In this article we will explain how to use epoxy coating powder to properly coat busbars, both aluminum or copper
Low Voltage Busbars and Medium Voltage Busbars
Whether you are using epoxy coating powder to coat low voltage busbars or medium voltage busbars, or whether you are using aluminum or copper busbars, this guideline will help you. This is what a sample process (or recipe) will look like. Once the process engineer completes the process development he will have something like what is shown below. Generally they will select the options on the HMI and the PLC will set the corresponding values for the line to run – for sophisticated systems.
| Part geometry (Width x Thick) |
Material | Voltage rating | Required Coating thickness (mils) | Preheat temp (°F) | Preheat Time (mins) | # dips |
Cure temperature (°F) | Cure Time (mins) |
|---|---|---|---|---|---|---|---|---|
| Top of Page | ||||||||
|
Epoxy Coating Guideline for Busbars
Low Voltage Busbars (up to 600V) |
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| 2 to 8″ * 1/4″ 50-200mm x 6.35mm |
Copper | 600 V | 20 to 30 | 340 | 20 to 24 | 1 | 380 to 400 | 20 to 24 |
| Aluminum | 600 V | 20 to 30 | 360 | 20 to 24 | 1 | 380 to 400 | 20 to 24 | |
| 2 to 8″ * 1/8″ 50-200mm x 3.18mm |
Copper | 600 V | 12 to 20 | 320 | 20 to 24 | 1 | 380 to 400 | 20 to 24 |
| Aluminum | 600 V | 12 to 20 | 320 | 20 to 24 | 1 | 380 to 400 | 20 to 24 | |
|
Epoxy Coating Guideline for Busbars
Medium Voltage Busbars (up to 38,000 Volts) |
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| 1/4″ (6.35mm) | Copper | 5 kV & 15 kV | 60 to 80 | 400 – 420 | 20 to 24 | 4 | 340 to 380 | 20 to 24 |
| 3/8″ (9.53mm) | Copper | 5 kV & 15 kV | 60 to 80 | 390 – 410 | 20 to 24 | 3 | 340 to 380 | 20 to 24 |
| 1/2″ (12.7mm) | Copper | 5 kV & 15 kV | 60 to 80 | 370 – 385 | 20 to 24 | 3 | 340 to 380 | 20 to 24 |
| 1/4″ (6.35mm) | Copper | 27 kV & 38 kV | 100 to 125 | 440 – 460 | 20 to 24 | 5 | 340 to 380 | 20 to 24 |
| 3/8″ (9.53mm) | Copper | 27 kV & 38 kV | 100 to 125 | 420 – 440 | 20 to 24 | 4 | 340 to 380 | 20 to 24 |
| 1/2″ (12.7mm) | Copper | 27 kV & 38 kV | 100 to 125 | 390 – 410 | 20 to 24 | 4 | 340 to 380 | 20 to 24 |
Please visit us at www.caplinq.com to learn more about our whole range of epoxy coating powders including our halogen-free Linqsol BCP-1504 which is developed specifically for busbar epoxy coating applications including both low voltage (<600V) busbars as well as medium voltage (up to 38kV) busbar applications.
If you have any other questions about how best to clean your molds, the products you can best use to clean them, or the application methods of these materials, please feel free to leave a comment below, or don’t hesitate to contact us.
Dear Mr. Chris Perabo,
Referencing to your this blog. I was trying to search any relevant literature related to Busbar Epoxy coating, until I reach to your blog. You blog would sure be beneficial to many of us.
From the same blog, I am interested to ask few question, for my understanding. In the tabulated data you present, for the Medium Voltage Busbars (up to 38,000 Volts). I noticed, that with the increasing busbar thickness, the pre-treatment temperature, coating thickness and the number of dips are decreasing. Whereas my assumption is that with increasing busbar thickness, the pre-treatment temperature (if we keep the same time), coating thickness and the no., of dips must increase.
Could you please explain for my better understanding.
Thanks,
Amin Ali Shah
Hello Amin,
You are correct that you want to have a thicker coating when you are using larger busbars. However, when you use larger busbars, these retain much more heat than smaller busbars, which means that there is MORE pickup of epoxy coating powder with every dip and therefore also a FEWER number of dips are needed to achieve the required thickness.
I hope this helps. If you have any more questions about epoxy coating powder for switchgear and power distribution including low voltage busbars and medium voltage busbar coating, please do not hesitate to contact us.
Dear Mr. Chris Perabo,
What type of processing issues would cause “pinholes” in the epoxy coating?
John
Hi John,
There are several processing issues that could cause pinholes. From the engineering side, we always look at three variables:
a) Process
b) Substrate
c) Powder
On the process side, pinholes can be linked to the busbar itself being too hot or too cold. If it’s too hot, the material could cure before the air has a chance to escape. If it’s too cold, the air bubbles may form too slowly to escape. It can also be caused by dipping the bar again too quickly or by taking too much time between dips.
On the substrate side, copper and aluminum have different thermal retention rates and you want to make sure you get the bars in quickly enough and get them out quickly enough that the “cool powder” doesn’t cool down the bar too much between dips.
Finally on the powder side you want to make sure that the product has the right balance between “Gel Time” and “Sticking Point”. The sticking point refers to the temperature at which the powder will stick to the bar, whereas the gel time refers to the amount of time the material will gel when exposed to the high busbar temperatures.
CAPLINQ’s team of sales and technical engineers are very well trained in using and troubleshooting busbars. Please send an email to info@caplinq.com if we can interest you in a sample for aluminum or copper busbar coatings.
Dear Chris..
Hope you are doing well..
Thanks for the detailing about epoxy process..
Actually I have few queries..
We had thickness of bus bar from 2.5,4.75,6.25,9.45 like that..
Could you please tell me..the parameters
1. Pre heating temperature-
2. Dipping cycle time-
3. No of dips-
4. Time Interval required b/w dips –
5. Post heating temperature-
Currently we are facing…issues like poor appearance of bus bars after epoxy coating and then few epoxy particles settled in bus bars while dipping intervals, it requires manual shaking of bus bars .and high thickness reflected than the margin..
Kindly pls advise on the above queries and paraameters for each thickness of bus bars them how could we eliminate all these cons against the process..
Your reply was much appreciated..
Hi Shafi,
Thanks for reaching out. Your questions are of course very good, but the answers to these questions will first require more questions to be asked. The reason for these questions is because each of the answers will depend on the busbar epoxy coating powders materials you are using as well as the material the busbar is made of (aluminum or copper).
Our most popular product LINQSOL BCP1504 is a very versatile halogen-free busbar epoxy coating powder.
So let me please start with questions to ask you:
If you have a specific customer inquiry, I suggest you also send us an email at info@caplinq.com and our Applications Engineering team will be able to help you optimize your settings.
Look forward to hearing from you,
Chris Perabo
Hi chris,
Thank you for sharing such valuable experience.
I had a doubt while powder coating bus bars, we are masking the busbar with high temp masking tape but the coating thickness on the busbar is too high that it covers the tape itself and when we try to peel the tape of with a sharp object it cracks up the powder coating on the component.
Which leads to my second question that how can we improve adhesion of piwder coating on a tin plated copper busbar?
Thanks
Saksham
Excellent questions Saksham,
Many first-time epoxy coating powder users see that they can mask off the areas of the busbar with a masking tape. This is true and it is also recommended. What they don’t realize is that you need to remove the masking tape while the busbar and the powder are still warm. Once the epoxy cures and the tempearture drops, the epoxy becomes very hard and brittle, making it difficult to remove the masking tape as you have described.
With even thicker layers of epoxy coating powder, it becomes trickier to peel off the tape before the epoxy cools done – but it is absolutely possible. I have peeled off tape from busbars that have thicknesses of almost 5mm of powder, which requires many dipping layers to achieve.
Another trick is to use aluminum foil to do the masking and only use a bit of tape where the foil overlaps with the tape. This allows you to use much less tape and it makes it a lot easier to clean up afterwards.
As for your second question, adhesion to tin. There are two ways to address this. The first is to use a good epoxy coating powder for busbars that has been formulated to have adhesion on both copper and tin.
– Linqsol BCP-1507 Epoxy Coating Powder
The second is to use an adhesion promoter to adhere better to. For this I would recommend you look at:
– Methacrylate Functional Adhesion Promoter
For medium voltage gear is sanding of the surface recommended to ensure adhesion. Will the silver flash on the ends tarnish/discolor even though it is taped due to oven temps. Gear is 5-15 kv