H18 hole in crossbar for mast step badly worn... *pic*

car_guy

Rank: Mate

Registered: Sep 25, 2010

Last visit: Oct 12, 2023

Posts: 180
Posted: Nov 01, 2010 - 09:06 PM

The mast step had about 1/4" of play in it from fore to aft. I could see the crossbar below was pretty worn so I decided to remove the step and see what I was dealing with. As you can see the cross bar is worn andout 1/32" into the top surface and the center hole is oblong.

Im replacing the entire dolphin striker assembly and Would like to repair the cross bar. I'm thinking of welding up the center hole and rivit holes and redrilling. I would also like to fill in the worn areas with weld and then grind smooth. Does any one know if the heat from welding will compromise the strength of the cross bar?

The other option is to drill the hole larger and use a stainless sleeve around the dolphin striker post.
turbohobo

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Registered: Oct 19, 2006

Last visit: Aug 16, 2017

Posts: 613
Posted: Nov 01, 2010 - 10:39 PM

there is a 3rd option, look in the used part section and see if you can pick up a used crossbar at a reasonable price. A good aluminum welder should be able to weld up existing hole(s) but there is always the chance that the heat from the welding machine will melt the original aluminum on the crossbar. You're going to have to remove that crossbar anyway to take it to a welder, so why not price a used crossbar, take original for welding estimate, and if that does not work out, order used one.

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TurboHobo
H14T
H16
P18
G-Cat 5.0
P16
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car_guy

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Registered: Sep 25, 2010

Last visit: Oct 12, 2023

Posts: 180
Posted: Nov 02, 2010 - 07:12 AM

A used cross bar was gonna be my fall back...

Does the newer mast step (post 1990) have a larger flange then the older style? I noticed that it does use an extra rivet on each side.
DaveW70

Rank: Lubber

Registered: Apr 28, 2010

Last visit: Jul 22, 2017

Posts: 69
Posted: Nov 02, 2010 - 08:35 AM

QuoteDoes any one know if the heat from welding will compromise the strength of the cross bar?

Yes. And, that is a high stress area too. Typically a Hobie crossbar is 6061-T6 aluminum which is heat treated for additional strength. The heat from welding can anneal (soften) the crossbar. If you do weld it, then the crossbar should be heat treated again to restore it's strength. Heat treating is usually not cheap. Option 3 seems to be your best bet.

Dave W

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Dave Wilson
Hobie 16, Hobie 14
Tampa, FL
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car_guy

Rank: Mate

Registered: Sep 25, 2010

Last visit: Oct 12, 2023

Posts: 180
Posted: Nov 02, 2010 - 05:21 PM

I figured it was a heat treated part... Heating that size furance aint gonna be cheap...

I think I'll go with a stainless sleeve around the post to take up the slop. As for the worn area I think I'll just cover it up with the new mast step and forget about it...