Casting Carbcaps

[DocRoot]

Broken carb-caps are a fact of life on Goldwings, and there are many fixes

A_01.jpg

JBweld smeared over the break
http://www.ngwclub.com/forum/viewtopic.php?t=40216
http://www.hondatwins.net/forums/56-fue ... -tops.html
... I haven't found the link but there is a cute fix with quarters drilled and glued together.

But I wanted an original look so I cast new carbcaps from plastic.

this is the product I used, mold making rubber: http://www.amazon.com/Amazing-Mold-Putt ... ing+rubber
and casting urethane: http://www.amazon.com/Alumilite-Amazing ... ng+plastic

alumilite.jpg

The first thing to do is to take a mold from an un-broken cap, inside and outside.
The molding putty is a two part product that mixes together by rolling around in your hands

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Then roll the putty over the outside of a good cap. Rolling from one side to the other pushes air bubbles out of the way while the rubber takes the shape of the cap.

Keep going until the whole top of the cover is molded... I used the raised letters as an index for when I had the mold in the correct place as I was casting. Make a flat spot on top, or even a bit of a depression for pouring in the resin later

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[DocRoot]

I rolled some molding rubber into a worm and stuffed it up into the slide hole, and pushed and pushed to really fill it up. I pushed until some rubber came out of the air hole.

CarbCapMold_02.jpg

When the rubber was hard, I broke off the cap and I pushed out the inner mold with the shank of a removable tip screwdriver

CarbCapMold_04.jpg

and cast a fill for the undercut

CarbCapMold_03.jpg

[DocRoot]

Drill a hole in the top of the mold (I used a burr on a dremel... drill bits are grabby in rubber)
I used WD-40 as a mold release, put all of the parts back into the open carb top (including the gasket for the carbcap) and mixed up some resin. There is a casting technique to get out the bubbles with a cover and a vacuum cleaner, and when I do this again I will do that. This time, I tapped, tapped, tapped to get the bubbles out of the mold

CarbCapMold_05.jpg

After 45 minutes, I opened the mold and took out the cap. The gasket is still attached, and shouldn't be removed as that will ruing the gasket, and you still want it for proper clearance and air-port access under the cap.

CarbCapMold_06.jpg

CarbCapMold_08.jpg

CarbCapMold_07.jpg

[DocRoot]

Sand the rough edges , press it into the carb top, and smear some silicone or epoxy down the side

CarbCapMold_09.jpg

#2 and #3 are new

CarbCapMold_10.jpg

[CYBORG]

excellent work. Hope I never need to do it, but good to know how, if need be

[El_Taco]

Beautiful. I don't think there's a better way to go than that.

[DocRoot]

Thanks!
This should be an exact replacement with all interior clearances the same as the original, so the action of the slide should be correct.

I made 8 caps while I had the mess on the table, and the thin "clearancefill" rubber was deformed by the WD40 after that, so when I do this again I will have to make another.

[wog]

Great job and write up!

For the ones that aren't broken or missing, I use a glass bead blaster to clean up the plastic.
Really brightens them up quickly.

[DocRoot]

Nice! What cabinet and compressor do you use and where do you get the glass beads.

[wog]

Just the standard bench top cabinet and a garage-style 60gal upright comp.

I dial the pressure down to about 75psi.

I've had the blast media for years, and just keep on recycling it out of the shop vac. But I think even Harbor Fgt sells it.
Other media might work as long as its not too coarse, glass is just what I use.

[Placerville]

This is excellent and I've bookmarked it. I think this should be in ShopTalk.

[Ramset]

This is excellent and I've bookmarked it. I think this should be in ShopTalk.

x2

[Halfnaked]

Amazing process. Really did a nice job. Looks like the original in every way. Glad you made more than one with all that preparation work.

Bob

[Dog Boy]

Fantastic work! Well done sir! "Shop Talk" for sure.

AL

[HOTT]

that is so slick.
Thanks, great 'How To'.

HOTT