Paint removal-cylinder head

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MikeG

MikeG

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When my 71 roadster was rebuilt by the PO he decided it would look real nice with the cylinder and head painted matte black and the edges of the head fins polished aluminum. It might have, but now it just looks nasty and dirty. I really hate the thought of removing and disassembling the head to have it blasted, there is absolutely nothing wrong with the way it runs, just looks. I was thinking of removing it and soaking in lacquer thinner. I know that will remove the paint but not sure what it might do to anything else in there?
Open to any suggestions.
 
I see you are in US...
rather than paint stripper which is becoming harder to find with methylene chloride, some do.
However the liquid brush cleaner seem to still have methylene chloride and will flow in every where.
N.B. It will kill the intake rubber seals if it gets on them.
Normally I walnut shell blast heads & cases in prep for painting...I never sand blast or glass bead aluminum.
Our New England Norton club may do a ride to and tour of this vapor blast guy in Hinsdale NH Mark @ NorEasterBlastWorx.com
 
Thought of that too, using it with the head still on. That stuff is pretty caustic and requires a water rinse after. Not out of the question, but it involves lots of masking of other stuff if done that way. Prolly not so bad with the head off though.
 
Soaking in lacquer thinners should do the trick, might need some brushing to stir it all up.

Speaking of walnut shell blasting, I've just used common sawdust to clean off alloy on assembled bikes.
Just wrap old towels etc around everything close, and blast away out in the garden (away from the neighbours ! ), may not even need much pressure.
Works well, alloy comes up shiny and new. Sawdust needs sieving first, to take out any large lumps - the local sawmill just gave it away, they couldn't get rid of it fast enough. If you put an old sheet under the bike, can collect it all and use it again...
 
The cylinder head on my Commando was also painted black. I removed the head, bought one of the cheap soda blasters from harbor freight and after all the paint was blasted off I put it in the dishwasher without any soap, on high temp wash and after the cycle was done blew it dry with compressed air. It worked great. If you time it right before a rain storm the rain will wash the baking soda away.

Dave
 
drp said:
The cylinder head on my Commando was also painted black. I removed the head, bought one of the cheap soda blasters from harbor freight and after all the paint was blasted off I put it in the dishwasher without any soap, on high temp wash and after the cycle was done blew it dry with compressed air. It worked great. If you time it right before a rain storm the rain will wash the baking soda away.

Dave
Click to expand...

Did you do it with the valves still in the head? Seems to me baking soda being water soluble would rinse right away from anything it might harm ?
 
You want to be careful using paint stripper on aluminium. Some contain causyic soda. Not very friendly with aluminium.
 
I've heard good things about the soda blasting, but I have absolutely no experience. I have an acquaintance that does it, but then we all try to sell what we do. You could probably do that without removing the head with some creative masking. That's what I'd do but it's your plan and bike.
 
Regarding soda blasting with the valves in place, I didn't because I was also sending the head to jim Comstock to have the exhauset port threads fixed but I don't see any reason why you couldn't, especially if you left the valve covers on and plugged the ports. I would probably flush the head with some solvent to remove the oils before blasting. I put the head in a cardboard box to catch as much of the soda as possible and it rained the next day and washed away the soda left on the driveway.

Dave
 
Soda blasting is good for cleaning up alloy castings and just needs washing away after. I don't think it is up to taking paint off though unless you use some heavy duty equipment.
 
I respectively disagree, soda blasting works great for removing paint and is used all the time on corvettes and when refinishing fiberglass boat hulls. . The soda blaster I bought was less than $60.00 from Harbor Freight and it worked very well removing both the paint and built up carbon on my commando cylinder head.

My only complaint was that it was a bit messy. I used the finer soda from Harbor Freight and if I had to do it again I would probably use the larger stuff. The only other issue is that when the bag of soda sits unopened it attracts moisture and doesn't feed well.
 
And of course no 2 paints are created equal. Thin coatings, thick coatings, easily fractured coatings, durable tough coats, well adhered coatings, poorly adhered easily fractured coatings, solvent delivered, solventless, e.g., powder, etc – not to mention the continuum from low quality consumer, good quality consumer, fleet coatings, industrial coatings, and the surface prep that was employed before applying each one. Every one of them will remove differently and a removal technique that works great for one won’t touch the next.

I’m presently cleaning some paint off ‘50s vintage Harley parts with a glass bead blaster at ~ 60 psi and find that every part cleans differently – on some the paint simply blows off like dust, some are more challenging but doable, and others are so difficult to remove the paint that I’ll be resorting to paint remover followed up by a final glass beading. No one cleaning technique is universal with the exception that high pressure sandblasting (capable of distorting metal) will remove anything, but inappropriate for delicate parts.
 
Ok, soda blasting may remove your paint but I would steer clear of any abrasive blasting media, glass, grit, beads etc in favour of soda. All the remaining debris is soluble and easily removed with soda. I know of one oil in frame Triumph and a Rob North racing Rocket Three that needed engine rebuilds after bead blasting.
I had my head bead blasted years ago and while I was happy with the cleanliness of it before re-assembly, when I stripped it down years later there was media in the flats of the rocker shafts just sitting there. Never again.
 
From the experiments I've done so far, I can remove the paint fairly easily, wire brush or solvent, but it leaves a dull finish. I'm thinking soda blasting is best, just trying to do it with the least amount of disassembly. In the FWIW department...I have glass beaded several BSA heads and cases over the years with no ill effects. I simply gave them a bath in boiling water and soap after.
 
Most older plating shops have trichloroethylene degreasers which will remove paint. If you use normal paint stripper, most of them contain caustic soda which will go for the aluminium big-time. Even immersing the head in vinegar after you strip it, won't remove the caustic hiding in any external porosity. It can keep going until it comes out the other side. Vacublasting is good but how do you ensure all the medium is removed from inside the passageways in the head before you put it back on the motor ?
 
MikeG said:
From the experiments I've done so far, I can remove the paint fairly easily, wire brush or solvent, but it leaves a dull finish. I'm thinking soda blasting is best, just trying to do it with the least amount of disassembly. In the FWIW department...I have glass beaded several BSA heads and cases over the years with no ill effects. I simply gave them a bath in boiling water and soap after.
Click to expand...
You are lucky to get away with bead blasting a head in my opinion it's the cleaning out after that is the problem,it's even worse on Norton head because of the integral rocker box cheers
 
MikeG said:
From the experiments I've done so far, I can remove the paint fairly easily, wire brush or solvent, but it leaves a dull finish. I'm thinking soda blasting is best, just trying to do it with the least amount of disassembly. In the FWIW department...I have glass beaded several BSA heads and cases over the years with no ill effects. I simply gave them a bath in boiling water and soap after.
Click to expand...
You are lucky to get away with bead blasting a head in my opinion it's the cleaning out after that is the problem,it's even worse on Norton head because of the integral rocker box cheers
 
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