D.I.Y casting cabinet handles and other bus bits

captincanuck · Posted: Tue Oct 21, 2014 5:07 pm Post subject:

Also made this today

Image may have been reduced in size. Click image to view fullscreen.

I need to sand the bottom down a bit as its a little curved, but overall I like it. And colour is nicer than my yellow junk yard one (on the left)
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1979 Westfalia "FireFly" Subaru 2.2 with Subaru gears 5spd.
Build Thread: http://www.thesamba.com/vw/forum/viewtopic.php?t=634777&postdays=0&postorder=asc&start=0

420GOAT · Posted: Wed Oct 22, 2014 4:52 pm Post subject:

nice job.
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once you realize im not impressed we will get along just fine

eche_bus · Samba Member Joined: October 07, 2007 Posts: 1318

Agreed - very good work. Been PM'ing back forth about the color with captaincanuck and am sooooo appreciative of him stepping up to the plate to make some of these! Very Happy

raygreenwood · Posted: Thu Oct 23, 2014 7:40 am Post subject:

raygreenwood · Posted: Thu Oct 23, 2014 7:42 am Post subject:

captincanuck · Posted: Thu Oct 23, 2014 10:25 am Post subject:

That is a base plate that goes under the faucet and holds the pump switch on a deluxe (or my not so deluxe with a deluxe stove/sink). Rumor has it a repro isn't available and a few folks including eche_bus have contacted me about making one

Still don't know if my handle buttons should be gray? Thoughts?
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1979 Westfalia "FireFly" Subaru 2.2 with Subaru gears 5spd.
Build Thread: http://www.thesamba.com/vw/forum/viewtopic.php?t=634777&postdays=0&postorder=asc&start=0

Bala · Posted: Thu Oct 23, 2014 10:33 am Post subject:

I'd be interested in one of those base plates. I'll shoot you a PM.

Yes, I believe gray buttons is corrrect for '79s.

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1976 Westy

1966 Beetle

raygreenwood · Posted: Thu Oct 23, 2014 1:31 pm Post subject:

captincanuck · Posted: Thu Oct 23, 2014 7:15 pm Post subject:

Nice!
A suggestion....as resins have a different structure both chemically and mechanically....and its a sink part.....take either one of these parts of something else made with the same resin and soak it in a container of water with just a little salt and some dishwashing liquid. The alternately take it out and let it lay in the sun. Alternately back in the water, dry it and then into the freezer. Alternately heat to about 120-150f (the average heat encountered in an enclosed vehicle in the summer).Do this for a few days or a week and then bolt it back up into the sink.

.many resin manufacturers will advertize light safe or UV resistant....but that is not the same as "weatherable". The key is uv exposure with and alternating with heat, cold, moisture and basic water borne chemicals. Weathering is far more destructive than fading. Ray[/quote]

Oooo destructive testing. I like it. Think I even have a long wave UV light kickin around at work.
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1979 Westfalia "FireFly" Subaru 2.2 with Subaru gears 5spd.
Build Thread: http://www.thesamba.com/vw/forum/viewtopic.php?t=634777&postdays=0&postorder=asc&start=0

Tcash · Posted: Fri Oct 24, 2014 11:00 am Post subject:

A lot of info, not Bus but it pertains to the subject at hand.
Thanks to raygreenwood.
Casting new ball joint and tie-rod end boots for 411/412

raygreenwood · Posted: Fri Oct 24, 2014 1:07 pm Post subject:

captincanuck · Posted: Sun Oct 26, 2014 9:43 am Post subject:

captincanuck

Not exactly quantitative testing but I went at the handle with a heat gun. Copy on the left and original on the right. That copy was the first one I made and had 2 bubbles in it (that's why the bottom where the button goes is cracked), that's why it was the victim of this experiment. you can see that by the time the copy started to blister and smoke (it wont melt, just burns eventually) the original was already a floppy mess.

Also tried putting both of them in a -60C liquid bath for a couple hours then hitting them with a hammer. Couldn't break either of them. Just chipped the copy where the bubble was (as seen in the photo)

Still waiting not so patiently for Canada post to deliver my inserts... Confused

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1979 Westfalia "FireFly" Subaru 2.2 with Subaru gears 5spd.
Build Thread: http://www.thesamba.com/vw/forum/viewtopic.php?t=634777&postdays=0&postorder=asc&start=0

raygreenwood · Posted: Wed Nov 05, 2014 4:15 pm Post subject:

Since this is the defacto molding thread...here are some updates on my ball joint boot molds.

Rubber and elastomers are tough. Getting a release agent that works for the original rubber part is not always the same as getting one that works for the casting resin itself. Thats what failed on this second attempt. These were done with Alumilite as well.

The inner boot cores are done with a medium speed epoxy. Its not as accurate...has a slight amount of shrinkage...but thats perfect for these boots because the the final part will be a percentage thicker when I cast it.

I did not originally use the epoxy for the molds.....because it takes so long to cure that eventually the epoxy combined with release agent starts to defeat any tape or glue holding the mold partitions together. Not a big deal...just messy.

The third mold try worked well and its full epoxy. Its a three piece mold.

I know I should be molding these with metal molds but its another 2 weeks until my new low temp metal gets here. I need the boots by this weekend. Trying to get the front end on the ground before really cold weather hits

There are plastic/polyester based super accurate molding compounds...that are even more accurate than the casting metal....but they are just as expensive and prone to bubbles. too expensive to do multiple attempts...and they get medium hot as well.

The new core castings on the delrin baseboard

The core in the boot after separation

The failed mold. It was a two part.. You can see the casting line at the curve in the part on the right.

A different view

This told the tale. This is a front speedo grommet mold. It nearly separated completely. The little tracks in the right hand part are bubbles from the oils in the release agent literally boiling and expanding. The liquid release agent is too low temp to use on this product which gets very hot because it cures in 3 minutes.

These are the new all epoxy three piece molds which were successful so far

You can see the parting line in the deep curve

The best mold releases I like to use are the dry powder sprays, (silicone Urethane etc.)...especially for casting resins like epoxy that dont get hot.

But on non-silicone rubber parts with polyester or urethane casting products like alumilite...you need an oil type physical barrier.
If the rubber is rough or has surface cracks you need an liquid release more oft than not as well.

I sstill have to clean up the mold edges, drill vent holes and feed holes and thread hold down screws through the molds before I can inject silicone.

I dont plan to make many with this mold. If others are interested I may make a metal mold. But...in the next six months I plan to have a better solution for a new ball joint instead of just trying to preserve old ones or NOS ones new boots for the 411/412.
Ray

eche_bus · Samba Member Joined: October 07, 2007 Posts: 1318

Thanks for sharing some the details of the process, Ray. I find this sort of thing fascinating!

raygreenwood · Posted: Wed Nov 05, 2014 6:08 pm Post subject:

The silicone injection/vacuum process is even funkier. Ray

captincanuck · Posted: Wed Nov 05, 2014 9:56 pm Post subject:

So Cool. I wont be at a loss for projects this winter Laughing

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1979 Westfalia "FireFly" Subaru 2.2 with Subaru gears 5spd.
Build Thread: http://www.thesamba.com/vw/forum/viewtopic.php?t=634777&postdays=0&postorder=asc&start=0

raygreenwood · Posted: Wed Nov 05, 2014 11:06 pm Post subject:

The molds look crude....but they actually turned out decent for the materials used. This expoxy had a 7 hour lock up time but stayed very cool. In that, period of time the release agent started attacking the poly coated board I was using for the enclosure....and even went, after the solvent proof tape that was holding it together. I had to add an extra layer just to keep the depth, right.

Thats one of the problems with synthetic lubricants. So the outer shape looks ugly ...but I squared that up this evening and also drilled four .030" vent holes at the top cuff and a single .030" feeder hole at the bottom.

Probably friday night I will try molding a part in it.
I will photograph the mold assembly sequence before I start.

I have a polished delrin plank with guide pins installed. The bottom curvature ring mold gets pinned and adhered to the plank in register with RTV first. Then the core goes in on its pins RTV'd to the board....then a thin smear of rtv between the top and bottom mold layer....then yhe top goes on and the two screws go in to clamp it all together.

Let it dry....and then mix the silicone....and pump it in. I'm hoping I wont need vacuum but im ready to do that at the top vent holes.

Once I get the parts I need to get the car back on the ground I will make an easier to use two piece mold of casting metal with a little bit of shape change to allow me to use a two piece mold.

The outer will be a single mold. The inner shape will be able to slip in so the walls of the cast part will be thicker... Ray


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D.I.Y casting cabinet handles and other bus bits
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