Piranha PWI-GR

[Wardukw]

Building models that fast is still kinda in the blood but it's not something I do much anymore mate ...space is my problem too ..so slowing down had helped me alot there but like you I'll bet ..tons of ideas 😆
Making ya turret mount taller was a good idea..there's not that room inside of a LAV-25 and even less at the sides ...im liking this one 👌

[Jakko]

It will also make the Piranha look much more top-heavy, like it does in the photos of the real one. With the turret ring I initially put on it didn't give that impression nearly as much, but the few extra millimetres make a lot of difference.

[Jakko]

Next, I needed to tackle the rounded bit of armour below the turret riser. After first considering how to make this from a piece of plastic card to fit between the riser and the sloping side armour, I didn't feel like actually working that out: it's an plane that intersects a cylinder at an angle, so you could calculate and draw the exact shape it should have, but that was too much theory for me. I turned to a practical solution instead:

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I placed the riser on the roof and then used the tip of my modelling knife, held as vertically as I could, to scratch a line in the hull that follows the outside of the riser. I then drilled a line of holes just above that line (perpendicular to the side armour, not vertically) and connected those using the knife. After that, it was a matter of scraping, cutting and filing to get the inner edge vertical.

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All that remained was to glue in a bit of plastic card:

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To work out the length of this, I put the riser back on, made two pencil marks on it at the ends of the hole I had just cut, and rolled it along a ruler to measure the distance between them. I then cut the plastic slightly longer so I could trim it until it fit, and bevelled the edges where they butt up against the roof. Finally, after taking the photo, I filled the seam with putty.

[Rick Lowe]

but the few extra millimetres make a lot of difference.

That's what She said... 

Good move on the filler piece - I would have Brute Forced it; slapped some filler in there and sanded it into submission, but your solution is more elegant.
A piece of soft wire used as a measuring line would work, too.

[NARSES2]

That's a nice piece of miniature engineering 

[Jakko]

Good move on the filler piece - I would have Brute Forced it; slapped some filler in there and sanded it into submission, but your solution is more elegant.

I had half a mind to do that instead. Add some pieces of flat plastic card below the riser to roughly fill the gap, then use putty for the rest, but I decided against it because getting that putty nice and round would be difficult, especially with the hull slope getting in the way.

A piece of soft wire used as a measuring line would work, too.

Good idea, I hadn't thought of that.

That's a nice piece of miniature engineering 

Thanks, but it's not that well-made — look at the big gap at the front. The drawbacks of being entirely self-taught, I guess

[Jakko]

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The basic shape of the commander's hatch is now on too, made from two discs of 0.5 mm plastic card, 20 mm and 18 mm in diameter. Of course, it still need lots of details added. Also the basic shapes of the passenger vision blocks, made from 2 × 2 mm square rod which I filed to an angle on one side to fit the hull, but this also still needs the actual vision blocks added. I found out that the vision blocks on Piranhas are in different locations than on the LAV-25, BTW: the rear edges on the left are at 21 and 36 mm from the rear plate (at the level of the tops of the blocks), on the right at 27 and 42 mm. Now I need to figure out a way to make six discs of 7 mm diameter for the lids for the firing ports. Oh, and I sanded and scraped away all the moulded-on lines for locating parts, as well as the hatch lid that's on the left side of the LAV-25. I don't really know if Piranha 8×8s all have that lid, but the Dutch production version for sure didn't

To the turret, I added the lifting eyes, including a scratchbuilt one because one was missing from the sprue. I also made the bolts at the back myself because two of the four had been moulded short on the sprue — they're just a 1 mm hex of 0.5 mm card with an 0.5 mm disc of 0.25 mm card on top, which are the same dimensions as the ones moulded onto the sides. I also put a cover over the muzzle of the 25 mm gun from Green Stuff, which fits nicely with the covers I installed on the sides of the turret. (On the real vehicle, those concentric rings towards the front of the turret are removable black plastic covers that protect the ejection ports outside of combat. They're often seen on photos of YPR 765s on exercise.)

[kerick]

Next, I needed to tackle the rounded bit of armour below the turret riser. After first considering how to make this from a piece of plastic card to fit between the riser and the sloping side armour, I didn't feel like actually working that out: it's an plane that intersects a cylinder at an angle, so you could calculate and draw the exact shape it should have, but that was too much theory for me. I turned to a practical solution instead:

You cannot view this attachment.

I placed the riser on the roof and then used the tip of my modelling knife, held as vertically as I could, to scratch a line in the hull that follows the outside of the riser. I then drilled a line of holes just above that line (perpendicular to the side armour, not vertically) and connected those using the knife. After that, it was a matter of scraping, cutting and filing to get the inner edge vertical.

You cannot view this attachment.

All that remained was to glue in a bit of plastic card:

You cannot view this attachment.

To work out the length of this, I put the riser back on, made two pencil marks on it at the ends of the hole I had just cut, and rolled it along a ruler to measure the distance between them. I then cut the plastic slightly longer so I could trim it until it fit, and bevelled the edges where they butt up against the roof. Finally, after taking the photo, I filled the seam with putty.

I would have tried a tiny plumb bob. But that's just me. It's a remarkable tool of the survey trade. A big one, not a tiny one.

[Rick Lowe]

For the discs, what about using a .30 or similar casing, with the outer edge filed to sharpen it up to act as a punch?*
7-&-a bit mm yes, but by the time you clean up the edge of the disc, it'll be closer to the 7mm-even that you need.

*Careful of fingers! (voice of experience...)

[Jakko]

I would have tried a tiny plumb bob. But that's just me. It's a remarkable tool of the survey trade. A big one, not a tiny one.

I hadn't thought of that method, but doing that now, I'm not sure it would have worked well given the tiny amount of room there is between the hull side and the riser. If I ever have to convert a full-size vehicle, though, I'll keep it in mind

For the discs, what about using a .30 or similar casing, with the outer edge filed to sharpen it up to act as a punch?*

Good idea, but you say that as if empty cases are easy to get hold of I guess they are if you're in a country like the USA, Czechia, Switzerland, or similar. In the Netherlands ... not so much. (That said, I do own some that would be suitable, but I consider them part of a collection and not something disposable that I would just go and modify because I need a specific tool.)

Hollow punches of these kinds of sizes are easy to get, but my experiences with using them on pastic card have not been positive. It's difficult to punch a neat disc, it's usually bent, and the edges tend to be ragged — those punches seem to be intended for making holes in things rather than making discs.

[Wardukw]

I would have tried a tiny plumb bob. But that's just me. It's a remarkable tool of the survey trade. A big one, not a tiny one.

I hadn't thought of that method, but doing that now, I'm not sure it would have worked well given the tiny amount of room there is between the hull side and the riser. If I ever have to convert a full-size vehicle, though, I'll keep it in mind

For the discs, what about using a .30 or similar casing, with the outer edge filed to sharpen it up to act as a punch?*

Hollow punches of these kinds of sizes are easy to get, but my experiences with using them on pastic card have not been positive. It's difficult to punch a neat disc, it's usually bent, and the edges tend to be ragged — those punches seem to be intended for making holes in things rather than making discs.

Jakko mate inknow the feeling with a hole punch set not giving a clean cut..like ya said ..bent and ragged edges but a high quality set does work very well .
I use em regularly making gaskets and the crap sets would do the same with paper..the harder the cutting edges the cleaner the cut.
Also even tho there sizes are similar ..paper or ticket punching tools..ive got several different sized ones and these will cut out a clean disc from 1.0mm sheet styrene with ease 
Oh and leather punch tool with the multiple sizes..a high quality one of those works damn good 👍
I've gotta get a new one as I've worn mine out 

[Jakko]

I went through a bunch of spares boxes yesterday looking for something suitable, but nothing. Well, one sprue with discs on it that looked pretty much spot-on, even with two rivet-like things that look like the ones on Piranha firing port covers — OK, they're 6 mm diameter (which I can live with), but there are only five of them On further investigation they were 1:72 scale fuel drum lids (I found the rest of the drums too ) and by the feel of the plastic they're from Hasegawa, but I have no clue what kit they're from. Most importantly, there are only five of them and I need six, so they're not going to work, either.

Another thing I considered was a simple hole punch, for putting paper in binders, but they make 6 mm holes and very much bend the discs into a U-shape. Anything over paper-thin plastic card is very hard to flatten again.

I figure I may have to go to my father's shed to see if he has a 7 mm hole punch (I suspect he does), then try to make the best of that.

[Rick Lowe]

You may have to cut discs out of rod and file them to an even thickness.
Or a tube and fill the centre.

[Wardukw]

I went through a bunch of spares boxes yesterday looking for something suitable, but nothing. Well, one sprue with discs on it that looked pretty much spot-on, even with two rivet-like things that look like the ones on Piranha firing port covers — OK, they're 6 mm diameter (which I can live with), but there are only five of them On further investigation they were 1:72 scale fuel drum lids (I found the rest of the drums too ) and by the feel of the plastic they're from Hasegawa, but I have no clue what kit they're from. Most importantly, there are only five of them and I need six, so they're not going to work, either.

Another thing I considered was a simple hole punch, for putting paper in binders, but they make 6 mm holes and very much bend the discs into a U-shape. Anything over paper-thin plastic card is very hard to flatten again.

I figure I may have to go to my father's shed to see if he has a 7 mm hole punch (I suspect he does), then try to make the best of that.

Jakko mate the hole punch ya want is the ones without the curved cutting edge ..those curve the plastic..the flat edged ones are what I use ..they work great 👍

[Jakko]

You may have to cut discs out of rod and file them to an even thickness.
Or a tube and fill the centre.

Both of those I had also considered, but I don't have any rod of the right diameter so that's out I think I have some 7 mm tube, though.

the hole punch ya want is the ones without the curved cutting edge ..those curve the plastic..the flat edged ones are what I use

I didn't know those existed. All I've ever seen have been ones with curved punches.