Verell, When I sent you the pocket I did not look that closely so your observations are already more detailed than my own. Nothing of value I can add here. On the topic of using a female threaded insert in place of the 2 bottom studs there is no problem that I can think of. Regardless of which way you choose to go, installing the door pocket requires removal of the door card so it is not as though having studs serves to locate the pocket in order to facilitate installation or removal. Once installed there is no visible difference between one mounting technique or the other so I would suggest going with the one which poses the fewest manufacturing challenges and/or provides a stronger insterface. Kind Regards, Paul
From the pic it looks like someone epoxied the bolt in because it was easier than looking for the correct stud. The door plastic was broken so they used what was at hand. I would vote for the stud if possible. Would the stud leave the most amount of plastic around it for strength as opposed to an insert?
Looking at both broken out stud locations, I'm pretty sure that originally a hex head screw was molded in. A stud directly into plastic doesn't work well, it won't be retained & it's very easy to strip the threads. Stud inserts have a body with knurling that prevents it from turning when a nut is being tightened down. It is common to mold a female threaded insert into plastic, much less common to mold a stud in. Neither MSC or McMaster-Carr have stud inserts for plastic, but both have multiple types of female threaded inserts. Hmm, I guess I could make a stud insert by red loctiting a stud into a female insert before molding...
Maybe it was a running thread rod with a hex nut on it? The extension of thread into the plastic boss beyond, past the nut for retention??? We use that trick in concrete inserts sometimes, dropping the rod thru the form and leaving the nut (often another at the end of the rod) in the concrete for pull out resistance. Seems like the long way around to get the result though, vs. a threaded insert/bolt attachment.. *think like an Italian*
Close but no cigar... I should have been more specific about the stud insert's requirements: The threaded stud needs to protrude above the plastic by at least 10mm. Also, for max strength I'd like to mold the insert body about 10mm deep into the plastic, so am looking for an insert with about a 20mm to 25mm long stud. The Yardley M5x0.8 stud's threads are only 7.13mm[0.281"] long which is too short. It wasn't a nut & stud molded in, two different thread sizes: the stud is M5x0.8, the threaded hole extending past the HEX cavity looks to be M4x0.7 with no sign of thread damage. IMHO someone tried was using a M4x0.7 bolt to mount the pocket.
Verell, you could double up on the Yardley stud insert if you possibly used the open ended kind? I am not very apt in the plastic molding processes, but I have done that insert application in woodwork, where I needed to affix a particularly long stud to a beam. Regards, Alberto
Just finished the outer mold shell halves! For more details, & regular progress reports "like" Unobtainium Supply Co. on Facebook.com.
One back: The first half of the mold came out flawed. As best I can tell, the silicone didn't completely flow & fill the gap between the shell & the pattern before it became too viscous. Part of the problem was that it took a long time to vacuum de-air the large batch of silicone before I started pouring it, so it was already thickening when it was poured. I'm pretty sure I've got work-arounds for the problem: - I'm opening up the fill holes from 1/2" to 3/4" which will also help it flow faster. - The silicone will be thinned with a viscosity reducing oil. - I can pour it and vacuum de-air it in place, will mean having to make 3 or 4 small batches & de-gassing each in place, otherwise it would foam out of the shell. The small batches will also help ensure that it doesn't thicken much before it is poured. EXPERIENCE: What you get when things don't work the way you expected them to.
I've modified the mold shell to give me more openings, they will help remove trapped air as well as permitting me to insert multiple funnels so I can get a batch poured into the shell before it thickens much. I'm planning on pouring tomorrow afternoon, most likely will have to make at least 2 pours 24 hrs apart to finish the 1st mold half, so most likely will only finish the 1st half next week.
Poured the 1st mold half again today. Unlike the previous trys, this one seemed to go well. Will know Friday when I separate the mold shells. Key was a combination several things, that I'd tried individually with only partial success: 1) I tilted the door pocket in the outer shell half at about 45 degrees & filled it with mold compound. Then rotated the inner shell hslf into place, squishing the compound. This minimized the chance of viscosity related problems. 2) I added a silicone oil viscosity reducer to the silicone while mixing it. 3) The upper edge of the inner shell had 19mm vent/fill holes every 4 inches or so to allow air elimination & filling. 4) I pullled a vacuum on the filled mold half 3 times, each time trapped air boiled some silicone out of the vent holes that I had to replace. The 3rd vacuuming only removed a small amount of air, leaving the vent holes almost full. Topped them off & called it a day. Check mid to late next week. Assuming the 1st half is good, I should have the 2nd half of the mold completed!! If so, then a couple of more days after that & the 1st part will be cast. I don’t expect the 1st part to be perfect, but should only have some niggling problems to resolve at that point!
When I went to separate the mold shells I discovered some smallk (pencil sized) air voids between 3 of the fill/vent holes due to the shells not being perfectly level. Not a big deal, just need to mix a small amount of mold material & use a level to prevent repeating the problem. Also I'll build up modeling clay around the holes to ensure that the holes get filled. Will do it Monday afternoon after digging out from today's snowstorm, assuming my knees will still let me stand. Otherwise will do it Tuesday.
Inner half of the mold is completed!!! Thursday I received the silicone I needed to complete the mold. It was ordered in early November with delivery expected in 2 weeks. I planned to finish the door pocket mold during my annual 'holiday shutdown' between Thanksgiving & Christmas to make molds & catch up on backlog. Unfortunately it was not to be. In late November I was told it would ship 23-DEC. On 27-DEC was told "Dow had a process problem, will ship 30-JAN". New Years thru April is Unobtainium's peak season as everyone wants to 'get my car ready for driving season'... So I'm juggling production with mold making. Up side is I now have a part time assistant who is offloading some manufacturing, & most p acking & shipping. He is a BIG help as they have been consuming 20%-30% of my time. I should know more about the mold by the end of next week. If all goes well I'll have begun work on the 2nd half. You may even see new door pockets in late Feb.
