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agk23

Helmet building question to those who worked with rasins and epoxies

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I am trying to put together a camera helmet and need your help:

I have a ski helmet (with round top) that I want to convert into camera helmet with cx-100 mounted on top.
Here is what I have for the project:
-Ski racing helmet made out of ABS (provides fairly good impact protection) with almost round top
-cookie chincup with cutaway
-cookie flatlock mount (without top-mount helmet adapter)
- camera cage for cx-100 made out of aluminum (similar to one made by Blink)
-cx-100

the first problem that i have is how to attache flatlock mount to the round surface of the helmet?
I thought about buying cookie adapter, but i do not know which one will fit, plus with shipping to canada it becomes pretty expensive (it can get up to $80 with shipping, duties and custom clearance) especially if i need to ship it back and forth to figure out which one fits.

So I need your help in figuring out what options do I have to DIY something like cookie adapter

The first I idea that came to my mind was to do something similar to what Ronaldo showed a while ago on this forum http://cid-b5905376ce73cf21.skydrive.live.com/self.aspx/Capacete%20freefly%20%5E5Free%20Fly%20camera%20helmet%5E6/Suporte%20fotografica%20008.jpg (I also attached three pics from this link)
But I am not sure I understand why he made a master mold and then used it to make the part instead of just making a part right on the helmet. and I do not know what type of rasin would work best.

Do you think the following approach would work:
-cover helmet with shrink wrap (to release the part)
-make a form from cardboard or balsa wood right on the helmet using playdough for support and sealing any cracks (instead of just playdough in Renaldo's case)
-use bondo fiberglass resin jelly (is there anything better for this job?)
-put thin (1mm-1.5mm) sheet of aluminum cut to size on top of bondo.
-clean up edges after it dries
-attach finished part to helmet together with flatlock using bolts in a similar fashion to cookie adapter

Is there any easier way to solve the problem?
"Gravity is a habit that is hard to shake off"
Terry Pratchett, "Small Gods"

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Hi,
First, would it be possible for you to post a picture of the helmet/ cookie base together? It will be easier to visualize a solution. Also, are you willing to paint the helmet? Would you mind if the base doesn't match helmet color?
BTW, I did a master mold for a few reasons:
- It would be much more difficult to finish the sides (trim the edges) of the flat top base right on top of the helmet.
- With the master mold I was able to make a perfectly flat top part. It was not shown at the presentation but the part was molded against a flat wood block (although glass would have been the perfect choice)
- At that time I was planing to do a full face version of the same helmet (which I did but never finished).

Have fun with your project! :)

Engineering Law #5: The most vital dimension on any plan drawing stands the most chance of being omitted

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Yes, I am planning to paint it and no, I do not mind if the base is different color from the helmet (because i will paint it anyway)
as for finishing sides - i would not be doing on the helmet, i will take it off and trim then and glue it back to the helmet when it is finished (I was planning to use JB weld for that as I think it can bond both ABS and fiberglass) just as you did with your final part.
As for the perfectly flat top - I was thinking to use a sheet of aluminum place on top of the epoxy while it is still not cured. It will bond right to the part and i will later renforce the whole thing with screws when attaching flatlock.
I will try to get pictures later today, but it's top looks very much like cookie ozone (maybe a little bigger though to allow for crashable foam protection)
"Gravity is a habit that is hard to shake off"
Terry Pratchett, "Small Gods"

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I decided against JB Weld as it seems brittle when cured and more so when subjected to cold temps. I used an aviation grade epoxy to secure my base to the helmet.

I used a piece of fiberglass honeycomb as my "perfectly flat top". I used one bolt in the center as insurance for the epoxy. For my top mounting plate I used counter sunk nuts in the fiberglass honeycomb so the aluminum plate could be easily removed and reconfigured in the event I wanted to make changes.

See attached pics.
Blue Skies, Soft Docks and Happy Landings!
CWR #23
(It's called CRW, add an e if you like, but I ain't calling it CFS. FU FAI!)

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A local guy recently did this.



I have seen this. Great work, but looks like a lot of work and an overkill for my purpouse. all I want to do it to attach flatlock to the round top helmet.
"Gravity is a habit that is hard to shake off"
Terry Pratchett, "Small Gods"

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I decided against JB Weld as it seems brittle when cured and more so when subjected to cold temps. I used an aviation grade epoxy to secure my base to the helmet.


I noticed that JB is a little too brittle especially if attached to softer materials and in cold.
Where would I get aviation grade epoxy (is there particular brand/grade i should be looking for?)

Quote


I used a piece of fiberglass honeycomb as my "perfectly flat top". I used one bolt in the center as insurance for the epoxy. For my top mounting plate I used counter sunk nuts in the fiberglass honeycomb so the aluminum plate could be easily removed and reconfigured in the event I wanted to make changes.

See attached pics.



Is the white stuff in the pic - aviation grade epoxy? it looks like some kind of foam.

What did you use to create a form to shape the epoxy?

Anyone ever use Bondo-Hair® Long Strand Fiberglass Reinforced Filler or Bondo® Fiberglass Resin Jelly? do you think it is any good for the job?
"Gravity is a habit that is hard to shake off"
Terry Pratchett, "Small Gods"

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There are probably dozens of ways to do it depending on the materials and tools you have in hand. Here is one suggestion:

1. Get an aluminum plate at the size you want the flat top to be (obviously larger than cookie’s quick plate);
2. Remove the lining inside the helmet
3. Drill 3 holes on the plate and also at the top of the helmet (you will have to estimate the best position in both). See figure 1
4. Sand the top of your helmet to improve bonding.
5. Mark the area below the plate and drill a bunch of small holes inside it
6. Fix the plate on the helmet using bolts/nuts/ washers (figure 1)
7. Install the camera temporarily on the plate using rubber bands, duct tape or whatever you got (just don’t damage it!)
8. Tricky part: find the best alignment of the camera. Place a mark on a wall approximately at your eye’s height. Put your helmet on (with the camera), look to the mark (with your head and not only with your eyes) and record video. Make adjustments with the 2 rear bolts until the mark is in the center of the screen.
9. Once the proper alignment is reached, remove the camera and cut 3 pieces of rigid cardboard, balsa sheet or any other material that is stiff enough to stand handling and resin later (see figure 2). Cut the cardboard as accurately as possible (this may take a few tries). The more time you spend here the less you will have to trim and sand later.
10. Attach these pieces using strong duct tape (i.e silver tape). Make sure all the edges are sealed otherwise you may end up with a lot of mess to fix. Put tape inside the helmet covering all the holes.
11. Position the helmet as shown in figure 3 and fill the cavity with epoxy or polyester resin (sorry, I can’t help you with brands in Canada).
12. Once it has cured, remove the cardboard, sand and paint. You should be able to remove the bolts/ nuts applying a little torque.

Tip: If you want to reduce weight you may wax the bottom of the aluminum plate before starting and detach it once the resin is cured.

This may seem a lot of work at first but requires only very basic materials. You may change this process a little bit depending on your creativity

Post a picture later

Have fun!

Ronaldo
Engineering Law #5: The most vital dimension on any plan drawing stands the most chance of being omitted

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I noticed that JB is a little too brittle especially if attached to softer materials and in cold.
Where would I get aviation grade epoxy (is there particular brand/grade i should be looking for?)



I was lucky and had access to some through an A&P mechanic friend. He says that you should be able to order some through Avial. He says to use Hysol EA934. Here is the spec sheet. http://www.mtpinc-exporter.com/chemicals/tds/Hysol%20EA%20934NA.pdf This crap is expensive. The only place I found it on the net was $100 per quart. It might be overkill but I'd compare anything else to the Hysol before I used it.

Quote

Is the white stuff in the pic - aviation grade epoxy? it looks like some kind of foam.



The white stuff is a polyurethane foam which I used as a light weight filler since I wanted a plate which was larger than my helmet. I then covered the foam with nylon screen material and covered that with Devcon 2 Ton Clear Epoxy http://www.devcon.com/products/products.cfm?familyID=179 This may be strong enough to use for mounting the plate. I used it because it dries crystal clear.

Quote

Anyone ever use Bondo-Hair® Long Strand Fiberglass Reinforced Filler or Bondo® Fiberglass Resin Jelly? do you think it is any good for the job?



I stayed away from all fiberglass since I was hoping to keep the weight down. I had intended to use some carbon fiber with epoxy but had a timing issue and I live in a small town which meant ordering carbon fiber off the internet.
Blue Skies, Soft Docks and Happy Landings!
CWR #23
(It's called CRW, add an e if you like, but I ain't calling it CFS. FU FAI!)

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For starters, your best result will be starting with a different helmet, something made for skydiving by a company that also builds camera hemets. Various aspects of the helmets design will cater towards mounting a camera, and having the helmet fit such that it will be secure and not shake.

Don't underestimate the need for a tight and proper fit to avoid camera shake. Your camera helmet should not be a 'comfortable' fit when it is cinched up in ready-to-jump mode. It may fit well on the ground, or with the chin cup or backstraps loose, but once it's in go-mode, you'll be glad to get it off in 6 to 7 minutes when you're back on the ground. It shouldn't hurt, but it's not there for comfort, it's there to literally bolt the camera to your head so you're in control of every move the camera makes.

If you're hell bent on using your ski lid for this, the easy and simple way is to make a flat top mount of some sheet aluminum. You can start by using some stiff single-ply cardboard to make a mock up.

Use the carboard to create a mock up that will start off looking like a weird 'I' with the vertical part of the 'I' being the same size and shape you want your flat top to be. Now bend the 'legs' sticking out of the flat top down to form a little table. Set this table on top of your helmet where you want to mount the camera. Now trim the legs of the table until the table is sitting as low to the helmet as you can get, and at the right angle you want your camera to sit. Now you have mocked-up your mount, and when you flatten it out, it becomes the pattern for your mount.

You'll need to add an inch or so to the length of each leg. This extra material will allow you to bend it up and make a 'foot' at the bottom of each leg where you can drill mounting holes and run bolts to hold the whole business on.

Now lay the pattern on some sheet aluminum, trace it, cut it, bend it, drill it, mount it, and jump it. That's the easy way.

If you want to start molding things, and doing layups with resin and fiberglass or carbon fiber, then do yourself the favor of starting with a real skydiving helmet. If you're going to put that much work into, be sure that the helmet itself is going to do the job before you invest the time and money in making a complicated mount.

The aluminum job I described above can be done for about $30 bucks, and within 2 or 3 hours. If the helmet itslef turns out to be a dud for camera flying, you're not out that much in time or money.

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There are probably dozens of ways to do it depending on the materials and tools you have in hand. Here is one suggestion:

1. Get an aluminum plate at the size you want the flat top to be (obviously larger than cookie’s quick plate);
2. Remove the lining inside the helmet
3. Drill 3 holes on the plate and also at the top of the helmet (you will have to estimate the best position in both). See figure 1
4. Sand the top of your helmet to improve bonding.
5. Mark the area below the plate and drill a bunch of small holes inside it
6. Fix the plate on the helmet using bolts/nuts/ washers (figure 1)
7. Install the camera temporarily on the plate using rubber bands, duct tape or whatever you got (just don’t damage it!)
8. Tricky part: find the best alignment of the camera. Place a mark on a wall approximately at your eye’s height. Put your helmet on (with the camera), look to the mark (with your head and not only with your eyes) and record video. Make adjustments with the 2 rear bolts until the mark is in the center of the screen.
9. Once the proper alignment is reached, remove the camera and cut 3 pieces of rigid cardboard, balsa sheet or any other material that is stiff enough to stand handling and resin later (see figure 2). Cut the cardboard as accurately as possible (this may take a few tries). The more time you spend here the less you will have to trim and sand later.
10. Attach these pieces using strong duct tape (i.e silver tape). Make sure all the edges are sealed otherwise you may end up with a lot of mess to fix. Put tape inside the helmet covering all the holes.
11. Position the helmet as shown in figure 3 and fill the cavity with epoxy or polyester resin (sorry, I can’t help you with brands in Canada).
12. Once it has cured, remove the cardboard, sand and paint. You should be able to remove the bolts/ nuts applying a little torque.

Tip: If you want to reduce weight you may wax the bottom of the aluminum plate before starting and detach it once the resin is cured.

This may seem a lot of work at first but requires only very basic materials. You may change this process a little bit depending on your creativity

Post a picture later

Have fun!

Ronaldo



Thanks Ronaldo for such detailed post and the drawing.

I had something like that in mind (probably did not explain it well in my first post though), the only main difference was to keep the top open when pouring the resin and then putting aluminum sheet cut to size on top prior to curing. I thought that way there is less chances that it would retain any air pockets, but i guess depending on how thin the resin is your approach can work too. as for leveling top sheet to the right angle, I have already made a mock up and figured out the angle of the top and dimensions of the sides, so if I build a form to hold resin to the correct size and just drop the sheet on top, it should be at the right angle
"Gravity is a habit that is hard to shake off"
Terry Pratchett, "Small Gods"

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Your method will surely work. Just remember that the top will be dense (not hollow) and this will add a little bit of weight to your helmet.
I work with polyester resin (much cheaper) which comes usually thick but I adjust its viscosity with styrene solvent depending on the application. I buy the fiberglass material from a local supplier but it should be very similar to these ones:

http://www.shopmaninc.com/polyesters.html
Engineering Law #5: The most vital dimension on any plan drawing stands the most chance of being omitted

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For starters, your best result will be starting with a different helmet, something made for skydiving by a company that also builds camera hemets. Various aspects of the helmets design will cater towards mounting a camera, and having the helmet fit such that it will be secure and not shake.



Can't really agree with that (using skydiving helmet). Initially I bought Nvertigo-V, ended up selling it. It offers almost no impact protection (which is unfortunately true of all skydiving helmets), and in terms of fit, my ski helmet has much better fit and a lot more secure.

Quote


Don't underestimate the need for a tight and proper fit to avoid camera shake. Your camera helmet should not be a 'comfortable' fit when it is cinched up in ready-to-jump mode. It may fit well on the ground, or with the chin cup or backstraps loose, but once it's in go-mode, you'll be glad to get it off in 6 to 7 minutes when you're back on the ground. It shouldn't hurt, but it's not there for comfort, it's there to literally bolt the camera to your head so you're in control of every move the camera makes.



fully agree. this is one more reason why I went with ski helmet, i could try on 10 different types in different sizes, when as with skydiving helmets, i can not get access to many different helmets types and sizes here in Canada.

Chincup will also help to keep it tight

Quote


If you're hell bent on using your ski lid for this, the easy and simple way is to make a flat top mount of some sheet aluminum. You can start by using some stiff single-ply cardboard to make a mock up.

Use the carboard to create a mock up that will start off looking like a weird 'I' with the vertical part of the 'I' being the same size and shape you want your flat top to be. Now bend the 'legs' sticking out of the flat top down to form a little table. Set this table on top of your helmet where you want to mount the camera. Now trim the legs of the table until the table is sitting as low to the helmet as you can get, and at the right angle you want your camera to sit. Now you have mocked-up your mount, and when you flatten it out, it becomes the pattern for your mount.



I have already done that portion and have a very good idea of how this part will look like, its dimensions and angles.

Quote


You'll need to add an inch or so to the length of each leg. This extra material will allow you to bend it up and make a 'foot' at the bottom of each leg where you can drill mounting holes and run bolts to hold the whole business on.

Now lay the pattern on some sheet aluminum, trace it, cut it, bend it, drill it, mount it, and jump it. That's the easy way.

...

The aluminum job I described above can be done for about $30 bucks, and within 2 or 3 hours. If the helmet itslef turns out to be a dud for camera flying, you're not out that much in time or money.



This is what I wanted to do initially, but i do not have instruments to bend or weld aluminum and manually it does not work well. that is why i started to look at other options
"Gravity is a habit that is hard to shake off"
Terry Pratchett, "Small Gods"

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I pretty much bought the same stuff but I have a cookie MXV helmet. You need the Flatlock adapter for a round helmet. Hope that helps.



as I said it would be the easiest solution, but I do not know which one and with shipping it to canada, it will cost me probably around $80 anyway
"Gravity is a habit that is hard to shake off"
Terry Pratchett, "Small Gods"

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This is what I wanted to do initially, but i do not have instruments to bend or weld aluminum and manually it does not work well. that is why i started to look at other options



Just for reference, you can build a mount with a hacksaw and file to do the cutting, two pairs of vice-grips (or one vice grip and one bench vise) to make the bends, and a drill for drilling.

Even if you have your mind made up, I just wanted to point out to others that you can build an excellent, lightweight mount with hand tools and inexpensive materials. I have built many helmets this way for myself and others, and they have all functioned properly and proved to be very durable.

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A local guy recently did this.



I have seen this. Great work, but looks like a lot of work and an overkill for my purpouse. all I want to do it to attach flatlock to the round top helmet.


It was a lot of work. But, I have the molds!!!! call me at 612-280-9046 Maybe I'd be willing to pull you a part from my molds. Once you have the molds, making the parts is easy. Keep in mind, there might be a good bottle of Canadian Wiskey involved in this deal.....B|
Birdshit & Fools Productions

"Son, only two things fall from the sky."

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Just for reference, you can build a mount with a hacksaw and file to do the cutting, two pairs of vice-grips (or one vice grip and one bench vise) to make the bends, and a drill for drilling.

Even if you have your mind made up, I just wanted to point out to others that you can build an excellent, lightweight mount with hand tools and inexpensive materials. I have built many helmets this way for myself and others, and they have all functioned properly and proved to be very durable.



Totally agree, I just do not have proper material (or experience working with what I have)

I have almost finished making my own box out of aluminum using only the tools that you mentioned above, but I used fairly thin sheet (which is fairly solid when you have it in a box form).
For the mount I would prefer to use something thicker. The stuff that I have is 1/8 inch T6 aluminum sheet, which I could not bend cleanly (plus it starts to break and is fairly heavy)

I think will try what Ronaldo suggested. Now I just need to figure our what is the best epoxy to use with ABS and aluminum
"Gravity is a habit that is hard to shake off"
Terry Pratchett, "Small Gods"

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It was a lot of work. But, I have the molds!!!! call me at 612-280-9046 Maybe I'd be willing to pull you a part from my molds. Once you have the molds, making the parts is easy. Keep in mind, there might be a good bottle of Canadian Wiskey involved in this deal.....B|



Thanks for the offer, but I think your part will probably not fit my helmet (bottom curve). Besides, that way I will not have fun messing up my helmet.
"Gravity is a habit that is hard to shake off"
Terry Pratchett, "Small Gods"

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