parting methods

[graham]

hello,

In the very near future i will be spraying two halves of a cf6/50 engine case internally,i have all the masks from Gerards,, so as to not waste to much powder i would like to have the two halves joined,,,what would be the best way of doing this,so that the two halves can be easily parted after spraying.

The powder i will be using is 450 bond coat followed by 54ns,,,

Any help on this matter would be much appreciated,

Graham.

[Gordon]

Hi Graham

Hoping someone with actual experience of processing this part may help. I can only suggest placing spacers in between parts, so forming sufficient gap to avoid bridging of the coating.

Moving this thread to Surface Engineering Forum.

[LEN WOOD]

Hello Graham,

We mask and blast-prepare casings in halves then remove abutment face tape (after blast). Then depending on assembly geomoetries & fixturing we either remask with new tape, antibond or use available 'reusable' masks. The two halves are then adjoined but with a gap (10mm min on 54 NS) - mask exposed bolts or adjoinment hardware to avoid overspray bonding. To enable this gab use suitable hard spacers - remember that things are going to get hot and could start to move or drift! Make sure that there are no areas likely to cause an inline bridge otherwise later overspray removal could chip or crack onto the coated area. It's a good idea to periodically check (especially with Pure Aluminium) that things are going to plan and the tape hasn't lifted and coating build up isn't encroaching on required area edges. You can 'dress as you go' so long as you're careful and the gap between halves is sufficient. It is wise to keep break areas that will be breakaway points when you seperate after application is complete. Be careful when seperating.

Make provision for spent-unbonded powder (overspray) to vacate the assembly. Otherwise entrapment of this turbulence will compromise your coating quality/integrity.

As with all TS applications there are things to discover and learn everyday. Hopefully with a little fore-thought you'll be able to minimise any negative learning and do the job right first time!

Hope this helps

GlenB

[Gordon]

Hi GlenB

Thank you for responding. Advice sounds good to me