||Get blow gun in B&Q to modify into a spray gun for use with 35mm film canisters, as shown in Kitplanes being sold by Wicks. Check measurements & alignment of Zip gun air & paint holes. Pop waste gel-coat off paper cups - weighs 7g in total, which is rather a lot of waste out of 33g mixed. Find instructions downloaded from a website ages ago for Ted Edwards' similar spray gun and print out for reference. Only tricky bits seem to be ensuring alignment of air & paint holes, and getting the paint cup at the bottom when the gun is screwed onto the blow gun in place of the supplied nozzle. The male thread on the nozzle is 1/4" BSP with an O-ring to seal. Notice that the whole of the rudder port surface has a slightly gritty feel now from the overspray, rather than the beautiful porcelain-like finish it had before.
||Rub down sprayed patches on rudder with 240 grit wet on ali channel. Seems to smooth up easily, much better than the brushed efforts. Main area of rudder returns to a good finish with a light rub over. After drying off, another look shows it still needs more work, and one patch on the root is still grinning through. Maybe not quite enough coverage there. Decide to leave further touch-ups until later (maybe with film-can gun when built) and try spraying starboard side of rudder. Rub off a few nibs of gel-coat that have run around the edges and wipe clean. Notice that the overspray has bounced up off the table onto the underside too, so mask off port side with polyethylene sheet to keep it clean. Support on mixing cups as before & degrease with acetone wipe. Check quantity of gel-coat used for other side of rudder; 100g enough for brushing, so much less should be needed or spraying. Mix 50g + 5g gel-coat; original bottle of hardener runs out here so have to decant last few grams rather messily from larger bottle that came with 5kg pack. Start to spray but very little seems to be coming out. Take out paint nozzle & check for blockages with #53 drill. Seems OK, but does go a bit better on re-assembly. Still relatively slow as spray pattern is quite small. Runs out with the side barely covered, so first guess was not far out. Decide to give it 4 coats as first one so meagre. Decant some hardener into the small dispenser bottle using a filler funnel. 2nd coat, 60g + 6g, seems to go much further. Some drips off the end of the gun where stray droplets collect land on the workpiece, making a bit of a mess. This and the slow pace make me think I'll risk using the good spray gun for the next coat. So, for coat 3, mix 60g + 6g and decant into gravity-feed gun cup. Difficult to get a good fan (probably because of high viscosity) and have to settle for a smaller circular pattern. Seems a bit faster to cover, but also looks more of an orange-peel effect. Gun needs quite a lot of acetone through it to clean it out. Return to Zip gun for 4th coat. Need to open 5kg drum of gel-coat resin now; stir & decant some into 1kg drum for easier handling. Mix 60g + 6g and spray on. Remember to wipe off the nose of the gun regularly to prevent drips. Rather less orange-peel effect, but it seems reluctant to pick up the last few drops in the cup, although it doesn't seem to be going off and stiffening up much. Maybe a larger paint hole would help. Plan to make up one in brass.
||Finally make and put up wall bracket on which to store DA sander. Remove battens from table and reposition for access to starboard side of rudder. Rub down gel-coat with 240 grit wet on ali channel. Some patches go through to filler. Start to turn up new zip-gun paint nozzle from 1/4" scrap brass.
||Finish making zip-gun nozzle with larger internal diameter. Start to draw up parts in CADintosh for
35mm film can spray gun.
||To save threadcutting work, get some M6x50mm full-thread brass screws from Moorhouse Fasteners.