Hey Chuck.... thanks for the comment!
I read a post in a leather (belts, holsters, etc) sewing forum that indicated that the Organ brand of needles have a longer scarf area.... better for timing the rotary hook to the needle on the wide zig-zag setting. I had some good Schmetz needles and compared them, not any difference in scarf length that I could see. Anyway, I purchased Organ brand's Titanium regular point, ten needles per size from 16 - 22 (Singer sizing) in 16x95 (1738A) Needle System, from 'Cleaner's Supply' at what I thought was a ridiculously low price. Everything they sell is at least half price compared to everyone else's prices it seems. Got a bunch of spare bobbins and some feet, too. They didn't have the PTFE thread, though. They are pronto on the spot, too... received the goods in two days!
I purchased the 8oz spool of Aruvo PTFE tex 90 (Denier 1350) thread from 'Jukie Junkies' for half the price that everone else wanted! I didn't then know that the DBx1 needle system changes it's shaft diameters between size 18 to 19. The 'cool-running' Organ needles that I ordered here, of 19 and 23 didn't fit my machine, having 2.0mm shafts instead of 1.62mm. Doh!
https://jukijunkies.com/aruvo-tex-90-ptfe-thread-black/
Yeah, I rigged up a super-simple 'table' system using two saw-horses, 4'x3' piece of 3/4" plywood I use as an outside work table, and a big tarp (four layers) laid over everything including part of the sewing machine bench. Maybe not as a low coefficient of friction as those white plastic tables, but it works well enough, plus it makes perfect sloped transitions so that the tramp material doesn't hang up on any corners.
I took apart the ol' clutched motor and cleaned and slightly roughened-up the cork clutch pad with a small bronze welding brush and sanded/buffed the steel clutch plate. It works so much better now. Not quite like a good servo, but good enough for now. If I merely make the clutch-control linkage attach a bit closer to the pivot of the foot peddle, I think it will be just about right.
I'm getting much better at helping feed the tramp with the feed-dog cycling rates, as long as I keep the incoming tramp material positioned something like a wave coming into the beach, and help it a bit behind the machine. It keeps you on your toes.
What PTFE thread brand and what size did you use? I was thinking of going with tex 135 (Denier 2000) Aruvo (same price) but I was concerned that the smaller bobbins of my machine wouldn't hold much of that thread. Though, when I got the tex 90 Aruvo, I was surprised at how much thinner it is compared to what I have in bonded polyester tex 90 thread.
Woo Hoo!
Another installment of progress on the Mystere 6.0 ....
Hard, sticky, time-consuming labor will continue until moral improves!
So. Both hulls' centerboard pivot indent were eroded by many years of use, beach sand, abuse, whatever.Â
Also, I'm guessing the method of molding the fiberglass centerboard well cases was by using a male mold with the forward edge a seam to pry the cured part (well case) apart to extract the male mold, then bond the forward parting edges together with bondo, gelcoat, and hopefully some fiberglass tape on the 'exterior' of the casing seam.Â
That casing seam had a few cracks as well as bondo failure near the cases' bottom pivot indent. So out came the media-blaster. Nothing like blasting sand all over the place. But it's pretty good at abrading surfaces and loosening chunks of gelcoat that are not adhered well.
The above pixs show the forward casing seam of the port hull after blasting first with 'play sand' which kept on clogging the blasting gun, then with silicon carbide 80 grit which flowed out of the gun like a full-automatic's shower of lead. Oh yes! Don't go super-cheap on blasting media.
You can see a possible faux pas at the bottom of the seam (2nd pix)... it was pretty deep.
So for those not familiar with Tornado and Mystere centerboard casings, the slots on either side of the internal casing is a track for the centerboard pivot pin. At the bottom of the slot resides a close-fit pivot indent so that the pin doesn't wiggle around too much. The blue painters' tape on both pix above cover up part of the pin track so that I didn't booger-up those tracks with epoxy goop. It's a bit tight in there as maneuvering room goes.
The above pix: after painting and smoothing first some neat epoxy, then thickened epoxy (high density filler), I layed-up three layers of 4 oz. crow's foot (4-harness) 'glass on the laminating table, then gingerly slid the assembly down the case seam. Then used a small paint brush taped on an extension (scrap piece of thin wood) to smooth everything down.Â
In the lamination process, I had a piece of plastic sheeting on the table with markings on it showing the width and length that the laminates where to be. Then whetted out each layer of 'glass on top of the sheeting, then added a top piece of clear plastic sheeting. Cut the whole sandwich with a sharp razor blade. Removed the bottom plastic sheeting, then applied the whole mess with a long,thin stick that I had taped the 'bottom' of the wet, goopy sandwich too. Slid the sandwich-stick down the case, aligned the sandwich to the seam, smoothed it all out with the extended paint brush, and BAM!! Done. After cure, the top sheeting came off easier than the blue tape did.
So the next job was to re-form the pivot pin indents at the bottom of the tracks. Both sides of the cases, both hulls. They were chewed up pretty badly.
I got ahead of my camera and ground out the left side of the pivot indent (right side in bottom pix) with a long-shaft pneumatic grinder with a carbide bit. Chased plenty of gelcoat/bondo cracks.
Above.... you can't get much more inexpensive and useful tools compared to the ol' Harbor Freight air tools. The air-valves on them are a little less accurate than a more expensive brand, but keep 'em oiled and they do just fine.
The next vid exemplifies the process of re-forming those pivot indents. Everything came out like I was envisioning. Yay.
Next, I want to make the centerboard slots on the bottom of the hull a bit tighter fit to the centerboards to the centerboards from knocking around and increasing their angle of incidence in relation to the hulls' centerlines, in effect reducing their angle of attack to oncoming water flow.
Gotta keep in mind that I also have to provide indents to the hulls' surface surrounding the centerboard slot so that I can add centerboard gaskets.
And no.... the trampoline re-stitching is not complete.
I tend to go bouncing around the workload just to keep my interest peaked. Though, I hate grinding gelcoat/'glass especially in this HOT weather. That's my next task.
Nasty.
Alright! It's hot Hot HOT outside, so I'm taking a bit of a break in the air conditioned comfort, just to provide you guys and gals with a little update on the Mystere refit....what a guy! 🤣Â
After re-molding the centerboards' pivot pin indents, I noticed (duh!) that there was a good bit of lateral slop between the centerboard and the well sides, allowing the angle of incidence of the board to vary quite a bit, and not in a good way as would be something like a well-designed tacking daggerboard.
What i measured is that the board would actually be at a lower angle of attack to the water's flow compared to that of the keel line. Just opposite of what is required for efficient windward performance. Or even downwind performance.
So the fix was to position the centerboard in the fully down position, grind the well/hull to allow for a proper angle of incidence, then fill the gaps between the board and well-bottom with thickened epoxy.Â
Test the incidence again....
Then position the board in an 'up' position, but without the pivot pin installed so that the board could be pushed down far enough past the bottom of the hull/well so that the thickest foil sections of the board would be right at the bottom-hull/well interface.Â
Then fill the resulting gaps with more epoxy....
Trim the cured epoxy so that the board can be raised and lowered without binding or drag....
And drink a cold, dark Guinness Stout on the deck. Ah!
Next job will be to vacuum-bag some style 1700 'glass/epoxy reinforcement to the keel line of each hull. Then fair and gelcoat just the 'glass repairs.... for now.... gotta get that cat into the water to race!
So... thinking about an appropriate name for the Mystere 6.0....
GRIMALKIN!
Perhaps 'Greymalkin'.... or 'Graymalkin'.... Shakespeare, Macbeth ya know.
Perfect for an old, gray catamaran.
Yeah, I know all about the infamous 1979 Fastnet race. But that boat survived to race a year later! Anyway....
Whadya think guys? Cat got your tongues? 🤣Â