Powder Coating

R

redbloke1956

Well Known and Active Forum User
Non-VOC Member
Hi to all, I am currently trying to powder coat my Timing Chest Cover and am having a lot of dramas, Has anyone had experience with Powder Coating Vin Engine Alloy bits.
I have tried every possible degreaser and cleaner, Glassblasting, hand sanding with 800grit, I have completed a pre heat to in excess of the required temperature for powder as a form of pre-degassing and eliminating any contaminants.
I have coated with powder and baked, sanded back the finish until smooth, re shot and baked the cover and, while getting a small improvement, I am still getting the tiny eruptions all over the Cover that are not dust or contaminants but appear to be gas/air released from the alloy (under the powder) upon heating.
I have used the aforementioned methods very successfully on steel components.

Any tips/clues/insights would be greatly appreciated
IMG_7015.jpg
 
C

clevtrev

Well Known and Active Forum User
VOC Member
It`s caused by the porosity in the casting. If you were to do a weld repair, the perimiter of the weld would produce the same result. It`s all about expansion of air.
 
T

timetraveller

Well Known and Active Forum User
VOC Member
If you can obtain access to a vacuum facility try keeping the prepared cover under vacuum for 24 hours prior to powder coating. If that does not work then lots of members have used paint with great success.
 
R

redbloke1956

Well Known and Active Forum User
Non-VOC Member
Thanks to all, TT...I have been teaching myself to paint over the last year or so and discovered that as far as painters go, I make a great Electrician, about 5 - 10% of the time I manage a great finish and the rest are rubbish.
I managed a great (paint) finish on the primary cover until 2 weeks later a tiny bit of fuel dripped onto it and destroyed the finish. I would like to have a crack at 2 PAC but I love the tough finish of Powder.
I will keep investigating and practicing with powder until I get the finish I want :)
 
T

timetraveller

Well Known and Active Forum User
VOC Member
Just as an aside; I notice that you are covering all the surfaces, including the one where the magneto drive cover fits. There are special heat resisting masking tapes made for powder coaters. I know that they work as one of the jobs I did a few years ago was renovate and modernise a 150 year old telescope, fifteen feet long and about twelve feet high. I had some of the cast iron parts, weighing hundredweights each, powder coated in ' antique bronze', a gold and black speckled finish. With the masses involved the heating process in the 'walk in' oven took a long time. The value of such a telescope is way beyond my means and so working on it was fraught with the danger of destroying an irreplaceable classic. It was really important that everything should work afterward and on pealing off the masking tape after the coating was done it was perfect. Phew!! Your local powder coater will probably give you a foot or two of it if you ask him nicely. Good luck with it.
 
J

johnmead

Well Known and Active Forum User
Non-VOC Member
Are you doing the powder coating yourself or are you using an experienced powdercoater. On my special I had the crankcases, cylinders, heads, timing, magneto and kickstart covers powercoated and my powdercoater did not have any problems. Only the primary cover is left to do and I am waiting for Osman to finish his covers for the 40mm Newby beltdrive and that will go to the same powdercoater.

John Mead
 
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