Glazing / Windows - I want FLAT Flush windows

[70021 Morning Star]

THE SECRET OF GETTING TRULY FLAT & FLUSH-FITTING WINDOWS WITH MICRO KRISTAL KLEAR

 

I'm creating a rake of BR Mk1 coaches from a mix of Mainline, Hornby, and Bachmann coaches. The biggest giveaway of my mixed stock is the glazing. The Hornby and Bachmann have nice flush glazing, but the Mainline coaches have very deeply recessed windows, so I need a replacement 'flush fit' option.

 

My choice appears to come down to:

• Finecast's 'Flush Glaze' - good for the main windows, but the vacuum moulding process fails to make the top lights
• MODELMASTER's Acrylic glazing - looks promising, but I'm not sure whether I'd need to cut out the top frames? (They're not answering their phone, so I can't get an answer.)
• Microscale 'Kristal Klear - but these products appear to be giving a curved, rather than 'flat', window.

As Kristal Glaze is the cheapest option (around a fiver, and next day delivery from Amazon UK) that was my starting point.

 

On delivery, the problem - as others have noted - is a lack of detailed instructions. I'd watched a few (typically, out-of-focus) you tube videos. But, as ever, there's more to getting good results than these guys tell you...

 

The problems most people encounter are:

1.  getting the Kristal Klear to form the 'bubble'. It's like PVA glue, and following the few instructions you are given, using a toothpick to apply around the window frame, then twiddle (or whatever) to stretch a film across the window, supposedly up to 1/4 inch!, isn't easy;
2. once you've formed the 'bubble', it will sag, or most of the liquid ends up at the bottom of the window, so you end up with variable thickness;
3. the most serious shortcoming is that the stretched film - the 'bubble' - will be quite thin in the middle, but much thicker around the frame. Looks a bit like )( , which isn't really what we're after.

Of course, the answer to the problem of making, even thickness, flat, flush-fitting windows with Micro Kristal Klear is hiding in rmweb, but it ain't obvious! Someone posted some instructions he'd found, but I'm not sure he picked up on the 'secret'.

 

 

THE SECRET

 

Do you remember blowing washing-up liquid bubbles through a plastic hoop, as a child? It's that bubble forming hoop is the secret.

 

Make yourself a plastic hoop. (DON'T use wire, as Kristal Klear will rust it in minutes, and you'll contaminate your solution!)

 

Dip the hoop into the Kristal Klear, and wipe away the excess.

 

Notice that the Kristal Klear forms that )( shape, thicker around the edges, and a nice thin and flat glaze in the centre. We're going to use that central part, which is uniformly thin and flat.

 

Wait a minute or so for the film to stabilize and partially dry. That's important: as the central film needs to have begun drying, but be still tacks, so you can successfully transfer it to the model.

 

Once you've reached the 'tacky' stage, position your glaze over the window you want to glaze. (In my case, I needed a big enough hoop so the central part covered the main window and four top lights of the BR Mk1 coach.) Ensuring that your hoop can't move, very gently, blow onto the hoop, so the tacky film adheres to the window frame.

 

Leave for about a minute, then clean away excess Kristal Klear, from around the window frame and carriage walls, with a moistened cotton-bud.

 

In the case of my Mainline coaches, the window frames (side walls of the carriage) are about 2.5mm thick. But, when I use this technique, the glazing sits about 0.25mm - effectively 'flush' - with the outside carriage walls, and is completely flat.

 

Anyway, give it a try, it certainly works for me.

 

Richard

[forest2807]

Sounds intriguing. Can we see some pics?

[70021 Morning Star]

Hi Forest,

Yes, I'm hoping to post some pictures tomorrow. Delay is because I should really show the 'how to' technique, not just the end results.

 

So, 'watch this space', as they say.

 

Meanwhile, I'm looking to hear other's advice. Anyone used  MODELMASTER's acrylic glazing? I think that's the route I'll probably go. But, an interesting possibility from Krystal Klear is that I can glaze from the inside, as well as the outside. That allows me to have the glass of the two slide-opening central window panels further back than the two outside ones. That offers interesting possibilities.

 

Anyway, will post more tomorrow (should have said Monday :-) .

 

Richard.

[70021 Morning Star]

Ok, here's the problem with Micro Kristal Klear - what you DON'T want !

 

The problem is that this polymer glue forms a bubble, that dries from the centre to the outside. So, if you get too much glue on the window, it'll dry so it's thicker at the window frame, and looks like these:

 

[70021 Morning Star]

Now let's have a look at how you can control the thickness of the Micro Kristal Klear by using a bubble former.

 

I've simply cut a circle out of an old train ticket. Then applied the glue with a moistened cottonbud. It took a few attempts to form the bubble, because you need to wait until the glue becomes takky enough to work. Simply keep drawing the cottonbud across the hole, until the magic happens. Then WAIT.

 

The bubble will start to thin and the surface will dry a little. I find about a minute or two is ok. Also, please notice that only part of the bubble is really thin - the bit in the middle - which is the part you want to use. This does mean that your bubble former needs a big enough hole to allow for the fact that the outer edges of the bubble aren't usable.

 

Once sufficiently dry and, therefore, stable, you place the glue former over your window and gently blow it onto the window frame.

 

Again, allow things to dry for a minute or two. Then use a moistened kitchen towel to carefully wipe away the excess glue.

 

You'll notice I've made use of the depth of this Mainline coach to glaze the outside window flush with the carriage wall, and made the slide-opening window by glazing from the inside of the carriage.

 

The finished result also used Flush Glazing to make the bottom, main, window.

 

[When you do this, please make sure your window frames are absolutely clean and free from bits of flaking paint and other grunge. I did these rather quickly - in fact the door glazing isn't dry, but it wasn't done with my surface application technique. There's quite a lot of paint flake and plastic making the edges of my glazing look a bit rough, but take your time with a thoroughly clean and prepared carriage, and it works very well.]

 

 

[70021 Morning Star]

...and the rest of the pictures.

 

I'll redo this a bit more carefully, and then you'll see how smooth the glazing can look without the crudd around the edges. That said, I think this gives an idea. Certainly not perfect, but there's nothing else around.

 

 

[70021 Morning Star]

I've had another go, and think these look right.

 

Only problem is that the glazing isn't terribly resilient if it's completely flush. So I've tried blowing a little harder, to seat one of the windows a little deeper. I think that's what I'll do on my coaches. Also tried spray varnish, but the varnish reacted with the Kristal Klear, so applying the windows will have to be the final process in my model making.
 

 

First image show the completely flush glazing, with the slide-opening window behind. Final image shows the slightly recessed window, and that door glazing, which is now dry.

 

.

 

 

[Jeff Smith]

I have tried using this stuff with varying results. Great for signal spectacles and small windows in loco cabs etc but I believe too curvey and probably too fragile for larger windows. I tried it for some cast Radley Underground cars with windows smaller than yours and it just didn't look good. I concluded that the only way to get good flush flat glazing was to file pieces of 40 thou clear styrene and carefully glue in with superglue. A real pain/labour of love, but worth it.

[70021 Morning Star]

Hello Jeff,

I've moved on from Kristal Klear, which I may use in some applications, and am about to try Finecast's "FLUSH-GLAZE" products.

 

Alas, MODELMASTER don't do a version of their flush acrylic windows to fit Mainline coaches, otherwise they'd have been my glazing of choice. As regards to cutting, filing, and hand-fitting over 250 clear styrene windows into my 4 Mainline coaches -- that's a definite "NO", Jeff :-D !!

 

Anyway, I'll post some pictures and my experience of using FLUSH-GLAZE over the next week or so.

 

Cheers,

Rick

[Re6/6]

Rick, have you considered using microscope glass cover slips (roughly 0.6mm thick).

 

There's nothing quite like glass for representing glass.

 

In MRJ 180 & 227 there are articles on using them.

 

I bought a cheap tungsten-carbide scriber and the cover slips (approx 2" x 1") from Ebay. I find about 50% breakage rate but they are cheap enough not to worry.

 

 

Info here: 

 

http://www.rmweb.co.uk/community/index.php?/blog/1391/entry-14131-coach-glazing/

http://www.rmweb.co.uk/community/index.php?/topic/80894-microscope-slides/

 

This method does require patience but is well worth the results!

 

I haven't tried using it for the small vent windows but it should be possible. I does away with the awful 'spectacle' effect with SE Flush glazing.

[70021 Morning Star]

Re6/6,

Now THAT is an incredibly good idea! Thank you.

 

I've spent most of the day battling with the FLUSH-GLAZE. It works well, but does require a lot of 'fettling' to get each window frame correct, so the smaller windows don't crush. So it wouldn't be any more work to cut all of those microscope cover slips, and I'll bet they look fantastic on a full rake.

 

Darn, I'd also have to upgrade the other 4 acrylic glazed coaches.

 

Rick

[70021 Morning Star]

Re FLUSH-GLAZE, Do NOT use a craft knife unless you have a proper cutting mat. It'll crush your windows. I found a pair of scissors are best, especially the paramedic shears, which have a step on the blades, that gave the manufacturer's recommend uniform 1mm of flat plastic around each window.

 

Anyway, pictures and findings later this week. - Rick

[Jeff Smith]

Re6/6,

Now THAT is an incredibly good idea! Thank you.

 

I've spent most of the day battling with the FLUSH-GLAZE. It works well, but does require a lot of 'fettling' to get each window frame correct, so the smaller windows don't crush. So it wouldn't be any more work to cut all of those microscope cover slips, and I'll bet they look fantastic on a full rake.

 

Darn, I'd also have to upgrade the other 4 acrylic glazed coaches.

 

Rick

Rick,

 

I'm a little surprised that you would consider glass as this would have to sit behind your window frames and therefore not be flush - which is what I thought you were trying to achieve....!

[70021 Morning Star]

Hi Jeff,

Indeed not! What John (Rm6/6) is proposing, is to use the very thin glass microscope glass-slide 'cover slips'. If you're not familiar, these are ultra-thin glass sheets that you sit on top of the specimen you're looking at, on top of the main glass microscope slide. John is suggesting cutting these ultra-thin cover slips to fit flush with the outside of the window frame. As he says, you get a few breakages, but using a tungsten-carbide scribe cutting tool, the job should be simpler than filing the plastic of my carriage window frames to accept FLUSH-GLAZE without crinkling the darned things! These cover slips are extremely thin, so rounding the corners on wet-and-dry shouldn't be a problem. They're also incredibly cheap. I think the effect would be astounding.

 

Rick 

[Jeff Smith]

Yes I think the effect would be astounding but surely a lot more difficult than shaping clear styrene. I think what John was proposing was cutting them slightly oversize to put behind the window as in his etched brass photo.

[chrisf]

From [at the moment] the sidelines:

 

Kitmaster got flush glazing right in 1960.  They moulded complete windows in clear plastic which were fitted from inside.  Replica do something similar for their 64 ft suburbans and as they also make a couple of MK 1 corridor coaches may produce what is needed here.

 

Since then we have, between us, laboured over flush glazing and not always got it right.  We have thick plastic sides with bl00dy great window sills which Rascally Bear is aiming to fix with his methods.  Then we have etched brass sides which although enviably thin cannot possibly give flush glazing if the window material is mounted behind them.  Tony Wright has pointed to the difficulties of moulding sides from clear plastic and painting everything except the windows.  If you know someone with a laser cutter, problem solved.  I'm looking forward to installing the Extreme Etchings product in a rehabilitated Lima CCT but despite the sterling efforts of these nice people even they will never sell windows for all deserving prototypes.  A Bachmann Collett BCK is glaring defiantly at me right now.  Cutting up some damaged CD cases may be its only hope.

 

Chris

[Jeff Smith]

This is a MAJ coach I built about 30 years ago and it is the nearest you get to flush glazing. The coach sides are molded in clear styrene and the paint job is a self adhesive overlay. The most difficult aspect was cutting out the windows in the overlay. It really could do with proper grab and door handles rather than the printed on one's - maybe I'll get round to it one day.....

[Re6/6]

Yes I think the effect would be astounding but surely a lot more difficult than shaping clear styrene. I think what John was proposing was cutting them slightly oversize to put behind the window as in his etched brass photo.

 

Although I haven't tried it Jeff, I will be experimenting with cover slips cut to fit inside window apertures, but having said that, the very small vent windows would be a challenge to shape. I shall give it a try (finger cuts permitting!).

 

I do have some ultra clear plastic sheet in various thicknesses up to 60 thou from Squires Tools (site down ATM) that is used in model aircraft canopy work I believe which will be an option worth trying.

[70021 Morning Star]

I'm thinking that something like those 'tile cutter' guillotines (used for cutting bathroom tiles) might work well for cutting the micro-thin glass cover slips, especially for doing rounded corners. We use something similar in stained glass window cutting. Anyway, it's worth a try. Those cover slips come in packages of around 250, so loads to play with. At those prices and quantities, I could order some and post to those with good ideas to test out.

 

I'm also wondering about clear resin moulding. Sacrifice a carriage to create the mould should be ok. I've some experience of these materials. The top surface does need rubbing back and polishing, but would give a perfect finish.

 

Alternatively, I could stop playing around at 'fixing up' cheap Ebay coaches, + the costs of materials, and purchase some decent Bachmann/Hornby flush glazed carriages. Probably the sensible option, but where's the fun in that ?!

[PhilH]

Just a thought, haven't tried it, and I'm thinking things like Bachmann Bulleid coaches (I've got loads), has anyone tried putting something such as the slips mentioned above over the existing window material just to make the surface of the windows more flush with the bodyside?

[Re6/6]

Rick,

 

If you experiment with the cover slips, only the lightest weight is needed to do the business. I say weight because the weight of the tungsten-carbide cutter held lightly in the hand with a single stroke is all that is needed.

 

If too much pressure is applied, the thing will crack all over the place. I broke an awful lot at first but practice makes perfect as they say!

 

Do have a roll of masking tape to hand as using it is the best way to pick up all the broken pieces, both large and tiny as some of the bits can be hard to see and can be painful on the fingers!

 

Phil.

 

I think that is an idea worth trying. The problem that I see is that the sides are gently curved but I'm not sure if the glass on the real thing is actually curved

[70021 Morning Star]

Very much like the traditional glass-cutting techniques for stained-glass windows, Phil. Might be worth a Google to look for technical advice.

 

My problem is that research on the Capitals United Express coach formation suggests I need to glaze 11 coaches! Asarrrggghhh!!!!!!

 

Time to find a new hobby? Anyone interested in buying some nice Mainline, Hornby, and Bachmann Mk.1 coaches? 

[chrisf]

Rick,

 

 

I think that is an idea worth trying. The problem that I see is that the sides are gently curved but I'm not sure if the glass on the real thing is actually curved

 

It isn't.  The sides are pressed flat alongside the windows to allow the use of flat glass.  Bulleids, on the other hand, have glass matching the body contour.  This, with some dimensional oddities, could be why EE will not be laser glazing them.

 

The MAJ coach a few posts back is commendably flush glazed.  Sadly the prototype is not!

 

Chris

[Re6/6]

Thanks Chris. I had a feeling that the Bulleids did have curved glazing.

 

That being the case the clear glazing sheet sold by Squires Tools would be thick enough (20/30 thou) for cutting to shape and curving using a tight(ish) fit to keep the curvature and stay in place without twisting out of shape as would be the case with the usual 12 thou glazing material.

 

I'm thinking that the sheet could be warmed and bent first around a curved former to impart the correct amount of curvature prior to shaping. I think that the extra thickness like EE glazing is the key here.

 

I haven't tried any of this yet but do have a Bulleid to hand and experimentation beckons!

 

Unfortunately the Squires Tools site is down for maintenance ATM so I can't give a link.

 

Edit: The stuff is called PETG. It isn't like clear styrene as it's softer in texture but comes with protective sheets on both sides which keeps it pristine.

[70021 Morning Star]

Just found something amazing about FLUSH-GLAZE.

 

You know the problem where you cut a well formed window from the sheet, only to find those four top lights have crinkled during the cutting process?!!

 

Well, if you hold the whole window by its ends, and give it a good twist, hey presto!, those crinkled top windows often come back to pristine condition.

 

I'll edit this with a few pictures after I've had my tea. It really is amazing!

 

Rick