Casting epoxies from Smooth-on

[src]

I dont know if this is the correct forum for this question, if not will one of the mods please move it?

 

I am looking for a water clear casting epoxy or rigid polyurethane for my quarter badge windows. I had intended to use a product from BJB Enterprises because we had some at work and I have experience with it; WC784: http://www.bjbenterprises.com/polyurethanes/castable/rigid/water-clear/ Unfortunately it didnt get stored properly and we wont be buying any in the foreseeable future. At $65.00 a quart I cant justify buying for what amounts to about 0.5cu inches of product .

 

I did a search online and found something from Smooth-On Corp. I dont have any direct hands on experience with their products except their So Strong tints (great stuff by the way). Has anybody used either the EpoxACast690:

http://www.smooth-on.com/Castable-Epoxy-Res/c1295_1377/index.html

Or the Tarbender encapsulant? 

http://www.smooth-on.com/Castable-Epoxy-Res/c1295_1395/index.html

I can get a sample of either for about $30.00 which is easier to justify in my mind, still a lot of money for 6 windows.

 

I have some Micro Crystal Klear but it dries pretty flexible and I dont know how long it will hold up over the years.

 

Any advice or recommendations for a castable product that wont break the bank would be appreciated.

 

Thanks

Sam

 

[TBlack]

Sam, Why does it have to be a castable product? Can't you just use a sheet of clear plastic or even microscope slides to do the job?

 

Tom

[mtaylor]

Alternately, use the MicroMark product: I haven't used it yet, but reports from other builders say it works very well.  Gill Middleton used it on his Victory's lanterns.

[JPZ66]

I agree with Tom..that is, unless these windows have some strange complex shape.... Some clear sheet, even if you have to use a transparent color paint on it, would be so much cheaper and easier then molding and casting.

 

But, the Smooth-On product is good. I don't have the data in front of me, but I do think it is the one you mentioned. If you are looking at the specs, it's the one that has a mixed viscosity of 200cps. That is one of the lowest viscosities I have found for clears, and works especially well if cast under vacuum. And yes, it can be tinted or colored.

 

Joe

 

******Just checked the link you provided...yes....that's the stuff.

Edited November 27, 2014 by JPZ66

[mtaylor]

Sam,

 

If you go with the clear plastic, use canopy cement (the aircraft guys use this stuff) so the plastic doesn't craze.

[src]

Tom, Joe,

It doesnt HAVE to be castible, it is just the direction I was going. My frames are certainly not complex; small parallelograms really.

http://modelshipworld.com/index.php/topic/113-enterprise-by-src-constructo-151-or-lessons-in-adapt-improvise-and-overcome/page-29?hl=+enterprise%20+src I made them thick to simplify construction so glass or plastic feels like it will be too far back. Certainly an option though.

 

Mark, any idea of how the Micro Mark product holds up over time?

 

Joe, casting under a vacuum or just degassing with vacuum? I have never left a casting to sit under vacuum while it kicks. One of the first times I degassed a mix I left it under vacuum to long and ended up with a deli cup full of hardened foam, an interesting look but not the crystal clear I was shooting for. I have heard of curing under pressure but have never tried it. 

[mtaylor]

Sam,

 

I have no idea of longevity.

 

In a former life, I made clocks that used a clear epoxy (photo glued to wood and then epoxy the whole mess).  I used a hair dryer on cool to degass and get rid of any bubbles.  Might work for you.

[JPZ66]

For molds, I always vacuum degass the mix before pouring... For castings, I have used vacuum, pressure or nothing at all. If the working time after mixing allows for vacuum degassing of the resin, I will often times do it, though with low viscosity materials it really isn't necessary.

 

Also, as Mark mentions....sometimes a careful application of heat can be used to break air bubbles. More often than not, I am casting in closed, two piece molds, so that's not usually an option for me. Pressure casting is a good idea for epoxy clears, but again, it depends on a number of factors, and often won't make any difference.

 

There are so many factors that come into play when dealing with casting resins ! What type of resin, working time / curing time, amount or mass, the type of molds being used and so on. Different resins respond differently to various techniques. This is where trial and error and experience come in. Clear epoxies are a bit of a different animal as compared to polyurethane resins.

 

I could probably write a couple of pages just on the aspect of bubbles....the origin, the type and how to deal with them.

 

 

I hope some of this proves helpful, and feel free to PM me if I might be able to help further !

 

Joe

[BANYAN]

For the glass in my Endeavour build I used a two-part epoxy called 'liquid gloss'  (another is called liquid water) which I purchased at a local craft store.  The trick is to do it in several layers to build it to the required thickness, and to blow across the top of it after pouring it into the mould (framing in this case) to remove any micro-bubbles.

 

My description is at: http://modelshipworld.com/index.php?/topic/400-hmb-endeavour-by-banyan-al-160-circa-1768/?p=4039  There was an article on this written by another Member and myself on the site, that incorporated the use of of artists (clear) medium to help with the levelling, but it may have been lost in the 'great crash' of MSW 1 - I will have a dig around my archives (if I remember) and see if I can find it again.

 

Just another way.

 

Pat  

[hornet]

I use a two part epoxy to give a crystal clear protective coat to the whippings (bindings) on fishing rod guides (runners) that I custom build. I see no reason why it would not also work for this application. Sometimes it gets tiny bubbles in it after application, but these are easily removed by blowing with a hair dryer on a warm setting. It is available in a variety of brands at most fishing tackle shops.

[mtaylor]

Joe,

 

I didn't use a heat setting on the hair dryer back then.  I guess it could be called a pressure type of thing in that blowing the air across the epoxy caused the bubbles to come to the surface and break.

[JPZ66]

...And here is the thing.... There are many 'generalizations' regarding various resins. It's always best to read the manufacturer's specific literature for any given material.

 

There are soooo many types of resin and resin systems out there. The reason for that is the fact that over the years the formulations have been tweaked for specific applications. Some clear systems are designed for casting, some are for surfacing, like découpage, some are crystal clear, others are not, some will have UV inhibitors, others will yellow when exposed to sunlight... On and on. Some systems can be used for things the manufacturer didn't even design them for.

 

A lot of times it comes down to experimenting and testing. Try to find the most cost effective solution.

 

 

In looking at the quarter window frames that you made ( quite nice btw ) .....based on the size, and the fact that you dont want the 'glass' too deep......

What about backing up the windows with clear sheet stock, glued in from behind and carefully seal the edges, then , from the front, carefully add a small amount of MM Crystal Clear, in successive layers until you achieve the thickness and level of fill you want ? ...is that a possibility ?

 

Joe

[Ulises Victoria]

For small openings, a thin film of white glue dries transparent. Experiment first!!!

[src]

In looking at the quarter window frames that you made ( quite nice btw ) .....based on the size, and the fact that you dont want the 'glass' too deep......

What about backing up the windows with clear sheet stock, glued in from behind and carefully seal the edges, then , from the front, carefully add a small amount of MM Crystal Clear, in successive layers until you achieve the thickness and level of fill you want ? ...is that a possibility ?

 

Joe

Joe,

thank you for the compliment on the windows. I had not thought about backing up and then the MM product. Certainly cheaper than a $30.00 kit that I ma never use again - another reason for using a few grams of existing stock from work. I may just go that rout. The MM product does look good, I used some on one of my frames that was too big. I just wasnt sure how long it would hold up its so soft and thin.

 

Hornet, there is a tackle shop around the corner from my work that sells rod blanks I am sure they would have the epoxy you are referring to. If it is water clear, that would be another option.

 

Ulises, I agree, even before I began this build it seemed my work life was one huge experiment!

 

Thanks for all the advice.

sam

[BANYAN]

Sam, I found the article by member "Adrift" which I have added some detail to and tidied up.   I hope it is of some use to you or others.

 

 

Admin/ Mods please place this in the Article section if you think it worthwhile.

 

cheers

 

Pat

 

Glazing Ship Windows.pdf

[src]

Pat,

Thank you!! I will check that out.

sam

[mtaylor]

Pat,

 

Excellent article. Send it to Chuck.  He has the access to do add it.

Edited November 28, 2014 by mtaylor

[twintrow]

Gene Bodnar over at Model Ship Builder swears by Puzzle glue.  The glue you spread over the back of a puzzle to hold it together  He has shown some pictures and the glazing looks a lot like old glass with a little waviness in it.

I've used the Micro Mark glazing and it works well so long as the space it has to cover isn't too large.

Tom

[hornet]

In a previous post on this thread I suggested that the two part epoxy that is used to provide a flexible, crystal clear coat to the whipping/bindings on fishing rod guides/runners might be used to create `glass' for ship windows. I decided to experiment with the idea.

 

The epoxy I used was Erskine Epoxy. I think it is an Australian product but I am sure similar products are available overseas. The epoxy can be purchased from most fishing tackle stores (my second home!!)

 

 

I use syringes so as to get a precise (50/50) mix of Part A & B of the epoxy.

 

I made a `window frame' out of scrap material for the experiment. It was mounted onto a board that had been covered with cling wrap. I hoped that the cling wrap would not stick to the hardened epoxy and that the window frame with its `windows' would come away easily. The window frame was clamped to the board covered with cling wrap to prevent epoxy seeping under the sides.

 

 

I applied the epoxy mix to the window frame using my `squadron' CA glue applicator. After leaving overnight to harden, I removed the window from the cling wrap. Happily it  came away very easily. The result of the experiment is shown below.

 

 

 

Having succeeded with the experiment, I decided to apply the epoxy to windows and stern lights that are soon to be fitted to my current build, HMS Supply.

 

I had already used clear plastic backed by black card on the stern lights of the supply so I applied the epoxy directly over the plastic. It worked well, giving a more 3D look to the windows. Because this epoxy is used on fishing rods, it is flexible and will bend and twist without cracking. Another advantage of using it.

 

  

 

The first picture (above) shows the job half done and the second one is complete. I think that the epoxy finish looks far better than the `flat' finish visible in the windows not epoxied in the first picture.

 

I had not as yet put clear plastic behind the ship's other windows but did so after seeing the results above. The epoxy was again applied directly over the clear plastic and also produced a more 3D effect for the windows.

 

 

I had an amount of left over `mixed' epoxy. rather than letting it go to waste, I raided the Admiral's kitchen cupboards and found some food colouring. I added a very, very small amount to the epoxy and was surprised to see that it actually mixed smoothly and evenly with the epoxy. It also dried hard and flexible. I have no need for `stained glass' in this build but will keep this in mind for the future. I hope the results of my experiment are helpful to others.

 

I would also like to thank `Neek" the ship's cat for her valuable input in this experiment!!

 

 

 

 

 

[BANYAN]

That looks really good Hornet, no sign of bubbles etc from the two-part mixing and curing?  That is the only problem I had with my method using the liquid gloss/water (which may not be flexible also).  I'll have to give this stuff a try.

 

Any ideas on what to add to give the slightly cloudy look of glass back then?  I have the same problem with the liquid gloss I used - too shiny for that period (personal taste) but this looks easier than doing it with the other stuff.

 

cheers

 

Pat

[hornet]

Hi Banyan. There were minute bubbles when I first mixed the epoxy. I have had a lot of experience with the stuff having built many, many custom fishing rods. Often letting the mix settle for a minute or two allows the bubbles to dissipate. You can also blow on the mix which helps, or use a blow drier on a warm setting to get rid of them. I have found that if you 'fold' the part A & B mix together gently rather than stirring furiously, you get less bubbles. As to creating a more cloudy appearance in the glass, you could experiment with food colouring as I did - maybe a very small amount of black. I had a puddle of leftover epoxy about as big as a 5 cent piece (about 1cm or 1/2 inch for Non-Aussies) I used only enough food colouring to fit on the end of a couple of pins to get the yellow colouring that you can see on the epoxy blob on the bottom right corner (almost under the hobby knife) of the 4th picture in the post. The erskine epoxy is about $16 for the two 30ml bottles so you have plenty to experiment with.

[twintrow]

Hornet

You can pretty much eliminate the warped glass look by stretching some Thule across the panes.  Thule is a micro mini netting available anywhere they sell material for wedding dresses. Some of us also use it for simulating hammock netting.  The effect when laid diagonally is of cut glass windows.  And is also period correct for much of the 17 and 18th C.

 

Tom

[hornet]

Thanks for the tip twintrow. I suppose tulle could be stretched between the cling wrap and the window frame then the epoxy could be poured thinly over the top. I'll have to give it a go!!

Edited December 6, 2014 by hornet

[hornet]

Any ideas on what to add to give the slightly cloudy look of glass back then?  I have the same problem with the liquid gloss I used - too shiny for that period (personal taste) but this looks easier than doing it with the other stuff.

 

cheers

 

Pat

 After considering this observation, I attempted to make the two part epoxy more cloudy. Firstly I mixed a small amount of acrylic paint to  a 1 1/2 centimetre puddle of epoxy.

 

On the first picture I used about twice the amount as on the hobby knife below. It came out quite opaque. The second picture I used about the same as on the hobby knife. The acrylic mixed OK but I think it was a little grainy (visible on the second picture only.)

 

 

Only a small amount of paint was used

 

 

I then tried mixing enamel paint with the epoxy. I used about the same amount as with the acrylic. It mixed in much easier. The pic below sort of shows the result but it was difficult to get a clear shot. The epoxy is still transparent but slightly milky/cloudy.

 

 

 

 

 

Edited December 8, 2014 by hornet

[twintrow]

Try just spraying with a clear matte spray.   First try one side then if not enough spray both sides.

 

Small cans of clear matte can be found at any hobby shop, Hobby Bench, or at Lowe's or Home Depot ( not sure of an equivalent store in Australia) in larger cans.

 

Tom

[src]

All,

Sorry for my silence lately, work has been .......interesting the last few weeks. Lots of great information here and I will be doing some 'speramentin after the holidays.

For the opaic/cloudy look I like the ideas shown, much more hobby friendly then calcium carbonate we used on a larger project in the recent past.

Sam