foodstick

For you guys that hang out in the spad forum on ocasion you know they use a cutting board material from walmart as motor mounts and firewalls. Do any of you know, or have a guess whether this material would take the heat..be threadable...or have any other reason it would or would not work? I have been scouting for some cheap available material for the job.

Thanks for any help !

w8ye

My Feedback: (16)

It's a little towards the butter side for carb use. Too soft for threads and will mash out and deform with heat.

captinjohn

I got a free sample about 6 inch long from Menards. It is a type of artficial wood used for steps ect for decks. It may work for manifolds...have not tested it to much yet. I did drill and tap a hole and tested to see if I could strip the treads. They did strip...but next I will try hot stuff to strengthen threads. Capt,n

w8ye

My Feedback: (16)

The cutting boards are usually a material that from McMaster-Carr is referred to as UHMW plastic. It is basically what we old timers used to call Nylon back in the good olde dark ages of the 50's.

I think the deck boards are made from a material like recycled milk jugs. It is basically the same material as above but seems to have a grainy structure to it and be a little lighter in weight per cubic volume.

The guy's that have been professionally converting engines have been using a fiberglass based G10 board. It is not as flexible as UHMW and maintains it's shape better. Don't know a convenient source other than McMaster-Carr?

foamcut

My Feedback: (40)

G-10 is a commonly used material in custom knifemaking.

From the Jantz knifemakers supply website:
"a woven fiberglass fabric impregnated with epoxy resin, much like Micarta. Always use a respirator when working with this material. Strong, durable, resistant to moisture and climate change."

You might try micarta as well.

arobatx

G10 is not cheap though!

captinjohn

I think aluminum is fine used with a gasket at each joint. I think most people have a idea you got to have a thick heat dam on every RC engine carb set-up. The reason it is used on power equipment like chain saws ect...the engine is run hard and is tightly cowled and often covered with saw-dust dirt ect. That holds a lot of heat in and can make restarting hard. Most our engines are running in a far cooler set-up. I am going to make a 90 degree turn type of manifold and hope to make a carb set-up that will not stick out so far and at same time make throttle hookup a breeze. Wish me a good out-come. Thanks Capt,n

Tom Johnson

My Feedback: (2)

Capt'n is right. I used to build a lot of racing 2-strokes and when we were experimenting with different intake tract lengths I made a bunch of all-aluminum spacer blocks to replace the stock phenolic (garolite) unit. Surprisingly, we saw no degradation of performance when comparing the aluminum directly to the phenolic on the dyno. It turns out the only negative effect was the engine was slightly harder to start when warm. Our supposition (never pursued) was that the aluminum allowed enough conductive heat transfer to boil the gasoline in the carburetor (vapor lock) after a dyno run.

If you really want a garolite spacer go to a local machine shop and see if they have some scraps. If you offer them $5 for a piece they'll probably give it to you for nothing! Unfortunately I don't have any. This is one of the few materials I refuse to run in my shop (abrasive, clogs filters, EHS hazard, etc.)

w8ye

My Feedback: (16)

$214 for G10 1" X 12" X 12" ?

http://composite-laminates.com/g10-sheets.htm

Tom Johnson

My Feedback: (2)

More reasonable prices from McMaster.

Try www.mcmaster.com and look up part number 8557K432

Lots of other sizes available.

foodstick

Has anyone ever considered making one out of alumilite? I think there website claims it is good to 415 degrees? Said it would misform at about half of that with a heavy load on it...

captinjohn

Bend-a-bal 3/4 dia alumnium tubing. Should be able to weld a aluminum flange at each end? Capt,n

aero nut

what about plywood coated with epoxy?????

flyjoe540

I make mine from the cutting board material with a aluminum backing plate the same thickness as the nylon works great for five bucks. the carb bolts to the aluminum spacer with the nylon inbeetween the carb and the spacer and the spacer bolts to the engine with counter sunk screws

captinjohn

flyjoe540: Can you post a photo of your carb spacer set-up? Thanks Capt,n

flyjoe540

capn'
I am not photo capable at this time , sorry . but my point is that it works fine , mine is over a year old . it is a little squishy, you need to control yourself when tightening your carb .
another thought I had ,to eliminate the aluminum back plate ,was to use brass threaded inserts in the carb mount holes.

airbornrc

My Feedback: (9)

While I have not used the cutting boards, I do use nylon. I either use studs to retain the carb or put helicoils in the plastic for the bolts to thread into. You may have to pick one up and give it a try. I have looked at them many times and think they will work. I get round nylon bar from Onlinemetals.com they may also have sheet.
On aluminum intakes My 50 was very difficult to restart and ran erratically when it was hot out . I put a .125 teflon gasket from Toxic marine between the carb and intake which eliminated the problem. The intake was transfering too much heat to the carb boiling the fuel.

flyjoe540

has anyone tried plexi glass as a spacer?

mikenlapaz

http://www.mcmaster.com/
8557K332 (Same as 8557K33) $15.50 2" X 24" X 3/8"
RCIgn uses this and I have found the thickness sufficient.
The price seemed fair for the number of heat dam/ manifolds that could be cut from one piece.

As mentioned above: 8557K432 (Same as 8557K43) $20.40 2x24x 1/2"
Enough for 10 or 12 engines. Delivered to your door.

The cutting board (LDPE) is softens quickly and needs really sharp tools to work. I have not tried to shape an interior bore.

Plexiglass has a rather low operating temp. 150-18-F the LDPE shows a 220-260 range I believe.

flyjoe540

I am going to try to post this picture . its of my homelite 45 on my edge , here goes .