I figured I would post some of my experience with different syringe filter types. Mainly about the type of membrane in the filter, but from my experience the membrane in the filter means alot when it comes to filtering, time, and success. When I was first ordering my 1st filters, I found alot of posts about filters but all ppl ever suggested was .22 or .45 micron. That's not all there is to a syringe filter though.
1st - there's the company that makes the filters, such as whatman,millipore,nalgene etc... which most everyone suggests Whatman as the best, and that's all i've ever used. 2nd - you've got to decide which membrane which works best for the type of solution you're going to be filtering. 3rd - filters are sold in diff. sizes. Such as: 13,25,and 33mm's. The smaller the millimeter the more pressure you're going to have trying to press the solution through and also the volume you will be able to filter before clogging is smaller the smaller the filter size. 4th - you've got to decide whether you want .22 micron or .45 micron,or even smaller in a few cases, pore size in your filter. .45 micron filters will do a good job at removing all of your particulates, but not all of the bacteria or viruses that could be in the solution, whereas a .22 will take out all the bacteria and viruses as well.
Personally I like to start with a .45 the 1st time I filter my solution, then filter solution again through a .22 filter, as the .45 1st gets out all the bigger particulates and makes it easier for me to run through the .22. I just like to do it the 2nd time with this because I like to know my final solution i'm putting into my body is perfectly clean and sterile.
5th - You can also elect to purchase a syringe filter with a prefilter in it ,in some cases, that can also help and maybe save you from having to filter twice, if that's what you choose. These prefilts are usually made from glass microfiber and the ones I've seen go from .45 micron pore size all the way upto 5 microns. I think around 1.0 micron is the most common for a prefilter though. I learned there's alot more to just ordering a .22 or .45 micron filter than picking one of the two, and the sites I use to purchase mine have a wide selection of diff. filters. In this huge array of filters, basically every single filter is available in .22 or .45 so where do you even start?? Below is what I've learned from my experience. It's a little bit of reading and kind of long, but I wish I'd had it to read before I ever tried to order myself filters to use and have to go through several different ones before finding one that was actually efficient for what I wanted to do.
It would have saved me a ton of time and a little bit of money as well, not to mention the time you spend waiting while your filter is being shipped to your destination and in transit. It'd be diff. if these babies were sold in a big selection in alot of diff. local stores, but their not so ordering and waiting on them to arrive is part of the process and adds to the difficulty of deciding on the right choice so you don't have to reorder and wait again and just hope you bought yourself an efficient filter.
From my experience and trial and error procedures, I've noticed that the best filter membrane, by far, for oil solutions is NYLON. You can also use PVDF, although you need to take into accountthe speed of which the different membranes can process your solution.
From what I"ve used, the PVDF membrane, especially in .22micron has a speed that is extremely exaggerated on many websites like the Whatman homepage. To me, using this filter with a GSO type solution is about as bad as watching the grass grow. That is my best description of how slow PVDF is in filtering in a .22micron size. .45 microns in PVDF allow for twice this speed, but it's likedoubling the speed of a turtle. It's still gonna be way too dam slow for myself.
As far as syringe filters, not bottle top or filter units, the best ones i've found are the "Whatman AutoVials." They're only available in 5 or 12 ml sizes, which sucks, but I'm still able to filter 50ml's of solution with these 12ml autovials in about 20 or 30 mins. If I wanna get it super clean I can filter 50mls twice in under an hour everytime. You can also still use these autovials with a caulk gun. Just have to use a lil improv. and put a vitamin lid at the end of the gun with a good sized washer to strengthen the area at the end of the autovial or syringe, where most of the pressure is being exerted on the unit.
I also think it helps to put either a 16 or 18 guage tip on the autovial because the end tip isn't exactly like a syringe and is a lil recessed inside the end of the unit where the end of the tip is flush with the bottom of the autovial. But like I was saying, it has taken me hours to filter 50mls of an oil solution with a PVDF filter. I ABSOLUTELY HATE THEM!!
PVDF is also supposed to be better at removing particulates than nylon is, but I've had solutions I've filtered once and twice with the PVDF and NYLON both and compared them after once and after twice and I think personally, the NYLON filtered solution always looks alot better. Even with a .45 micron NYLON after filtering twice, which still takes hardly no time, I have never had even one small particulate left in my final solution. I have had them several times w/ .22 micron PVDF though. Alot of ppl will advise you to filter your solution while it's still hot or at the least while warm.
With the autovials, your flow rates don't differ enough to notice whether hot or cold so I just mix all my ingredients, get whatever i'm making to the required melting point temp, keep this same temp for a period of 30mins or so, remove and let cool. As soon as it cools to room temp,I will then filter my stuff the 1st time. This will remove 75% or more of the things u don't want in your solution. I will then let that solution set. After it has set for a descent while, which is never over 24 hours. I will filter again. My final solution is always professional looking with nothing but good "crystal clear" liquid left.
At 1st I was worried the stuff that settles to the bottom when cool could be some of my prop or hormone, but after alot of research once you get your solution to the melting point and the whole solution clears and stays at this temp for a lil while, your BB/BA or solvent/co-solvents purpose is to keep this hormone suspended in the solution when it is cool so what your seeing settle, if done correctly, is not your desired hormone. It is your fillers/ binders/estrogen that is settling. If your solvents/co-solvents arent correct though, yoursolution can "crash" and then your hormone will settle and unsuspend from your solution and then would be filtered out. So make sure your ratios are correct and it'll come out great. ***PES*** is for water based solutions, not oil based solutions!! Don't try and filter your prop/enanthate/cypionate/deca etc..... oil based solutions through PES, it doesn't work. It will work for test suspension, but again test susp. is water based, so there ya go! I hope this helps some ppl just starting out and maybe having some trouble. Remember all this is only about "Syringe Filters" and not "Bottle-Top filters or Filter Units." They are somewhat different and require the use of a pump which creates a vacuum to pull your unfiltered solution through the filter. Although the same principles about diff. membranes would apply to these 2 diff. filter units, like nylon being really good for oil based solutions and PES just working for water bases ones.
If you don't know anything at all about different filters though, know that you have to also have a certain vacuum pump, whether mechanical or manual, to operate these things. Don't think you can just buy one of these, dump a large amount of ml/cc's in this thing and it will filter right through and be alot more efficent because they're really not that expensive, but the expensive part is the pump you have to have. I guess you could but you're going to be letting it set there and filter for one long long long time.