Fitting stack sections

[LMP Maple]

So I went to run my 7" stack through the tin roof in my new sugar house last weekend. The roof jack went well. When I ran the pipe and tried to connect two sections together I could not get them to fit. This was the pipe given to me with the arch from the dealer. I tried everything I could think of with no luck. I then put a few small slits in the male end thinking that would help, frustrated at that point no luck. Any tips? I thought about a little heat but that may make things worse. Thank you

[maple flats]

I assume you are trying to put the crimp end into the non crimp end of each section. The crimped end should always point down. If a crimped end will not fit, it might need more crimp. Heating contractors have a hand tool which crimps new crimps or makes existing crimps deeper to shrink that small end. You can also do it with 2 pair of good needle nose pliers. Simply hold a tigh grip on 2 adjacent folds and bend it farther than it is now. This can be time consuming but can be done. You might try doing that on about every third crimp, if it still will not go, do the adjacent crimp to the ones you already did.
Those crimps make the pipe smaller, eventually it will go. By the way, Home Depot and Lowes carry crimping tools. I use a 5 blade tool, I think they carry a 3 blade (one blade on each side with one in between forcing the metal to crimp as you close the handles. Here's a link for what lowes has: www.lowes.com/pd/Stanley-FATMAX-2-5-in-60CrV-Snips/50201625?cm_mmc=SCE_PLA-_-ToolsAndHardware-_-UtilityKnives-_-50201625:Stanley&CAWELAID=&kpid=50201625&CAGPSPN=pla&store_code=2289&k_clickID=go_625706834_34613745430_111132553630_au d-431535000460:pla-201942063204_c_9005246&gclid=Cj0KCQiAxNnfBRDwARIsAJlH29DRu-UnJruztG5pI_ppAIyYT4KclAoTmJSi5V6b41zp1IXR1ZlxIQka AkHwEALw_wcB

[LMP Maple]

Thank you, I will give that a try and see if I can get it to go. Thanks again.