Here is a cheap, clean and very professional way to make glue fillets. You will be working in a bent over awkward position so the more control you have of the epoxy the better your work will be. Remember the cleaner your joints are, the less clean up, sanding and "fixing" you need to do. The next layer of fillet will go down better too. To glue joints, such as the bulkhead to hullsides, you need to get the glue fully into the seam. This is critical. You want no dry joints as they are a weak point. This will be virtually impossible with a tongue depressor stick or a plastic knife. Many epoxy manufacturers will sell you plastic syringes for this purpose. These are fine for small gluing tasks but they get expensive! Instead try a plastic bag, any kind will work though I use 'ziplocks'. The gluing epoxy I am using is from System Three. I'm using Gelmagic, which when mixed has the consistency of vaseline. It is hard to spread cleanly but it's great as it has no sag. After mixing up the appropriate size batch, transfer it to the bag and when you are ready clip a corner of the bag with wire cutters. They do a cleaner job than scissors. Now you can squeeze the glue out the hole like you are icing a cake. Unlike a syringe, you have better control over the size of the fillet as you can clip the corner to a size that matches the fillet you want. If you pre-tape the joint (I did one side only but two sides would be better and will tape both sides in the future) you can fair the joint, as necessary after having spread all the glue without worrying about the glue that flows beyond fairing tool.