How do you polish clear epoxy filled windows

[marc111]

Ok, On my refit I am trying the trick of filling the small windows witha very clear epoxy.

If you use no tape on the outside you end up with a slight dome that needs to be sanded/polished down.

If you put scotch tape across the outside you have a nice flat surface, but the adhesive leaves enough roughness that it again needs some poilishing.

The steps I tried in order were:
1) Wet sand with 600 grit
2) Wet sand with 1500 grit
3) Wet sand with the green plastic micro sanding film
4) polish with a paper towel and toothpaste

My problem is I still do not get a clear window that is as clear as before I start the whole process.

If there is a method that works nicely I would really like to hear about it.

Thanks,
Mark

[DLMatthys]

I like to use these progressive mesh sets of flexable sanding pads from Micro-Mark Tools, Mark111

The Photo:
http://www.micromark.com/prodimgs/81601.gif

The URL: http://www.ares-server.com/Ares/Ares.as ... t&ID=81601

A few local modelers here, into cars only...also like to use the Micro mesh set too.

For the most part I use these Soft touch pads...lots'a water too. I get the clear resins to a real high polish befor resorting to the Future Floor wax tricks.

[TER-OR]

Don's on the right trick. You might end with some toothpaste on soft cotton fabric like a t-shirt. Then, when all done, finish with a bit of Future. That will fill in the remaining imperfections. It can be removed with alcohol if you need.

[Wug]

Each grit of sandpaper should remove the scratches produced by the preceding grit. Is the 1500 removing all the scratches from the 600? If not try some 1000 between them.

You might not need the Micro-Mesh. Try Novus or another plastic polish. Your toothpaste might not have any abrasive in it. Then finish it with Future.

HTH

Mike

[Kylwell]

And wet sand to reduce heat build-up and remove the little granules that like to stick.

[marc111]

Thanks for the help guys. I will try out the suggestions and report back.

Mark

[TER-OR]

Absolutely wet-sand with plenty of clean water. Particularly when you're getting toward the end it must stay pretty clean.

[kitty]

If they are small enough windows, you might try Micro Kristal Klear (by Microscale), apply it on the outside to the edges of the windows with a tooth pick, then use the toothpick flat and draw it across the window, it wil form a extreme thin film across the window, like a soapbubble.
cohesion is the key here, if the windows are small enough this will work.
If they are too big, gravity will pull the film apart.
The stuff is milky, but it dries up clear.
You will have a extreme thin and strong clear window.
when it has dried (when it has become clear), you can use a 2 component clear epoxy(or a few more thin layers of kristal klear) to fill the rest of the window from the inside and you will have a clear window that doesn't need sanding or polishing on the outside.
Most epoxies should cure without affecting or deforming the thin window you made with micro kristal klear.
I have done it before on an enterprise-D, but you need to test the epoxy with the dried mikro kristal klear, because the epoxy i used (from poly-service) is only for sale in the netherlands as far as i know.

I also use kristal klear to glue transparent parts into place, because it dries up clear as glass and it has the advantage of a longer curing time over epoxy glue.

[Lt. Z0mBe]

Also, clean your wate in between grits. Otherwise, the coarser grits will be on the fine paper and you'll still leave scratches.

Here's what you do. Get the stuff relatively smooth. Get thee to Wal-MArt and pick up one of those $1.50 nail buffing kits. Use it wet in the order prescribed and then seal with Future. You'll be impressed.

I hope this helps.

Kenny

[entlim]

ok try this- fill with a small amount of Micro crystal clear, - dry hard- and a small coating og Johnson's Klear/ Future

[marc111]

Thanks everyone. I tried a few experiments and my best result came from using a brand I found at Michaels under the brand name EasyCast Clear casting epoxy. It is a 1 to 1 mix and although low viscosity(nicely lets the bubbles out and is not prone to form bubbles) it has enough to stay in the small windows. After polishing, a small coat of future on the outside made the saucer window clear enough to see the trees in my yard through the tiny window.

I appreciate the additional polishing instructions and will try them. This is the first time I have tried polishing a clear part as it were.

The micro crystal clear as an outer seal to eliminate the dome and sanding/polishing is intriguing. I like saving labor on this as there are a lot of windows in the refit. I will have to order some if my local hobby store doesn't carry it. Thanks for the suggestion.

One question on the Micro Kristal Klear : Has anyone seen any yellowing issues over time?

Mark

[kitty]

I have had no yellowing issues with crystal clear, but i usualy finish a model by having a loacal paintshop put on a 2 component clear UV blocking topcoat , so light has no effect on decals etc.
And the oldest model i used micro clear on was a 1/18 scania truck that i only finished 5 or 6 months ago.
I haven't got a clue what happens after 2 years or so, but since it has been around for quite a while and i know quite few people who use it to make or glue clear windows, i trust that it doesn't turn yellow or i would have heard it by now.