Beyond The Sprues

Modelling => Tips, Tools & Techniques => Topic started by: kitnut617 on May 20, 2020, 10:26:04 PM

Title: Silicone Mould Boxes
Post by: kitnut617 on May 20, 2020, 10:26:04 PM
When I make my mould boxes, I use Lego bricks. But there's a big problem you have to fix before you can. When the bricks are snapped together they "look" nice and tight ----- NOT! Used as they are, the silicone in it's fluid state will find any gap anywhere and the Lego boxes leak like a sieve.
To solve that I started using modeling clay by pushing it into the gaps, it's a lot of work not just applying it, but cleaning up afterwards too. Very messy ----
But I've found something else to use which works fantastically,  Plumber's Teflon Tape. I just lay strips of it on top of one brick layer before I snap on the next level. It seals the joint and then afterwards, being Teflon, just peels right off.

Another plumbers item I use it the glue, Lego is made from ABS plastic, so is the black plastic pipe plumbers use. I've made a number of sides up by gluing the bricks together, saves on using tape all the time  ---
Title: Re: Silicone Mould Boxes
Post by: Frank3k on May 20, 2020, 11:26:59 PM
The Teflon tape is a good suggestion! I would keep the same bricks together - the hardened silicone would act as a seal. But you can’t always get the same bricks in the same spot. I’ve also tried standing on the bricks, but that still doesn’t fully seal them.
Title: Re: Silicone Mould Boxes
Post by: Buzzbomb on May 21, 2020, 07:06:04 AM
Good idea.

I got a set of these laser cut boxes for a local Aussie guy Laser2Stun.

Hopefully you can see this image.. his site is on Facebook
(https://scontent-syd2-1.xx.fbcdn.net/v/t31.0-8/17918081_1390459147680984_427683838746420917_o.jpg?_nc_cat=108&_nc_sid=8024bb&_nc_ohc=DM3E_C0o18QAX8ZfqYL&_nc_ht=scontent-syd2-1.xx&oh=d3d5d1c2295c03c5d4ece1bcd90bb5e3&oe=5EEA623D)

Which go together like this
(https://scontent-syd2-1.xx.fbcdn.net/v/t31.0-8/17973655_1390459137680985_5484315126384081269_o.jpg?_nc_cat=104&_nc_sid=8024bb&_nc_ohc=JVEi7d44XRwAX-Aa-fd&_nc_ht=scontent-syd2-1.xx&oh=0cae387030bd0208157279c80a19f0da&oe=5EED3088)

Size is limited but for the majority of moulds, more than adequate, I have found leakage to be minimal.
Title: Re: Silicone Mould Boxes
Post by: Jeffry Fontaine on May 21, 2020, 07:41:42 AM
I saved up a few containers that previously held sliced lunch meats such as roast beef, ham, turkey, etc.  These are shallow in depth about 5cm X 12cm long and 9cm wide.  They also have a hard lid so keep the contents fresh[er] after unsealing the inner bag.  I figured these containers would be ideal for creating moulds but have yet to proceed down that path. 
Title: Re: Silicone Mould Boxes
Post by: Frank3k on May 21, 2020, 10:17:49 AM
I saved up a few containers that previously held sliced lunch meats such as roast beef, ham, turkey, etc.  These are shallow in depth about 5cm X 12cm long and 9cm wide.

I use those to keep parts, especially when I'm collecting bits for a build.
Title: Re: Silicone Mould Boxes
Post by: Kerick on May 21, 2020, 11:19:29 AM
What if you lined the Lego boxes with plastic wrap?
Title: Re: Silicone Mould Boxes
Post by: kitnut617 on May 21, 2020, 10:41:00 PM
What if you lined the Lego boxes with plastic wrap?

After finding out the hard way, I started by wrapping electrical tape around the boxes. But the problem was the fluid silicone still got into the bricks and the electrical tape was wasted afterwards. I wanted to stop the silicone flowing through the bricks altogether and using the clay did solve the problem. Just messy that's all. The Teflon Tape just eliminates all the mess and saves time in the process. The Teflon Tape is also cheaper than the electrical tape.
Title: Re: Silicone Mould Boxes
Post by: tankmodeler on May 22, 2020, 10:50:52 PM
Been using lego for mould boxes for years, but I lose an infinitesimal amount of rubber into the cracks. It makes the exterior a bit tatty looking, but I just pull off the little flaps of rubber and all is good.

Do you actually lose that much rupper intot eh craks to be an issue or is it more of an appearance thing?
Title: Re: Silicone Mould Boxes
Post by: kitnut617 on May 23, 2020, 03:19:44 AM
I wouldn't say it a huge amount, but the silicone isn't cheap so I use the absolute minimum I can get away with. Any amount saved helps but mostly it's for the clean up of the bricks afterwards, and that takes time ---- But the Teflon Tape has eliminated the problem.
Title: Re: Silicone Mould Boxes
Post by: Frank3k on May 23, 2020, 03:44:47 AM
It also depends on the mold material - Smooth-on ooMoo barely gets half way into the Lego brick. There was one fairly thin silicone (Alumilite or similar) that managed to seep all the way out - not enough to ruin the mold, but enough to make demolding and cleanup very annoying.
Title: Re: Silicone Mould Boxes
Post by: kitnut617 on May 23, 2020, 05:17:09 AM
Yeah, I use Alumilite silicone and resin. I've actually just got some new supplies in today, I got some black resin which I thought would look good for the props I've got in mind.
Title: Re: Silicone Mould Boxes
Post by: uncle les on May 23, 2020, 04:21:58 PM
I gave up on Lego as a mould-making accessory back in the '90s.  I now rely on polypropylene sheets ( aka those advertising placards found for free at your local Coles if you get in good with the store manager) for the larger castings and for everything else I have a large collection of Dazjantos as Brian mentioned beforehand I find them more than adequate to the task.
(https://scontent.fmel5-1.fna.fbcdn.net/v/t31.0-8/p720x720/18358971_1310346479084629_1891165689602304008_o.jpg?_nc_cat=108&_nc_sid=8024bb&_nc_ohc=Mjm5Ga5skZcAX9MdZkh&_nc_ht=scontent.fmel5-1.fna&_nc_tp=6&oh=91952ced6553c12f92688ed451e99b7c&oe=5EEF1134)
(https://scontent.fmel5-1.fna.fbcdn.net/v/t1.0-9/p720x720/89510882_2783703151748947_8103243960467587072_o.jpg?_nc_cat=100&_nc_sid=8024bb&_nc_ohc=_LAU2OxXpfIAX9jwHND&_nc_ht=scontent.fmel5-1.fna&_nc_tp=6&oh=9a0614f948905b8435b40ae62baf0477&oe=5EEF45EE)
(https://scontent.fmel5-1.fna.fbcdn.net/v/t31.0-8/p720x720/18422944_1313947728724504_6662871977920044492_o.jpg?_nc_cat=101&_nc_sid=2d5d41&_nc_ohc=S8MWRnDZzKsAX_8VL_c&_nc_ht=scontent.fmel5-1.fna&_nc_tp=6&oh=ed95bd17c81cddd89fce221f5cd18815&oe=5EEDF8EA)
(https://scontent.fmel5-1.fna.fbcdn.net/v/t31.0-8/p720x720/17991501_1283547505097860_761907024984636603_o.jpg?_nc_cat=103&_nc_sid=8024bb&_nc_ohc=NEtVaZ-pbeUAX_2p23A&_nc_ht=scontent.fmel5-1.fna&_nc_tp=6&oh=5d7cd3eda24c763284789e49a7caf855&oe=5EEF21CC)
As I vacuum all my moulds thus making the RTV expand and bubble momentarily during the process I asked Darren to design and cut some custom versions to allow for the expansion and thus prevent overflow.  I have never had an issue with leakage with this product and I still have a bucket of the kids' Lego from the '90s covered in RTV !
Title: Re: Silicone Mould Boxes
Post by: kitnut617 on May 23, 2020, 09:34:39 PM
I've been thinking of switching Alumilite silicone to another because trying to get it from the States is a major problem getting it over the border. I've found it on Amazon but every time I enter my address, it just says can't be shipped here. I do know the Hobby Shop that gets it was put through the wringer by CBSA but now has the permits to import it.

Do you know if the silicone you use can be shipped to Canada Les ?

I don't use Facebook, so I'm wondering how I can get some of this Dazjantos too?
Title: Re: Silicone Mould Boxes
Post by: uncle les on May 23, 2020, 10:55:10 PM
I've been thinking of switching Alumilite silicone to another because trying to get it from the States is a major problem getting it over the border. I've found it on Amazon but every time I enter my address, it just says can't be shipped here. I do know the Hobby Shop that gets it was put through the wringer by CBSA but now has the permits to import it.

Do you know if the silicone you use can be shipped to Canada Les ?

I don't use Facebook, so I'm wondering how I can get some of this Dazjantos too?
Re any silicone product, the internet is your friend as you can Google many places and make enquiries.  All you'll need are some reputable names to look up - I get my stuff from Dalchem, Barnes, Solid Solutions and Aldax, all have websites that can be found quite easily by entering the names I've mentioned here and yeGoogleising them.   I would suggest though that sending this stuff to Canada will probably be prohibitively expensive and I have no intel on the customs situation.
Re Darren Winter's wonderful moulding boxes - have a look at my first photo - it has his contact details etched into the side of box that include an email address: info@lasertostun.com.au.    Tell him Brian and Les sent you !
HTH
Title: Re: Silicone Mould Boxes
Post by: kitnut617 on May 23, 2020, 11:54:10 PM
I've been thinking of switching Alumilite silicone to another because trying to get it from the States is a major problem getting it over the border. I've found it on Amazon but every time I enter my address, it just says can't be shipped here. I do know the Hobby Shop that gets it was put through the wringer by CBSA but now has the permits to import it.

Do you know if the silicone you use can be shipped to Canada Les ?

I don't use Facebook, so I'm wondering how I can get some of this Dazjantos too?
Re any silicone product, the internet is your friend as you can Google many places and make enquiries.  All you'll need are some reputable names to look up - I get my stuff from Dalchem, Barnes, Solid Solutions and Aldax, all have websites that can be found quite easily by entering the names I've mentioned here and yeGoogleising them.   I would suggest though that sending this stuff to Canada will probably be prohibitively expensive and I have no intel on the customs situation.
Re Darren Winter's wonderful moulding boxes - have a look at my first photo - it has his contact details etched into the side of box that include an email address: info@lasertostun.com.au.    Tell him Brian and Les sent you !
HTH

I've made an enquiry to Solid Solutions, I'll see what they have to say.
I think the Alumilite has a problem with what it's made of, the CBSA think it's bomb making material ----- at least that's one explanation I've been given.
Title: Re: Silicone Mould Boxes
Post by: Frank3k on May 24, 2020, 01:14:03 AM
Can you get Smooth-on? (https://www.smooth-on.com/) They have distributors in Canada (https://www.smooth-on.com/distributor-regions/canada/).
Title: Re: Silicone Mould Boxes
Post by: kitnut617 on May 24, 2020, 01:59:11 AM
Thanks Frank, according to that link, there's a distributor a couple of hours to the south from my place and another three hours to the north. I will have to check them out.
Title: Re: Silicone Mould Boxes
Post by: Frank3k on May 24, 2020, 03:30:23 AM
The Smooth-on tin cure rubbers tend to be 1:1 mixes - brain dead easy to use. They also have platinum cure rubbers, which may be closer to Alumilite.