Stearated Sandpapers and Waterborne Flowout Issues

Advances in technology seem to have eliminated the flowout issues previously seen with waterbornes and synthetically treated sandpapers. October 28, 2009

I use Target water based products and in the past have had good success sanding with Klingspor ps33 aluminum oxide. I ordered another sleeve but accidentally ordered the silicone carbide pl35 in 320 grit. I think they use the same sterrate but I am wondering if I will run into any contamination problems?

Forum Responses
(Finishing Forum)
From contributor P:
Do a test on a sample. Leave some sanding dust on a first coat, spray a second coat and see what happens! I use all different types and brands of sandpaper, and have never had any problems with the Target products.

From contributor K:
As I understand it Klingspor has reduced the stearate level to an acceptable level.

From contributor T:
To the original questioner: please don't add to the existing confusion of siliconE with silicon. This is not a spelling error correction. Misuse of specific terms regarding products critical to the trade can and has caused too many mistakes.

From contributor A:
They don't usually stearate silicon carbide paper. What color is it? They primarily use silicon carbide as wet/dry not for wood.

From contributor J:
I have just finished testing all the stearated sandpaper I could lay my hands on from Klingspor, 3M, Mirka and Norton and have let to find a waterborne finish that presented flowout issues (crawling, cratering) with any of them.

I did use a 5% denatured alcohol to water wipe-down after sanding to remove the residue. While there certainly are more stearated aluminum oxide papers out there, stearated silicon carbide is used and might be considered a slight upgrade for sanding certain finishes. 3M Tri-M-Ite (415) is one example.

From the original questioner:
Thanks to everyone. I did a worse case test on a sample leaving behind some sanding dust and the finish laid out perfectly. Now with all of the confirmation from you guys I feel much better. This paper seems to have a slightly less aggressive grit and resists loading a little better than the p33, maybe this was an ordering accident worth making.

From contributor A:
Thank you for sharing the valuable knowledge. A lot of us have been avoiding Klingspor for years simply because of potential problems. We switched from Klingspor to Mirka Gold for that reason about seven years ago.

From contributor J:
I'm not being critical but when you do a test like you mention you are testing for flowout. Adhesion is a separate issue. While I do not think you should see any problems, you should wait 72 hours and perform a cross-hatch adhesion test. I have seen beautiful flowout of finishes that I could later peel off like Saran-wrap.

On a separate issue, I'm not necessarily buying the argument that the stearate content is reduced or calcium stearate is better than zinc stearate for waterborne finish problems. These two stearates are virtually identical, the main difference being the melting point which I don't think comes into question when sanding finishes. I believe the "non-issue" of stearated papers and waterbornes today comes from two things. One - different manufacturing methods by the abrasive companies, and second, but more importantly, waterborne manufacturers are formulating for potential flowout problems caused by low-surface energy surfaces. This is done with complex additives that are constantly improving.

From the original questioner:
I conducted an adhesion test and there was no peeling, it works fine.