Renovating and Modifying a Mares Mirage

[Diving Gecko]

Hi David,

The OD of the shaft tang on an 8mm shaft is 9mm and it's 8mm on a 7mm shaft. You will only be able to use nude shafts if you replace it with the above SS washer.

The length of the outer barrel and the pre-loading barrel fit each other. So you have to make the outer barrel the thickness of the Delrin washer longer if you add an extra Delrin washer.
Next thing is if the Delrin washer will be deformed due to the pressure.

Is the pre-loading piston the metal or the Nylon version? You could consider to "reshape" the top of it - if it's because it's top edges have become a little rounded or conical...
The OD of the pre-loading piston is 10mm (as I recall).

Edit: just a thought: Have you tried if the pre-loading piston can pas all the way through the opening of the pre-loading barrel - it might be that the thin end (reduced diameter for the "O"-ring) of the barrel is a little out of shape or has a narrowing/oxydation.

Jégwan

The piston can run smoothly all the way through - the issue is actually, as you suspected, that the piston front/top edge has become conical can can now get jammed inside the washer. So, I actually like your idea of reshaping it flat.

My idea for a smaller ID washer was exactly because I don't see me using anything else than nude shafts for the time being, so I could reduce the ID and thus, the piston would have more support. Either that, or if I can get the old washer out, I might just have a new SS washer made with a smaller ID.

(The pre-loading barrel is 10x14mm in most of its length and 10x12mm at the very front)

 

[Diving Gecko]

That small washer part 60 (it used to be part 65 on the original diagram, see attached) is there to protect the face of the plastic socket in the lower rear of the nose cone that holds the front end of the pumping barrel. Otherwise the pumping piston on its return to the nose cone after each pumping barrel stroke would hammer the plastic socket face and damage it, particularly for the first couple of pumping barrel strokes where the pressure in the rear of the gun is still high. The pumping piston sticking at the start of the first pumping barrel stroke is normal, especially if the gun has not been used for a while. The same thing occurs with the main piston as the sliding seals tend to stick on the barrel's inner wall if the piston has not been moved for a long period, especially if the gun is at 40 Bar initial pressure. You don't need to change anything. View attachment 40104

Hey Pete,
If your gun is still taken apart could you have a quick look at your washer and pre-loading piston to see if they are anything like mine (beat up and conical/beveled)?

Or Jegwan, if you have a spare piston - can you check if it has a flat front or is shaped like mine in the pix below?

If you add another washer then the pumping barrel becomes a tiny bit longer and may affect the clamping of the gun, remember the "Mirage" is only held together by the off-axis main barrel sitting above the pumping barrel; the gun tends to "banana" slightly at the ends as is, so no need to exacerbate that effect.
View attachment 40104

Pete, yes, if I do add another mm of washer, I would have to shorten the front of the pre-loading barrel by the same amount. Also, to make sure the front o-ring still manages to be fully seated and not be pushed backwards too much. But since the washer came out quite easily, I am now thinking of having a new one made in proper 304/316 SS. That would negate the need for a Delrin washer (I was just afraid the old one had gotten stuck).

 

[Diving Gecko]

OK, so managed to snap and (heavily) crop some phone pix of the piston and washer.
The washers does indeed have conical inside beveling on one side (sorry, if I am messing up the lingo again).
That's the side that faces the pre-loading barrel which in turn is tapered a bit too, so they seem to fit each other.

I've removed some of the corrosion for the sake of the pics but what I am not sure of is whether the shape the front edge of the piston is as intended or has been shaped involuntarily by the washer?

This shows the beveling of the piston - is this normal? Are yours like this Pete and Jegwan?

This shows the washer in the correct position. The conical face is downwards where the barrel would be

This pic shows the washer in the upside-down, wrong position - just to show how the piston seems to fit "nicely" into it and to show the conical shape better

 

[popgun pete]

The metal washer is just flat in my gun, but that is from memory as the nose cone is still jammed in the tank. The pumping piston is metal, however it has a plastic sleeve at the front end trapped in an annular recess in the piston. That hard grey plastic sleeve (part 51), which is cracked deliberately on one side to fit it onto the piston, centralizes the piston in the bore of the pumping barrel and there is no need to align it as it strikes the washer. The main piston has a similar hard grey plastic sleeve (part 8) that performs the same function, however my early production "Mirage" has a rubber cone washer with the flared end facing forwards (another part 10) in its place. When I bought a repair kit both plastic sleeves were included, but I have never used them.

I have not seen the plastic pumping piston before, hence the correct shape of that piston nose is unknown to me. Mares not redrafting the parts diagram is not much help as they used the same shapes from the earlier diagram, check out the pumping piston in the various diagrams.

Actually I just had a look and the "Mares only" version of the diagram has been changed, but is not revealing of such details.

 

[Jegwan]

The top on both the new and the old type of loading piston shall be flat - and the same applies for the metal washer.

Here's some photos of both the old and new type (sorry for the insulting quality for a pro):

I will recommend that you make the washer the same dimensions as the original (if you are going to have one machined) - so you don't reduce your possibilities of shaft that can be used in the gun... Just my opinion..

Jégwan

 

[Diving Gecko]

Perfect timing! I'm literally in the taxi on the way to the machine shop now. This is very good info. Thanks!


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[Diving Gecko]

An update from MirageLand:
Some of the issues that I've had with the gun has been my own fault. Like using a carbon fiber tube from a different batch than the one which worked flawlessly last time. But with copious amounts of teflon tape, I finally managed to seal the gun.

I've been using it quite a bit at around 28-30 bar and that's the limit for me now as the final loading effort even after the 5 pre-strokes is still right on the limit for me. I suspect I have a leak somewhere internally in the power regulator bulkhead/pre-loading system as others report that after 5 pre strokes the spear should sort of just slide into the main barrel with minimal effort.

On the positive side, it has taken some very nice fish indeed. I have missed some too - but I think I can blame that on my fiber optic sights. An idea I still truly believe in but which has now proven to not be "calibrated" as the gun shoots high. (Tested it on water bottles today but kinda knew from reviewing video and seeing how most of my fish had been shot high).

My take on the gun is that the two main concerns before buying it - the bulk of the gun and angle of the handle - are not really cause for grave concern. I have alleviated a bit of the bulk with a buoyant camera/reel holder as well as saved a tad of weight with the carbon outer tank.
The handle angle may or may not contribute to me shooting high, but I have one last outing to check that. And in case it does add to it, with some muscle memory exercise (more shooting), that should be solvable too.

Anyways, enough words - here are some pics:

The modifications and add-ons are:
- Vacuum Muzzle. It came with an STC set, but I busted the shock absorber so cannibalized my MediSten to get its Vuoto
- 7mm Nude spear from STC/Sigalsub
- Magnetic Line Release from Pelengas (THANKS Jegwan)
- 1.3mm Trigger Pin Set from UBL (soft and sweet when running gun at 30 bar)
- Carbon Fiber Outer Barrel
- Fiber Optic Sights
- DIY Buoyant Carbon Fiber Reel and Camera Wing
- Reel from LGSub

 

[popgun pete]

I've been using it quite a bit at around 28-30 bar and that's the limit for me now as the final loading effort even after the 5 pre-strokes is still right on the limit for me. I suspect I have a leak somewhere internally in the power regulator bulkhead/pre-loading system as others report that after 5 pre strokes the spear should sort of just slide into the main barrel with minimal effort.

It might be worth checking the bore of the transfer port as a scratch in there will cause a leak, as will a scratch in the "O" ring on the brass power regulator piston that serves as a plug for the port. The latter you can easily fix, but I don't think there is a way to fix the former unless you replace the plastic bulkhead. Normally it would not get scratched, but a piece of metal left over from machining the gun's metal parts could pass through there. Using the lower pumping barrel the loading effort should be decreasing noticeably with each successive stroke, hence your gun is definitely not working properly in that respect. Alternatively the piston is not pushing far enough into the transfer port to seal it which, as you mentioned in the other "Mirage" thread, may be due to the length adjustment in the selector shaft being out.

 

[Diving Gecko]

It might be worth checking the bore of the transfer port as a scratch in there will cause a leak, as will a scratch in the "O" ring on the brass power regulator piston that serves as a plug for the port. The latter you can easily fix, but I don't think there is a way to fix the former unless you replace the plastic bulkhead. Normally it would not get scratched, but a piece of metal left over from machining the gun's metal parts could pass through there. Using the lower pumping barrel the loading effort should be decreasing noticeably with each successive stroke, hence your gun is definitely not working properly in that respect. Alternatively the piston is not pushing far enough into the transfer port to seal it which, as you mentioned in the other "Mirage" thread, may be due to the length adjustment in the selector shaft being out.

I think and hope it is as simple as the whole bulkhead not sealing properly against the outer barrel.
That would be my guess anyways, as I had trouble sealing the handle and nose cone and teflon-taped them to get it to work. But I did not tape the bulkhead.
I will take the gun apart again in the next few weeks and most likely, I will add some coats of epoxy on the inside ends to build up the thickness a bit and then wetsand down to about grit 2000. Hopefully, that will do the trick.

 

[popgun pete]

You should not need to use Teflon tape or epoxy if the "O" rings are good, unless the seating surfaces on the plastic mouldings are damaged and then it is a last resort and probably not long-lived fix. The plastic components looked in good condition in the photos and the critical surfaces should not be damaged unless someone has used a metal awl to work the original "O" rings out of the grooves and scratched the sealing areas. Ditto for the grooves in the inner barrel, but they can be fixed by careful sanding with fine grit "wet and dry" paper. Pressure changes inside the gun as it is being operated cause minor movement of the seals which is accommodated by the "O" rings and their smooth seating surfaces. I think that you should closely inspect the parts and try and find out why they are leaking.

 

[Diving Gecko]

Dear Pete,
I have inspected everything very closely. I did this a month ago and spent 2-3 full days going over everything.
I am almost certain that the fault lies with my custom made carbon fiber tubes. More specifically, I think they are a tad low on resin for this purpose which results in the surface of the uni-directional fibers (which make up most of the layup) coming through a bit too much. Normally, this is a good thing for composites - low resin and high fiber content - but I suspect this is the reason, I am getting a very slow leak. And since they have very little resin in them, when I started sanding, I did not get a smoother surface - I dug deeper into the fibers.
Hence my idea to epoxy coat the insides and sand down. I am fairly certain that will work. I was just more lucky last time I had tubes made for this purpose.
Furthermore, it might or might not be 1/10mm larger on the ID than the stock tube, but that should not really be the main reason. O-rings are new and in perfect shape. Bulkhead and grooves too.

The teflon tape was never meant for anything than a quick, short-term fix and honestly, I am surprised it has worked and kept air for a month now.

 

[popgun pete]

I had forgotten the carbon fibre tank tube, now the epoxy makes sense, for some reason I associated the replacement of the alloy tank with another gun, not the "Mirage". The tank tube bores will not be an exact match and I guess that is why you have those green "O" rings that look a bit thicker in section. Did you ever try the gun with the original alloy tank and did the pumping barrel pressure transfer system work OK before changing the tank?

 

[Diving Gecko]

Not really that much to glean from this - it's just me doing a bit of target shooting to see if my fiber optic sights were placed correctly.

Password is: mirage



BTW, how have people measured muzzle speed in other tests?

 

[Diving Gecko]

So, I will slowly bring this thread back to live.
I am obsessed with modifying my Mirage to my liking and my next modification borders on sacrilege. Perhaps, the most iconic part of the the Mirage design is its distinctive grip angle and fold-out foot rest:

(Not my pic. I nicked this one ages ago from an Italian forum)

Well... Sometimes icons have to be taken down...
For now, I will spare you a pic of the sawed off Mirage and instead share a mock-up of the new handle, that I'll slowly be working on in the weeks to come:

Before I go into more details, here is my reasoning for this drastic move;-). Skip it if you want to.

The thing is, the more I thought about it, the more I dislike the sloped back angle. It was one of the reasons I hesitated even buying a Mirage in the first place, but I gave it a chance and tried to get used to it.
On a 3-4 week long vacation in Thailand, where I did a lot of spearing, I did get used to it and after about a week's time my aim was great. That is, when I had time to properly aim.
Then recently, on a trip to the Philippines where I managed to squeeze in a few days of spearing my aim was off. I even spent time making a target and doing some target practice and on the target, I could hit what I aimed at. But back hunting, I missed on pretty much everything.

Then I reviewed some spearing footage of the missed shots I had in the beginning in Thailand, before I got my aim straight. I also checked some very quick shots that I missed under pressure. I confirmed that when I miss, I pretty much always shoot high. I'd say maybe 80-90% of the times, I shoot high.

So, I started reading about about pistol shooting and grip angles. I found that shooting instructors often talk about a natural grip angle or rather, a natural angle of your hand on your arm.
They propose a simple way to figure out if a particular gun's grip angle matches your wrist angle. It goes like this:
You close your eyes and throw a punch holding an unloaded gun and then upon opening your eyes you notice whether you naturally aim high or low.

When I first got the Mirage, I did notice that I had to strain my hand downwards to get a straight aim and that I had to do it consciously.
But now, after having read what the gun instructors propose, I have been "throwing punches" with just the handle of the Mirage, and sure enough - I aim naturally high with it. Way high.
Not much of a surprise, but the point is that under pressure or with lack of target or hunting time as was the case in my latest trip, it seems very plausible that the extreme grip angle could have a lot to do with me missing shots I would easily have landed on the longer trip to Thailand.

So, a lot of words to appease the old Italian design Gods and the purists in the world;-)​

I cut off 2/3rds or so of the handle and the question now is how to built the new handle.
I am leaning towards epoxying a block of balsa onto the handle, shaping it and then covering it with carbon fiber. I might put in some CF stringers for added strength.
I definitely need a stringer of sorts to work as an anchor point for my float line.

I could use polymorph plastic as in the mock-up but it is just too heavy on a gun that I am working so hard to keep as light as I can. Balsa with carbon could be the strongest, yet light weight solution. Polystyrene foam could work but it is almost too soft to work with.
If I had done more handles and was a better wood-worker, I'd go for mahogany, sapele or walnut in a heartbeat. It would look stunning next to the black handle and the carbon fiber tank.

Ideally, I would make it detachable or make it in a way that I could easily reproduce the shape if and when I get my second Mirage, but for now, I think I will just make it as a one-off, epoxied in place.

Also, I did the quick mock-up to test one key thing. Would I need to add a fold-out foot rest to the new handle?
I think with the less generous angle of my new handle and the upper hand rest just near the pump valve inlet, the answer is that I can get by without it. That would simplify the build greatly.
For decades, people have been loading Superstens, 135 Assos and now, long PredaTHORs without a foot rest, so I should be good.

But now, the first cuts are made and there's no going back

 

[Diving Gecko]

I also plan on making a new trigger. The trigger is quite a reach for me on the original handle and still will be on the new one. I need to bring it as much as 10-15mm closer. Too much to just modify the original trigger.

If I knew how to CAD draw, I would consider laser cutting the new trigger in stainless steel but I don't and since I had some carbon fiber plate lying around I glued up four pieces of it. Part of the laminate is thinner with just two plates as I want to make a new line release for the Sporasub One Air while I am at it:

Quick note, when making shapelock/polymorph handles (or sizing other custom handles) do wear the intended glove size you'll be wearing in the water. It's amazing how much off my shapelock handle is without gloves. I mean, it is still "my hand" and somewhat OK, but my fingers don't really fall in the right places at all.
I put a latex glove on top of my neoprene gloves - otherwise the shapelock sticks to the neoprene and when you remove your hand, you mess up the shape of the handle:

 

[Diving Gecko]

Well, I felt like cutting into some plastic once again, so even though I likely wont be needing it, I modified the original trigger, too.
At least, I can use it for a backup somehow.
Even with this much plastic taken off, the trigger is still not too wobbly.

I also took away some of the handle - the part behind the trigger. Originally, it slopes downwards, but I want to get my hand as high up on the handle as possible. It's not much of a structural spot anyways.

 

[Diving Gecko]

A block of balsa came in today:

I realized I don't have a wood file/rasp and I have a bit of real work to finish, too. So, it's take a few days until I get to the shaping part.

 

[foxfish]

Are you going to cover the handle with something?

 

[Diving Gecko]

Are you going to cover the handle with something?

Yup, very likely carbon fiber.
I might have to put in some stringers, too. The CF will make sure the outside will be stiff, but if the inside is not there's a risk the handle will come loose.
I am beginning to think, I might have to make it a detachable handle, so I can make sure it is properly epoxy coated, even in the places that wont have the carbon skin.

 

[foxfish]

Do you have a plan to cover it with carbon cloth? I did that once it took a few goes ....