Packaging -- Rubber Baby Buggy Bumpers

Maybe look at that self skinning foam overmolding. Similar to auto dashboards.

It could also be done using low shore urethane. Molds don't have to be fancy - machined ally.

Similar to this:

O ring splicing kit:

I bought a tube of this to seal a fender lip repair. It looks interesting for molding flexible parts, perhaps in wax molds cast from a positive pattern since it takes time to set. :

-jsw

Find an O-ring size that suits. You can mill groves to that you can run multiple rings crossing for multi-directional bumpers.

"Ecnerwal" wrote in message news: snipped-for-privacy@88-209-239-213.giganet.hu...

There is generic rubber weatherstripping for restorations:

-jsw

If you want just the perimeter protected take a look at the self fusing silicone tapes they sell.

If you want something like the snap on shells sold for cell phones/tablets you might consider a 3D printer. Would also be handy for prototyping.

A possible thing would also be to make a metal form the same size as the item, place it on a handle and spray it with a layer of truck bed coating. You can get those in a range of textures and feel from slick and solid to rubbery and flexible. Many can be colored as well.

Spray on, let cure, trim the edge and pop off the mold. Should snap onto the item.

RTV Silicone rubber! (Perhaps GE RTV-11 for white, if I remember correctly.

Molds made by 3-D printing. A bit o f tricky design to allow the RTV parts to be extracted after they cure.

The 3-D printing should allow fairly easy updates.

Broken arm, so I am not as wordy as usual.

Enjoy, DoN.

On 2 Nov 2014 01:09:49 GMT, "DoN. Nichols" Gave us:

RTV-11 is for HV pow4er supply potting, and it has such a weak shear strength, you could tear a block of it with a sneeze.

Absolutely the wrong stuff for a molded "case wrapper.

Polyurethane is the right stuff. Get some that allows you to foam it just as it loses pot life, and the foam ill set into the medium, costing you far less, and actually doing the job better.

Conap is nearly bullet proof. Expensive and heavy, which is why you need a foaned variety.

This is in no way like packing foams.

How do you foam it?

How do you foam it?

===============================================================

Mix part a with part b for about 45 seconds and pour while it foams, total pot life about 90 seconds. I know I have posted their link before but I'm a happy customer - contact

for advice and products. I've used a few of their polyurethanes, both to pull molds off of a small original and to cast flexible and rigid pieces. If you check the op's dimensions I don't think 3d printing is going to work for moldmaking;

25x150x600 mm or 1x6x24" is larger than any of the low end printers. I think this would be an easy mold to mill in aluminum, or maybe even rout into a wood frame then sand and varnish until smooth. Make an outer piece for each side and if wood, shape all four thin sides of a 2x6" board for the inner piece, then screw each outer piece to a side to create a c shaped channel for the mold cavity. You could even do it with a dado blade on a table saw since there are no pocket "ends" to worry about. Tweak the overall size to allow for some shrinkage in the cure and to give a snug fit. Provide multiple fill and vent holes. See what smoothon recommends, either silicone or polyurethane rubber or polyurethane foam rubber.

----- Regards, Carl Ijames

**********

OK on the foam. Regarding molds, I'd make a sweep mold ("running mold") out of Plaster of Paris. It's cheap, fast, and easy. I've used it to make replacement pieces for crown molding.

This one is pretty elaborate. Mine was much simpler. I sawed and filed the template our of 1/8" Plexiglass, which I happened to have on hand:

It's worth watching it being done:

You can get really elaborate with sweep-molding techniques. I've watched experts making slip-casting molds for complete toilet bowls using this method. Straight lines are much easier, of course.

There are lots of ways to skin this cat. I was thinking in terms of a complete rectangle with the corners molded in, while I think you are thinking of casting a linear piece and then gluing the ends together. Never seen details of sweep molding before, thanks. Kind of comes down to what kind of hammer you are holding, to determine what your nail will look like :-). I think the op has lots of options now.

----- Regards, Carl Ijames

===============================================================

Mix part a with part b for about 45 seconds and pour while it foams, total pot life about 90 seconds. I know I have posted their link before but I'm a happy customer - contact

for advice and products. I've used a few of their polyurethanes, both to pull molds off of a small original and to cast flexible and rigid pieces. If you check the op's dimensions I don't think 3d printing is going to work for moldmaking;

25x150x600 mm or 1x6x24" is larger than any of the low end printers. I think this would be an easy mold to mill in aluminum, or maybe even rout into a wood frame then sand and varnish until smooth. Make an outer piece for each side and if wood, shape all four thin sides of a 2x6" board for the inner piece, then screw each outer piece to a side to create a c shaped channel for the mold cavity. You could even do it with a dado blade on a table saw since there are no pocket "ends" to worry about. Tweak the overall size to allow for some shrinkage in the cure and to give a snug fit. Provide multiple fill and vent holes. See what smoothon recommends, either silicone or polyurethane rubber or polyurethane foam rubber.

----- Regards, Carl Ijames

**********

OK on the foam. Regarding molds, I'd make a sweep mold ("running mold") out of Plaster of Paris. It's cheap, fast, and easy. I've used it to make replacement pieces for crown molding.

This one is pretty elaborate. Mine was much simpler. I sawed and filed the template our of 1/8" Plexiglass, which I happened to have on hand:

It's worth watching it being done:

You can get really elaborate with sweep-molding techniques. I've watched experts making slip-casting molds for complete toilet bowls using this method. Straight lines are much easier, of course.

The basic technique is used mainly in restoring or reproducing old architectural moldings, today, but it's an old method that was used for many more things. The "sweeping" can be performed around curves -- thus the bathroom-fixture example I gave. It was widely used for making plaster slip molds for ceramics. That was a very skilled craft at one time.

If you have a steady hand, it's not difficult to sweep arcs, as well as straight lines. And it's kind of fun.

I've also tried doing it with polyester body putty, using liquid polyester resin for a lubricant. I can't say I ever got good at it, but I saw that it wouldn't take much practice to do it well. I like plaster because it's as cheap as I am, and that's pretty cheap. d8-)

Ed Huntress

Spectacularly stupid trip/flip exiting High-School Auditorium seat row. Caught folding desk arm between legs. Converted momentum to

180 degree flip while right arm hooked on back of seats or arm.

sheared ball joint and muscle attachment spur off end of long bone (Humerus) right below shoulder.

Got X-rays on CD, and should have CAT scan CD next week. Scan done, CD burner down last Thursday.

Fun talking to radiologist and CAT tech, even with the pain. The CAT tech not used to patients who know what CAT stands for, let alone how it works. :-)

Spectacular bruise color patterns.

Maybe a web page after I can type better again. :-)

Enjoy, DoN.

[ ... ]

That's (HV) what we used it for -- decades ago. Not *that* easy to tear back then, but ...

We also had some three-digit stuff which was a deep red, sort of like Glyptal -- also from GE.

Sounds good. Hope he has a vacuum chamber for the foaming.

Probably from later than my late-'60s experience.

Enjoy, DoN.

And a tray to catch the overflow. My vacuum oven had a thick buildup of epoxy baked onto the bottom that was a lot of work to chisel out.

Condolences to Don "Stuntman" Nichols.

That's gotta hurt...

Yes, fun. I love talking to doctors, techs, chiropractors, masseuses, etc. All it takes is a little attention to life as you live it to gain enough knowledge over the years to talk intelligently to these folks. It's even more fun to help braindead workers into discovering your vehicle's actual dilemma when they can't do it themselves.

Excellent! We'll be waiting for those pics. Hmm, got video of the actual fall, too?

Owwww! That sucks bad, DoN. Sorry to hear.

Pete Keillor

Amen!

Thanks, DoN.