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HOWTO: Bolted rubber sealed removable eye lenses


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Hi folks! So I've had several questions regarding how I did my helmet lenses and so I thought I'd put a little guide up for anyone that may be interested in the process I used for their own builds. I think it came out rather slick with a neat end look while being solid and easily replaceable. Here is a shot of what this technique looks like when completed from the inside:






Sugru moldable rubber

Shade 3 flexible welding visor - https://www.amazon.com/gp/product/B00209I0UG

M3x20mm screws and acorn nuts

Index cards


Xacto knife

Micro ruler


220 grit sandpaper


Dremel and/or belt sander


Thin black heat shrink tubing


Step 1: Create eye socket templates


I don't have a picture of this first step but you see me using mine in later steps. So all you do here is take an index card, ho ld it flush over the eye opening inside the helmet then with a pencil trace the opening from the outside. Make sure it is centered on the index card because you are now going to extend it for overlap margin. With the socket outline traced on the card, using a ruler measure half an inch out from the outline and place a mark, do this many times tracing around the outline so you're basically making the original socket outline half an inch larger on all sides. Then simply draw a new line around this outer outline and cut the template out with a scissor. Make sure you label what eye socket each label pertains to, and store these for future needs even after this project is done in case you want to cut new replacement lenses, switch out colors, etc.


Step 2: Shape a rubber mounting surface


In this next step you are creating a rubber mounting surface that the lenses will bolt onto and create a flush connection to the eye sockets. Take your Sugru (I used like 5-6 packets per socket) and create a nice think outline around the whole inside of the socket. You'll want to ensure that the rubber around the socket's plastic mold is slightly taller so when you rest a lens onto it is sitting flush on the rubber bed. You have a lot of time to work with the rubber before it starts to set so take your time and get the outline right. Important last step here, after you're happy with the rubber mount take an index card (or two to make it thicker), lay it against the rubber outline and press down lightly to ensure that you have an even surface all around to avoid having an uneven mounting surface outline.




Step 3: Cut your mounting bolts


I used five bolts per lens, you may want less or more but found that to be a happy place for getting the connection tight. Ok so here you are going to take your M3x20mm (you don't need to use this specific bolt size, can be M4, M2, whatever, just something you're happy with size wise) and cut them so you have a set that will have even height protruding upwards from where you will be mounting them. The gist is you will be adding these bolts to the rubber mold you created in step 2 with more rubber, but first you need to look at where each bolt is going to rest and measure how far over the rubber they are sitting uncut. Since the topography of the helmet here varies, some bolts will be extending quite far, others not so much, and you want an even extension from all bolts. I wanted about 8mm of extension to bolt into so I held a screw in the place it will be mounted, measured how far above the rubber it sticks out to calculate how much I needed to cut (so if it stuck out 13mm I cut 5mm off). Keep track of where these screws are going to be mounted since you measured it for that spot! As I was measuring and cutting, I placed them on my templates at the spot they will be mounted. To cut them down I just put a nut on the screw exposing the amount after the nut equaling how much needed trimmed, then put it on a vise and dremeled that excess off. You may find a cutting solution that works better for you, but I found that easy. Careful handling these little bolts after cutting them, they will be very hot! 


NOTE: Never cut metal bolts that are already mounted in your helmet, besides making a mess their heat will likely melt the plastic creating a huge problem.




Step 4: Mount your bolts


Now that you have your rubber mounting surface and your bolts cut for specific locations around the surface, it's time to attach the bolts. Using Sugru again put a nice wad on the bottom of the bolts, then just mold them to the mount at the correct locations where they were measured. Get the attachment between the mount and the bolt nice and tight, use more Sugru liberally and work it in. The one thing to be careful of is to not have any Sugru on the bolt that goes over the height of your mounting rubber from step 2, otherwise the lens will stop bolting in too high and not rest on the flush surface you created. However, being rubber this stuff can very easily be trimmed with a Xacto knife, so you can just snip any excess off to keep your base mount surface flush. After you've finished mounting all your bolts, you may want to double check you didn't get rubber smudges on your helmet and clean it off well, don't worry if you do, it will remove without much effort. Clean your hands thoroughly as well! Now that you have your cool rubber mount with sized bolts, you need to let that rubber set for 24 hours.




Step 5: Add mounting points to your templates


After you've allowed your rubber to set overnight, you'll be taking your two socket templates and marking where the bolts you mounted relate to it. Simply press the template down onto the bolts to make impressions on the paper where the bolt tips are, then punch through those holes with a pencil. Afterwards, place the paper template into the actual bolts to ensure that all the bolts align right with your template and your template rests nicely into the mounting surface you've created. This is a preview of what your lens will look like when you cut them to the template shape and drill the holes!




Step 6: Cut and shape the welding lenses


I used a shade 3 welding lens which is flexible and fairly easy to cut, after looking around and trying a few options I found the one linked above in the materials list to be the best for this project. Ok so what you're going to do now is rest your templates onto the lens stock, trace the outline lightly with your Xacto knife (just enough so you can see where you need to cut), then cut out each shape with your scissors. Your cut lens will be a little rough, so curve it more naturally by (carefully) running it down a belt sander or Dremel tool. You just want to make the shape of the lens natural and curve to make the template and avoid any sharp points (your eyes don't like sharp points). After that, take some sandpaper and sand the edges all down nicely so they are nice and smooth. For the last step, place your paper template back onto the cut lens, then with the Xacto knife mark where each hold is going to go. Take your drill and open up each hole, making them plenty big enough for the bolts to go through with some room for flex, but not too large that your acorn nut won't compress down against it. Note that while doing all this, be careful not to scratch the lens surface by a stray cut or tool.




Step 7: Mount your lenses


Ok almost there! Here you simply need to push the lenses down through the bolts and screw in your acorn nuts to secure the lenses down into place. You may need to bend the lens a bit to get the fit to work, here is where making those holes a little bigger than needed helps. Whatever you do, try to not allow the tops of your bolts to scratch your lens. To hide any excess exposed bolt shaft I cut very small pieces of black heat shrink tube and put them on the bolts then put the acorn nuts back on and screwed down tightly.






Ok so this may not be the easiest method of creating and mounting lenses, but the end result is pretty nice (in my opinion), and I like the effect having the acorn bolts gives. You have a well sealed lens over your sockets without any gaps by virtue of the rubber mounting surface and bolts securing them into place. The lenses themselves aren't flimsy and are high quality, plus easily cleaned with mineral spirits if heavily soiled, or just your standard glass wipes. Another plus is you can easily replace them just just unbolting them! I hope this guide helps anyone interested in this type of technique, cheers!

Edited by kamikaze
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  • 6 years later...

Thank you for this awesome tutorial, I used this for my lenses and unfortunately, the sugru just doesn't seem strong enough to hold the bolts in place, so I had to use almost triple the amount causing a large gap at the top of the lens, but I believe it should be approvable. 

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