Thread & needle advice please?

[WildAtlanticWay]

I really am a beginner so please be gentle with me. 

I’m attempting to repair DS’s lunch bag and it has a thin plasticy (?) outer cover with a metallic insulated lining. One seam was completely ripped so I’ve cut it all open at the seams and plan to re-sew it with a fold over top.
However, I’m wondering if I can just use ordinary gütermann polyester thread? 
And what type of needle?
I’m thinking a universal needle size 14.

All advice gratefully received.

[Holly Berry]

Gutermann thread will be fine. 80/12 or 90/14 depending on the thickness of the layers.  I’ve just looked oil cloth up on the schmetz app and it suggests either universal or microtex needle.

Personally I tend to use microtex for most fabrics, including jersey and haven’t had a problem.

The Shmetz app is free to download and is very useful for identifying which needles to use.

[Ohsewsimple]

No reason why you can’t use gutermann poly thread.  As for needles, I would use a microtex or sharps....same thing, different name depending on brand.  They are very sharp and if I have problem fabric, they are my  go to needle. If it’s plastic you are sewing, you might need some tissue paper over it to stop it sticking to the bed of the machine or the presser foot. 

No problem being a beginner.  We all were at one time.