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Base coats and top coats for vacuum metallizing



A discussion started in 2004 & continuing through 2017 -- add your Q to bring it back to the Hot Topics page.

(2004)

Q. Dear friends,

I am research student. I want to know something about air drying base coat and top coat which are being used in vacuum 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

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
PROCESS:
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

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.

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey



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


March 1, 2012

Hi, Akhil. For a more enthusiastic response, please include your company name and a description of your needs. Vendors sometimes ignore inquiries with no details because they are often from people looking to sell something rather than to buy something :-)

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


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.

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey



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

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

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