G1 Prowl windscreen repair

As with many other G1 Prowls (and Smokescreens and Bluestreaks), the windscreen of mine broke at the bonnet in childhood. I glued it many times with superglue and other glue but it would break again. So I decided to pin it. I hope my experience might be of use to others attempting repairs.


Equipment - hand drill and bits, pin, pliers and wire cutter to cut pin. I used a hand drill and micro bit (0.55mm) obtained from Jaycar but they can be bought from elsewhere like ebay. I found some random pin in my hardware box. Make sure the drill bit is slightly smaller than the pin diameter so friction holds things together. Micro screws could be an alternative.

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Method - nothing really special, just a lot of care lining up the broken pieces and imagining how the pins would run, and slow hand drilling with repositioning of the bit if the placement looked wrong (in 3D). The plastic is easy to drill slowly by hand but it may depend on how good your bit is. I couldn't remove the hardened glue and sanding it down may have altered how the broken ends fitted. Fortunately my ends contacted well in a jagged way, so alignment of ends (and the windscreen relative to the car) was ok.

1. I used 2 pins to prevent rotation of the windscreen around just 1 pin, to add strength, and to reduce stress of plastic around just 1 pin.


2. Planning - I aligned the windscreen with the bonnet and imagined how and where the pins (drill) would enter the broken surfaces.


3. On the bonnet part, there are 2 ridges of plastic underneath that allow for more plastic around the pins, so I put my bit in the centres of these areas. I drilled 3-4mm deep trying to keep the bit horizontal. There is a slight curve of the bonnet so drilling too deep may penetrate the top of the bonnet. I drilled 1 side first then lined up the windscreen and drilled the windscreen rather than doing 2 holes in the bonnet first, thinking it might make alignment better.

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4. I put the upside down windscreen on top of the bonnet to align the horizontal position of the windscreen hole.

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5. My windscreen had broken such that it forms a right angle surface, so I drilled horizontally (perpendicular) into that. On the inside and the bottom of the windscreen, there are small plastic blebs, so I drilled taking these into account as my centre. That is, not the centre of the windscreen main front edge. The vertical position of the bonnet and windscreen holes were really determined by Step 2 and trying to have as much plastic surrounding the pins.

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6. After doing the left side, I put the pin in and connected the windscreen and bonnet to check all the alignments, then drilled the right side. I pulled the pin out and cut it in half.


7. Finished repair. It looks solid but there is very slight play around the windscreen holes and I still will be careful with transformation so I don't crack the windscreen around the pins. The roof sits well but there is some upward angulation, which I think reflects the horizontal angle of the windscreen holes (but this is really hard to do perfectly). Luckily the rear hatch windows and their hinges are sturdy enough to hold the roof down and without stressing the windscreen holes. There's still a bit of lifting but I often couldn't get it flush when it was glued before anyway. On the front view, the roof sits quite squarely with the bonnet (previous glue attempts sometimes had it tilted slightly). I could trim the pins a bit more but it looks fine in both modes.


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FINAL THOUGHTS

• This is such a small area to operate on so there is little room for error.
• Because each hole has to be drilled separately, it can be easy to have them misaligned, especially if you are drilling into a glued surface that's rocky and uneven. I had to reposition and guide the bit against my finger for one hole.
• Once a hole is made, that's it, unless you can fill it again and redrill, but this is a small area that might only take so much drilling before integrity is lost.
• If it doesn't work, and you haven't ruined your figure, at least it could be glued again without noticeable leftover holes.

That glue is bringing back all the memories of my G1 Prowl, and the repair job my Dad did when I broke that part.

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Originally Posted by Paulbot

That glue is bringing back all the memories of my G1 Prowl, and the repair job my Dad did when I broke that part.

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When this broke as a kid, I was pretty sad and as I superglued it back, I thought "This clear, hard plastic isn't going to hold longterm with superglue." And here we are today... Still, there's part of me in each layer of glue that's now part of the toy plastic. It's history! Every time I've glued this, I've been worried I'd get glue on the windscreen or put my finger on superglue then leave a permanent fingerprint (done that before to other toys).

I guess Hasbro didn't count on kids pushing that roof down a thousand times too hard in order to pop up Prowl's head (now I push on the rub sign).

Edit: Heh, just checked the instructions, and the roof doesn't need to be touched - just rotate the front of the car down. In theory ;). But then why have a hinge just below Prowl's head/a movable roof at all?

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Looks great!

My mum did jewellery making as a hobby when I was growing up, so her knowledge around strengthening those types of breaks was always helpful.

The micro-drill you use, is it just a pin-vice or is a spring-head? Do you have a preference or recommendation on which sort to look for?

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Originally Posted by Seraphim Prime

The micro-drill you use, is it just a pin-vice or is a spring-head? Do you have a preference or recommendation on which sort to look for?

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Yes, it's a pin vice. For those who haven't used these, it works just like a jeweller's screwdriver with the hexagonal end able to spin freely. The bit inserts in the other end and the lower cylinder is hand turned to squeeze the collet chuck around the bit, just like a regular drill. Drilling is done like the jeweller's screwdriver with the index finger placed over the hexagonal end and the thumb/middle/ring fingers twisting the middle part of the shaft. Alternatively, you can hold onto the middle shaft between the thumb and the index/middle fingers and roll it like a cigarette. If I need a bit more force, I place the hexagonal end against my palm, near the base of the fingers and rotate with the index and thumb while pushing with the palm.

I'm not familiar with spring drills (spiral or Archimedes drills) as I think I get finer control rolling my fingers. When starting a hole, I'm only doing several quarter turns, or even smaller, at a time before reversing out to remove plastic debris and to check alignment. Spiral drills look like they need 2 hands to operate - one to steady the tool and one to pump up and down. The pin vice gives me the other hand free to hold the object if needed, or guide the drill bit against my finger.

Thanks!

I've been looking into getting a fine drill for some repair work and wasn't sure what to be looking for.

Now to a hobby shop for a pin vice.