Anyone cast their own plastic parts?

[canuck750]

I have been doing some research on casting plastic parts, specifically reproducing the Aprilia signal light lens and the CEV clear plastic fuse cover as used on the V7 Sport / 750S.

Bevel Heaven sells reproduction Aprilia signal lens for $58.00 a piece but I can not find any source for the CEV fuse cover. I could use eight Aprilia lens and at $58.00 a pop I am hoping I could make them for a fraction.

A local plastics supply business sells the silicone mold making material and a variety of optically clear (tintable) urethane resins. Making the silicone molds looks simple enough and the pouring and setting the resins looks straightforward. I have watched several YouTube videos produced by the material manufacturers on how to make a two part mold and pour the resin.

Anyone with real world DIY experience?

On another angle there are online sites to order resin cast parts from Chinese specialty order shops, but I doubt it would be practical without ordering a 100 or more pieces.

[Antietam Classic Cycle]

Have you contacted Greg Clauss to see if he can reproduce them? http://claussstudios.com/

[canuck750]

Wow that is quite the site Charlie, I will check with him.

Thanks

Jim

[Triple Jim]

Greg is well known in the triples community too.

[canuguzzi]

Sometimes 100 pcs  from China is less costly than 5 pcs sourced otherwise. You probably aren't the only one who needs them. Might be able to sell the others and come out with a zero cost for your stuff.

[tris]

These the beasties you're looking for?

http://www.mgcycle.com/index.php?main_page=product_info&cPath=37_156&products_id=1588&zenid=8aca946bf2c5bbfa43be1a42757a3ae0

http://www.mgcycle.com/index.php?main_page=product_info&cPath=37&products_id=3166

Failing that 3D printing?

[ed.bremner]

@canuck750;  If you have a go at moulding your own, please tell us how it goes, or even better take a few photos and write the experience up.

I have often wondered exactly the same thing and as you say, it really looks like it shouldn't be too hard, but I havn't actually put silicon to mould to give it a go.

Would like to though, so tell us how it goes.

eib

[Phang]

These the beasties you're looking for?

http://www.mgcycle.com/index.php?main_page=product_info&cPath=37_156&products_id=1588&zenid=8aca946bf2c5bbfa43be1a42757a3ae0

http://www.mgcycle.com/index.php?main_page=product_info&cPath=37&products_id=3166

Failing that 3D printing?

I think Jim is referring to these -

Am I right Jim? 

[dsrdave]

Casting your own is labor intensive.  There is a lot of hand finishing needed.  The mold has a very limited life also, you may not get 5 pieces off it.  Three d printing is the way to go.  Although I have not tried it, my friend did with very nice results.

[canuck750]

I think Jim is referring to these -

Am I right Jim? 

Yes sir, the Aprilia lens is unique and the CEV clear plastic lid is also unique to the V7 Sport type fuse box.

[canuck750]

Casting your own is labor intensive.  There is a lot of hand finishing needed.  The mold has a very limited life also, you may not get 5 pieces off it.  Three d printing is the way to go.  Although I have not tried it, my friend did with very nice results.

My son has a 3D printer that is large enough to replicate the parts but the plastics he can source are not transparent.

The silicone products made for molds will last up to 100 uses, typical life is 75 uses.

Silicone mold making may be a good Christmas break project to try my luck with.

[lost]

Trying to get optical clarity from a silicone die and poured resin is difficult. I don't think you can get a good enough finish with 3 D if you want to match original. You can get cast cavities in epoxy type materials that would hold up to injection molding a limited number of parts. In order to get a clear optical finish requires a good polish on the cavity. If someone has the equipment to make a metal cavity I can mold the parts, but in low volume the parts are expensive.

Jim

[canuck750]

I stopped in at a local plastics molding / casting supply shop today and took them an original Aprilia Signal light lens and the clear CEV fuse box cover. The guy at the counter told me has sold several kits to guys casting tail lights and signal light lens and there is no problem with getting a clear casting for the fuse cover.

He recommended a silicone mold product, two part mix, high viscosity so I don't need to worry about vacuum extraction of air bubbles out of the silicone as it mixes and this particular silicone is fairly flexible too, given the varied surfaces of the inside of the Aprilia lens and the two screw holes to be able to cast a two part mold and get the original out of the mold. The cure time on the silicone mold is 16 hours. The clear resin is another two part, slow activation, can be injected into the mold pour opening(s) with a small syringe and is tintable, I picked up an orange tint for the lens. I also got a spray bottle of silicone mold release, a couple medium size syringes and non-sulphur content modeling clay for sealing the original item to the bottom of the mold base. I should have enough product to make both of the two part molds and enough resin for at least a half dozen CEV fuse box lids and hopefully 8 signal light lens.

All in the total cost of materials was under $160.00. I need to make up the mold forming boxes, plastic PVC pipe sections recommend for the signal light and I will make a rectangular two part box for the fuse cover.

This will a project for over the X-Mas break, will share my results.

Considering that one repro Aprilia lens costs me about $75.00 CDN I will be way ahead if this works out.

Cheers

Jim

[PeteS]

I've cast about a dozen different parts for model trains. Not labor intensive at all assuming you have an original part to use as a master. I use a Smooth-On  product called OoMoo 30 for the mold. They make quite a few different compounds depending on the application. I use a polyester resin for the part. I have not tried clear plastic yet.
The detail is exceptional. I have a sheet of 1/16 styrene sheet I use to make the container. My photo hosting site has gone belly up and I don't see a way to upload here directly so no pics.

 I use a longer setting resin for the both the mold and casting to allow more time to allow the air bubbles to escape.

http://www.smooth-on.com/

Pete

[canuck750]

I've cast about a dozen different parts for model trains. Not labor intensive at all assuming you have an original part to use as a master. I use a Smooth-On  product called OoMoo 30 for the mold. They make quite a few different compounds depending on the application. I use a polyester resin for the part. I have not tried clear plastic yet.
The detail is exceptional. I have a sheet of 1/16 styrene sheet I use to make the container. My photo hosting site has gone belly up and I don't see a way to upload here directly so no pics.

 I use a longer setting resin for the both the mold and casting to allow more time to allow the air bubbles to escape.

http://www.smooth-on.com/

Pete

I bought the same stuff, Smooth-On products. Glad to hear you have had good results.

Thanks

Jim

[nobleswood]

There's a bunch of topics I'm interested in tonight on the Forum.

 

[averb]

Upside - the cost saving and the satisfaction of making it yourself
Downside - the cast material is not as robust as injection moulded material and I don't think it will stand up to the outdoor environment particularly well, this is offset by the fact that you can always make another one.
Lets face it, its a challenge, you will learn new things and gain news skills, whats not ot like
Steve

[tris]

Upside - the cost saving and the satisfaction of making it yourself
Downside - the cast material is not as robust as injection moulded material and I don't think it will stand up to the outdoor environment particularly well, this is offset by the fact that you can always make another one.
Lets face it, its a challenge, you will learn new things and gain news skills, whats not ot like
Steve

and the up upside is that you can become the mogul for replacement CEV clear plastic lid for the V7 Sport type fuse box and retire to the Bahamas - RESULT 

[canuck750]

I got started on my resin casting reproduction Aprilia orange signal light lens, started with a piece of 4" diameter plastic pipe coupling and cut the bonding seam out of the inside on my lathe, next a flat piece of wood as a base. I bought a block of sulphur free modeling clay to make a sticky base onto the wood. Then I rolled the clay flat and pressed the plastic pipe onto the clay pad. Next I set the original Aprilia signal lens I want to copy onto the centre of the clay pad. A ring of small acorn nuts are presses onto the clay to act as mold pins.



Then mix up a batch of 2 part silicone mold, I used a bag od old rice to fill the empty mold cavity to get a rough idea of how much silicone to mix. Then pour the silicone into the first half of the mold. I sealed the plastic pipe coupling to the wood with more modeling clay.



Mix it for at least five minutes and then slowly pour it into the mold.



24 hours later I pulled the wood base off and removed all of the clay and the acorn nuts.



Then spray the silicone with release agent



Mix more silicone and fit another plastic pipe coupler ring to the mold for the other half of the mold

With a glue gun I glued a fill tube and vent tube mold.



I filled the other half of the mold and wait another day



Then separate the mold halves and remove the fill and vent tube sticks and remove the original Aprilia lens



Now with the original lens out of the mold press the two silicone mold halves back together and mix up the resin

Just one small drop of orange dye for the lens and then using  a scale to measure the correct weight ratios the resin is mixed



Then with a syringe fill the mold through the fill hole and keep filling until resin comes out the vent hole, the mold is set on some mix sticks to tilt the mold slightly with the fill tube at the bottom







Tomorrow I will separate the molds and see how this experiment turns out.

Stay tuned, I hope the resin casting works as good as the mold making.

[Triple Jim]

Great photos, and it looks like it's going very well so far.  I have some Smooth-On products myself, but haven't tried the clear casting resin.  I'm guessing that the orange will be a little on the light side, but I'm probably wrong.        I'm looking forward to more photos.

[lucian]

Very cool process, thanks for taking the extra time to share. Looks like it will be a complete success. Will you have to drill the screw holes after casting?

[Hahnda]

I used to work at a place that did this type of casting on a large scale. A couple things that we did different is that each half of the mold was in a composite wood box. That allowed us to bolt the halves together under a bit of pressure. We also injected under much more pressure than you are using so you might be able to get away with the way you are doing it. We also put the molds in a pressure tank and put them under 80 psi while curing. It was to hopefully reduce the amount of air bubbles in the part.

[canuck750]

First attempt not so good, I need to make round plates for both the top and bottom of the mold and apply clamps to keep the two halves of the mold tight, far too much resin leaked out and the result is an incomplete casting at the base in a couple places.





And the female half of the mold lost the positive piece that forms the bolt hole on one side, will need to recast this half of the mold.



Tiny air bubble in the casting in some areas, I need to figure out how to apply more pressure into the injection or how to ensure I am not drawing air into the syringe while filling the syringe. Maybe if I can get the mold to be super tight fitting I won't see the air bubbles?

Heading back to the dealer tomorrow for more supplies and a second attempt later in the week.

[jbell]

Jim, you're a f***ing wizard.  Simply amazing.  When you retire, you could open your own technical school. 

[bmc5733946]

Maybe putting the whole thing in a vacuum chamber after filling.  With your ingenuity I am sure gou could create one using an a/c evacuation pump and some kind of container.  Vacuum should ensure complete filling of mold and extraction of all air bubbles.  Probably wouldn't need to create more than a few inches of vacuum to make it work so vessel wouldn't need to be able to contain maximum vacuum, six to ten inches would probably do it.  I know I've seen it somewhere, probably one of the auto restoration shows.

Brian

[rbm]

+1 on vacuum.  Try vacuum bags used for fibreglass lamination work.

[canuck750]

I need some help with this vacuum idea, how do I make one, what do I need?

Trying to figure out how a vacuum will draw the resin into the mold and not suck the resin out of the mold??

Any direction would be appreciated.

Thanks

Jim

[Hahnda]

As I said in an earlier post, we used to put them under pressure, not a vacuum. I can't remember the pressure for sure though. That might be easier to rig something up than for vacuum. Worth a try.

[canuck750]

As I said in an earlier post, we used to put them under pressure, not a vacuum. I can't remember the pressure for sure though. That might be easier to rig something up than for vacuum. Worth a try.

How was pressure introduced?

Introducing pressure could be pretty easy.

I can secure the mold shell with rigid caps top and bottom and seal it all with threaded rod at four corners.

Does it make sense to add air pressure direct to the fill port with a regulator and an air fitting? I would assume the vent port would need to be capped.

[Hahnda]

We put the entire mold inside a large pot and then clamped on a lid. Pumped in "x" amount of psi and let it sit until the curing time was up. I seem to remember something like 70-80 psi. Do you have a pressurized paint pot hanging around that is large enough to fit your mold in?



Were I worked at we had really large pots, about the size of a 55 gallon drum, they could hold several smaller molds at the same time.