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Top end blasting and coating

2K views 20 replies 8 participants last post by  rambo 
#1 ·
Hi again everyone I am getting started on my top end rebuild so obviously the first step is clean it all, what kind of blasting is best as there are lots of different types available now also the barrels look like they could do with a face lift what kind should I go for with them and what kind of coating do they have, many thanks Chris
 
#2 ·
Hi Chris,

Be careful with a lot of blasting media because Triumph ally castings are relatively soft and pressure plus an inexperienced operator can embed media in the ally, which'll be released when the casting heats up. :( If you want to be absolutely sure that blasting media cannot be left in the casting, go for either dry-ice (frozen carbon dioxide) or soda (soluble in the water of a finish wash). If you can get access to a compressor and gravity-fed gun, you can do soda blasting yourself - do it on, say, the drive (not on the lawn ...) then hose away the evidence when you've finished. :whistle

Otoh, if you must go for vapour blasting, ime this guy at least knows about the problems with Triumph ally; if you catch him at the right time, he'll also do it while you wait (or sample the fleshpots of Sevenoaks ...). :thumb

Coating a cast-iron barrel, ime simple bbq paint or the high-temp. paint Lidl sells from time-to-time; if you go for the Lidl stuff, because "time-to-time" inevitably means it won't be in stock when you need some touch-up, :rolleyes: have some spare, clean the can nozzle well and store it carefully. :)

Hth.

Regards,
 
#3 ·
Barrels needing a facelift and what to go for ? i am guessing yours are worn and considering a rebore.Far better to be buying a 750 big bore kit which is just a bolt on and go with no rebalancing of the crank.You will notice considerable pulling power increase on the road and up hills especially if carrying a passenger.It is also a chance to drop compression just a little to around 8.5 to 1.Cost around £300.Good value compared with a bore and pistons.Allow a little more if replacing small end bearings.
I have always used ordinary spray can acrylic paint.The type for spraying car bodies etc and not even heat resistant.It does not bubble or burn off.Use a spray can red oxide primer.
 
#4 ·
I should have said this is not my Triton (which already has a Morgo big bore) it is new acquisition the bike is a 72 TR7 frame and a 73 TR7 140V single carb engine and I do not think it will need a bore it has a head gasket problem so that will be skimmed, and it seems that what has been done in the past has been done on the cheap with little knowledge about what was being done, we confirmed head gasket being the problem by holding a candle around the joint while running which was promptly blown out on the R/H side, what I had in mind for the barrels was blasting clean and coating with whatever they use when newly supplied however I will know more when in pieces, many thanks Chris
 
#5 ·
For barrels there is a perfect product called Granville Cylinder Black, Satin..simple sandblasting works fine on those....or use VHT spray paint hi temp black and then bake it as per instructs. I highly recommend vapour blasting by TSR Vapour Blasting, Dave Cunningham in Sevenoaks/Kemsing for any Triumph parts...VHT optional satin clear sprayed on after will give extra protection against smudges and oil marks..but will need baking as per their instructs..US automotive on EvilBay sells a huge range of VHT products from USA. You can F#cebook TSR and find them easy.
 
#7 ·
This is also a good option for barrels.

After spraying, some paints need to be heated to 200 deg C, to obtain maximum durability.

Either by placing the barrels in an oven or running the bike.

http://www.rustoleum.com.au/product-catalog/consumer-brands/auto/specialty-paints/engine-enamel

http://www.whiteknightpaints.com.au/specialty-paints/high-temperature/engine-enamel

http://www.supercheapauto.com.au/Pr...l-Paint-Engine-Enamel-Satin-Black-340g/324063

http://www.eastwood.com/paints/hi-temp-engine-paints/engine-paints.html

There are many other brands also worthwhile.
 
#11 ·
Years ago,they used to be stove enamelled.I dont see powder coat as being any problem at all for a durable coating.I use spray cans of normal low temperature black car paint because it just works well and can be touched in on the bike.Total cost with primer is £6.
Having seen modern powder coat,it has improved and not to be confused by the black coating on your flower baskets which does fall off.My BSA has been powder coated about 30 years ago i would think when it was last restored.It looks very good except a little fading from the sun on the headlight ears.No rust anywhere.
 
#14 ·
Pete,even the acrylic car paint i use does not peel off with the heat.Powdercoat will easily accept the cylinder heat.Marc does have specialist knowledge of powder coat and i would trust that knowledge.His own engine is powder coated so i guess it works fine.
 
#16 ·
Shouldn't really use my motor as an example as it doesn't run yet. :wink2: But I'm certainly not concerned at all. Powder can withstand spikes of over 500°f, if your cylinders are that hot you have much more serious issues than worrying if your powder will burn off.
 
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