I was at Walmart today and I saw some really small fuel filters like this

http://www.walmart.com/ip/Fram-Fuel-Filter/16817247

It reminds me of the msr siltstopper prefilter. I think it looks like it could work, but I'm wondering if there is anything harmful in these filters? They are only $2.96 at my local store... Super light and small. Anyone know?

I would never use that filter because it is likely not meant for human consumption materials to be filtered through and ingested.

Interesting - they're only $1.99 at my local W*.

There's a risk, perhaps, of something leeching out of the plastic, but as long as you're only prefiltering cool water 'I' wouldn't worry about too much (but I'm no scientist). My thinking is that it's not like you'd be soaking the plastic in the water for a period of time, nor heating the plastic.

If you're worried about it, you could make a prefilter out of some fine screen and the end of a small [water?] bottle of some sort that you know is safe. A small hole in the cap of the bottle, with the screen sandwiched underneath?

I use a handkerchief for prefiltering purposes - light, extremely packable and multiuse.

A small plastic funnel with coffee filters is probably a more versatile and faster choice: with a fuel filter you have to have hoses running to it, the element isn't replaceable, it's probably relatively slow and you can make coffee with your filter/funnel...

I second coffee filter and funnel technique. Personally, I wouldn't risk the unknown.
At the very least, I doubt they are made in sanitary conditions...?
Otherwise, you might call the manufacturers?

+1 using a coffee filter to pre filter.
Interesting video on using biodiesel filters to make lightweight hiking water filters at
http://www.youtube.com/watch?v=is7X6JS9vUo

includes use of coffee filters to prefilter.

I once purchased this very filter to try it as a prefilter. When I opened the package, it smelled strongly of petroleum so I didn't use it. My guess is that the actual filter element has been pretreated with oil during manufacturing.

I've been using a 1 micron diesel fuel filter that I got off ebay. This is the exact bag I ordered.

(Sorry cant get the link to work on here)

http://cgi.ebay.ca/1-Micron-Singed-Polyester-Filter-Bags-4-x-8-Size-3-/350331084520?pt=LH_DefaultDomain_0&hash=item51915c1ee8#ht_2155wt_808

Bought a small funnel and cut circles out of the filter. Then I used some Gorilla glue to hold it in place at the bottom of the funnel. Seems to work great! I can upload a picture if its needed but just cut a circle about 1 inch bigger than where you want to filter rest.

I really just started using these but my current one at a cost of about $1.25 has lasted me at least 30 liters of filtering. Its still going strong, I usually back wash it or just rinse it in water.

A bandanna works pretty good too as others probably use them as well. I made this little contraption to get the buy in from the wife. When I'm with her I usually have to pre-filter, treat with Aqua tabs and boil. She's in charge of boiling though as I tend to just go with the Aqua tabs.

Not something a gram counter would bring but its pretty light.

Edited by coreyfmiller on 06/29/2011 16:41:57 MDT.

That reminded me of an earlier thread with a YouTube video that I remembered being impressed by (I like using stuff 'out of context').

I note that comments have been added since then questioning just how much sub-micron stuff is actually filtered by the '1 micron' filter. I have no information either way; just raising the issue for consideration.