My question is can I iron on rubber backed curtaining before I sew the hem??

That would be a blind stitch but be aware that even blind stitches may still show. To be absolutely sure the stitches don't show, you may want to consider hand stitching the hem in place.

How To Sew Blind Hem Stitch

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Please follow the link. http://www.missbizibee.com/chic-living-on-a-budget-how-to-hem-curtains-yourself

If the needle is hitting something, make sure you have the machine set for straight stitch and the needle is in the center position. If it is still hitting and breaking, then the machine is out of adjustment and needs to be repaired.

Probably depends on the fabric and the look you want. You can use a blind hem stitch if you don't want the stitch to show from the front of the fabric, or you can use a simple straight stitch or possible use a twin needle (if you machine accommodates it).

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well aside from trying all the normal things like thread tension adjustments and such , another neet little method is to use a flat piece of thin tissue paper (sew right thru it ) layed over fabric , this will add the stiffness to fabric u may need to complete this task, then very slow and carefull tear the paper away from it to leave the threads behind!! if you think you can get away with it use tissue paper on back side and leave it there , hey holds a hem and pleats real nice !!

Try ironing the hem in place first and then loosen the bottom plate tension. Does sound like a tension issue though

I don't think so, the D in your model name would denote that it has Differential feeding but is probably a 3/4 Marrowing stitch only. So this means it would do 3 thread overlock, 4 thread overlock and you can probably set it up for rolled hemming too.

Coverstitch is fairly new to home sergers and is available on some machines along with the 3 and 4 thread stitches, but changing between the regular overlock and a coverstitch takes a few minutes. The model number will usually have a "C" in the name. Also, during coverstitch the blades are disenaged and don't trim your fabric so you still need often to go back with blunt scissors and trim the raw edge.

And sewing coverstitch can be finicky, with skipped stitches a problem. Use high quality thread and XL (extra long) or SUX (stretch extra long) needles to avoid this.

However some manufacturers are now making dedicated coverstitch machines; if you are assembling a garment with your regular serger, you can then just move over to the coverstitch machine to sew the hems and necklines and not spend 20 mins changing over your machine's functions. Much more productive.

You may wish to check out the Brother 2340CV, this is their dedicated domestic coverstitch machine. Link to product info is http://www.brother-usa.com/homesewing/ModelDetail.aspx?ProductID=2340CV

In the meantime, best solution is a twin needle to stitch the hem from the right side of the garment on your regular sewing machine, looks much the same, and you can get twin needles with a 4mm or 2.2 mm gap and in stretch and sharp tips for less than $10 each. Just iron up the hem about 1.5cm deep, and thread up your sewing machine with the twin needle and two spools of same colour on top (I just wind an extra bobbin and use this plus the original thread spool rather than buy two spools).

Just sew really slow as the twin needle builds up a lot of heat and will break if you push it along. I use this finish on all my knit garments and it works just fine. Sometimes I'll iron in a 2cm strip of fusible web inside the hem to give it some firmness in a neckline, then twin needle stitch at about 1.7 from the folded edge.

Hope this answers your question.

bunching up on the bottom means that there is no upper tension...

You can find some instructions on a narrow double hem at http://www.sewjanetmoville.co.uk/content/learning/viewArticle.asp?lcArticleCategoryID=0&lcArticleID=3&pgid=learningCentre. Instead of machine sewing it, use a hand slip stitch as seen here: http://www.hutchal.clara.net/curtains/sewguide.htm.

You can find more info on these techniques at http://www.repair-home.com/how_to_sew_repairs.html

Hope this helps! Let me know if you need more info.

Your machine cannot do a cover stitch. Check the Brother website, they make a cover stitch only machine, it works much better than any of the serger/cover stitch combination machines, and it is a lot less money.