Zmodell accessories at www.1zu220-shop.de

[Alex_dn]

I was inquired about exact sizes of the photo-etched chains I introduced above in this thread some time ago. So, here is a drawing with very detailed dimensions. Areas in blue color are half-etched and have a thickness of 0.075 mm; red parts have full thickness of 0.15 mm:

Full length of chains including end rings is 50.5 mm - it equals to 11.11 meters in 1:1 scale.

Greetings,
Alex

[Alex_dn]

Greetings everyone,

I would like to introduce a couple of new accessories that can be useful to many. For of all, I added one more variant of windows inserts - now for BR 38/P 8 steam locomotive. I don't actually know Märklin's principle which steam locomotives should feature windows glazing and which not, but in any case, I decided to fill this gap somehow.

Like similar product for BR 78 locomotive, these windows are produced on precise CNC cutter from 1.5 mm acrylic glass:

These windows inserts are compatible with the following models, equipped with both 3/5-pole motors and coreless motors: Märklin 8130, 8899, 81302, 81428, 81437, 88991, 88993, 88994, 88997, 88998 and 88999.

Installation is very easy: disassemble the locomotive and remove the metal body, pick the parts with sharp tweezers and insert them into the cab windows openings. Then fix them in place with a very small drop of glue, wait until it dries completely and then reassemble the locomotive. It is better to pick up a drop of glue with a toothpick.

I recommend using lasercut (PVA) glue due to the number of reasons: it cannot destroy plastic and paint coating. Even if something goes wrong, it can be easily removed and any time. Once it dries, it will hold these small parts very reliably.

Important note about Märklin 88993 steam locomotive: This model is manufactured using different technology that has higher dimensional tolerances. Therefore, installation of these windows inserts into this locomotive in some cases can be more difficult and may require more complex efforts and/or minor rework.

Results of this small but useful upgrade just speak for themselves:

Windows inserts are available here:
https://www.1zu220-shop.de/Zmodell/Zube ... 47568.html

[Alex_dn]

One more thing I would like to introduce today is new sliding contacts - made with new technology and materials. 0.05 mm high-flexible brass I currently use is a good and reliable material suitable for most cases when you need to establish constant electric contact between moving parts. However, it has one downside: if the model is not used for a long time, often some time needed to restore good electric contact by running the model during 5-15 minutes until the light flickering is gone completely.

Of course, this issue can be partially resolved by adding energy storage circuit to analog or digital interior lighting solution, but I was looking a way to improve the parts that pick up the electricity from the wheelsets themselves. Initially, it was an idea to add a gold plating over the brass surface. Although it may seem to be a good solution, it has two obvious downsides: a) the price may increase quite noticeably; b) thin gold plating will inevitably wear out with time, and the problem with oxidizing will return back again.

Then I came up with a different idea - to use a different material that does not oxidize with time, just like gold. Of course, it is a stainless steel. This material is much stronger than brass with the same thickness. That's why I decided to use even smaller thickness - as low as 0.025 mm! It was quite difficult to find such a material, but I finally managed to order it.

0.025 mm stainless steel is just wonderful - it offers the same material strength as thicker 0.05 mm brass, but much more flexibility and as a result - much less rolling resistance. However, performing photo-etching process is much more difficult in this case. After a number of tryouts with my colleague in Ukraine, we finally found a perfect production formula - desired density of chemically reactive mixture and correct timing. The last parameter is extremely important fur such a thin material, where almost every second counts!

Once again, it is worth noting that photo-etching still takes place in Kiev, Ukraine - at the industrial facility with appropriate photo-etching equipment. I decided to start from the most popular variant - sliding contacts for Märklin standard IV-VI Era 4-axle passenger cars. This is a 3D illustration of the new sliding contacts:

As soon as I received new parts, I immediately decided to try them out with some of the passenger cars from my own collection. First of all, I have to say that new material is very strong and hard to cut, despite that it is very flexible at the same time. I recommend using only very sharp and strong manicure scissors for this; otherwise, the part can be accidentally "chewed up".

After cutting and very careful bending of these parts, I installed them into the bogies of SNCF passenger cars from 87408/87409 sets. Rolling tests showed absolutely wonderful results - the cars were running so freely as if there were no any sliding contacts installed at all! And of course, reliability of electric contact with the wheelsets was increased noticeably:

And here is a comparison of the new sliding contacts with previous variant made of 0.05 mm brass:

Now I have to add probably the most important point: for soldering these sliding contacts, you need a special chemically reactive flux. It is impossible to solder stainless steel with rosin or any other basic fluxes. The best flux for this purpose is phosphoric acid, also known as "soldering acid". Stainless steel is soldered with this substance just like a normal copper of brass with rosin. Soldering acid can be easily found on eBay, Amazon or anywhere else on the net.

But there is one more, also very important point: it is absolutely imperative to clean residues of the flux after soldering in order to prevent further corrosion of metal and plastic parts. Tap water either 100% IPA (Isopropyl Alcohol) can be used for this. Also, soldering acid should not be used to solder other joints like connecting cables with pads on the circuit boards etc., it should be used only for soldering stainless steel.

Although all described precautions are absolutely important and should be considered in any case, there is nothing to worry about: phosphoric acid is not strong, it is absolutely safe to use it - everything just needs to be done carefully, precisely and quickly.

Of course, 0.025 mm stainless steel is quite expensive and rare material, but in any case, it is much cheaper than the brass with gold plating. New sliding contacts are available here:
https://www.1zu220-shop.de/Zmodell/Zube ... 47567.html

I also added a short installation manual with some important information for these sliding contacts, it can be downloaded here:

ZM-SC-001S.pdf

(1.05 MiB) 59-mal heruntergeladen

Note: if a reasonable demand will be met, I will add other variants of existing sliding contacts to the current lineup. Please I ask to inquire about this.

Best regards,
Alex