There are fillers for going under powder coating. Several years ago I renovated a telescope for Marlborough College. The telescope was made in 1860 and the iron castings probably earlier. There were some serious holes in these casting which were filled prior to them being powder coated with 'antique gold', a black and gold speckled finish. I have tried to add a photograph of the finished telescope which is about seventeen feet long but even after trying to reduce the photograph file size it still will not attach so have given up for now.
Powder coating frame
- Thread starter nahma
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My understanding is there is no "filler" which can be used for powder coating. The reason being, unlike twin pack and cellulose paint, powder coating is subject to high temperatures. Usual fillers are not suited to high temperatures. Hence, the only way to get a good surface for powder coat is to abrade the surface which makes it thiner. Also, powder coat can be applied overly thick which can be detrimental to heat dissipation on engine cases etc. Also, build up on mating faces may need to be removed to ensure fit of mating parts and electrical continuity. I believe cellulose can be easier to apply but not sure how it stands up to modern fuels. I have heard there is a process which ensures a thin coat of powder coat. This sounds like a good option where the surface is sound and good. Still looks to me a finish which allows the surface to be filled is more practical. Always willing to learn more so will watch this thread.
The start of this was regarding frame, but I'll chime in. Before I had my front stand pivot casting powdercoated, I spent some time planning where the masking needed to be to maintain spacing, etc. For instance, on the ends, stand pivot bolt holes.
And remember that you have to use a special masking tape with powder coating because of the high temperature. Your local friendly powder coater will have some.
Indeed, a decent powder coater can produce wonders, as by example my just completed Harley Davidson MT350:
and my Land Rover that 98% of it was powder coated:
My powder coater has a VERY deep gloss, which most blacks are not, so I am at this moment pulling my Comet apart so that he can powder coat all the parts in this medium.
and my Land Rover that 98% of it was powder coated:
My powder coater has a VERY deep gloss, which most blacks are not, so I am at this moment pulling my Comet apart so that he can powder coat all the parts in this medium.
I cannot claim special knowledge ref. powder coating except as someone who has had bike parts so finished with mixed results. The steel parts came out well but a few problems were apparent on some alloy parts, which needed to be re-coated, unfortunately with the same result owing to "out-gassing", which left small bubbles in the finish. Two pack finally was used on these problem bits. Another defect that can occur is "orange peel" effect in the finish, which gives an antique look to the coating, but probably not what you need on your prized Black Shadow............There is plenty of internet info available, but personal recommendations from previous customers would help when finding a competent powder coater, preferably one familiar with motor cycle powder coating experience, so that you get it right first time. Done well it provides a very hard and durable finish, although I did not wish to use it on the engine.
Col.
Below: Extract from a powder coating information pamphlet.
The term out-gassing is a reference to the release of trapped air in a cast substrate during the cure cycle. Porosity in the casting traps air. When the casting is heated the air expands and blows through the partly gelled coating leaving pinhole defects. Out-gassing is a serious problem for powder coaters, depending on the type of casting, zinc die cast being of a problem and sand casting being the worst. Pre heating or the use of 'out-gassing forgiving powders' can be used for dealing with the problem.
Col.
Below: Extract from a powder coating information pamphlet.
The term out-gassing is a reference to the release of trapped air in a cast substrate during the cure cycle. Porosity in the casting traps air. When the casting is heated the air expands and blows through the partly gelled coating leaving pinhole defects. Out-gassing is a serious problem for powder coaters, depending on the type of casting, zinc die cast being of a problem and sand casting being the worst. Pre heating or the use of 'out-gassing forgiving powders' can be used for dealing with the problem.
From my powdercoating friend I know that there exists a metal based ( could be alloy) putty filler. you need he metal inside so that the electric path for powder coating is not disturbed. the filler does not sand very easy and takes a bit of getting used too, but then you can have good results.
when it comes to the finish, my powder coater now has a new very thin clear overcoat and the results a fantastic. Just talk to your friendly powder man what he can offer you.
Bernd
when it comes to the finish, my powder coater now has a new very thin clear overcoat and the results a fantastic. Just talk to your friendly powder man what he can offer you.
Bernd
knowing how to powdercoat correctly
a good powder coater will know how to diminish the pitting marks but as for filler there is none availble as i know, please check out the shadow parts we did last week on our gallery at www.fastlinecoatings.co.uk .
a good powder coater will know how to diminish the pitting marks but as for filler there is none availble as i know, please check out the shadow parts we did last week on our gallery at www.fastlinecoatings.co.uk .
Hi nahma,poder coat is very durable,and can give a really good finish, what I would say is ask around because in my experience there are varying degrees of capabality, two pack is also very good but because it is so hard (brittle) it chips very easily,although it gives a very deep lustre, over the years I have tried them all ,cellulose is still my choice but it is very time consuming,I did have a Comet powder coated but as has been said before the prep is the most important thing,bcause the bare metal was quite badly pitted in places I stripped what was left of the paint and tried to remove as many of the imperfections myself,as far as I know ther are no fillers that can stand the oven heat required for P/C ,However because of the depth of P/C you are able to flat back with 1200 wet and dry and polish from flat after levelling the imperfections Good luck.
Go to the powder coater and get some of the special tape they use and tape the stuff off after you clean all the oil,crease and paint off yourself
cheers
Peter
cheers
Peter