If the link-o-loon arch is completely free standing, I would suggest to fill the balloons with helium.
If it's possible to place the arch between the buffet table and the wall, you can use air and won't need a frame. Alternatively, you could attach the center of the arch with fishing line to the ceiling. This would also give it some stability.
Hi I was thinking of buying the link o loom balloons as I want to make a arch over the Buffett table do I have to use a frame or can I just use the link o loom balloons as I want to air fill them much appreciated