Bring your own chair. If you own your own metal one. Grab a can of rustoleum and spray paint it white.

It will blend right in!

:)

I'm glad you came to the forum for advice. I have been many years a Wedding Planner (hubby is a photographer) been to many weddings and married into a large Italian family with four sis in laws that are total drama queens. My first advice is stop worrying about what has not happened yet. Absolutely you need to be at the wedding. And most of all don't give the bride any more things to put on her checklist in making her guests comfortable...especially being held at her aunts house. Doesn't matter if the place is large or small and intimate...you need to think on your feet. Seriously, no pun intended. Try to arrive slightly before most people would. If they say reception at 5:30 Be there five minutes earlier. Scope the place out and the chairs. If they are the white plastic garden chairs that I am imagining. They are one piece moulded and will not break. If the venue is outside check under the chair. Is it grass or uneven...Yama Yama. Then figure out if the seating has been prep landed or you just grab a place. No matter even planned seating usually gives you a table number but not the place setting. At any rate have your chair behind the table looking toward the middle, preferraby the perimeter. If you are worried still about the chair, quietly look for other types of chairs. If there are waiters, ask discretely to find you another chair. This you can do. It doesn't add drama to the event...you will be so pleased with yourself that you didn't make things difficult for the bride and you will enjoy the wedding. I have been 340 lbs, helping my husband with weddings and when he didn't need my help, I had to sit alone and strike up conversations. Believe me, some of those clear plastic chairs they rent and place at halls, look pretty intimidating. So trust me, don't worry ahead of time. Think when you get there. If it is an aunts house...there are other chairs there but you will not need them. If the bride is asking you to help her out with anything before the wedding, be there for her. Maybe she needs someone to make little centre pieces for the tables. Perfect, you can be there ahead of time, do one thing for the bride and scope out the place for your comfort. Does this make sense to you? I hope so. 

Thank you for this.  It really helped to put everything into perspective.  I do need to be there, and our friendship means so much more to me than my own ego.  I can only hope everything works out okay.

Like we always say to the bride....Everything will be wonderful. Glad you have a great friendship with the bride. She really needs you there. Just keep an eagle eye out for a comfortable chair. We don't want to bring attention to you. All eyes on the bride.

I'm not sure I would dare go without a folding chair of my own ... I would just put it ext to my car go inside and ask a waiter to go get t and set i up where you're assigned to sit.  It can be done very discreetly ... 

Definitely plan to go and have a great time ! I personally have broken a white plastic chair at 130 lbs ...they do get weakened over time and by the sun.   

I used to weigh far more than 400 lbs and I would always be honest.  People who'd have an issue with my weight and me sitting in a different chair would still have an issue if I was in the same chair as them, frankly.  I was upfront and would first thank them for inviting me to their special day, and ask if I could have a better chair for health reasons, and explain why if they asked.  Since it is your best friend, I am sure she will understand and be empathic.  It can be mortifying, but hang in there and remember what is important is spending time with your friend on her special day :)

I would have a back up chair in the car. I think a folding chair painted white is a great idea. You don't want to stand out... you want it to blend in. While I never broke a chair even at 400lbs, they were very uncomfortable to sit on, or I could only sit on the front edge. Depends on the chair. If you don't need it great, and if you need it, it is there....peace of mind.

Not only take your own chair, but if there are others going with you, take the same chair for them as well, so this way you won't feel singled out with the only one with a different chair...The important thing to remember is that you are there for the special occasion, so pop out your chair and enjoy yourself.

Hello to everyone *****sponded.  I'm not sure if this message will alert all of you.  But I just wanted to say thank you for all the help.  The wedding was this weekend, and a success.  I brought a back up chair in my truck, but didn't need it.  The plastic chairs held up.  My thighs on the other hand are still sore two days later from assuming the position in the chair.  But the point is that I got to be there, and I'm not sure I would have attended if you guys didn't give me the advice you did.  So thank you again!!!

Wonderful! :)