Mast to Fuse Connection Repair

[darippah]

Can anyone here suggest how to repair this crack at the bottom of the Mast? I filled it with Marine epoxy and left a thin coat twice and it cracked away after a few sessions each time

It seems there's some water inside the crack.

I use this set up for boosting with 548 and 600 wing so it gets a good amount of stress at this connection point.

[Matty V]

Either very thin viscosity resin to penetrate the crack, clamp it and hope.

Or grind the crack deeper, it might go very deep, Lilly at least the depth of the screw inserts and fill with chopped carbon and the thin resin and again clamp and hope.

Likely though is that you won’t every get a full repair as the inserts will be moving from the landing/twisting for e you put on it when you land and the mast ultimately will be toast.

Try option 1
Try option 2

Try option 1 again keep it as a spare and get a new mast.

[airsail]

Moses mast fuselage connection plate

There will be contaminates inside the crack on each surface, it is highly unlikely you will get adequate adhesion with an injection of glue. Very high stress area, and the insert plate has debonded on one side, that’s why it has cracked. Without a full rebuild it is almost impossible to fix and even then it may fail.
Time to save for new mast, the perils of boosting with a foil.

[darippah]

the perils of boosting with a foil.

Hey, better the foil than my knees

[TheJoe]

Either very thin viscosity resin to penetrate the crack, clamp it and hope.

Or grind the crack deeper, it might go very deep, Lilly at least the depth of the screw inserts and fill with chopped carbon and the thin resin and again clamp and hope.

Likely though is that you won’t every get a full repair as the inserts will be moving from the landing/twisting for e you put on it when you land and the mast ultimately will be toast.

Try option 1
Try option 2

Try option 1 again keep it as a spare and get a new mast.

I would go with option 2. Try to get the water out as best as you can.

[tegirinenashi]

Drill 2 mm hole along the crack. Open crack a little with knife. Use syringe to fill in the void. Clamp it.

In my experience bondo fiberglass resin from Home Depot is perfect for this kind of repair (no thinning is necessary).

[darippah]

Drill 2 mm hole along the crack. Open crack a little with knife. Use syringe to fill in the void. Clamp it.

In my experience bondo fiberglass resin from Home Depot is perfect for this kind of repair (no thinning is necessary).

I will try this. Thanks!

[revhed]

Post would have been much better either in hydrofoil or gear builders, that said.
Put your STRUT in a black plastic trash bag and tape it shut.
Place in full sun.
Sometimes boards take days to dry but this should be quick, like an afternoon.
When u r sure absolutely sure NO H20 then proceed.
Open crack twisting inserted flat screw drive, sand with folded paper or even nail file.
Rough up well every where!
Use sun light or halogen to see well.
Clean acetone. also like as good as you can.
As posted above drill tiny holes if u think needed.
Then at least for me having done many repairs on many different problems the epoxy choice is vital.
At least here in E U I,we access ARALDITE from Huntsman in UK.
420 A/B is amazing!
I read and believe that this exact product is, was used to glue cameras to the outside of B-1 bombers.
But banned now here in France for toxic reasons.
I am sure you can find good quality epoxy either on their site of other well known company, 3M maybe?
Respect mixture ratios like to the tenth of a gram if doing small batches.
Mix well.
Wear chemical mask and better outside or well ventilated.
Make sure all surfaces are coated.
I use Seran wrap or normal kitchen cling wrap to stop over flow stick and sometimes in unison with thinnest layer of grease possible.
The two together can lead to ultra fine work!
Clamp, vac sack, sand bag what ever it takes to keep tight until FULLY dry!
ENJOY!
I have fixed delamed wings, broken boards, cracked fuses and STRUTS doing this, great success rate.
R H

[darippah]

Drill 2 mm hole along the crack. Open crack a little with knife. Use syringe to fill in the void. Clamp it.

In my experience bondo fiberglass resin from Home Depot is perfect for this kind of repair (no thinning is necessary).

I tried this. The repair definitely held up better after a big boosting session. However still some minor cracking. Drilled another hole and will leave it in a black garbage bag in the sun for longer this time and see how that does. Hoping to not need a new Mast!

[darippah]

Broke my third Moses Mast in 3 years ... same spot each time... I love the versatility of Moses but unfortunately I'm going to have to find something stronger