The BSA A7-A10 Forum

Technical (topic titles must be descriptive) => A7 & A10 Engine => Topic started by: bsaketcase650 on 24.08. 2009 21:41

Title: Cylinder barrels and head paint finishes
Post by: bsaketcase650 on 24.08. 2009 21:41
I have just embarked on the restoration of a 1953 A7 Star Twin. Unlike my 60 A10 GF, which had the cylinder barrels and head powder coated, I would prefer to have a more traditional finish on the Star Twin. Although aesthetically pleasing, I have some reservations about the heat dissipation qualties of powder coating, particularly on iron heads which run a little hotter.

Can anyone recommend a durable paint product suitable for the job?

Regards to all,

Simon

Title: Re: Cylinder barrels and head paint finishes
Post by: cus on 24.08. 2009 22:46
G'day Simon,
I use Motorspray heat proof paint, available in spray cans.
Make sure head & barrels are clean, you don't need primer,
but spray lots of thin coats, not one thick coat. After the engine
has heated up, goes a nice satin finish, & is easy to touch-up if
it gets chipped. Hope this is of some help.
Cus
Title: Re: Cylinder barrels and head paint finishes
Post by: RichardL on 25.08. 2009 01:53
There is a product called "Granville Cylinder Black".  I bought a can of this from Leigh Classics. This can be brushed or sprayed on to bare metal or on top of existing finishes (probabaly not powder coat). I am yet to have a chance to use this on a whole cylinder, but my test patch showed that it is satin leaning more toward the flat side. If you want gloss, I don't think this is the stuff. However, If you want an antique look, this may serve well. In any case, it is cheap enough to buy a test amount.

Richard L.
Title: Re: Cylinder barrels and head paint finishes
Post by: dpaddock on 25.08. 2009 03:05
Powder is definitely not a good coating for heads and barrels.
There are spray and liquid heat resistant paints from e.g. Rustoleum which are perfectly suitable for these purposes. They are used to restore cooking grilles, among other purposes.

David
Title: Re: Cylinder barrels and head paint finishes
Post by: Rusty nuts on 25.08. 2009 11:14
The guys who stoved my cycle parts used a high gloss polyurethane paint that has higher temp, oil, petrol resistance.
Think was developed for marine use..
It produced a lovely gloss finish but does seem to chip quite easily.
Will revert to good old stove enamelling for the next one.
Title: Re: Cylinder barrels and head paint finishes
Post by: BSA_54A10 on 25.08. 2009 11:46
I use "Pot Belly Black" on barrels a paint designed to be used on stoves and heaters.
Works well but dose tend to rust if left standing in the rain.
Bike Beesa
Trevor
Title: Re: Cylinder barrels and head paint finishes
Post by: muskrat on 25.08. 2009 12:42
G;day all,
Another vote for the motospay. The aluminium flavour works well on the head and cases as well.
Cheers
Title: Re: Cylinder barrels and head paint finishes
Post by: beezalex on 25.08. 2009 13:49
Contrary to conventional wisdom, powdercoat has a miniscule impact on heat transfer.  If you actually do the math, it, on average will cause a temperature rise of about 2 degrees C at 150 C as compared to bare iron.  Not enough to worry about.  I have two street bikes with powdercoated barrels without any issues, and I ride hard.  Haven't tried to powdercoat a head yet.

OTOH, I have found any regular rattle-can spray paint to work just as well as any other, high heat or not.  Never tried the "stove enamel" or such, but found the original thick enamel to flake very quickly from an NOS A50 barrel.
Title: Re: Cylinder barrels and head paint finishes
Post by: flashblack on 25.08. 2009 17:20
Just to add yet another option for you, i have had very good results using Hycote engine enamel in a spray can, from motorist discount centre, a nice deep gloss finish if that`s what you`re after.
    all the best,      Richie
Title: Re: Cylinder barrels and head paint finishes
Post by: bsaketcase650 on 26.08. 2009 21:19
Thanks one and all for the tips. The Hycote finish looks very promising and I may give that a try.

Simon.
Title: Re: Cylinder barrels and head paint finishes
Post by: fido on 13.10. 2010 07:51
I had wondered if stove enamelling was something that could be done at home but it looks like quite a complicated procedure involving specialist equipment. I've tried various products like those mentioned in this thread over the years but nothing has stayed on long term. I've never had the top end off my A7 but it looks like I will have to do so just to properly remove the rust and old paint. I can sand blast them myself as long as I clean them very carefully afterwards.
Title: Re: Cylinder barrels and head paint finishes
Post by: BSA_54A10 on 14.10. 2010 14:59
Fido.
Boil them in a 20% caustic soda solution.
Wash in boiling water
Wash in cold water with a bit of vinegar in it
Rinse off in boiling water.
No need to blast with iron barrels.
 Paint asap after treatment as it will rust before your eyes
Title: Re: Cylinder barrels and head paint finishes
Post by: Billybream on 02.02. 2012 16:24
Just about to paint my barrel on Super Rocket, hoping for powder coat, but this is not recommended, saw thread about Hycote Engine Enamel gloss spray,  this is only rated @ 140C, any advice, as not sure of operating temperature of barrel.
Title: Re: Cylinder barrels and head paint finishes
Post by: iansoady on 03.02. 2012 12:12
Fido.
Boil them in a 20% caustic soda solution.
Wash in boiling water
Wash in cold water with a bit of vinegar in it
Rinse off in boiling water.
No need to blast with iron barrels.
 Paint asap after treatment as it will rust before your eyes

I did this to my head which was caked in burnt-on oil and it came up a treat. It is pretty scary stuff though and the fumes nearly knocked me out. You need to treat it with respect.

But of course don't try it with alloy or it will just dissolve as you watch.
Title: Re: Cylinder barrels and head paint finishes
Post by: t20racerman on 15.02. 2012 20:47
Just about to paint my barrel on Super Rocket, hoping for powder coat, but this is not recommended, saw thread about Hycote Engine Enamel gloss spray,  this is only rated @ 140C, any advice, as not sure of operating temperature of barrel.

Powder coating is fine - I've always had power coated barrels. It is the only finish that stays put for years, always looks good and cleans up nice too. As explained above it doesn't cause overheating either. My A10 is tuned with gas flowed head, big pistons, carb, cam etc and gets thrashed regularly and does not overheat (as far as I can tell).