Page 1 of 1
Starting Grit for removing scratches
Posted: Mon Jun 11, 2018 2:34 am
by TwoFlowersLuggage
I'm trying to remove a ton of scratches from a blade that was abused by its previous owner. I understand the progressive method of starting with a coarser grit of wet/dry and not moving to the next level of more fine grit until ALL the scratches are gone. I bought a "variety pack" of wet-dry that has 220, 500, 1000 and 1200. I started with the 500 and although it looks better, I'm having trouble getting all the scratches out.
So, my question is, should I back off to the 220 or should I just keep trying with the 500? I'm thinking that as long as I try to be consistent & even in my sanding, and just don't go to far in the amount of material being removed, there isn't really any danger in dropping down to the 220, is there? I'm just going to go back to 500 after the 220 anyway. Am I thinking correctly on this?
Re: Starting Grit for removing scratches
Posted: Mon Jun 11, 2018 3:31 am
by whitebuffalo58
220 to 500's a pretty big jump, it sure wouldn't hurt to have a grit or two in between. 320-400? It'll all work out in the end, just a whole lot more elbow grease.
WB
Re: Starting Grit for removing scratches
Posted: Mon Jun 11, 2018 3:55 am
by TwoFlowersLuggage
Yeah - that's why I was trying to start at 500. I'll have to see if I can find something in-between. Selection at the big box stores around me was pretty poor.
Re: Starting Grit for removing scratches
Posted: Mon Jun 11, 2018 10:33 am
by orvet
I have found auto parts stores that carry automotive paint usually have a decent section of wet or dry sandpaper.
I often ure s light machine oil on the sandpaper when sanding to help it cut better and faster.
Re: Starting Grit for removing scratches
Posted: Mon Jun 11, 2018 12:24 pm
by Tony_Wood
I second the auto parts for fine sandpaper.
I like to use windex for a lubricant while sanding. It is not as messy as oil.
The sandpaper from Sherwin Williams paint stores is good stuff as well.
Re: Starting Grit for removing scratches
Posted: Mon Jun 11, 2018 2:06 pm
by OLDE CUTLER
Another thing to consider is what brand the sandpaper is. I typically use only 3M Wet or Dry sandpaper. I was in Harbor Freight recently and bought some of their brand that was labeled 1000 grit to try out. On my next project I went from my usual 400 Wet or Dry to the 1000 grit and the scratches were larger. The Chinese sandpaper grit markings don't correspond to the ones used here. The 1000 grit Chinese was approximately like 220 would be here in the 3M brand.
Re: Starting Grit for removing scratches
Posted: Mon Jun 11, 2018 4:26 pm
by TwoFlowersLuggage
Thanks for the mention of Harbor Freight - because that is exactly where I got my combo pack!

Auto parts and paint stores are also great suggestions - I hadn't thought of either of those!

Re: Starting Grit for removing scratches
Posted: Tue Jun 12, 2018 12:41 am
by FRJ
Here are some abrasives I bought on Amazon some time ago. It's pretty fine stuff but worth having around I think.
I haven't taken the time to use this stuff so I can't recommend it. I thought it was worth mentioning.
I was going to use it on some of my kitchen knives.
Re: Starting Grit for removing scratches
Posted: Tue Jun 12, 2018 3:59 am
by TwoFlowersLuggage
The little bit that I have learned about sandpaper grits (from my 20 minutes of google-fu) is that there are several different grit standards used in different industries and/or countries. The stuff I got from Harbor Freight is marked with a leading "P" (eg P500, P1000), and according to this chart, that seems to be the ISO scale:
http://www.seabean.com/polish/GritScales.pdf
HOWEVER, does the cheap Chinese manufacturer REALLY use the ISO scale? Or do they just mark it with the ISO numbers? Who knows...
Re: Starting Grit for removing scratches
Posted: Tue Jun 12, 2018 4:39 am
by orvet
FRJ wrote:Here are some abrasives I bought on Amazon some time ago. It's pretty fine stuff but worth having around I think.
I haven't taken the time to use this stuff so I can't recommend it. I thought it was worth mentioning.
I was going to use it on some of my kitchen knives.
I regularly use the 3M polishing paper that you mentioned in your post. I think it is really the best thing for someone who does not have a buffer or belt sander available to them. The scratch pattern and grit numbering system is different than regular sandpaper. I will usually use regular sandpaper to about 1000 grit and them drop down to the 400 grit 3M polishing paper and then work progressively from 400 grit to 8000 grit. If you use all six grits in succession, 400, 600, 1200, 4000, 6000 and 8000, by the time you have finished you can have close to a mirror finish on a blade.
The scratch patterns produced by the abrasive on 3M polishing paper are different than the scratch pattern produced by a comparable grit sandpaper and they are not as deep as the scratch pattern of sandpaper, that is why I sand to 1000 grit was sandpaper before dropping back to 400 grit polishing paper.
Re: Starting Grit for removing scratches
Posted: Tue Jun 12, 2018 10:40 am
by TripleF
Good info here fellas!! Thanks!
Divots in blades is what messes me up.....
To remove pitting I've gone down to 80 grit....
Re: Starting Grit for removing scratches
Posted: Tue Jun 12, 2018 12:13 pm
by FRJ
Thank you, Dale.
It's nice to have some conformation of the use of that 3M product.
Would you consider going to the higher grits with the wet dry sand paper I showed?
It's rated up to 3000 grit.
Thanks
Re: Starting Grit for removing scratches
Posted: Tue Jun 12, 2018 2:47 pm
by muskrat man
Nothing wrong with starting out with 220, I usually do. I use water as a lube when hand sanding a blade. 220-400-600-buff ifs my normal routine whether I'm hand sanding or machine sanding
Re: Starting Grit for removing scratches
Posted: Wed Jun 13, 2018 5:35 pm
by orvet
FRJ wrote:Thank you, Dale.
It's nice to have some conformation of the use of that 3M product.
Would you consider going to the higher grits with the wet dry sand paper I showed?
It's rated up to 3000 grit.
Thanks
I would certainly try it and if I like the results I would definitely use it.
I have not seen that brand before. Did you get it online or purchase it locally?
Re: Starting Grit for removing scratches
Posted: Wed Jun 13, 2018 5:38 pm
by FRJ
Thanks Dale.
I bought both the 3M and the CWR Trading Company abrasives from Amazon.