MADD Insert Repair

This project started after an inquiry was posted to an alpine snowboard enthusiast site.

This involves a fairly unique snowboard with a spinning insert.  The damaged insert renders the board unrideable, and it is most certainly a board worth riding.  I made a few suggestions as to how I might approach the repair, and some time later, was asked to do the job.

It took me way too long to get started, but that is how it goes sometimes with one-offs.mill tableHave mill, will dabble.

I had several ideas on how to approach this.  I really wanted to draw epoxy around the insert with vacuum, but wasn’t sure about the flow path.  The easiest thing would be to drill a hole through the base, and pull from the top side.  I didn’t like the idea of putting a hole in the base if it could be avoided.

Then I thought of using one or two vertical pins to lock the foot of the insert to the core above.  Perhaps one of those holes would work as a point of entry?

Or, simply use the lock pins without the vacuum draw?  This might get complicated so far as maintaining the alignment of each hole for each pin.  Seemed like I would have to drill one hole, then glue in a pin, then drill the second hole etc.

Somewhat involved.

Finally settled on what seemed to be the simplest and least invasive idea:

Drill a small hole through the center of the threaded part of the insert, into the air space below.  Thread a nozzle into the insert to pull vacuum, and flood the insert well with epoxy, where the vacuum would draw the epoxy around the insert, and up through the center of the  nozzle.

ToolingCast of characters. The gauge teed into the draw line provides insight into how well the epoxy is flowing, and also the relative porosity of the surrounding area.  As it turned out, there was a lot of porosity, which I blocked with electrical tape.

Epoxy is West System, 5:1 mix ratio.

Nozzle came from a tube of RTV silicone.

Hypos courtesy of the local horse doctor.

center finderLocating the insert center with a wiggler. Arrows indicate loose inserts.  One spun, the other wobbled.

end millBlurry photo of 3/32 end mill.  Run at high speed, mill cut faster than the insert could spin.

suction1Trimmed nozzle threaded tight.  Epoxy does not stick to this plastic.

suction2Aluminum platen held in the mill vise, vise grips secure the board to platen.

epoxycoreAbout 8 hours later, the epoxy had set enough to unscrew the nozzle.  This is extra epoxy drawn up the nozzle.  Electric tape is sealing the area against vacuum loss.

filled insert


Insert well filled with epoxy.



Spotfacing the insert well.

detailsDetail of test insert and finished repair.  Vacuum draw hole is visible in center of close insert.

doneA pair of classic rides.


packedReady for transit back to California.


The hardest part of this repair was deciding how to proceed, and then getting started.

I don’t know if this would work with stainless inserts, as the metal might work harden before the milling bit could make it through.  Not a problem with brass.

Also, might not be worth doing for anything other than a collectors item, as the cost of shipping adds up quickly for a board of this size. One more inch of package length would add nearly $30 to return shipping.


Bonus footage: ‘Helicoil’ repair.

This is a repair to a second generation 158.  This board was damaged while out on demo. the user had some custom spacers under their binding, and the hardware didn’t have enough purchase on the insert threads.

recoil repair 3Secure the patient to the cheapo mill.

Recoil repair1Core out the damaged threads.  This end mill is the correct diameter for the oversized threads of the repair coil.

Recoil repair 2Tap for the repair coil.

recoil repair 4Done deal.  This board took seven or eight inserts.  Three years later, the glue let go between the top sheet and the core, and that’s that…