fiberglass cloth vs. chopped and sprayed application.

L

lee kent

Member
I used fiberglass cloth on my last boat project and it turned out ok for my first attempt. I can say that I learned the importance of quality prep work. I have a friend that builds all fiberglass fishing boats for a living and he is encouraging me to chop and spray my new boat project. I would like your thoughts on this application of the glass and resin. I feel like it will increase the weight but this is not a big factor. I appreciate your thoughts.
 
they spray some mass produdeced hulls because its easier less labor intensive cheaper and heavier...thats the way your bud does it at work so naturally he says its the way to go....dont let him talk you into it.....if you have to get a new friend
 
Lots of reasons... The biggest for me is that the resin would be poly and poly isn't the best for glass over wood construction as it does not bond to wood well.

T
 
When you have been to as many boat builders as I have and seen the difference between chopped and mat construction, you would never build with a chopper gun. Unless you have access to the chopper gun and can set he proper length of fiber you want, many mistakes can be made.

Was at one builder who did a study on the weight of his sprayed hulls built on a Monday verse the weight of the hulls built on a Tuesday or Wednesday and the difference averaged over time was 20%. That's a lot of weight on the size boats this customer was building.

Mark W
 
When you have been to as many boat builders as I have and seen the difference between chopped and mat construction, you would never build with a chopper gun. Unless you have access to the chopper gun and can set he proper length of fiber you want, many mistakes can be made.

Was at one builder who did a study on the weight of his sprayed hulls built on a Monday verse the weight of the hulls built on a Tuesday or Wednesday and the difference averaged over time was 20%. That's a lot of weight on the size boats this customer was building.

Mark W
Click to expand...


And you don't even want to hear about the Friday hulls!
 
I guess i messed up on my last project because I used poly resin. I just used my friends shop and sprayed the cloth. What kind of problems might I have with this boat in the future?
 
Epoxy does not kick as fast as poly so it has a lot more time to soak in and bond with the wood. This eliminates for the most part the possiblity of the glass delaminating (seperating) from the wood. I guarentee my boats against delamination with marine grade plywood as long as the glass is not penatrated.

I'm sure some of the other builders will chime in here too. I may not have covered it adaquatly.
 
The quality of a chopped part depends on the operator knowing what he is doing and if he cares about building a quality boat. Chopper guns are not a bad thing in the right hands and used along with biaxle knitted glass. As far as glass over wood you should use epoxy resin with glass cloth of various weights. As far as consistant weight from part to part all you need is a stroke counter that is used for every part.
 

Like anything who does the chop makes a difference. I've seen plywood small lobster boats (20 feet) around Wellfleet on Cape Cod with chop on the outside only. They "live" on a mooring & get used hard.
 
I may be wrong, but I always thought that the estuaries were all made with a combination of chopped and hand applied glass

there is no doubt that they are a quality job.

but they were sprayed in a mold.
 
Marine ply w/ epoxy glass is great to work with for the amateur garage builder and it turns out a superior product in regards to weight to strength ratio. The supplies are expensive and it takes a lot of time.

Chopped and sprayed takes more expensive equipment, but it cranks out hulls fast. Most use a mold, usually female. It isn't as strong as marine ply/epoxy FG, but it is strong enough. It is a lot heavier. I wouldn't put any ply anywhere in a poly FG hull.

I am in no hurry and I want a boat to last obscene periods of time and I love that it is hell-for-stout, so I like marine ply/epoxy FG composite. If you are in a hurry and don't want to spend a fortune, build a mold and borrow your buddy's set up.

Nate
 
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