Fin fillets and tip-to-tip glassing

kruland · Nov 20, 2015

Hi all,

What's the consensus on fin fillets and tip-to-tip glassing - which to do first? I'm thinking make fillets first so the glass doesn't have a sharp bend. This also makes the fillets more structural since they are bonding the fins to tube.

Kevin

blackbrandt · Nov 20, 2015

I do fillets then T2T.

JohnCoker · Nov 20, 2015

Yep, fillets first. In the days when I used West Systems (same epoxy for bonding and laminating), I would let the fillets gel, but not completely cure then put on the tip-to-tip 'glass. That way I would get a chemical bond between the fillet and reinforcement.

There is more description and pictures on my tip-to-tip jig page.

Barkley · Nov 21, 2015

JohnCoker said:
Yep, fillets first. In the days when I used West Systems (same epoxy for bonding and laminating), I would let the fillets gel, but not completely cure then put on the tip-to-tip 'glass. That way I would get a chemical bond between the fillet and reinforcement.

There is more description and pictures on my tip-to-tip jig page.

John, do you know the limit of West System with respect to heat and motor mount tubes, retainers, MD fin fillets, etc? The numbers on Rocketpoxy are excellent for heat tolerance, and I'm wondering when I need to switch from West.

JohnCoker · Nov 21, 2015

Barkley said:
John, do you know the limit of West System with respect to heat and motor mount tubes, retainers, MD fin fillets, etc? The numbers on Rocketpoxy are excellent for heat tolerance, and I'm wondering when I need to switch from West.

I believe the Tg for West Systems is in the 120°F range. Unless you're bonding fins to a minimum diameter tube, I doubt it will matter though. For high-heat applications such as retainer mounting I use JB Weld, and for more extreme heat the Cotronics line.

n27sb · Nov 21, 2015

T2T over fillets is my choice. This allows the FG to use the fillet as a core material

dixontj93060 · Nov 21, 2015

kruland said:
...so the glass doesn't have a sharp bend.

Yep.

tfish · Nov 21, 2015

Here's a couple of videos that may help.

[video=youtube;PtYYsX3VEmc]https://www.youtube.com/watch?v=PtYYsX3VEmc[/video]

[video=youtube;7Aqj3xcCWjU]https://www.youtube.com/watch?v=7Aqj3xcCWjU[/video]

Tony

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