Does anyone know how long preservatives can extend the shelf life of soaps for?

I'm looking in to CP soap making and i really don't want to use any preservatives, but I just wanted to know if there was any significant difference when making with or without preservatives.

Any info will be appreciated as i am completely new to this, have only got as far as researching!

I made this for my boyfriend for his birthday 



I followed this recipe here and added the juice of another lemon to the icing as the comments on that website said the icing wasn't zingy enough.
Unfortunately the icing wasn't thick enough so it all soaked into the cake and it looked like I hadn't iced it, so I got my mum to put a thicker lemon drizzle on the top to decorate it as I didn't want to cover the whole thing in icing again and make it too sweet. The icing reminds me of those naughty cupcakes that were posted on here some time last year  I can't find the post for them at the moment but I'm sure some of you will know what I'm talking about!

I didn't actually try any of the cake as i got distracted by the chocolate cake his mum had bought, but everyone said it was really nice and it all went straight away.. go me!

(it's not just sitting on my kitchen worktop by the way, it was on a really small board at this point so i could fit it in a box to keep it fresh!)

I'm new to this whole sewing thing and am currently trying to make a wallet/purse.
I went to the fabric shop and picked out what i wanted, and the lady there told me that the fabric i'd chosen would be too flimsy for a wallet. So she gave me this,



she told me to iron it on and showed me which side etc and told me how it worked, but i've just tried it at home and i can't seem to get my fabric to stick to it.

I came on craftster and searched google, and have been looking for a while but i can't find anything that has worked.
I've tried to iron it on both sides of the fabric, turned the interfacing over and tried the other side, adjusted the heat on my iron (which burnt my ironing board cover, but did nothing else), soaked it in water and dried it before using (i found that suggestion on another site)..
..but nothing seems to be working.
this is my day off work and i really wanted to get some of it done today but i can't seem to figure out where i'm going wrong  .

I rang the shop I bought it from but I'm assuming theyre shut today as they're not answering.

Any help would be greatly appreciated.

This is my FIRST COMPLETED PROJECT (YAY!).. So yeah, I’m pretty excited I actually got this done so there are a ton of pictures and a huge story ahead.
I’ve obviously never done this before, so if the pictures are too big or anything needs changing in my post please let me know.

Anyway, I decided it was time for a new hoodie, but seeing as I’m incredibly poor at the moment I decided it would be in my best interests to buy some cheap material and do it myself. I headed off to the fabric shop not knowing what to get, then I stumbled across this gorgeous unicorn and rainbow fabric.



I decided not to get it as it was too expensive (£8 per meter).. Carried on walking around the shop and found some polka dot fabric, then as I made my way to the counter I realised I didn’t want the polka dot fabric and couldn’t leave the shop without the unicorn fabric.
So I ended up buying;
2 meters of unicorn fabric
2 meters of white/cream fleece
a long white zipper (which I later found was a reversible one)
½ meter of white ribbing/cuffing (whatever it‘s called)
a box of pins (that’s how new I am to this)

I ended up spending £30.. So much for my cheap hoodie  .

So anyway, I went home and started to plan it out.. I put an old hoodie on the floor and traced around the pieces on to tracing paper to figure out how it all went together and what changes I needed to make etc..
I cut out 2 sets of tracing paper pieces.. One set I left to the side, the other I sellotaped together and put on to see if it fit. It ended up looking a bit boxy as it was paper but I knew it would fit so I carried on cutting out the fabric. I changed the shape of the hood as I didn’t like the 2 piece flat hood (if you know what I mean). I had to make 3 different paper hoods to find one I actually liked.

ANYWAY.. One day as I was sorting out pieces for the hoodie, it started raining (living in London and all).. And it suddenly clicked that THE HOODIE WOULDN’T BE WATERPROOF.
So the next day I went to Argos and bought a £4.99 plain shower curtain.. CUT OUT THOSE PIECES.. Then I sewed all of those pieces together then ran it under the tap in the bathroom and it was indeed waterproof..

So I sewed every layer, the unicorn layer, the shower curtain layer and the fleece layer.. Then fixed them all together..

And Voila..



And the back..



A big thank you to my lovely brother Lloyd for putting his reputation at risk and modelling for me! 

Anyway, going back to the reversible zip business.. COMPLETELY UNINTENTIONAL, but the hoodie would also be reversible had I not done this;



I got so stuck on how to attach the zip I ended up messing it up at the bottom but I’m not going to wear it that way so it kinda doesn’t matter.
But it would have looked like this;



This was a couple of days after the making (hence the loss of Lloyd‘s hair and CLOTHES!.. Tut tut)



I made him put a t-shirt on for this one so his niplets weren’t on display.

The only sort of visible stitching is on the hood which was the last bit I sewed up,




SOOOOO.. I’m really pleased with how this turned out.. The sleeves look a little short but they fit me fine so I’m not fussed about the pictures. Any comments/criticism/correction of terminology would be wonderful