John Kimball

Check this out if you want to try your hand at making your own set of walking poles. Not telescoping, but super light.

Any and all carbon fiber / epoxy products are susceptible to UV degradation over time. As Rock West's tubes are made of an Epoxy matrix, they will degrade over time. That time is a function of UV, so the area you are in will determine that lifespan. Usually, it first appears as yellowing of the resin (but the amount of yellowing is determined by epoxy resin type), then it may oxidize on the surface and start to expose the fibers. You can clear coat the tubes with an automotive clear coat with UV inhibitors to prolong the life. However, without proper prep, the UV coating can begin to peel and blister.

First off, we don’t condone reverse engineering or duplicating somebody else’s product. Having said that, in my opinion, That insole will use a special resin system and or proprietary process to achieve the desired flex in the right places, while creating support where flex isn’t wanted. If they are as flexible as they say, then it won’t be a standard epoxy prepreg as those materials are designed for stiffness rather than flexibility. By using a more elastic resin system, they can get good flex, but stiffness is compromised.

1 bar is equivalent to 29 inhg. This can be achieved at sea level, but nothing more. 3 bar is not achievable with vacuum. This is equivalent to ~42 psi. This can only be achieved with mechanical pressure (press or clamp) or a vacuum bagged and autoclave cure process. Even cello wrapped parts, like the video above, will have limits on external pressure and is entirely controlled by the number of wraps you can put on the part and the tension of the cello tape.

Testing a scale version of the part out of an arbitrary material won't necessarily give you a data point that you can use as you aren't using that same material or construction that you would use on your 1:1 version. And as composites are hard to scale for testing purposes, I don't see any advantage to building a scale version for strength testing. However, you can build a section of the actual planned structure and test that for stiffness, bending, etc. you will need to extrapolate from there to see if get what you need. This is how aerospace designers quantify the materials they plan to use. you will need to find a test house and determine what tests will quantify your needs. You can also rig up your own static load tests if you know what you are looking for.

I have a spreadsheet calculator, but don't think I can post that type of file on here. But if it is a wet layup or infusion, you can use the same weight as your fiber for a good start. just weigh your cloth, and if it weighs 100 grams, then you can start with 100 grams of resin. With infusion, you will need to add extra to account for the tubing and flow media. Hope this answers your question.

@Anthony Fairhurst, here's the BOM. You can pick and choose what you need for your application.

I’m still working on the BOM, but should be able to get something soon. I really like my PID with Bluetooth. It doesn’t necessarily record, but you can monitor it with a nice graph. However, if you walk away and lose Bluetooth, you lose the record. I use my iPad to record, so I can walk away. The screenshot below is an example of what it can do. Just keep in mind that it can only show 1 thermocouple. The 3 values are: Set point (red), TC value (blue) and power input (green)(% of full power).

Shouldn’t be a problem. It’ll take me a minute to collect it though. the best part is that you could do this same thing with an old kitchen oven if you need larger space.

Welcome to the forum. I can’t wait to see what you do and your thought process along the way.

Please! I’m blushing. And keep at it.

Loft is the materials ability to rebound after being compressed or in other words, the fluffiness of the material. And the value is the relevant value for the insulation or sound absorption. For instance, more lofty insulation will have a higher “R” value which is a number assigned for how well it insulates. With sound deadening it’s similar, but most sound deadening is foam, but batting can be used as well.

I think the short answer is that you will need at least 2 layers for something like this. One layer would be too flexible, especially at the tab and connection point. I would still be concerned about the heat of the exhaust pipe. Just try to keep the composite clamp below 200F or you could see some issues.

Dan, As you have come to hear me say too many times: “it depends”. Sandblasting is an acceptable way to prep a surface for bonding, but is only the first step. proper cleaning is just as important. Also you consider what blast media you use. For metal, sand is excellent as it won’t damage the metal too severely, but can if you blast too long. With composites, it is plastic and much softer than sand, so it can blast right through the resin and fibers quite quickly. for softer materials like plastic and resin, you can use media like walnut shell or baking soda (you can get a 5 lb bag at Costco). These should pit the surface, but not erode it like sand would. But you will still need to clean it aggressively to get any embedded particles out. You can use a stiff brush to help clean it with IPA.

I’ve been thinking about this today and a few things came to mind. I think you should go with the 4 ply, but maybe consider the orientation of the mold while curing to increase the flow of air to the path of least resistance. maybe up side down or at a 45 degree angle. Also, if your edges are not filled with resin and fiber, then the majority of trapped air will simply fill those voids before it has a chance to leave the mold. For vents, try a couple to start at opposite sides of the tool and tilt the tool at a 45 to allow air to travel up. RTM molds will sometimes fill from the bottom and push air out the top as it fills. What you suggest above should work. Start small and adjust from there. I’ve also heard of people vacuum bagging their compression tools to help evacuate air. Yours is small enough to give it a try. Also,I noticed that you are using a kitchen oven to cure. you have to be careful when doing this as the oven will try to heat up as fast as possible. This can flash cure the surface closest to the heat source and prevent percolation of air in the resin. maybe heat the oven to it’s lowest setting before putting your part in the oven and then slowly increasing the heat by 50F every thirty minutes until you reach cure temp, then hold for 90 - 120 minutes. Ideally, you want to heat the parts at a rate of 2.5 - 5 degrees F per minute. this allows the tool and the material to heat up at the same rate. there’s a lengthy post on how to modify an oven with a temp controller on here somewhere if you’re bored.