I had a Slimline pitts on a YS 140 that had broken pipes right where yours did and used J&B Weld to fix it several times. It didn't take long for the J&B to give up the ghost. You can try aluminum brazing rod with a propane or mapp torch to fix it. Sears and some hardware stores sell it. I've even seen it at Home Depot. Other than that you just have to buy a new one. Next time cut the exhaust pipes shorter and use silicone extensions to get the gases out.

Good Luck

Big Mike