Wildguzzi.com

General Category => General Discussion => Topic started by: canuck750 on December 09, 2015, 09:46:16 PM

Title: Anyone cast their own plastic parts?
Post by: canuck750 on December 09, 2015, 09:46:16 PM
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.
Title: Re: Anyone cast their own plastic parts?
Post by: Antietam Classic Cycle on December 09, 2015, 10:06:56 PM
Have you contacted Greg Clauss to see if he can reproduce them? http://claussstudios.com/
Title: Re: Anyone cast their own plastic parts?
Post by: canuck750 on December 09, 2015, 10:10:49 PM
Wow that is quite the site Charlie, I will check with him.

Thanks

Jim
Title: Re: Anyone cast their own plastic parts?
Post by: Triple Jim on December 09, 2015, 10:37:25 PM
Greg is well known in the triples community too.
Title: Re: Anyone cast their own plastic parts?
Post by: canuguzzi on December 09, 2015, 10:53:55 PM
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.
Title: Re: Anyone cast their own plastic parts?
Post by: tris on December 10, 2015, 01:20:24 AM
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_156&products_id=1588&zenid=8aca946bf2c5bbfa43be1a42757a3ae0)

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

Failing that 3D printing?
Title: Re: Anyone cast their own plastic parts?
Post by: ed.bremner on December 10, 2015, 03:12:15 AM
@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

Title: Re: Anyone cast their own plastic parts?
Post by: Phang on December 10, 2015, 04:23:21 AM
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_156&products_id=1588&zenid=8aca946bf2c5bbfa43be1a42757a3ae0)

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

(http://img.photobucket.com/albums/v198/Phang/PDSCN1517_zps8dba5cf9.jpg)

(http://img.photobucket.com/albums/v198/Phang/PDSCN1523_zpsddfe615a.jpg)
Title: Re: Anyone cast their own plastic parts?
Post by: dsrdave on December 10, 2015, 05:15:32 AM
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.
Title: Re: Anyone cast their own plastic parts?
Post by: canuck750 on December 10, 2015, 08:55:18 AM
I think Jim is referring to these -

Am I right Jim?  :grin:

Yes sir, the Aprilia lens is unique and the CEV clear plastic lid is also unique to the V7 Sport type fuse box.
Title: Re: Anyone cast their own plastic parts?
Post by: canuck750 on December 10, 2015, 08:58:56 AM
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. :wink:
Title: Re: Anyone cast their own plastic parts?
Post by: lost on December 10, 2015, 12:33:01 PM
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
Title: Re: Anyone cast their own plastic parts?
Post by: canuck750 on December 10, 2015, 04:49:08 PM
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
Title: Re: Anyone cast their own plastic parts?
Post by: PeteS on December 10, 2015, 05:23:48 PM
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/ (http://www.smooth-on.com/)

Pete
Title: Re: Anyone cast their own plastic parts?
Post by: canuck750 on December 10, 2015, 05:36:38 PM
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/ (http://www.smooth-on.com/)

Pete


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

Thanks

Jim
Title: Re: Anyone cast their own plastic parts?
Post by: nobleswood on December 10, 2015, 08:49:36 PM
There's a bunch of topics I'm interested in tonight on the Forum.

 :popcorn:
Title: Re: Anyone cast their own plastic parts?
Post by: averb on December 11, 2015, 12:46:47 AM
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

Title: Re: Anyone cast their own plastic parts?
Post by: tris on December 11, 2015, 01:12:44 AM
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  :bow: :bow: :bow:
Title: Re: Anyone cast their own plastic parts?
Post by: canuck750 on December 26, 2015, 08:23:16 PM
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.

(http://i249.photobucket.com/albums/gg217/canuck750/Resin%20Casting/DSC04888_zpseqstnnnn.jpg) (http://s249.photobucket.com/user/canuck750/media/Resin%20Casting/DSC04888_zpseqstnnnn.jpg.html)

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.

(http://i249.photobucket.com/albums/gg217/canuck750/Resin%20Casting/DSC04889_zpshol8wfqv.jpg) (http://s249.photobucket.com/user/canuck750/media/Resin%20Casting/DSC04889_zpshol8wfqv.jpg.html)

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

(http://i249.photobucket.com/albums/gg217/canuck750/Resin%20Casting/DSC04891_zpsimskeczf.jpg) (http://s249.photobucket.com/user/canuck750/media/Resin%20Casting/DSC04891_zpsimskeczf.jpg.html)

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

(http://i249.photobucket.com/albums/gg217/canuck750/Resin%20Casting/DSC04893_zpsamymcf40.jpg) (http://s249.photobucket.com/user/canuck750/media/Resin%20Casting/DSC04893_zpsamymcf40.jpg.html)

Then spray the silicone with release agent

(http://i249.photobucket.com/albums/gg217/canuck750/Resin%20Casting/DSC04894_zpskefef7u5.jpg) (http://s249.photobucket.com/user/canuck750/media/Resin%20Casting/DSC04894_zpskefef7u5.jpg.html)

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.

(http://i249.photobucket.com/albums/gg217/canuck750/Resin%20Casting/DSC04895_zps5eeqvdln.jpg) (http://s249.photobucket.com/user/canuck750/media/Resin%20Casting/DSC04895_zps5eeqvdln.jpg.html)

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

(http://i249.photobucket.com/albums/gg217/canuck750/Resin%20Casting/DSC04896_zps4tfourrw.jpg) (http://s249.photobucket.com/user/canuck750/media/Resin%20Casting/DSC04896_zps4tfourrw.jpg.html)

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

(http://i249.photobucket.com/albums/gg217/canuck750/Resin%20Casting/DSC04899_zpsllwsyjbl.jpg) (http://s249.photobucket.com/user/canuck750/media/Resin%20Casting/DSC04899_zpsllwsyjbl.jpg.html)

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

(http://i249.photobucket.com/albums/gg217/canuck750/Resin%20Casting/DSC04901_zpsvbdavdc5.jpg) (http://s249.photobucket.com/user/canuck750/media/Resin%20Casting/DSC04901_zpsvbdavdc5.jpg.html)

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

(http://i249.photobucket.com/albums/gg217/canuck750/Resin%20Casting/DSC04902_zpslknqym9t.jpg) (http://s249.photobucket.com/user/canuck750/media/Resin%20Casting/DSC04902_zpslknqym9t.jpg.html)

(http://i249.photobucket.com/albums/gg217/canuck750/Resin%20Casting/DSC04904_zpsc3fskpbr.jpg) (http://s249.photobucket.com/user/canuck750/media/Resin%20Casting/DSC04904_zpsc3fskpbr.jpg.html)

(http://i249.photobucket.com/albums/gg217/canuck750/Resin%20Casting/DSC04905_zpswnc0fhyi.jpg) (http://s249.photobucket.com/user/canuck750/media/Resin%20Casting/DSC04905_zpswnc0fhyi.jpg.html)

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.
Title: Re: Anyone cast their own plastic parts?
Post by: Triple Jim on December 26, 2015, 08:30:10 PM
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.    :laugh:    I'm looking forward to more photos.
Title: Re: Anyone cast their own plastic parts?
Post by: lucian on December 27, 2015, 09:12:08 AM
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?
Title: Re: Anyone cast their own plastic parts?
Post by: Hahnda on December 27, 2015, 09:38:18 AM
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.
Title: Re: Anyone cast their own plastic parts?
Post by: canuck750 on December 27, 2015, 11:31:59 AM
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.

(http://i249.photobucket.com/albums/gg217/canuck750/Resin%20Casting/DSC04910_zpsucmgoxvk.jpg) (http://s249.photobucket.com/user/canuck750/media/Resin%20Casting/DSC04910_zpsucmgoxvk.jpg.html)

(http://i249.photobucket.com/albums/gg217/canuck750/Resin%20Casting/DSC04911_zpsu32kshxi.jpg) (http://s249.photobucket.com/user/canuck750/media/Resin%20Casting/DSC04911_zpsu32kshxi.jpg.html)

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.

(http://i249.photobucket.com/albums/gg217/canuck750/Resin%20Casting/DSC04912_zpsdn8svlf0.jpg) (http://s249.photobucket.com/user/canuck750/media/Resin%20Casting/DSC04912_zpsdn8svlf0.jpg.html)

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.
Title: Re: Anyone cast their own plastic parts?
Post by: jbell on December 27, 2015, 04:00:45 PM
Jim, you're a f***ing wizard.  Simply amazing.  When you retire, you could open your own technical school. 
Title: Re: Anyone cast their own plastic parts?
Post by: bmc5733946 on December 27, 2015, 06:15:03 PM
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
Title: Re: Anyone cast their own plastic parts?
Post by: rbm on December 27, 2015, 06:33:34 PM
+1 on vacuum.  Try vacuum bags used for fibreglass lamination work.
Title: Re: Anyone cast their own plastic parts?
Post by: canuck750 on December 27, 2015, 10:13:21 PM
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
Title: Re: Anyone cast their own plastic parts?
Post by: Hahnda on December 27, 2015, 10:17:23 PM
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.
Title: Re: Anyone cast their own plastic parts?
Post by: canuck750 on December 27, 2015, 11:40:32 PM
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.

Title: Re: Anyone cast their own plastic parts?
Post by: Hahnda on December 28, 2015, 07:43:51 AM
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?

(http://d2pbmlo3fglvvr.cloudfront.net/product/full/Z_LB2yfo5oy.JPG)

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.
Title: Re: Anyone cast their own plastic parts?
Post by: dibble on December 28, 2015, 08:14:13 AM
If you pressurise will any air bubbles that do form be at 70psi and likely to pop at stp?
Title: Re: Anyone cast their own plastic parts?
Post by: PeteS on December 28, 2015, 09:10:18 AM
If you mix your molding materials and casting materials slowly, air bubbles are not much of a problem. Keep it simple. It looks like you will need to clamp you two pieces of mold together better though. Maybe just use a big C clamp and some disks made to fit your molds.

Pete
Title: Re: Anyone cast their own plastic parts?
Post by: Toystoretom on December 28, 2015, 09:26:03 AM
Stuart on the RE5 forum (T140V) has made some nice tennis ball lenses and sells them on E Bay. (Tennis ball lenses are for the 1975 RE5 M are the turn signal lenses for the Italian styled space cowboy bike that no one liked back in the day but everyone wants now). NOS or even nice used are unobtainium now....

http://re5rotary.proboards.com/thread/2062/reproduction-indicator-lenses-relist-191662638473 (http://re5rotary.proboards.com/thread/2062/reproduction-indicator-lenses-relist-191662638473)

Possibly he could help?

Tom
Title: Re: Anyone cast their own plastic parts?
Post by: rbm on December 28, 2015, 10:00:36 AM
To do laminating work, vacuum bags are sold that have a "Ziploc" style opening to introduce the object and a vacuum port to extract the air.  The act of drawing the vacuum will draw air bubbles out of the solution as the air is removed from the closed bag.  Furthermore, atmospheric pressure on the mould at full vacuum will provide the pressure needed to close all the gaps in the mould halves (14 PSI at sea level).

An old refrigerator compressor can be repurposed as a vacuum pump.  Many designs available on the Internet.  Search Google for "vacuum bagging"
Title: Re: Anyone cast their own plastic parts?
Post by: canuck750 on December 28, 2015, 10:09:03 AM
The Suzuki lens; look great!

I may look for a used pressure pot, looks to be the best way to go.
Title: Re: Anyone cast their own plastic parts?
Post by: bmc5733946 on December 28, 2015, 10:12:04 AM
 Any vessel that would contain pressure will also contain vacuum.  Vacuum can be made several ways.  Automotive shops use vacuum pumps to evacuate moisture from A/C systems.  I have seen venturi type modules that use only shop air to create vacuum on one side.  Here's an example (http://www.instructables.com/id/Venturi-Vacuum/)   These can also be purchased at auto supply houses.  A/C systems need thirty inches of vacuum to remove moisture from the system but I think you could get by with much less for your use.  Pressure can't remove the air only compress it, that might work.  Vacuum will remove the air from the vessel and therefore from the mold.  Since the whole affair would be under vacuum the air would be removed leaving behind the resin in the mold.  So you would put the mold in your vessel, seal it, pump a vacuum, leave the vacuum pump running on it for the cure time.  Your vessel wouldn't need to be perfectly sealed as the pump (or other vacuum creator) would continue running.  Just spitballing here.

Brian
Title: Re: Anyone cast their own plastic parts?
Post by: PeteS on December 28, 2015, 10:33:51 AM
The Suzuki lens; look great!

I may look for a used pressure pot, looks to be the best way to go.

Are you seeing air bubbles in your lens? They are not evident in your pictures. The only problem I see is liquid seeping into the mold joint. One of the advantages of using materials designed for mold making vs things like epoxy or silicone glues are any air bubbles will escape quickly as long as you only stir and not shake the mixture. I have tried vacuum pumps and they only complicate the problem. Not had the need to add pressure other than clamp the molds together.

Pete
Title: Re: Anyone cast their own plastic parts?
Post by: lucian on December 28, 2015, 01:16:02 PM
Maybe the air bubbles would escape sooner if the resin mix could be of a thinner viscosity. I would ask your supplier if the resin can be thinned, also it may only need to be a little warmer to achieve the same goal. I don't know if perhaps vibration may be an option also as in concrete. Just thinking out loud as I follow this. The form leakage should be easily solved and I would only guess that a thinner visc.resin may give better fine detail as well as allowing trapped bubbles the ability to rise out. Best of luck with the next attempt.  dave
Title: Re: Anyone cast their own plastic parts?
Post by: canuck750 on December 28, 2015, 05:31:51 PM
Are you seeing air bubbles in your lens? They are not evident in your pictures. The only problem I see is liquid seeping into the mold joint. One of the advantages of using materials designed for mold making vs things like epoxy or silicone glues are any air bubbles will escape quickly as long as you only stir and not shake the mixture. I have tried vacuum pumps and they only complicate the problem. Not had the need to add pressure other than clamp the molds together.

Pete

On my first attempt there were very tiny bubbles in the casting, hardly noticeable and I could live with them. The resin leaking past the mold joint cam from the resin left in the fill and vent tubes and as the resin cured it continued to draw down the tubes past the cast part and left the 'holes' in the casting as the resin ran out the mold joint. I think If I can get the mold halves to be tightly sealed the results will be better.

My local silicone supplier is closed for two weeks so this project gets sidelined for a bit. I need to rebuild the female half of the silicone mold. I also have read up on other clear casting materials and found a two part epoxy that is tintable and is supposed to cure quicker and be much more rigid. The first part I made is still flexible after three days. The resin I used achieves full strength in 7 days.

I enjoy figuring out how to make things as part of my Motorcycling pastime so this is just another skill worth learning that I can see will come in handy to make all sorts of small things.

Its back to wheel building on my 750S project, no shortage of projects to keep busy :thewife:
Title: Re: Anyone cast their own plastic parts?
Post by: canuguzzi on December 28, 2015, 06:49:55 PM
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

Big model of the seal a meal. Vacuum draws out air.
Title: Re: Anyone cast their own plastic parts?
Post by: PeteS on December 28, 2015, 07:26:47 PM
The problem with using a vacuum is tiny air bubbles become large air bubbles. If your casting begins to harden before those bubbles are able to escape they will be more obvious than they would be if you hadn't applied a vacuum. You can observe the effect of a vacuum by putting the hose of a vacuum cleaner on a cup of water. Its essential that you have no air leaks over the cup.
Experiment with a small sample of resin before committing a vacuum to your mold.

Pete
Title: Re: Anyone cast their own plastic parts?
Post by: Larry Wiechman on December 28, 2015, 08:09:23 PM
 
 It is essential to use vacuum to degas the resin. I put the cup of resin in a pressure pot and apply vacuum. I use a paper cone for a sprue. This allows for a surplus of resin to apply a constant fill pressure. Plastic soda straws make fine vents; just make sure they're taller than the sprue. 
Title: Re: Anyone cast their own plastic parts?
Post by: canuguzzi on December 29, 2015, 01:06:44 PM
You could bypass all the vacuum , pressure, and other stuff and try UV activated casting resin.

That way you can let the air bubble escape if there are any and not encounter a time sensitive setup.

The resin doesn't set until you hit it with UV light.  Just use clear silicon for the moulds.
Title: Re: Anyone cast their own plastic parts?
Post by: tiger_one on December 29, 2015, 02:14:36 PM
Would a small DIY centrifuge work while curing?
Title: Re: Anyone cast their own plastic parts?
Post by: canuck750 on January 14, 2016, 10:25:20 PM
After a couple more failed attempts I think I have had some reasonable results.

I tried a different silicone casting material, a more elastic type of product from the same manufacturer Smooth-On.

For the CEV fuse box cover I made another mold with the new product

(http://i249.photobucket.com/albums/gg217/canuck750/Resin%20Casting/DSC04991_zpsujvex6zm.jpg) (http://s249.photobucket.com/user/canuck750/media/Resin%20Casting/DSC04991_zpsujvex6zm.jpg.html)

(http://i249.photobucket.com/albums/gg217/canuck750/Resin%20Casting/DSC04992_zps3qy8eyue.jpg) (http://s249.photobucket.com/user/canuck750/media/Resin%20Casting/DSC04992_zps3qy8eyue.jpg.html)

(http://i249.photobucket.com/albums/gg217/canuck750/Resin%20Casting/DSC04993_zpsiqqnpcod.jpg) (http://s249.photobucket.com/user/canuck750/media/Resin%20Casting/DSC04993_zpsiqqnpcod.jpg.html)

And I made a clamping jig for the signal light lens, very little pressure needed, I used to much at pressure and 'closed' the mold sections and had half a signal light formed

(http://i249.photobucket.com/albums/gg217/canuck750/Resin%20Casting/DSC04994_zpsux5xwvpj.jpg) (http://s249.photobucket.com/user/canuck750/media/Resin%20Casting/DSC04994_zpsux5xwvpj.jpg.html)

(http://i249.photobucket.com/albums/gg217/canuck750/Resin%20Casting/DSC04995_zpsmcyzjohj.jpg) (http://s249.photobucket.com/user/canuck750/media/Resin%20Casting/DSC04995_zpsmcyzjohj.jpg.html)

For the lid I just used elastic bands and some strips of plexiglass to distribute the pressure

(http://i249.photobucket.com/albums/gg217/canuck750/Resin%20Casting/DSC04998_zpsapobirkb.jpg) (http://s249.photobucket.com/user/canuck750/media/Resin%20Casting/DSC04998_zpsapobirkb.jpg.html)

The results are decent but not perfect, small air bubbles are evident but for the fuse box lid I don;t think it will matter or be noticeable, the signal lens is acceptable

(http://i249.photobucket.com/albums/gg217/canuck750/Resin%20Casting/DSC05000_zpsydwzrxn2.jpg) (http://s249.photobucket.com/user/canuck750/media/Resin%20Casting/DSC05000_zpsydwzrxn2.jpg.html)

I just need to trim off the fill tube residue, they are part of the CEV lid where the decal is affixed by snap clips and on the signal they are where the mounting screws pass through.

(http://i249.photobucket.com/albums/gg217/canuck750/Resin%20Casting/DSC04999_zpslqlpisku.jpg) (http://s249.photobucket.com/user/canuck750/media/Resin%20Casting/DSC04999_zpslqlpisku.jpg.html)

Now to start the one off assembly line :wink:
Title: Re: Anyone cast their own plastic parts?
Post by: SED on January 14, 2016, 11:14:25 PM
Great photo essay and recommendations.  You are a true craftsman. 
Thanks!
Shawn
Title: Re: Anyone cast their own plastic parts?
Post by: jbell on January 17, 2016, 11:19:28 AM
Great end result, Jim.
Title: Re: Anyone cast their own plastic parts?
Post by: canuck750 on January 17, 2016, 03:13:32 PM
I am still having difficulty to get all the air out and the resin to completely fill the forms, hit and miss, about 50% success rate. I have been experimenting with injecting the mold very slowly with resin, plugging the fill and bent holes and spinning the mold etc...   The resin always fills and pours out the vent holes but sometimes air gets trapped at the top of the mold and the casting is missing a bit on the edges, enough to make the part useless.

Definitely a trial and error exercise.  At least I got two successful fuse box lids which was the original need to go down this road.

Title: Re: Anyone cast their own plastic parts?
Post by: rboe on January 17, 2016, 06:18:29 PM
Have you tried holding a finish sander against the mold to vibrate it and shake the bubbles out?
Title: Re: Anyone cast their own plastic parts?
Post by: Matt Story on January 17, 2016, 06:43:34 PM
Those parts look great! 

We did a bit of low production resin casting at a place I used to work.  To avoid bubbles we would mix the resin, then place it in a vacuum chamber for 10-15 minutes before pouring/injection.  Also helps to be careful with the method used to mix so as not to introduce any air.
Title: Re: Anyone cast their own plastic parts?
Post by: earemike on January 17, 2016, 07:28:38 PM
Fantastic  :thumb:
Title: Re: Anyone cast their own plastic parts?
Post by: canuck750 on January 17, 2016, 10:23:51 PM
Have you tried holding a finish sander against the mold to vibrate it and shake the bubbles out?

I like that idea, will give it a try

Thanks

Jim