I have the opportunity to quote for a huge corporate birthday cake - they want it to be 36" x 16" in size.

I can't locate any cake tins that size here in Australia.  Do they exist?  If not, I have a 16"x12" sheet cake tin and can buy extras.

So, if I have to use 3 cakes side by side to get to the 36" wide - how do I "join these" so they don't move part once iced?  Does icing/ganache join sideways as well as it does vertically with my torte/layers?

I've also determined that I cannot buy lightweight cake cardboards or heavyweight cake masonite boards big enough, so will have to get hubby to make one up.

yes you just ice the sides and slide the cakes together -- it's going to be heavy and awkward so i hope hubby can help you deliver it too --

i'd still use two layers of foam core board and piece each layer together to get it the right size -- but 

i'd get the wide packing tape and piece together a foam core board to use for the base -- then i'd piece another one together in an opposite direction so the pieced boards are identical only in size and then securely tape the two together maybe use three even -- just depends on how secure it seems --

that's how i do it

i'd probably use some hot glue in there too

and yes just bake three cakes off -- no need to buy extra cake tins unless they make your life easier for other projects too

Thanks again K8memphis.  Once again you 'rock' when it comes to the cake advice!

I have made several cakes of similar size.  Check out my photos - one is on the 2nd page and the other on the 13th page.

K8 is right, but spread some icing on the edges where the cakes will butt together.  They will hold together just fine. Be sure to level the cakes AFTER you have it all together.

BUT.... I disagree w/her suggestion of using a double layer of foam board. I don't think that is going to be strong enough.   I think a wood board would be much better.  My husband cut me plywood boards.  Wash it well with bleach water, cover with foil or freezer wrap , then a plastic tablecloth or fondant.

But words of caution!!  Measure the doors you have to go thru.  BE SURE you can get a board that size thru them.  Remember the board has to be 38 to 40" X 20" so you have room for borders.    In my photos there is a picture of a safari cake - I had to deliver that to a private home and take it down to a basement on narrow steps YIKES!  We had to tilt the board with all those cakes and figures on it - I almost had a heart attack but nothing fell off. 

Thanks Kakeladi, I had thought of all the logistics except the door widths.  All OK at my end as I have french doors in the kitchen.  But must check that out the client's.  Awesome tip!  Thankyou.

I just made my daughters' school's birthday cakes - they were pretty enormous - rectangles about 40" by something?? - but I seem to have wiped the actual dimensions from my memory - it's probably like the trauma of childbirth, where your lack of memory means you will do it again!

actually, they were straight forward enough to do. I rented the biggest tin I could fit in my oven and baked 4 cakes to make one huge cake and torted and glued the whole thing together (including the internal edges/sides) with SMBC (12 litres of it!!) and then did it all again for the second cake. I put it on a hardwood board cut to size and then put the whole thing on a display board that had only the edges covered in fondant.

Biggest issue was that the cake wouldn't fit in my fridge and it was 40deg C here so I couldn't get the BC cold and firm enough to hot knife and make it really smooth. It really killed me, the cake looked terrible (in my opinion) but it was much loved. I ended up putting the cake in my bedroom overnight with A/C on Antarctic setting to get it cool enough to move - and I spent the night on the couch! The things we do for cakes....

LOL @Winniemog - my daughter and I both said to each other... wow, how many kids in your girl's class that she needed a 40" cake for her birthday to take to school.  Then we realised it was the SCHOOL that was having a birthday.  

Doh - my fridge is only 16" by 32"  I will have the same problem.  Antarctic setting here we come.

Oh yes there are only 18 girls in my daughter's class - but the school has about 1300 girls and then a few hundred staff! Let me put it this way - I had to put a carved mud cake in the shape of Uluru on top of this lower cake - and it didn't even cover 1/4 of the cake below!

I had thought of everything - I thought - door sizes, delivery assistants, even the size of my car - but I didn't think of the dimensions of my fridge and it was melbourne in February. I hope it's a wintry day for you!

And when I got that cake to school, they produced this enormous sword for the principal to cut the cake with - she had to use two hands just to lift the sword! Good to know the school fees are being used well....