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Scotchbrite

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cffd(at)pgrb.com
Guest

Posted: Fri May 05, 2006 7:52 am Post subject: Scotchbrite

Do not use silicon carbide based Scotchbrite on aluminum.

Below is a note I sent a while back.



---

lo2u

Joined: 11 Apr 2006
Posts: 46
Location: Upstate New York

Posted: Fri May 05, 2006 2:15 pm Post subject: Scotchbrite

 	  Quote: 	
		  From your post it appears only the maroon 7447 is safe but why then are most 

recommending the greay 7448 for finish? It is rated ultrafine but your post 
	


says it is silcon carbide...very confusing ..also several people have been 

advised that the grey is the only one to use.I am really confused now 

arrgh.. I guess I will have to contact 3M directly... Thanks for the 

information I would have possibly made a bad mistake..



Ron Culver 701 still cutting metal

---

cffd(at)pgrb.com
Guest

Posted: Fri May 05, 2006 3:13 pm Post subject: Scotchbrite

Silicon carbide  can cause corrosion of the aluminum.

Chuck D.



---

Doug Garrou

Joined: 16 Jan 2006
Posts: 18
Location: Richmond, VA, USA

Posted: Sat May 06, 2006 6:29 am Post subject: Scotchbrite

Chuck:



I can't resist revisiting this issue.



Do you have a citation or reference supporting the claim that silicon carbide Scotchbrite pads should not be used on aluminum?  I ask principally because the Scotchbrite people actually recommend one of their gray pads (and maybe others) for "finishing stainless steel *and aluminum*" including "light oxide removal."



http://multimedia.mmm.com/mws/mediawebserver.dyn?6666660Zjcf6lVs6EVs666yY4COrrrrQ-



Note that the pad in question (the 7440 series) is, as you note, a gray pad with a silicon carbide abrasive:



http://products3.3m.com/catalog/us/en001/electronics_mfg/esm/node_GSN1BGFPYDgs/root_GST1T4S9TCgv/vroot_DPB1Q1MJ7Nge/bgel_0GN1N5NLFGbl/gvel_2B4W8PPJ9Xgl/theme_us_electronicsesm_3_0/command_AbcPageHandler/output_html



I don't see, in the Scotchbrite people's response to you, that they said not to use the silicon carbide pads on aluminum.  That would seem to contradict their website.  Did one of their people tell you that? If so, did he/she offer a rationale?



Cheers

Doug Garrou

Project801

Bold and unrepentant user of ALL forms of Scotchbrite pads, and defender of the use of silicon carbide in Scotchbrite pads, baby food, and Peeps marshmallow candy.

www.garrou.com



--

cffd(at)pgrb.com
Guest

Posted: Sat May 06, 2006 11:23 am Post subject: Scotchbrite

Doug,

See chart on page 8 of Zenair News #84 September/October 1994 sent by Zenith

Aircraft Co. of Mexico, MO.

Chuck

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lo2u

Joined: 11 Apr 2006
Posts: 46
Location: Upstate New York

Posted: Sat May 06, 2006 12:21 pm Post subject: Scotchbrite

I checked that reference Chuck and it indicates about S class pads. On the 

3m site the only aluminum oxide that is listed as medium or finer is the 

maroon which is medium.No aluminum oxide Fine grade seems to be other than 

silicon carbide ..So what is to be used for fine polishing?

---

Tim Juhl

Joined: 21 Mar 2006
Posts: 488
Location: "Thumb" of Michigan

Posted: Sat May 06, 2006 3:20 pm Post subject: Re: Scotchbrite et al

I just checked the 3M website and found the following that might be helpful - 



Scotchbrite hand pads with Aluminum Oxide abrasive are available in medium and fine  PN 7447 and 7448 respectively.   For a really fine finish I suggest you try 3M™ Softback Sanding Sponges - these use Aluminum oxide and are thin, dense sponges with abrasive on one side. Microfine is PN  4181   Ultrafine is PN  4182.  I've used the softback sponges with great success.



There are a number of discount autobody finishing supplies outlets on the net.   Try entering 3M™ Softback Sanding Sponges in Google and see what comes up.



Tim Juhl

_________________
______________
CFII
Champ L16A flying
Zodiac XL - Jabiru 3300A
Almost done! It'll fly in spring!

Doug Garrou

Joined: 16 Jan 2006
Posts: 18
Location: Richmond, VA, USA

Posted: Mon May 08, 2006 9:53 am Post subject: Scotchbrite

Chuck - unfortunately a 94 Zenith newsletter (substantially) predates my Zenith involvement and my aviation library.  What exactly does it say?



Thanks

Doug



--

cffd(at)pgrb.com
Guest

Posted: Mon May 08, 2006 11:23 am Post subject: Scotchbrite

It says that using Scotchbrite S is prohibited on aluminum, magnesium, and

copper, and Scotchbrite A is recommended on aluminum.  S is ok for steel and

corrosion resistant steel.

Chuck D.

---

Doug Garrou

Joined: 16 Jan 2006
Posts: 18
Location: Richmond, VA, USA

Posted: Tue May 09, 2006 5:16 am Post subject: Scotchbrite

Hmmm.... So we have figured out the conflict.  Scotchbrite apparently says yes, Heintz says no.  Does the newsletter explain Heintz's reasoning?  Perhaps he was following Scotchbrite's own recommendation that has changed?



I'm on a mission.  



--

bryanmmartin

Joined: 10 Jan 2006
Posts: 1018

Posted: Tue May 09, 2006 9:03 am Post subject: Scotchbrite

Silicon carbide is a compound of silicon and carbon. Carbon and aluminum don't play well together, they're far apart on the table of electronegativities (large potential for galvanic corrosion). This is probably the concern 

Chris has for this type of abrasive. Although, as I understand it, the carbon is pretty tightly bound to the silicon in this compound and might not pose a large corrosion problem.



 -------------- Original message ----------------------

From: "Garrou, Douglas" <dgarrou(at)hunton.com>

[quote] 

 

 Hmmm.... So we have figured out the conflict.  Scotchbrite apparently says yes, 

 Heintz says no.  Does the newsletter explain Heintz's reasoning?  Perhaps he was 

 following Scotchbrite's own recommendation that has changed?

 

 I'm on a mission.  

 

 --

_________________
--
Bryan Martin
N61BM, CH 601 XL, Stratus Subaru.
do not archive.

moorecomp(at)yahoo.com
Guest

Posted: Tue May 09, 2006 9:33 am Post subject: Scotchbrite

Doug,



CH is simply repeating what is said in AC43.13-1B

Chapter 6, Page 6-22, Table 6-1. Silicon Carbide is

only for use on Ferrous or Titanium. Aluminum Oxide or

Garnet for Aluminum and Magnesium. It seems that no

matter what "anybody" says, people will use what they

want because "somebody" said it was OK. As for me, I

will follow "The Book".



Here is the link for the 43.13



http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/99C827DB9BAAC81B86256B4500596C4E?OpenDocument



Craig Moore A&P

701 builder wannabe



--- "Garrou, Douglas" <dgarrou(at)hunton.com> wrote:



[quote] 

 <dgarrou(at)hunton.com>

 

 Hmmm.... So we have figured out the conflict. 

 Scotchbrite apparently says yes, Heintz says no. 

 Does the newsletter explain Heintz's reasoning? 

 Perhaps he was following Scotchbrite's own

 recommendation that has changed?

 

 I'm on a mission.  

 

 --

cffd(at)pgrb.com
Guest

Posted: Tue May 09, 2006 10:31 am Post subject: Scotchbrite

It is probably the same reason that a regular lead pencil (graphite) should

be not used on aluminum.

Chuck D.

---

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