Is that an acceptible term? What I want to do is reproduce this item…
It’s a handle for a marine hatch. It has an angled tang on the end that applies clamping pressure on a bracket when it’s turned.
It looks like a cast plastic part. I don’t know what kind of resin its cast from, anybody know? I imagine I could produce a mold from the info here and try a few experiments. Any insights on how to go about it would be appreciated.
Could a casting resin w/chopped carbon fiber work?
The back, left side, looks a bit 3d. More than a one piece mold will be needed. Can you see a parting line?
If so, you can do a standard 2 part mold along the same lines.
You can mold it with anything if you have an injection port and a way to inject something!!! Maybe layup chopped carbon inside, clamp together, and inject resin / carbon powder or pieces from a kitchen marinade syringe. They normally have big tubes and luers.(sp?)
It looks like there’s a good parting line there along the tang you can see it. I’m going to order one tomorrow so I’ll have it in hand. Definitely a two part mold job. The thumbscrew should be easy I’ve seen black nylon screws that’ll work. Can you buy milled carbon fiber like you can in fiberglass?
Are you certain the part is plastic? Looks to me like anodised aluminuim investment casting.
Just checked the e-Bay listing. They’re definitely plastic.
Should be easy 'nuff to copy! I’ll need to make at least 18 and maybe more. My next project will be a prototype deck hatch. Probably going to have to make a mold for that too. Should be fun! 
probally injected abs plastic. have fun reporducing that part
We’ll give 'er a shot. What’s a few more hundred bucks in wasted materials eh? 
I wouldnt worry about the waisted material, it would be the numourous hours putting in to making it
Not much else to do up here in the winter when its -30 degs C outside! We have to have some distractions other than watching hockey, cooking back bacon, drinking beer and feeding the sled dogs! 
haha, atleast make your own version of this handle, make a different shape and use carbon fiber and a core material
If the original is plastic then its probably going to have been injection moulded, which will mean the unit cost is very cheap.
Making something like this at home looks an interesting project, but very labour intensive, and and I would think pretty costly, so fine as a hobby type thing, but maybe not a good idea commercially.
good point! think outside the box. if there is somethign you can change that might make it easier to make, do it!
As for milled fiberglass? Like, CNC machined G10 blocks. I’m sure somewhere. Or make your own CF block and mill it.
WOO! Maybe use glass renforced silicone mold. You can cut the mold as needed, maybe just enough to wiggle the piece out, not fully in half!
Good idears. I’ve done a lot of silicone molds for model railway stuff. This part isn’t all that big so it should be easy 'nuff to do. I like to build things so when they break I can just make more (and better hopefully). Our boat will require about half a dozen hatches which are my next project (a prototype). I priced out the six offshore type hatches and really don’t want to re-mortgage my house to buy them. I wimped out and bought some oval portlights (portholes) off of e-Bay 'cause they were cheap! Those and the windows will be the only production pieces on the boat. Everything else, doors, hatches etc. I’ll make.
I have some acetal delrin stock kicking around. If I can find someone to mill it from a CAD drawing that’d make a cool mold. It’s virtually indestructable and nuttin’ sticks to it!
Would powdered graphite add anything to a casting resin’s strength? I was thinking of concocting a mix of milled glass fibers, graphite and resin to see how that works. I think I can figure out how to inject it into a closed mold easy 'nuff.
You might want to buy a cheap DVD (but great along these molds) from http://www.freemansupply.com “Making Parts, Patterns, tools and Molds”
1 (800) 321-8511
And dont forget to watch the free tutorials on freeman. They are pretty good.
Now if someone would convince freeman to get rid of that stupid “quote” system and get a real shopping cart I would be one happy camper.
Not sure whether saving money, and doing things on the cheap is that great an idea when it comes to marine type items!
Thats almost like that old car saying: Cars can be cheap, fast, or reliable. But never all three at the same time.
Sorry, cheap was the wrong word to use. I should have said “good deal”.
These usually sell retail for over $200. I got 4 for $59 each.
That looks very good…what though would be the result if your home made latches failed due to something like UV degradation?
Personally I would get some latches made out of stainless steel, with nylon inserts where they contacted anything plastic.
The biggest problem with hatches on boats is that over time UV will cause the lexan or plexy to craze and possibly crack. The frame I intend to make will be glass over foamcore and painted. Some have problems with various sealants but those are improving. A product called “Sikaflex” works well and lasts many years.
Unless you use marine grade SS (306 & 316L) you’ll end up with corrosion problems. I’m working very hard to eliminate as many metal parts from the boat as possible. We’ve got a 20 yr old boat now who’s hatch dogs are plastic and there’s absolutely no problem with them.