I'm not sure i understand how you are installing the balsa.
Sounds like you are installing mat/cloth after you lay down the balsa?That can't be right,i get confused easy,can you clear it up for me.Thanks.
Can't be right? What do you think completes the process once it's bonded in place?
Rich, I'll be letting you know about that belt sander. I was hoping that since the shear strength of the balsa is pretty weak, I could get in under the glass and break a large portion of the balsa out. Then come over, borrow the belt sander and get rid of the bedding and clean up the wood/glass underneath. Don't worry, I'll be in touch with you shortly
The top layer of glass should be a cake walk to get off. The rest is gonna be messy.
Im not sure if everyone is talking about the same things here.
If the boat in question has a cosmetic layer of balsa in it for looks only thats one thing.
Alot of boats have layers of glass laid in the mold then a layer of balsa laid in and then more glass on top. This is a very definative structural aspect of the construction and most certainly makes the hull ALOT stronger. 2 layers of glass seperated by balsa are infinatly more ridgid than 2 layers of glass layed directly on each other. The cardboard anaology was a good one but if you use that to experiment with do it once with cardboard as it comes in a box then try it again with the cardboard running "end grain" as tho its a honeycomb material. You'll soon see the major advantages to end grain balsa. For almost no weight you can acheive an incredible amount of strength.
Old rigger I totally disagree with saying a boat with can be as strong as without, UNLESS you mean while being far heavier. Layering many many layers of cloth/mat to acheive strength is a poor way to build a boat. Using core materials is far better and if done right CAN last a looong time. (i.e. vacummm bagging)
I'm a tin boat guy by nature(now) but I know some guys that build boats and I even have a hydrostream project boat that actually needs to have the balsa core redone. Its removed right now and the outer hull is paper thin and your foot would likely go right thru it. Add balsa and more cloth and it becomes strong enough to drive again. Alot of builders use a core in the bottoms of boats. Better builders use it in the sides and decks. Check out this build thread and you will see what a well built glass hull looks like thru the build stages(sorry about the drama in the thread)
Pic: Would they do this for looks only?????
http://forums.screamandfly.com/forum...9&d=1133799538
forum link:
http://forums.screamandfly.com/forum...highlight=tuff
This guy is in out club and he makes a really strong nice boat(there is a reason they call them "Tuff")
Cheers
Rampager,
while it may seem that 2 layers of glass seperated by a core of balsa is stronger than just 2 layers of glass, that's not necessarily the case. More isn't always better. The balsa core may take away the flex that we were talking about earlier in this thread, it doesn't make it stronger. A boat can flex wildly and not break. In fact sometimes making it rigid can lead to other problems like stress cracks. You can take a Rogers hull, for example, lay it up properly and you'll never need balsa in a million years. The strength of his hulls were due in part to their shape.
And you're right about what I was talking about with the 20 spectras. They were built heavy, although the '79 we have now is half the lay up of the '73 hull we had a few years ago, but it's still tough as a brick. Adding a balsa core would not change a thing in that boat except to make it stunning to look at. It's still going to ride fantastic, perform well and do what's it's supposed to do because of it's near flawless design.
Vacumm bagging has benifed boat builders for decades. Find an old Aqua Craft from the 60's and you'll more than likely find fast, crack free hull that has nothing to do to balsa. Just good glass work.
As far as my being wrong about a boat being as strong without balsa, could be. I'm wrong about alot of things.I know everything is done better, faster, bigger than when I got out of the boat biz some 10 years ago. But from what I see out here in so cal, not much has changed with the builders. Poor glass work together with the aid of a core, be it balsa or a manufactured core, is still shity glass work. And there never seems to be a lack of that.
Back in the day before Dick Schuster started Tahiti he was a laminator for Powercat boats. They were building the race hulls out of nothing but cloth, no mat at all. They were very thin, dry lay-ups, running twin mercs. Mid 80s for speed back was what they were running. If I remember right, he told me their thinking (this was very near the begining of glass boats) was to build the boat like a helmet, nice clean layer upon layer of cloth. It worked. Clean glass work together with the design of the classic little cat made it a winner. On the other hand he also told me the first time the had resin deliverd to the shop, when they were making the change from wood boats to glass boats, they popped the lid off of the first 55 gallon drum and mixed the entire thing with catalist. They were on the very begining of the learning curve of 'high tech' glass work.
As far as Hydrostreams, no doubt about it. They are great looking boats, and very fast. Wickedly fast. Everyone knows that, but again I'll have to disagree with you. I don't have to follow along with your link to see a 'well built glass hull looks like through the stages' thank you. Couldn't log on anyway. I've seen hydrostreams and they can't hold a candle to the workmanship that's gone into say a Cole (like the one that started theis thread). Not even close. Are they fast? Sure. So what. Cole, Howard, Hondo, Stevens, Rogers, Hallett, Schiada, THOSE, and many others I didn't think of right now, are a lesson in workmanship.
I apreciate your oppinions and keeping it civil Old rigger
I wasn't meaning to say 'streams' were necessarily high quality just a good example of a boat built with a core in the bottom. I honestly think this is the only way to built a strong fast boat IMO
Obviously bad glass work is bad no matter what boat its in, I agree there.
One of the true tricks to making a strong boat is getting the flex there with enough stiffness for the boat to handle properly. Balsa can still be used to do this if the hull is desinged right. Rubber rafts are great for flex but a bitch to get to handle lol
Anyway I think we've shed enough light on the topic. Its easy to find alot more info online for the curious. Just make sure that balsa is cosmetic before you remove it or you'll have one floppy boat!
Cheers
Flatbroke:
Okay, talked to Ervin Capps about your question & this thread.
First, to your question: He said that the best way to remove it was to cut very carefully through the top skin of glass around the edged, and peel it away with a chisel down to the Balsa. Then remove the balsa with a chisel, as it doesn't take well to a sander or grinder. His next question was, what is he trying to acheive? I told him I thought it was just to remove some weight. He said that the amount of weight you were going to remove was miniscule for the amount of work you were looking at. He said that if it was only in your bilge area, that he doubted that you would remove 50 lbs. Might be worth it if you were racing, as 50 lbs might make a little difference in E.T., but wouldn't make a noticeable difference in top speed if that was your concern. He said go out and do a test run by yourself, and then take a 50 lb. kid for a ride with you, and note the difference. lol.....something to think about!
On the subject of the end-grain Balsa....he violently disagrees with the statement that it adds no structual strength, sighting the $7-800,000 offshore tunnels. They have two layers of one inch balsa laid in the bottom of their sponsons. He sited the aircraft industry, who for years has used the technique of laminating aluminum honeycomb betweeen layers of sheet aluminum. Same difference as what we are talking about. Ervin also used the example of an I-beam. The top, bottom & web of a beam as individual components are not that strong, however when put together as a
structure, they become incredibly strong.
I think we need to think about what kind of strength we are talking about here. Panel strength & rigidity. Sure, if you run into the corner of a dock, and poke a hole in the side of your boat, balsa wouldn't have done you any good, but such as in a deck, where you are trying to make it so you can walk on it, or the strength of the bottom of your sponsons, for hitting 3' rollers, yes it's going to make a difference.
Second point to me is that we are talking possibly about 2 different types of boats. The type which are laid up heavy enough so that the glass is the structure, or a light-weight lay up where layers of glass add weight. In the second situation, the balsa is definatly a structrual component in my mind.
From the website of Baltek Balsa: (http://www.baltek.com/products/egbc/egbc.html)
End Grain Balsa, a highly processed ultra light wood product, imparts impressive strength and stiffness to the sandwich panel. The end grain configuration of balsa provides high resistance to crushing, and is very difficult to tear apart. End grain balsa cored panels also have the ability to handle excessive dynamic loads with high resistance to fatigue.
Until recently, end grain balsa was excluded from some weight sensitive applications, as there were lower density foam cores available. Now, through controlled growing and careful selection, BALTEK SL balsa is competitive in weight, as well as offering superior performance in stiffness and strength, particularly where local crushing or bruising is a concern.
High Speed Power Boats:
End grain balsa has become the core material of choice for hulls and decks in high speed offshore power boats. The extreme slamming loads put a high emphasis on core strength and skin adhesion, areas in which end grain balsa excels. The new BALTEK SL product range allows the density of the end grain balsa to be tailored to meet the loads in different areas of the hull.
Again, I've really enjoyed this thread, it's really made me think & do some research!
Ken F
rampager,
off topic, but I've never been for a ride in a hydrostream. I know a bunch of guys over at 'screamandfly' and there's another web site I can't think of right now, love 'em. How fast did your's run and how'd it feel on top end? They always look like they take a set very well. I know the guys with the big motors are very fast but even the small engines fly with that boat. It's a wonder you don't see more of them on the west coast. Plus I love the way the sheer lines drops down in the front of the bow. Good looking boats.
Every now and then an older one will pop up on ebay or in the trader, always thought it be a fun boat to restore with an old merc inline.
Never driven mine rigger! lol
I got it for free off S&F cause it needa a recore as I said. Ther are alot of them around in this neck of the woods and a bunch of guys have em in our club. They do fly with the right setup and power. Was told mine would easily do 80 mph all day with an older 150 merc. Its a Vector and is 17' long
Ive loved the lines of those boats since I first saw em when I was little. Definatly not alot of boats around with lines like them. They are like a Corvette stingray on water
Cheers
p.s. that description of how to remove the core is exactly what i'd been told/read. Skill saw thru upper glass layer and scrape/sand/chisel out the balsa Supposed to be a very labourous and crappy job from what Im told but my core was already 90 % out hehe
I have the same flooring in mine, still looks good too, for an 88 model
Here's a '75 Sleekcraft thats getting the " For Looks" version of the balsa core. The only removing of material I have done was the un needed mat from the old glassed in deck, the transome wood, center stringer, rear shorty stringers and the 1/4" plywood that was glassed into the hull at the rear srtingers outboard. This project is still in full swing I just haven't posted in a while. I'm doing a foam core in the chines glassed in before the balsa goes down. One thing I have learned and will never do again is play with the mass production crap boats again. Built like a tank, the mat and glass is full of big air pockets, loads of un needed resin piles... Just a matter of "what is" when dealing with a production quality boat. I'm a believer in going with the high quality stuff from here out.
This pic is with most of the transition work finished.
http://www.hilsingermotorsports.com/...=&postid=62237
Here is the balsa and new stringer material thrown in just for pics.
http://www.hilsingermotorsports.com/...=&postid=62503
If you plan on doing a project like this buy youself a high quality airfile like this Hutchins model out of Pasadena. The cheap china model will cost you your patients.
http://www.hilsingermotorsports.com/...=&postid=62623
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