# twin for a mahogany boat



## johnlaudano (Oct 6, 2013)

I'm working on an inline twin for a 65 inch mahogany boat. both are my own design. the engine will be propane fueled and the displacement is 50cc's.
Does anyone have a suggestion on how to prep the aluminum before I paint it?


----------



## RonGinger (Oct 6, 2013)

Very nice looking models. Id like to see more of the boat as you work on it.

Why not anodize the aluminum parts- it will look much better than any paint and last much better as well. Anodize is not hard to do, although getting exactly the right c9olor is tricky. I think there are several articles here in this forum about anodize setups.


----------



## kuhncw (Oct 6, 2013)

That is an interesting engine and nicely done.  How about not painting the aluminum and brass parts.  Just paint the steel flywheel.  Maybe it is just me, but I like the look of the aluminum and brass as is.

I'd like to see some photos of some of the engine parts and a little more information about the design.

Regards,

Chuck


----------



## John Rus (Oct 6, 2013)

For painting alluminum you have to follow the manufacturer's recommendation for primers and surface prep. A clear coat would be on order if you choose jot to have it painted. I like green for engines and machinery. :

I LOVE wooden runabouts and will be following your progress with great enjoyment.

th_wwp

Cheers,
John.


----------



## JAndrew (Oct 7, 2013)

Mr. Laudano,

Nice motor! And nice boat too! Please post more pictures as you continue! Curious what that brass jobber on the side is? Looks like a raw water pump? If so I'd be very curious to see what's inside it...

As to the aluminum painting...

Raw aluminum must be etched for the primer to adhere well. There's two options I've used before for painting raw aluminum that hold up well. First is finding a can of *self-etching primer *from your local auto parts or auto body supply store. The stuff usually aerosol and usually pretty expensive. About $17-23 a can!

The cheaper option is to soak the part in a solution of *vinegar and water* for a bit before priming with any good metal primer. Search around the internet for how much vinegar and how long to soak it (I can't remember what I used before). The part should come out of the bath slightly more flat gray.

As far as paints go I strongly recommend Dupli-Color Engine Enamels. Available at any auto parts store. The cans spray a much better mist than other brands like Rustoleum or VHT. There's a wide selection of colors. The finish is very durable and resistant to heat/chemicals.

Hope to see more of your boat project.

-J.Andrew

P.S. probably goes without saying...(then why am I saying it anyway...?) Clean parts thoroughly beforehand with acetone or similar solvent.


----------



## nowramfg (Oct 7, 2013)

Check with your local(if any!) aircraft repair shop. "Alodine" is what you want to prep alum. with. You will not need much, just wipe some on the alum, wash off with acetone, prime and paint.
I am a lover of mahogany boats. Yours looks great. The engine is also impressive, I will be checking back on this. 
Thank you for sharing your awesome project.


----------



## ddmckee54 (Oct 7, 2013)

Unless you're thinking about painting that beautiful mahogany, why hide all that wonderful metalwork you've done?  I'm with RonGinger, anodize the aluminum.  The steel I'd either blue or chrome.  A lot of fine work has already gone into that engine, why hide it with paint?

Don


----------



## johnlaudano (Oct 8, 2013)

Thanks everyone for your support and advice. i'll post more as progress continues.


----------



## johnlaudano (Oct 8, 2013)

to J, Andrew.
The brass part on the side of the engine is a raw water pump. It's a gear pump of my own design. It's loosely based on a Jerry Howel pump.


----------



## JAndrew (Oct 8, 2013)

Mr. Laudano

Thanks for the reply on the pump. I'll have to look up the Jerry Howel pump.

-J.Andrew


----------



## Rustkolector (Oct 8, 2013)

Aluminum and brass are two tough base metals for good durable model paint finishes that don't chip or peal. I have tried a lot of paints and I have had the best results with the industrial baking finishes like Gun Kote (KG Industriesl). The extra effort is well worth it. It doesn't chip, peal, or scuff easily. It is impervious to any solvent I have run across, even brake cleaner. It goes on very thin so it creates no tolerance issues if parts are painted prior to assembly (which I recommend). Good stuff and available in a wide range of colors including clear. 

Your choice of propane fuel is of great interest. I have used it in a few engines and now prefer it, but have had mixed results. Have you used it before in a model sized engine? What is your design RPM range in this marine application? 

Jeff


----------



## johnlaudano (Oct 9, 2013)

See here for Howell plans etc.
http://www.model-engine-plans.com/


----------



## johnlaudano (Oct 9, 2013)

this is my drawing of the pump in the photo. 
pumps-Model.pdf 

View attachment pumps-Model.pdf


----------



## johnlaudano (Oct 9, 2013)

Jeff thanks for the paint info. I've used propane on a prior engine with fair results due to my crude carburetor which wasnt any better than a -control single speed venturi. I like proane because its safer than gasoline. 
This engine will use a propane carburetor from a Lehr trimmer engine.


----------



## John Rus (Oct 9, 2013)

Have you thought about a heat exchanger or radiator instead of raw water cooling? I aways felt that raw water cooling is just asking for corrosion. 

Just my two cents,
John.


----------



## Omnimill (Oct 9, 2013)

Very nice work on both the engine and boat! Sandblasting gives a good key when painting aluminium alloy.


----------



## Rustkolector (Oct 9, 2013)

John,
I assume you have had some experience with the Lehr carburetor.  I don't know much about them, but it sounds like a pretty large carb. I have had some good experience with propane using Jerry  Howell's two jet carburetor. It was designed to handle the Hodgson 9  cylinder radial and should work for your 50 cc twin on propane or  gasoline.  

Please give us more detail on your engine design and build. 

Jeff


----------



## johnlaudano (Dec 23, 2013)

The engine assembled ready for a dry fit into the hull.
I'll send more photos including the boat later this week.


----------



## kuhncw (Dec 23, 2013)

John, nice job on the engine.  I'm looking forward to more photos.  Also, do you have some photos or detail on your distributor and ignition system you can share?

Regards,

Chuck


----------



## johnlaudano (Dec 26, 2013)

Chuck it's just a simple distributor cap and rotor. the materials are black delrin and brass. The ignition is a Tim6 from Jerry Howell. I'll have more photo


----------



## JAndrew (Dec 27, 2013)

Wow! That's a beautiful hull! The chines look perfectly sharp! What's the length and width of that hull?

I was a boatbuilder for a year after the Navy. All fiberglass crap with big stereos though. Nothing as classy as that.

Brilliant work! Please keep posting your progress.

-J.Andrew


----------



## johnlaudano (Dec 27, 2013)

the boat is approx. 61" long and 18 1/2 wide.


----------



## necchiom (Dec 27, 2013)

"Un opera d'arte!". Awesome! With compliment John. Mose'


----------



## johnlaudano (Dec 28, 2013)

thank you for the compliment. my Dad gets the credit for the woodwork.


----------



## Aerofourcycle (Dec 30, 2013)

Impressive wood work.


----------



## johnlaudano (Feb 8, 2014)

here's my engine running. I can't seem to uplad the video directly to this forum. anybody know why that may be?

[ame="http://www.youtube.com/watch?v=wmubybcTVVI"]http://www.youtube.com/watch?v=wmubybcTVVI[/ame]


----------



## ozzie46 (Feb 8, 2014)

SWEET! that sounds real nice and looks great too.

Ron


----------



## dnalot (Feb 8, 2014)

I am a professional boat builder and I gotta tell you the lines of your hull are superb. I would anodise the aluminum parts of the engine. 

Mark T


----------



## kuhncw (Feb 8, 2014)

Congratulations on a fine running, strong sounding engine, John.  That was certainly a smooth first start. 

Maybe I missed it, but what is the bore and stroke? 

Regards,

Chuck


----------



## johnlaudano (Feb 8, 2014)

Thanks all.

Chuck the bore X Stroke is 34mm X 27mm yielding 49cc displacement. It has a 360 degree crank with a fixed 10 degee BTDC timing advance.

The boat is nearly complete but needs many coats of finish. Should be ready for march or april.

John


----------



## necchiom (Feb 9, 2014)

Please keep all of us updated! Moshe


----------



## OrangeAlpine (Feb 9, 2014)

Beautiful outfit!  Something to be very proud of.  

However, I think that maybe the engine could use more timing advance.  I have never made a miniature engine, so this may not be relevant and I do not know your intended rpm operation range.  A full sized engine can run very nicely at 800 rpm and 12-15 degrees advance.  It increase with rpm until reaching about 3,000 when it levels off at about 30-35 degrees.

Bill


----------



## johnlaudano (Apr 26, 2014)

Thought some of you might be interested in my boat's progress.
a few pictures are attached. 
John


----------



## Aerofourcycle (Apr 26, 2014)

Looks great! I look forward to the lake test video.


----------



## johnlaudano (Aug 20, 2015)

this is a video of the boat under power. unfortunately the twin engine in the beginning of this thread proved problematic due to inadequate cylinder liners. I replaced it with an OS FS 1.20 which I converted to ignition. it's air-cooled by a small fan and works well although it's somewhat small for the job.
the second video is of a YS 1.20 which I converted to water-cooled. perhaps good for a future power boat. 

[ame]https://www.youtube.com/watch?v=aaNAZsa6Zc8[/ame]

[ame]https://www.youtube.com/watch?v=xH_pFtHbt9s[/ame]


----------



## Herbiev (Aug 20, 2015)

A really great build. Thanks for the update.


----------



## kuhncw (Aug 21, 2015)

John, what sort of problem happened with the cylinder liners in your twin cylinder?

Your boat turned out very nice.  Thanks for the video.

Chuck


----------



## johnlaudano (Aug 25, 2015)

Chuck,
my lathe is old and not accurate so the liners i made had flaws in their bores that caused the rings not to seat well enough. it ran well for the first half dozen runs or so but the ring-to-bore fit deteriorated and compression couldn't be maintained.


----------



## kuhncw (Aug 25, 2015)

I'm sorry to hear that John.  Do you plan to make new liners and get the engine running again for your boat?

Chuck


----------



## johnlaudano (Aug 26, 2015)

no, i'm thinking i'd rather build a new engine for a new boat. it was a good learning experience.


----------

