Last night, I finished the resin/tissue coat on the sixth and final tube. Nearly had a disaster with it as it started to come apart and I only noticed 30 minutes into the cure. I got it *just* in the nick of time and patched it back together. They are not as structurally sound as they will be with the external rings to fully hold the form. They're going to take some sanding, though...

I got some cheap "matt" black spray paint from the £1 shop and sprayed the inside of one tube but it's very reflective. I'll try the very old matt blackboard paint I have and see if that's better. The red is £1-shop tile/paving paint. It spreads on lovely with a kitchen sponge (pack of £20 from the £1-shop).

The external ring took a bit of hand-rasping to fit and I skewed a couple of pins out the back but after flooding the slight gaps and letting it cure, it seems sound. The ones on either end of the middle tube are going to have to be as solid as possible. I may use a few pins to tack it in place and then pop in some 1/2" or 5/8" screws from the inside. Then flood with resin. I'll go round the inside mating surface at least 2 or 3 times with resin and let it soak into the MDF end-grain.

Need to get a wriggle on with designing and building the mirror cell, secondary mount and focuser so I can get these tubes assembled, weighed in order to start cutting and fitting trusses. Then it will start looking more like a telescope. With the added weight of the paint and extra resin that the MDF soaks up, I'm upping the estimate to 12kg for each OTA.