I have a 10" dobs that I assembled and a second-hand 16" dobs that someone else threw together. The difference is obvious. The big problem I see is that the timber is laminated particle-board. This stuff is pretty water-proof on the faces but open at the ends. Over time moisture will get onto the ends and degrade the board. Also, screwing into the end of particle board is not very strong.
If you want a long-term solution try this: Dilute some PVA wood glue 50:50 with water and paint all cut edges. Let dry and repeat. Then paint with straight PVA wood glue. This will soak in, harden and strengthen the end of the timber. Then paint with two coats of exterior house paint - colour doesn't matter as it won't be seen. This will help seal the end of the timber. Assemble as per instructions or instinct (whichever is appropriate
). Finally run a bead of waterproof silastic around all joins. This will also help seal the timber and add strength to the joins. I did the job over about a week working perhaps 30 minutes (or less) a day. Mostly you are just waiting for things to dry. If you don't have the materials lying around (I did) they aren't expensive. Alternatively, most handy-people will have them in their workshop. Throw yourself on someone's mercy. I'd do it but I'm too far away.