wtc endcaps - advice - info needed

[wolfsong]

hi Guys,

i have to make several (10) endcaps in different sizes (2"-2.5" -3")and need some advice.
i have no lathe, just a drillpress and a dremmel to start of.

i have already tried to cast a set out of polyester resin.. one turned out ok.. the other one... well got hot and busted the mold i made..

any thoughts on the resin ? any better material out there ?
i kinda like the casting idea.. that way it fits without having to use a lathe and i can make several in the same size (if my mold holds up)

thanks a lot
stefan

[boss subfixer]

Stefan,
Have you tried using a

Stefan,
Have you tried using a slice, if you will, of the wtc tube as your mold for the end caps? It's quite easy. Cut a slice to the thickness you want your end caps to be then wrap the outside diameter with something thin a rigid, I use very thin sheet teflon,with enough added to the top to make a flange. Then you pour your resin and when it cures, presto, instant end cap. You will have to cut an o ring groove in it though. The drill press should be able to handle that chore. As for resin check out smooth on products Here
I got the idea of using a piece of the wtc material from Big Dave and I believe he also uses smooth on casting resin for his end caps, I've used the smooth on casting resin for making parts for my Fleet boat and the stuff works really good.
Good luck and keep us posted as to your progress.

[Guest]

Use polyurethane resin to cast

Use polyurethane resin to cast the caps.

If you use polyester, make sure the resin has a filler added into it, otherwise the exotherm will be too high- that's what burned your mould out.

Andy

[wolfsong]

thanks a lot for the

thanks a lot for the advice..

i will keep you guys updated on my projects

stefan

[tmsmalley]

Long time SubCommittee guy -

Long time SubCommittee guy - Fung Pang - has a nifty (and CHEAP) way to make endcaps without a lathe.

He cuts a length of the WTC tubing to act as a mold (he uses PVC pipe). Wraps the outside with a piece of styrene to make the lip of the endcap and cuts a couple of notches out of the WTC tubing so you get ears to grab onto when you remove the endcap on your sub. Then a PVC pipe endcap goes over that (I think - I haven't tried this yet).

He cuts the O-ring groove by making a jig that the endcap can rest up against on a Dremel drill press and uses a Dremel round bit and rotating the endcap blank against the bit as the bit is running.

Note - when he took the photos he didn't have his usual Dremel bits (#199, #198) in the chuck - so he stuck one of his others in there, but you get the idea.

Here are his instructions.

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How to make odd size end cap

Why odd size? You could buy a standard one, why make it?
I need a cheap WTC to go in my cheap sub! That means I have no lathe! Not everyone knows how to use one - I don't!

I use part of the pipe as a mold, to cast an endcap, so any size pipe can be used.

For how to make a mold and casting, goto "smooth-on's website" but there is no free lunch. Most castings shrink, not too much on the small pipe, but the big pipe is a bit on the loose side.

Another thing to remember - the inside of most PVC pipe is not round.

All these end caps are made for pvc pipe you find cheaply in a plumbing store.

It could be any type of pipe.



small one is 2", the big one 3".




The taps are to make remove the end cap easy (I copied this from another Subcommittee member's idea )

Making the mold...

One ring goes on top of the other.

Outside ring made from card stock, about ½ inch tall,
center ring is made from pvc pipe end cap, with cut out for taps (ears), about ½ inch tall

note]http://home.att.net/~cheap-sub/endcap4.jpg[/img]

Cutting the end off a PVC pipe cap with saw in Dremel drill press



This is a setup on a dremel drill press, a real drill press will do even better with lower rpm and more torque.

I set this up to take a picture, but it is a bit misleading.

The cutting bit should move in to the chuck little more, the spacer should be on the cutter.

Think of it as a router table, I start up on the Dremel router table setup with the stopper, it works very good on the end cap, until I try the taped end cap!




This doesn't show the pins that go on the baseplate of the drill press that you push the endcap up against to get an even depth cut.



I use the drill press as a upside down router, use brass tubing on the cutter as a spacer to adjust how deep it cuts and move the drill up or down to cut the width of the O ring, or just as Deep Sea Designs shows at http://www.deepseadesigns.net/wtcplans.html

Cutters - Dremel #199, #198 and spacers [brass tubing] to cut the grove for the 'O' ring

The brass tubing goes on to the shaft of the cutter, one after anther to build it up, so it will not cut too deep,
or the Dremel will jam to a stop. I like to run my Dremel at low speed, if i can, don't want to smoke it.

The cutter is thinner than most of the “O” ring that I find.

To fix this set the first cut at the high point of the cut, turn the end cap as the cutter cut in to it, when finish cutting around the end cap.

Put some paper under the end cap, this will adjust the end cap higher for next cut, check for size.

Add paper, cut, check, add paper, cut, check, remove brass tubing., cut remove paper cut, check, remove paper cut check.

Put a vacuum next to the cutter so it sucks up all the PVC cut out of the groove to stop the indoor snow storm!



Here is a view of the jig used for cutting the groove.

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Thanks FP for the great idea!