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topic 28527

Base coats and top coats for vacuum metallizing

A discussion started in 2004 but continuing through 2019


Q. Dear friends,

I am metallizing on plastics. I want to get their properties and results on plastic. Can anyone reply? I want to know how they work? Is it a chemical reaction while metallizing on it? Which compound is formed after metallization (especially of ALUMINIUM). thanking you for going through this question.

Rushi N. Daftary
student (research student) - Morbi, Gujarat, India

"A User's Guide to Vacuum Technology"
by John F. O'Hanlon
from Abe Books
info on Amazon

August 11, 2010

A. The base coat is a chemical which is used in vacuum metallizing plants. To metallize on plastic (which is silver colour) base coat is used without base coat it is not possible to get silver coat on plastic but there are some plastic which don't required base coat but that can't be done golden colour
1) Base coat is used 1st, then put in oven for 1.30 min at 75 °C temp
2) After it is dry, then to metallizing machine where it gets silver color
3) After silver, top coat is used to get golden colour or any other colour

kirit ganatra
- mumbai india

March 1, 2012

A. Thank you, Kirit for the answer. But I will add one thing: the top coat is not there solely to change the silver color to gold or another color, but also to protect the aluminum layer from oxidation or quickly wearing off. The top coat is always required, even if the desired color is silver.


Ted Mooney, Teds signature
Ted Mooney, P.E. - Pine Beach, New Jersey
Striving to live Aloha

March 1, 2012

RFQ: Can I get the information regarding the dealers of base and top coat used for vacuum metallizing.

akhil gandhi
- faridabad, India
^- Sorry, this RFQ is outdated
     View Current RFQs

August 12, 2012

Q. I want to know is there any reaction that takes place between aluminium and top coat which can make it dull after curing, or is there any other reason for the component getting dull? I'm facing this problem for some time. Can anybody guide me?

abhishek kakkar
- delhi, INDIA

May 7, 2013

A. Hello dear,
Your plastic pieces are getting dull after topcoat curing due to some other reason. Your base coat is not dried well. So increase time of curing base coat. Best of luck.

Rushi Daftary
- Morbi, Gujarat, India

June 22, 2014

Q. I do metallizing on polystyrene without using base coat, as polystyrene itself has a very good shining property so results are very good after metallizing. But I want to know to protect its lustrous silver shining what kind of top coat should I use, as traditional top coat will make it dull after using? If anyone knows please help me. THANKS

Gautam Sethi
Vacuum metallizing - Delhi india

July 6, 2014

Q. Why is base coat required before metallizing?

Rahul dudi
- hesar, haryana, india

July 2014

A. Hi Rahul. Gautam says a base coat is not required on polystyrene. It is usually required on most materials as a primer for adhesion and to deter corrosion, and for smoothness for good reflectivity.


Ted Mooney, Teds signature
Ted Mooney, P.E. - Pine Beach, New Jersey
Striving to live Aloha

March 12, 2016

Q. I am writing for the quality problem of our products of vacuum metallization.Our substrate is ABS and after applying top coat there is so many blister on the surface.Before applying the top coat the product seems good quality.So lot of products are rejecting due to this quality problem.What is the cause & the probable solution of this problem.Top coat is an acrylic Lacquer type top coat.Before baking this is happening and after backing this blister also increasing.

Subrata Biswas
Walton Hi-Tech Industries Ltd,Electronics Products - Dhaka,Bangladesh

January 31, 2017

"Understanding Modern Vacuum Technology"
by Steve Borichevsky
from Abe Books
info on Amazon

Q. We had been applying vacuum metallized on our electronic plastic parts and accessories.
ABS and PC are the most popular plastic resin material that we used for our vacuum metallized plastic parts and accessories.
Our objective is to get the similar performance as electroplating performance ( bright and shiny performance, good surface leveling ).
But applying base coat and top coat with spray method, causes us meet problems as below :

Orange peel ( spray effect )
Over spray on corners or edges of substrate

Fyi, most of our metallized plastic parts already have mirror polished on the surface.
For this reason, we thought that we could remove the base coat but still apply the top coat. By removing base coat, we hope orange peel defect can be reduced.
We tried this method, and we got a beautiful surface ( shiny, bright, smooth surface ) after vacuum metallized. Then continued by top coat sprayed.
After curing, the problem come :

Surface turn into foggy / hazy , not as bright and shiny as before top coat applied.
Wrapping film mark ( we protect the substrate using film wrapping once after plastic injection process ). Before top coat spray applied, we didn't see this.

Regarding to my explanation, seem we need top coat that will not turn into foggy or hazy after sprayed on metallized substrates without base coat.
Kindly support us to solve this problem by giving the proper top coat information.

Priya Tri Kurnia
PT HARTONO ISTANA TEKNOLOGI - Kudus, Jawa Tengah Province, Java

March 30, 2017

Q. Hey Everyone, Is primer possible before base coat for metallizing purpose? We want to build some more dft on the contents to hide some moulding related issues. So, is primer possible or not?

Sumit ahuja
- gurgaon india

July 2, 2017

A. I'm a chemical engineer and doing Metalising on ABS for 4 years. As you know, basecoat is used to provide a base of aluminium finish -- but it gets black after 2-3 day. To provide it some life and different colours like blue metallic look or green or pink we use topcoat and mix it with different colours (or you can say toners) to provide it some life and durability. The product that I used generally comes from Delhi which deals only in basecoat, topcoat and ABS paints and their solutions.

Nishant Wadhwa
Mateshwari hari nagar - New delhi, India

January 10, 2018

Hi Friends!

I am evaluating to apply basecoat through dipping process and also looking for suppliers who manufacture basecoat dipping + flashing off line. Any lead or help in this regard will be highly appreciated.
Further, do the same basecoat and topcoat products work with ABS and PP?

Rakesh Agarwal
- Kolkata, West Bengal, India
  ^- Privately contact this inquirer -^

Ed. note: Readers publicly please reply to the technical aspects of this inquiry; we don't publicly post sourcing suggestions (why?).

March 17, 2018

Q. What should the thickness for base coat to ABS plasticor A?

Vikas kumar
- Baddi himachal india

March 2018

Hi Vikas. Tell us more please! Googling for "plasticor A" came up empty for me, but I saw dozens of plastics companies from every corner of the world with names from Plasticor to Plasticore to Plasticorr to Plasticon to Plastikor to Plastocor.

Please describe your situation because many of our regular responders tell us that they love intriguingly detailed shop problems but they won't acknowledge abstract questions :-)

Thanks & Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET - Pine Beach, New Jersey
Striving to live Aloha

May 30, 2018

Q. Please I have a big problem with metallizing on glass. Can anyone tell me how can I metallize glass, and what type of basecoat and topcoat to use?
And thank you much.

Mahmoud Anwar
Coating company - Cairo , Egypt

October 4, 2018

Q. Hello
I'm a researcher in a coating company. I have a question about metallizing polyethylene. Do you have an experiment about metallizing polyethylene? Which resin is used for base coat on polyethylene? Do I use flame activation for this substrate? Thank you for helping me.

saman khadem
sakht ara coating - tehran, iran

Rainbow defect in vacuum metalizing topcoat

March 16, 2019

Q. Hello,
we are coating manufacturers; we are supplying a uv coating, base coat and top coat. Customer is facing rainbow defect after top coat applyied on abs after metalizing.
Please rectify the issue and what causes may be for this type of problem and what will be the remedy, what type of resins should we use for eliminating these defects, thanks

Saboo coatings - Chandigarh, Punjab, India

March 2019

A. Hi Nitin. It seems to me that such a rainbow would be caused by the same phenomena which causes a rainbow when a drop of oil is placed in a puddle of water: the film being of only partial wavelength thickness such that light is reflected from both the outside and inside surfaces of the top coat, causing interference patterns.

So my first guess is that your customer is applying the topcoat too thin. But rainbows are not always caused solely by the thickness of the main coating; it's probably possible that the coating ingredients are separating in some fashion during curing such that there is sort of an oiliness between the metalizing and the top coat, or on top of the top coat. I'm not an expert in either topcoats for metalizing or glass, but I have heard that tempered glass can offer undesirable rainbows if tempered in a way that causes areas of differential diffraction.


pic of Ted Mooney
Ted Mooney, P.E. RET - Pine Beach, New Jersey
Striving to live Aloha

April 2, 2019

A. Check thermal oven temp. & uv light setting and intensity.

raushan raj
- delhi, delhi, india

Want non-scratchable UV coating for glass

April 20, 2019

Q. Hey guys I am looking for UV curable coatings for application on glass and which are strictly non-scratchable, not even scratchable with a knife after curing UV top coat. Kindly suggest me a company name or dealer's name.

Raghav upadhyay
  ^- Privately contact this inquirer -^

April 2019

A. Hi Raghav. We don't publicly post suggestions of particular companies or dealers (why?) -- but people are welcome to contact you privately. I would suggest that you visit because that seems to be the premier technical education society / trade group for that topic.

Gorilla Glass

Your question is a bit abstract in that you haven't told us anything about this glass or its application so I don't know whether unscratchable glass could suit your needs instead of coating it, but my understanding is that the scratch-proof glass on smart phones does not have a UV coating. Good luck whether you go with better glass or a UV coating.


pic of Ted Mooney
Ted Mooney, P.E. RET - Pine Beach, New Jersey
Striving to live Aloha

June 28, 2019

Q. I am relative new to this process so excuse my naivety. I am seeing a very high scrap rate due to scratches in the surface. It is very easy to scratch and sometimes it can even take on a finger/palm print. Is there any suggestions to make the surface more robust against scratches? This is metallizing plastic parts using the vacuum process.

Charles Boots
- Oxford, Michigan USA

July 2019

A. Hi Charles. Decorative vacuum metallizing has 3 layers: a base coat, the vacuum deposited aluminum layer, and a clear top coat. It sounds like your top coat is not as hard and robust as you'd like. What can you tell us about it?


pic of Ted Mooney
Ted Mooney, P.E. RET - Pine Beach, New Jersey
Striving to live Aloha

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