Dear Thermal Spray experts,

We have two identical Praxair powder feeders model 1264. Both are well-maintained and are running fine for years and years. 

Last week we noticed a reduced buildup on one of our HVOF installations. We changed powder feeders and the problem was solved.

We compared both powder feeders on one product and the buildup was only have with the "problematic" powder feeder. The powder consumption was also half so it is a feed problem. 

We have disassembled the powder feeder already twice and checked all items below:
1. We changed the slotted disc for a new one
2. We checked that all nitrogen & powder channels are free
3. We checked the RPM settings of the machine with the actual revolutions
4. We changed all wear parts with new ones

The problem still remains... Could you please share problems that you have had with your powder feeder installations so that I could find some inspiration as to where the problem might occur?

Thank you,

Jeroen Belis

Hello all,

i was wondering if someone know this spec and their how to process?
Thanks!

Dear all,

Alternate method for thermal spray coating removal is by high pressure water (waterjet). The requirement is not to remove base material more than 0.001 inch.

My question is how exactly to measure this material loss? 
If by Metallographic, it could only measure the sample thickness after stripping process. But how to compare with before stripping process and calculate the material loss?

Hi everyone. My first post here.

I am based in the U.K. and am currently building my new workshop. I am not an industrial user but rather to restore cars for clients and an enormously interested in buying a zinc spray setup.

We will now have a dedicated media blasting booth (made from a converted shipping container with extraction and mesh doors), with a reasonably large compressor (40CFM) and we currently use oxy-acetylene in the workshop.

There is another restoration business in the country (who work in a different field) who I greatly admire and they use zinc flame spray with some sort of Metco gun and this is the system I would like to emulate.

However my budget is limited. I did call metallisation for a quote on a new setup and was staggered at the cost (5-figures).

Could anyone tell me the model of gun as used in the video clip below at around 7-minutes 8-seconds in? From google images I’m guessing it’s a Metco 12E. Having a similar setup here would significantly improve the quality of our builds.



Any advice on ways in which the parts needed to assemble such a kit can be sourced and refurbished inexpensively would be very welcome.

We are very small scale (mainly myself with some ad-hoc help) and in the past we have outsourced zinc spray - but this is time consuming and inconvenient. Not to mention costly as it is a long drive to the nearest place that can do the work so they have to reblast the components before coating.

Really appreciate any help.

Hello everyone!

I am currently trying to figure out the significant cracking issues on parts. We spray Metco 71vfns-1 to meet the PWA 257-1 coating spec. Setup is as follows:

9MB torch
9MC Powder feeder
Argon only 
1000 amps
47 volts
45 g/m feed rate
724 nozzle
standard electrode
primary 90 psi @ 212 scfh

Part we are spraying is an aerospace component.  7.5" diameter. Top of diameter to radius is 3"
samples have all passed through the lab, good microstructure and tensile strength exceeds 10k psi.

when it comes to the part, we seem to be always having cracks. I use 2 external cooling jets combined with air frontals on the gun. table speed set to 300rpm with a 20mm step. 3.5" standoff.

i feel as so that the part is reaching too high of a temp during the spray process vs the samples and bond bars ( between 220 and 275 f ). depending on the amount of passes we do.

any suggestions as to why this could be happening? or a better way to control the temp? any input will be greatly appreciated!!

We spray dry and supply the 99.99% spherical Y2O3 powder for APS.
And we have 20+ years experience on oxide ceramic powders and serving 500+ coating companies on the earth.
sales@spraying-powder.com

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We spray dry and supply the 99.99% spherical Y2O3 powder for APS.
And we have 20+ years experience on oxide ceramic powders and serving 500+ coating companies on the earth.
sales@spraying-powder.com

https://www.spraying-powder.com/2021/01/...%e7%b2%89/

Hi everyone,

This is my first post but I have been following this forum for a long time and I always found helpful topics.
Thanks to everyone for this. 

I need your help about one issue that's why I'm writing. Recently we have a pit problem on the plasma coating that we see after grinding operation.
We use F4MB-XL gun and 81vfns powder. We don't see it on all the parts but it occurs sometimes. What can be the reason for this? I also added some photos for the pits that we encounter. We have some doubts about the gun spare parts but even we changed the newly we still see after changing.

Hello all,

I wonder if anyone has experience coating plate rolling machines' rollers. A company uses a plate roller to form a cylindrical shape of aluminium sheets, and as the roller has some scratch marks due to wear over time, those scratch marks leave unwanted stains on the aluminium sheets. What would you suggest to me? I thought applying 2 mm metcoloy 2 coating those rollers would be enough. As the machine is the core element of their production line company hesitated to apply a coating and consider using it the way it is.

I do not have any info about the machine yet but to my best knowledge, the roller material is 1050 steel with a 500mm diameter.

Thank you all in advance

Hi everyone,

I'm developping the NiCrBSi coating with DJ-2600 gun, and I met one problem with the air cap in the gun.

After sevelal passes, there deposited much coating on the surface on of air cap like below.  
https://i.postimg.cc/d3KvKpMH/2022121174346909.png

Parameters are: H2 600NLPM, O2 200NLPM, Shroud gas 300NLPM

Could U help me?