Motor Mounts Keep Breaking Loose.. Help???

[Tuslow1]

Hello Gents, Why is it that my motor mount keeps breaking loose from the tunnel on my HOTR hull? Everytime I get a 50+mph flip I can almost guarantee one side or the other of the mount will be loose but when it comes up the 30 minute epoxy comes up with the mount. I've tried everything to get the epoxy to adhere better.. scuffing the surface, cleaning it with alcohol, soap and water and nothing works. Should I add a layer of CF to the tunnel or slow the boat down so she don't slam down so hard???

[jb1234]

I don't have a lot of experienc but I use a 24 hour epoxy like west systems 105 resin and 206 hardener. Its expensive but thin and seems to soak into what its applied to. It drys clear and hard as a rock. Seems like the epoxy that sets quicker doesn't bond as well. So far I haven't had any problem, I'm not running 50 mph though. Just make sure to scuff the hull good so the epoxy will soak in.

[m4a1usr]

Or slow the boat down so she don't slam down so hard???

Screw that! What would be the fun of RC'n if you dont dance on the edge. Can you use a round headed screw thru the FG to secure the mount to the tunnel? Maybe use a plate of some type, Alum/CF/FG/thin wood to distribute the load over a greater area?

John

[Doby]

Get rid of the epoxy and use JB Weld.

[Boatman]

Screw that! What would be the fun of RC'n if you dont dance on the edge. Can you use a round headed screw thru the FG to secure the mount to the tunnel? Maybe use a plate of some type, Alum/CF/FG/thin wood to distribute the load over a greater area?

John

As bad as that sounds thats likely what it will come to. I know many dont like to put any kind of disturbance near the ride surface but with those speeds and the mass of the motor it will likely continue. Also running those speeds shaving off half a mph won't matter. Adding another layer of glass may help as you can run it across more area but will likely just cause a mess over time. Good idea John!

[Boatman]

Shoot, thought it was a dual motor setup. Disregard the ride surface crud.

[tiqueman]

What kind of 30 min epoxy are you using? Ive had a lot of issues w/ the 2 part in a single applicator style that you can get from such places as Walmart, Auto Parts stores etc. I used a 2 part from the LHS, comes in 2 different bottles and have blown my cat over a few times in the mid 50s and never had an issue. This was before it was inlayed w/ CF. Another option for you may be to just lay the motor mnt area w/ some fresh glass. Then put your motor mount onto that. Once you start puting in aluminum anlgle etc, its starts to look "chunky" IMO. Theres no reason you can not get the epoxy to work on its own.

Oh and as for the CF in the hull, Id do that regardless. The HOTR hulls are layed up quite thin. Its amazing what a layer of CF can do.

[properchopper]

Get rid of the epoxy and use JB Weld.

[Tuslow1]

I'm ordering a sheet of CF and I will try the JB Weld on the CF
(It's hard for me to believe that JB is stronger than 30 minute epoxy)
but without a doubt I will take you guys word on it
Thanks, Ken

[Rumdog]

It's prob. because the tunnel is flexing from the inertia of the crash plus the weight of the motor. Stiffen up the tunnel floor with some glass or cf.

[Brushless55]

I have this same issue in my T29, looks like I'll try JB this time..

[video200]

X 2

[properchopper]

here's how I did my Vegas. Survived many flips and stayed put with a heavish Neu 1515 1Y/water jacket. JB in place & coat with epoxy

[BakedMopar]

So how's the jb weld working? The stringer in my mono came loose today. I used epoxy with micro ballons. Thinking of going to jb weld too.

[crabstick]

It's prob. because the tunnel is flexing from the inertia of the crash plus the weight of the motor. Stiffen up the tunnel floor with some glass or cf.

thats what im thinkin too.