Got a Eunos a while back. 91 BRG, RHD, auto, 45k original miles, straight and unabused.

Started with the basics, tune up, general maintenance:




Had to dremel my thick walled 'Murican spark plug socket to fit my tiny asian car.

Ordered new hoses as part of the refresh. Wanted white, got yellow. I hate yellow. Rather than ship them back to carbonmiata in china I got some silicone mold making material and added paint. I was going for tiffany blue, I got like a robin's egg kind of shade.






They now look like *** because oil and dirt love silicon for some reason, but they keep air in and **** out, so idgaf anymore. Pulled the charcoal canister at the same time and routed the lines back to themselves.

Wheels and tires came next, Enkei RPF1s 15x7 on 195something Dunlop Direzza DZ102's
Also put on my MOMO Prototipo at some point

 

Replaced the headlight housings with Cibie H4's and sylvania silverstar bulbs, much better visibility was attained.

 

Picked up a new diff to replace my 1.6 glass POS.




Mentioned a P/S delete to the guy, who referred me to Bob Bundy, a local Miata gent who knows his ****. Called him up and schedule the P/S delete with him.




It just wants a hug






Also pulled the A/C and anything else I could pull out without breaking things.

 

Bought brakes and accompanying thingies, some bushings for the diff, other stuff...



Pimped my diff that nobody is going to see, probably the prettiest part on my car now...



Called Bob up, scheduled another weekend to work with him, did the diff, axles, driveshaft, brakes, rear hubs, probably other things I cant remember and don't have pictures of...






Kind of weird how a 12 hour day of busting the **** out of my knuckles can be summed up in two pictures...
Centric Rotors
R6 pads (bad ******* idea)
Lines from whoever I ordered this all from, probably 949/supermiata
ARP 7077(?) studs which are actually for mitsubishi or something, check the "have you replaced your rear hubs lately" thread for info, towards the end (if I figure out how to link and remember and care I'll come link this)
Motul RBF 600 for the brakes
Redline for the Diff
Did an oil change too, Royal purple and K&N filter

The pads were the screechiest god damn pads on the planet and whoever I ordered them from did not in any way indicate that, I had to go to the manufacturer website to find out this bullshit. Replaced them with whatever autozone's top tier is, they still had better bite with the new rotors and stainless lines. As far as braking goes, the R6 were great, perfect modulation, nice pedal feel, exactly how brakes should feel. Maybe if I was a little more deaf I could have kept them.

Did not replace the driveshaft bolts with OEM bolts, went to the hardware store and picked up some grade 10 with nuts and lock washers. They hold together fine, but I get this weird 2-5 clicks from underneath the car anytime I accelerate from a stop, no other issues. I assume it's a slight difference in the diameter of the hole and the diameter of the bolts, and the driveshaft just loads slightly every time. Probably not great, but my 90ish hp isn't bending anything anytime soon (or torque, whatever number that may be)

 

Started putting together parts to turbo the car, put that on hiatus and then subsequently sold them because I thought a baby was on the way. Considered selling the car, got some garbage trade offers from CL and a flame war here, so I kept it.



MS3 from Rev
AEM Uego

 

Then I decided I needed a project that would destroy my savings and make me consider setting my house on fire, so I built a fastback hardtop from scratch with no experience in materials engineering, aerodynamics, molding, or fiberglass. I had also never seen any sort of hardtop on a miata in person, and had no idea how they attached except that there was a silly bolt.

At this point I'll let you go find whichever meme you find appropriate...


My first idea was to mock it up with cardboard and maybe even build some sort of cardboard frame which I could fill with foam and use as the plug for the mold. That was dumb.




Then I watched some more youtube videos about how fiberglass works and took notes.

Stripped some of the interior and took the soft top off



I started building a structure to support stuff, but I wasn't really sure where I was going with it or what it would support, I just knew I would need it.




I started running some lines to get an idea of the shape. This was a waste of time honestly.







Kept building the platform to support whatever it was I was going to do.



Finished that and sealed it all up (poorly), masked some stuff off.




And then things got janky af because I started using spray foam to make car parts, and we've all seen the horrendous pictures of how that works out...







Masked more and made it into a fastback

 

Kept foaming to create a basic shape, then...

That reminds me, the only thing I used to shape was a pocket knife, so keep that in consideration while you're passing judgement...




I tried to sand it which worked very poorly, but did smooth it a bit... which I guess is what sanding is supposed to do now that I think of it...




Ran a string down the centerline to try and make things symmetric. It didn't really work that great, but then I figured that a 200lb driver sitting on one side of the car would make the car more off balance than slight irregularities in the hardtop, so I said **** it.



I kept wasting time on the rear window which was dumb since I was just going to cut it out of the final fiberglass anyway and I couldn't mold around it. I bumped it out to keep it at the same level as the foam 3 times and finally just foamed over it much later when I was already laying other **** down.



the sides started pulling away from the car as the foam dried more over time, so they had to be secured in place, ran some 6" bolts into the support structure to keep them down and in place.



did some trig when I thought I was being slick measuring things to make it symmetrical



The final can of foam. This was a big moment for my sanity.



It went to build this ducktail lots of you will hate. (this caused untold amounts of complication for the mold. Apparently sharp corners like this and molds don't work together well.)




The foaming process goes like this:
add some foam into a basic shape
cut the foam into a more complex shape
check if that shape is what you want
if not, either cut more or foam more
woops you cut too much, add more foam
you added another 3 cans of foam but probably only needed 1, cut more off
is it symetrical?
no, add foam to the small side or cut the tall side
rinse and repeat...

 

After the foam comes the drywall patching compound. The green lidded bullshit has a 24 hour dry time at 75 degrees. Meanwhile here in Washington state, our early summer is running in the 50's. So it took 5 days to dry and wasn't quite done when I laid other **** over it.






Over that I used basic *** plaster of paris which greatly simplified my life. Also the exothermic reaction created enough heat to finish drying the drywall patching compound.




Filled the rear window



Figured out part of my mounting solution. Grade 8 eyebolts in whatever thread pitch and diameter the frankenstein bolts are.



Started designing windows for no reason since I couldn't use the drawings since they would be further covered, and I couldn't make them part of the mold.



Started sanding, so I painted in contrasting colors to see where my valleys and hills were. Also filled most stuff with drydex, which was amazing because it dried in like 3 hours and sanded like a breeze.






Ducktail glamour shot because I was enjoying the **** out of these curves



After a few weeks we arrived at this point, which is the final stop before the trainwreck that is fiberglass laying for beginners. This is the cheapest latex house paint home depot offers. I should have tinted it something other than white because the plaster under it was white, it is white, and the fiberglass gel coat is white, so I had no idea where I had enough coverage and where I had gaps. This matters for reasons that you will see later.

 

I started precutting my fiberglass so it would be easier when it came time to resin it down.







Then the PVA mold release (green stuff), this in theory creates a layer between the plug (what I just built) and the mold (the fiberglass I'm laying). It didn't work for **** either time I used it, I may have done something wrong though because I have no idea what the **** I'm doing.



Let that dry for a bit, then lay the gelcoat down



fiberglass down mostly:




some support pieces that made no difference whatsoever in the rigidity of the mold:



Pulled everything off, which required me to wiggle my way inside the car through all of the support pieces, lay down, and leg press it off the car while my assistant wiggled the stuck *** end. It cracked a bit at the high stress corners, but came out fully useable. This all should have been done on a wrecked donor car because my paint is so fucked now, and everything is and will be covered in small pieces of foam, fiberglass dust, and other debris.



And voila, hardtop mold (after 3 hours of chipping out plaster, pulling out foam, and sawzalling out wood, plus lots of water because the PVA mold release is water soluble, and plaster weakens)

 

A couple important points for interested parties:

Fiberglass is actually cheap as ****. A light weight chopped strand mat is like $1.70 a yard, a nice S2 glass which is what I made the actual top out of (mostly) is still only like $11 a yard. You'll need 10-15 yards depending on the width and weight.

Epoxy resin is about on par with beluga caviar. Polyester resin is cheaper but brittle like the fiberglass you always hear horror stories about. Epoxy resin is impact resistant and more chemical and UV resistant. However a general purpose 1:1 Epoxy Resin costs about $200 a gallon, and you'll need 2 to 2.5 gallons. A nicer marine grade epoxy resin with a variable time hardener costs more like $250 per gallon.

Buy more rollers and mixing buckets than you think. You can mix maybe 3 or 4 batches on one mixing bucket in one sitting before the leftovers start making the new stuff kick off too fast. Rollers last about 1 layer of fiberglass before they get clogged and stop rolling and start pulling the fiberglass (bad)

DO NOT try to lay hot nearly gelled resin. It will hit the glass, gel faster, not penetrate, and you'll end up with a big ******* mess that you have to wait 24 hours to dry, spend hours sanding down, and then continue laying glass.

Don't get slick with the ratios, do what the bottle tells you. Put too much hardener into the epoxy and you can literally make it catch fire.

Chopped strand mat takes about twice the resin to saturate it as woven cloth like the S2 because there are more voids to fill. This sucks *** for a few reasons:
CSM is omni-directional meaning while the overall strength is somewhat low, it is strong in all directions whereas woven cloth is bi-directional, meaning it is strong front to back and side to side.
CSM doesn't print it's pattern through gelcoat like woven cloth does, leading to a nice exterior finish.
CSM is about 1/5th of the price of woven, and is great for bulking up parts that need thickness and rigidity.
Resin is stupid god damn expensive.

That said, cloth is much easier to work with because it lays more nicely into the mold, cuts more easily, you don't get hairballs when you use the roller, and it takes less resin which means you save money.

 

test fitted it on the car:



Interior clearance:


For reference, I'm 6'3", I constantly tapped my head on the soft top frame.




made a ghetto frame to keep the mold in the proper shape while I was laying the hardtop




Prepped the pieces to lay the actual hardtop. This was 4.5oz CSM on the exterior, 2 layers of S2 glass, some core mat in certain spots for rigidity, and another layer of s2 glass. The mounting pieces were laid on top of the CSM and under the S2 glass. The front mount is the soft top front mount cut off of the soft top and chopped up to drop the weight and give more grip to bond with the resin. Also laid fiberglass tape around the edges for strength and in x patterns on the main roof, and the curve of the ducktail.



I fucked up and laid too hot of a batch on top of the main core mat, so I had to wait, sand it, and continue later. I also ran out of resin for the second time.



Spent some time sanding my mistakes away before laying the final couple of layers. Had to sand the entire thing because once it has cured new resin doesn't like to adhere and the layers will delaminate.



Picked up a new slap and continued the inevitable process of ruining my car.




Had a bitch of a time getting this thing apart, took the better part of 3 hours just like the original.



Got them apart, spent some time cleaning them up. Which reminds me, one of the sides of the mold was too short next to the window, so I made due and cut up some plastic sheeting and taped it in place, hoping it would be taut enough to keep the fiberglass in position and fill the gap. It didn't. the gap is filled, but it's all warped and curved on that side.




Got it on the car though, trimmed pieces a bit, used some garbage home depot weatherstripping as a seal while I worked on my mounting solutions.




Side mounts, which are by far the strongest of the 3, and the least likely to fail. 1/8th inch mild steel bar, hammered into shape and drilled, bolts, big washers to spread the force, lock washers to keep them in place through vibrations




Rear mounts. Eyebolts thread into the frankenstein bolt holes, on the top there is a drilled galvanized steel plate with a T nut sandwiched into the fiberglass, and another set of eyebolts threads into that, they are connected on opposite sides by cables with a tensioner in the middle. This setup didn't last. The ferrules that clamp the cable onto itself need a special tool called a swaging tool. They cost 250 bucks or so. The internet said I could get away with a hammer and dull chisel, or a vise to crimp them down. I did both. I was tensioning one of the sets and the ferrule failed and I got whipped in the face with high tension cable. Not a fan. I was thinking of another solution when my army side came out and I'm not using 550 cord. They eyebolts are only rated for like 220kg (500 something) each, 550 cord is rated for 550 lbs obviously assuming you have the real stuff and not the pretty **** you buy on tactical websites. SO, I figured I didn't need 1000lb test cable when the eyebolts wouldn't handle those loads anyway. Same setup is currently in place, including the tensioners, just with 550 instead of cable. it's holding better and not slipping thus far, which is more than can be said for the cables.







So the leading edge delaminated from the front mount in a couple places which is obviously the kind of issue that leads to catastrophic failures and liability claims. So I got fancy and riveted it in place.



It was looking like smashed ***, so I decided to paint it for now. I call this particular shade "good enough". It's flat black high temp grill paint sprayed by an autistic monkey.







And now you have arrived at wherever the **** I am now until I make another update. Have a nice day, and please be merciful.

 

A couple thoughts:

I stopped here because I'm broke as **** now. In the future: the entire things will get stripped down and fixed up, the exterior will be reglassed, the interior will receive more reinforcement as well. Currently there is a large gap between the vertical portion of the windows and the hardtop, I'm going to chop the bottom edge of the top and remake the mounts to have the top closer in line to the windows. I need to figure out a solution for window weatherstripping, though so far rain storms haven't gotten in even with the windows cracked. The windows need to be cracked to open the doors because the glass will hit the top, so the top needs to be trimmed when I figure out the weatherstripping solution. It needs a rear window definitely, and side windows maybe, so I need to get the polycarbonate custom cut, mounting hardware, reinforcement, more glass around the edges to handle the drilling and flexing, etc... At some point I would like to line the inside with dynamat, or its cheaper summit racing counterpart, and maybe even do a headliner (crazy, I know).

If anyone in the Seattle area wants a Jank *** hardtop (copyright-ish), I can churn out another one for like $750 ($500 materials, $250 working fiberglass sucks ***), and I'll sell the mold for $1500

 

This is quite an ambitious project. Fiberglass does suck, huh? Cold showers make the itching stop!

I suggest using some sort of flat bar (steel or aluminum) molded into the top to secure the Windows and weather stripping. So long as it's malleable I think you'll have any easier time getting a consistent edge.

Looking forward to seeing your progress. Wish I was closer as I've wanted to do something similar.

 

I don't care for the fast back top, but I won't deny the amount of work and effort you put in to it. Good job.

 

Jonbmet: It was definitely fueled by inexperience, but it was a great learning experience to jump in head first. I eventually got around to picking up a pair of tyvek coveralls which helped a lot.
That was my plan too, I'm thinking polycarbonate on the exterior, with maybe an inch and a half of overhang, then the fiberglass, which I will reinforce in the local area with more coremat surrounding it and fiberglass tape right along the edge. Then on the interior an aluminum square backer. weatherstripping adhesive between the fiberglass and the polycarbonate. I'm more worried about the mounting hardware being expensive as ****. I'm thinking I'll just rivet it.
If I were going to do it again, I would lay a single layer of glass every day, or maybe every 12 hours. I think that would have prevented a lot of the ripples and bubbles that were caused by rushing to lay more glass before my resin cooked off and not spending enough time squeegeeing it down.

That reminds me, it cost me about 1500 total to build the plug, make the mold, and make the final top. I have tons of glass leftover, and a fair amount of all other materials I bought except for resin.
It's easily doable in your garage at home, plan about a month total to do it right, maybe less if you know what you're doing and don't go off on tangents. I did spend 5 days just waiting on one portion to dry...


Shuiend: You and me both at this point. Thank you

 

Hardware should be pretty cheap. If you aren't dead set on rivets I'd get some hardware from www.mcmaster.com. I'd use hex drive button head cap screws. Are you're planning to use lexan?

 

.

 

Same boat. I think it looks like doo doo but i build and **** **** up all the time for the sake of learning so right on.

Different, Entertaining. Would read again.

 

Would you be willing to build me a boat? It needs to be strong enough to get my family from Havana to Miami only once. I don't have much money but would be willing to do yard work for a couple of years. LMK.

 

Jonbmet: Those look pretty perfect, though I may go with the flanged version to spread out the force on the polycarb.
Yep, it's more impact resistant than acrylic, so even though it scratches more easily, I'd rather have a scratched up rear window than a broken rear window.

Art: Thanks man

Krissetsfire: I'm nothing if not entertaining

Six: **** yeah, a boat would be cake after this. I'll even throw in my 1.6 so you don't have to paddle. It would probably take longer than paddling, but you could relax in the sunshine!