Have I gone too far?

[JaCrispy]

I cut the back section of my cap off and feathered it back on. Glassing starts at post #85, link is my sig line.

Forget the belt sander, get an angle grinder and a coupla flap discs. I tapered out about 2-3" on either side of the cut and had the taper go down to just about nothing at the seam. Layers and layers of CSM until I was just shy of flush. Brushed on non-waxed gelcoat laced with cabosil and did a final gelcoat using the wax additive.

 

[ondarvr]

A true flap disc doesn't work that well, get a standard grinding disc and backing pad.

 

[JaCrispy]

A true flap disc doesn't work that well, get a standard grinding disc and backing pad.

What? A flap disc can put a hole right through your hull if you're not careful. It's by far the best thing I've used to grind fiberglass.

 

[Woodonglass]

Yeah, I think I'd just go ahead the put the cut out piece back in right now and patch it in Doesn't have to be perfect. then go on the inside and cut out the inner skin and remover the wood. Once that's done you could then do a Normal transom replacement as described here...Fabricating Decks, Stringers, and Transoms

 

[ondarvr]

What? A flap disc can put a hole right through your hull if you're not careful. It's by far the best thing I've used to grind fiberglass.

Flap discs work OK on metal, but on glass the individual flaps wear down too slow and don't expose fresh grit fast enough, this may work better for a person with less experience using a grinder because it will remove material slower. A single disc grinds much faster and leaves the surface with a better finish to laminate on.

For 20 years I was buying grinding and sanding products, along with cases of grinders at a time, I had a crew that may grind for eight hours a day for a week, and I was in there with them much of the time. So when it comes to cutting or grinding glass I have many years of experience. Now I sell the sanding and grinding products to the composites industry.

 

[Woodonglass]

Yeah, I have to agree with ondarvr on this one. This is the best sanding configuration if you're gunna use a grinder...

 

[AFlowers]

Luckily, I have a belt sander, a grinder with flap disks, and a grinder with a rubber backing pad thats probably 6" in Diameter. I will try each to see what will be the most efficient for me and safest for my boat.

 

[JASinIL2006]

My bet is on the flat disks... I found they worked best by far.

 

[gm280]

Just my opinion, and certainly not trying to start any controversial issues on these forums, but I have flat sanding disks (36 grit), grinder disks and flapper disks. And when I was grinding out my hull in prep for new polyester and fiberglass CSM, the flapper disks preformed way better for me then any of the flat sanding disks or actual grinding disks I tried. In fact the flapper disks lasted amazingly long for that itches, dust-filled, sweaty, nasty effort. But that is just my experience and certainly not saying others didn't have different results using other things. JMHO!

 

[ondarvr]

Flap discs do last longer, that's what they're designed to do. It's always possible that some brand had a style that worked well on fiberglass, it's also possible you purchased some normal grinding discs that were cheap and low quality types. I always avoid the cheap junk discs unless I'm only doing a very small amount of grinding, when you need to dive into a big job you don't want to stop and change discs or spend more time because they don't remove material fast enough. There can be huge difference in how fast a disc will cut and how long it will last between styles and brands.

Of the hundreds of glass shops I've been in I don't recall ever seeing a flap disc, that is unless the had a metal fab shop too, even then those discs were only used in the metal shop. I'm sure there's a shop out there that has used them, it's just not that common.

 

[gm280]

Flap discs do last longer, that's what they're designed to do. It's always possible that some brand had a style that worked well on fiberglass, it's also possible you purchased some normal grinding discs that were cheap and low quality types. I always avoid the cheap junk discs unless I'm only doing a very small amount of grinding, when you need to dive into a big job you don't want to stop and change discs or spend more time because they don't remove material fast enough. There can be huge difference in how fast a disc will cut and how long it will last between styles and brands.

Of the hundreds of glass shops I've been in I don't recall ever seeing a flap disc, that is unless the had a metal fab shop too, even then those discs were only used in the metal shop. I'm sure there's a shop out there that has used them, it's just not that common.

ondarvr, please don't take any of my comment(s) as anything but my opinion. I am NOT trying to be confrontational in the least. When I buy most any type grinding disks, I usually always buy 3M brands. I have tried other cheaper ones and they literally fly apart. So my purchases are mostly 3M brands. They may cost a little more up front, but they last so long, you actually save money in the long run. Again JMHO!

 

[ondarvr]

Not confrontational all, the difference is that for decades I've been buying and using the discs, when someone uses a few in their lifetime and reports the results, which can be accurate for their experience, but different, it doesn't give another person reading thread a true indication of what works the best in most applications. 3M makes several different grades of discs for different markets, most brands do, so in your experience with a limited number of product types a flap disc you found worked well for how you used it, there's no disputing that. What the industry has found, is that for most applications the single disc works better for removing material quickly and leaving a good "tooth" for bonding.

For a newbie grinder without much experience it can be easier to use a flap disc sometimes because they do tend to cut slower, this makes it easier to control, so they like it better. Typically they don't do enough grinding to really notice a difference in how fast it removes material.

 

[AFlowers]

No Title

Update.

This morning I was able to get the back of the boat glassed on with one layer. of fabric. I'll add more if needed as it id only temporary holding in into place.

I have decided not to cut the inside skin out. Given the small lip area that I have left after cutting it of I feel my new idea will be stronger and hopefully less time. I have decided as well to go with sea cast. Once I get the glassed on piece held firm (still temporary), I'll pour the Seacast, then, I'll come back to the outside and feather it down and then build up the layers for structural support. It may not work in the long run, but after seeing what I would have left after cutting the inside skin out, I am sure that will eventually fail.

Flap disks worked fantastic. 60gt for semi ruff stuff, and 30gt took of leftover chunks of resin..

I have also gotten two of the stringers removed.

Here are a few photo's after today's work.

 

[gm280]

Looks like you are recovering nicely. Since I have never use Sea Cast, I'll left the suggestions and "how to's" to those that have. But the hull looks better cleaned up now. :thumb:

 

[ondarvr]

It will take less time, but it will be significantly weaker.

 

[Woodonglass]

Since you have destroyed the structural integrity of the hull by cutting it, the only way get any significant strength back is with the tabbings on the inside. If you don't cut away the inner skin and re-establish these tabbings I'm in TOTAL agreement with ondarvr. The strength of the boat will be significantly decreased. I do not agree with the method you are proposing but...like I always say, it's your boat and you're free to do with it as you see fit. We can only recommend and state our opinions. After that's it's totally up to you.

 

[DeepBlue2010]

If you want to do this right, then your plan is inadequate. If you want to do it the way you want, then by all means, it is your boat and your call.

 

[AFlowers]

Ok. I'm going to go back to the old plan.

 

[gm280]

AFlowers, the actual strength is going to come from the outside fiberglass skin replaced back and the tabbed into place and the install with the new transom wood and tabbing for it as well. So once you have the outer skin replaced and holding solid, the inside skin then gets cut out. You will be amazed how solid this entire transom will become. JMHO

 

[AFlowers]

No Title

Was gonna take today off working on the boat but I couldn't stand it. Below are before and after pics of the inside skin and its removal. 36gt flapper disks are the bomb diggity.

You can't really tell from the pics but the inside is feathered down to almost paper thin,