR, very good info. It sounds like the mil-spec is another instance of a specification being frozen in time at the best reasonably attainable option when it was written, which was a long time ago.
I'm still waiting to hear any real downsides of teflon over anodizing. I was wondering if it might interfere with rollpins staying in place, but I've never heard of that being a problem with the commercial receivers that use it, nor has anyone so far posted that it is an issue.
Under what conditions does one need to worry about aluminim corroding?
Aluminum corrodes very fast in a saltwater environment. Far away from salt, it's naturally corrosion resistant because it forms a layer of aluminum oxide on the surface. Anodizing forms that same layer more thickly and under more control.
Under what conditions does one need to worry about aluminim corroding?
That's what I say when I see these pictures or AR's that seem to have fallen in the oil bucket... senseless use of oil.
Seawater has chlorides which inhibits the formation of aluminum oxide. This will promote corrosion. Contact with dissimilar metals or contact between dissimilar aluminum alloys also causes corrosion. Another condition that causes corrosion is fretting.
Anodizing is a process that converts the surface of aluminum to aluminum oxide which is quite hard and offers good protection.
Even with minimal maintenance, AR receivers have little trouble with corrosion
That's what I say when I see these pictures or AR's that seem to have fallen in the oil bucket... senseless use of oil.
What, you don't like your ARs waking up oily in the morning?!?:sarcastic:
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