Can I repair speaker foam?

I got an old pair of Polk Audio speakers and a mid range speaker foam has a 3/8's tear. Can I glue it or make some kind of repair?
Do the following 2 things.

1) do not use the speakers, as this may cause further tearing of the foam, and then has the potential of causing the voice coil to rub against the inside slot of the magnet. Once that happens you then need a full re-cone, and
that is when things get espensive.

2) remove both midranges, and call Millersound in PA, ask for Bill. Do web search, or look at Mail the pair of drivers to them. You will have speakers that perform like new.

I'm not affiliated with Millersound, but I have had numerous drivers repaired by them (different sizes, different manufacturers). I have friends that have been very happy with both the price, and the quality of the work.

It sounds like you caught this early enough.
It depends on the quality of the speaker - check with polk. I went through my manufacturer and have had drivers re-coned a couple of times (simple procedure common in high end gear - studios, for example, damage speakers regularly, transport, dropped microphone, incorrect patch panel setting etc.).

For lower end stuff it is cheaper just to replace the entire driver or speaker as the drivers are not worth much and labor is costly.

I would not recommend you go through a third party unless they are approved by Polk. Neither would I recommend you mess with this yourself....the interface between cone and rubber/foam surround is a significant source of distortion in most to get it done right or replace the driver altogether.
You can try a little tape on the back side, but I would bring it in to a shop and have them put a new surround on.
Better to have a professional refoam them with new foam. Not sure where glue will get you. Have both pairs done while you're at it.
Refoam them yourself. It's inexpensive ($25 for a pair) and easy. I've refoamed 2 sets of speakers myself with no problems.
I can second Millersound.
Go on eBay under Polk and buy the refoaming kit. I did it myself so I am sure you can do it as well. It just takes some time and effort. Good luck.
i take it that you dont want to replace the damaged speaker or send it off for a refoam job,you can buy a product called (vulkem)that will repair the tear,vulkem is a polyurathene sealent that comes in a standard sized caulking tube & it can be bought at most professional glass shops that sell high performance sealents,if your local glass shop dont have vulkem then ask for (sikaflex 1a) which is also a butyl based sealent that dries flexible.

both products should cost less than a $5 spot & they both come in colors that will half ass match your surround.
Refoaming a speaker is easy.
Just make certain the cone is centered and it is a snap.
Total klutzs need to have someone else do it.
First find out how much is the whole driver or speaker.
Maybe it's not worth to put effort towards there man!
Replacing the speaker instead of refoaming is usually a bad idea.
The new speaker has (unless identical from the same manufacturer with the same parameters) will have a different sound.
Every speaker has various parameters for impedence, proper enclosure size, rolloff..etc. no two different brand, model speakers are anywhere near the same!
Teh more I look at speakers and the idea of building my own it is really really hard to do. replacing a speaker in a loudspeaker cabinet is more than just getting the right size to fit the opening!
Replace the foam....