stress crack repair

[wayne272]

Stress cracks on Cigarette Bullet by sunpad vents. Best to use West epoxy w/404 after grinding out or filler. all info for the repair greatly appreciated. Glassdave??

[gcarter]

I think you would need to get underneath and reinforce the cracked area before grinding out the gel and mat or you might be doing it again soon.

[gripit]

Originally Posted by gcarter

I think you would need to get underneath and reinforce the cracked area before grinding out the gel and mat or you might be doing it again soon.

I need to do the same repair in my Bullet. How would one go about reinforcing the area? More mat and glass???

[gcarter]

I would grind out the bottom side of the crack almost all the way through w/a bevel of 12:1 and fill the ground out area w/several layers of +/- 45* 17 or 24 oz. stitchmat like Knytex. Start w/a narrow strip w/the mat side towards the repair, followed by ever wider strips until the ground out area is filled. Follow this up w/one or two overlapping layers. Remember that this was a weak area to begin with so it needs something additional to keep it from repeating.
Once the bottom reinforcement is complete, grind out the crack from the top. This doesn't have to be deep, or very wide as it's strictly for aesthetics but you have to grind out enough to compoletely remove the damaged mat that's directly under the finish. Then fill the top ground out area w/cut fiber filled polyester putty. You may find the cut fiber filled putty to be difficult to spread and it doesn't have to be real pretty. After carefully grinding or sanding flat, follow this up w/some milled fiber filled putty to completely fill the area and after sanding smooth and flat, gel or paint.

[glassdave]

Hi Wayne, good talking to you earlier. PM me your cell # or I will try your home number tomorrow. Looks pretty basic.

[c_deezy]

Probably wouldn't be a bad idea to bevel out from underneath and re-glass in that entire vent cut-out area. Then re-cut the hole, keeping a radius at the corners. Looks like that crack is the result of that square corner causing a stress riser. And maybe even a rib underneath that runs along the outside edge of the vent cut-out if possible.

[Wahoo ATV]

On smaller cracks that dont go all the way thru, I have used Adtech's Ultra Fair. It is an epoxy filler that sands nearly as good as bondo. Glassdave recommended it and it works great, especially on epoxy boats.