DIY POW­DER-COAT­ING

Ralph Fer­rand on why it’s now pos­si­ble to do at home.

Classic Motorcycle Mechanics - - CONTENTS -

Back in April at the Stafford Show, I found a stand that was demon­strat­ing a DIY pow­der coat­ing set-up which tweaked my cu­rios­ity: pow­der coat­ing at home? Sadly at the show their heat source wasn’t work­ing so all they could show was the special gun ap­ply­ing pow­der, so I couldn’t tell if it was ac­tu­ally any good but ed­i­tor Ber­tie was keen for us to give it a go for the ben­e­fit of CMM read­ers. I con­tacted Elec­tro­static Magic and told them that I would be in­ter­ested to test their prod­uct out, but would only be truth­ful about my find­ings in any re­port­ing. They were en­thu­si­as­tic about send­ing me a piece of kit to try, which I usu­ally only find to be the case with pur­vey­ors of prod­ucts that ac­tu­ally work. We shall see! The kit duly ar­rived and I just had to find the re­main­ing kit to use it with. Num­ber one on the list is a com­pres­sor that can out­put 50psi (3.5 bar) at 1 CFM with at least a six-litre tank. Not a prob­lem, I can turn the reg­u­la­tor down to 50psi. A de­cent breath­ing mask is also re­quired, which I have al­ready for us­ing with wet paint. The only thing I didn’t have was an oven and while a do­mes­tic oven is fine, they do ad­vise against us­ing the one your mis­sus puts the Sun­day roast in. My late mother had an old Baby Belling at her house, so I snaf­fled that. I popped down to a lo­cal dis­count hard­ware shop and came back with a large clear stor­age box to spray into; it’s best to col­lect all the pow­der that misses the item you’re coat­ing for re-use. Be­cause I only had a small oven the ini­tial test was go­ing to need to be per­formed on small parts. I had a cou­ple of brack­ets for a cus­tomer’s bike, but I wanted to try it on some­thing slightly less easy. I have lots of old Z900 han­dle­bar switches, so I thought that coat­ing a set of those might be an in­ter­est­ing chal­lenge. If you take them to any com­mer­cial pow­der coaters they gen­er­ally ruin them by putting too much thick­ness on and by omit­ting the cru­cial de-gassing process. As with all forms of coat­ings, be it wet paint or pow­der, prepa­ra­tion is key and no

form of coat­ing is go­ing to stick to grease or oil. I stripped the switches down, hav­ing care­fully pho­tographed them to give me a fight­ing chance of suc­cess on re­assem­bly. I de­cided that glass bead blast­ing was the eas­i­est way to clean them all up. I then gave them a thor­ough de­greas­ing with brake cleaner be­fore giv­ing them an­other good go in the bead blast cab­i­net. Glass bead blast­ing pro­vides a great key for the pow­der coat to ad­here to. To be hon­est I’m not sure whether han­dle­bar switch die cast­ings need de­gassing or not but I gave them half an hour in the oven any­way. This would also help to en­sure that any grease or oil trapped would be given a chance to leach out and be seen. I let them cool down and then gave them a fi­nal de­greas­ing with panel wipe and clean pa­per towel. I checked the tem­per­a­ture of the oven us­ing a ther­mo­cou­ple ac­ces­sory for my multi-me­ter, which soon told me that my in­her­i­tance had a bug­gered ther­mo­stat. To keep the oven at the cor­rect tem­per­a­ture, I had to keep turn­ing it on and off and vent ex­cess heat out by open­ing the door! It was a warm day and my work­shop was soon like a sauna. The pow­der came in a half-kilo zip-lock bag and I found that the eas­i­est way to de­cant it into one of the sup­plied pow­der can­is­ters was with a house­hold fun­nel with the can­is­ter very lightly held up­right in the bench vice. With a ba­sic kit you get one bag of pow­der free and I had re­quested a black satin, which is the most com­monly-used in restor­ing 70s, 80s and 90s bikes. This seems to go a long way and even when I need more it will only cost me £6.99 for an­other bag. Look­ing on their web­site there are all sorts of ex­cit­ing bright can­dies and metallics to play with and the most ex­pen­sive is still only £9.99 a kilo. As some­one who reg­u­larly buys pro­fes­sional paint, I have to tell you that this is very much cheaper than the two-pack paint I would use as an al­ter­na­tive, which would also re­quire a hard­ener, primer, thin­ners, gun wash etc. With this ini­tial test I didn’t re­ally need to mask any­thing, but I do know that mask­ing ma­te­ri­als for pow­der coat­ing are more ex­pen­sive and harder to work with than those used with wet paint. As per the sim­ple to fol­low in­struc­tions sup­plied with the kit I fit­ted the water trap to the gun and although they include a fit­ting to at­tach an air­line pipe, I pre­ferred to fit a PCL air­line con­nec­tor, so that I could fit it di­rectly to my air sup­ply. As in­structed, I then ad­justed the air pres­sure reg­u­la­tor screw at the bot­tom of the gun’s han­dle, while squeez­ing the trig­ger in my plas­tic box/spray booth un­til a gen­tle cloud of pow­der ex­ited the end of the gun. The parts need to be earthed to the gun. There is an earth strap snap stud on the side of the gun and a curly-wurly re­coil earth wire is at­tached to this. The other end has a crock clip to at­tach it to the work­piece. I made hang­ing hooks for the work­pieces from light alu­minium TIG weld­ing rods so that I could at­tach the earth to these, rather than the parts them­selves. Where there were threaded holes I fit­ted in screws and at­tached the hooks to those in­stead, which has the added bonus of mask­ing the threads into the bar­gain. Es­sen­tially, pro­vid­ing the work­piece is elec­tri­cally con­nected to the body of the gun, it re­ally doesn’t matter how this is achieved. The kit did come with a wrist­band to at­tach to the earth

Box of old Kawasaki Zed han­dle­bar switches cry­ing out for some TLC.

Oh dear, the ther­mo­stat in the Baby Belling is bug­gered! And it went much higher than 202.6°C later!

I turned the pres­sure on my com­bined reg­u­la­tor and water trap down to 50psi.

De-gassing in the Baby Belling.

I think these are past touch­ing in.

Af­ter a good blast in the cab­i­net.

Newspapers in English

Newspapers from UK

© PressReader. All rights reserved.