Inexpensive hull construction materials

[ondarvr]

It would be great to have a way to use recycled plastics in the composites industry.

Right now most of the plastic that is being supposedly recycled is going to the land fill.

There is no market for it, they keep the recycling systems in place because it took decades for it to be implanted into our culture and lives. If we stop recycling the fear is that we will forget the habit and it will take decades to get us back into the habit of doing it again.

The hope is that in the future, near future hopefully, a market for recycled plastic will emerge.

And it all has to do with the cost of processing it.

Collecting, sorting, grinding, sorting again, retreating it for use, certifying it for a certain spec, reprocessing into a form or material that will be correct to use in building the final product, etc, then transporting it to the customer.

So you’ve started with a product that was essentially free, but by the time it’s fit for use in another manufacturing process the cost is sometimes significantly higher than virgin material.

 

[gonzo]

Plastic (polymers) recycling is done for political and environmental reasons. Virgin material is cheaper, easier to use and higher quality.

 

[ondarvr]

Plastic (polymers) recycling is done for political and environmental reasons. Virgin material is cheaper, easier to use and higher quality.

You said it in about 500 fewer words.

 

[ondarvr]

Sadly, I went back read this thread from the beginning just so I could make sure we were still sort of on track.

It hasn’t drifted a great deal, but just about everything that can be said has been, probably three times.

 

[fpjeepy05]

Also, an analogy of a deck of cards to a foam core is completely wrong. It could be used as comparison to a laminated wooden beam though. Remember that you are dealing with a lot of engineers and designers, so take the time to use terminology and analogies correctly. Otherwise, you will be called on your errors.

Can you explain why it is a bad analogy? Is the force breaking the glue between the layers not shear?

Another mistake is to look at elongation at rupture as the only indication that one core is better than another. For example, you need to consider how much stress is necessary to attain that elongation.

I didn't say it was the only indication that makes a better core. You are correct shear strength is also important.

You started this thread asking about the cheapest material, and still insist that wood is not it. However, all your alternatives are more expensive. When nobody agrees with you, your answers turn to tantrums. Prove you are wrong by posting the price and physical characteristics of the material you claim is cheaper and better. Getting supplies for free will only count if they get compared to the free wood you can get by cutting a tree.

Please re-read the thread. I conceded that wood is the least expensive material. I even conceded paper was second. I was pursuing the second runner-up. My answers are not tantrums. I was attacked personally and aggressively. In turn, I have challenged everyone else with the same aggression directly. It is not my preferred mode of communication, but that doesn't mean it can not be successful (case in point Steve Jobs)

 

[fpjeepy05]

This is really getting crazy, I’m not sure where the discussion goes from here.

We make fiberfilled polyester putties, I know the price, it’s not cost effective, nor does it have good physical properties as a core.

I do multi-day composite schools and training seminars with the large distributors, the fabric, core, catalyst, resin, gel coat, mold release, filler suppliers and others are there to help customers choose the correct products and methods for building boats and just about every other thing made from composites.

We also do onsite production audits for large customers to help them be more efficient in building whatever it is they produce. I’ve also done this internationally.

I’ve known these people and have done training with them for decades. We vacation together, our families are friends.

So, if my information is bad, or you consider me uninformed, then the entire industry on every continent is.

Again, I’m not being negative, I’m only giving you information aquired over decades of manufacturers and suppliers looking at doing exactly what you’re talking about.

If you have some ideas that are better or different, then please, by all means, bring them up and explain why you feel they will work. I would love to be part of that conversation.

To this point you haven’t presented any details about anything, just saying that you “know” some undiscovered or undisclosed filler “will” work in polyester resin as a very low cost and strong core.

My comment wasn't meant to contest your credibility. I understand you are knowledgable about the topic. I'm not debating that. I was cutting on you, because the only reason you didn't suggest adding a filler like glass fiber is that it didn't help your argument.

I didn't say I know there is a polyester filler that will work as a lower cost strong core. I know that 50/50 recycled plastic / polyester resin fashioned into a 1" 1ftx1ft square will be stronger and cheaper than 1" 1ftx1ft square of H80 Divincell.

The reason we don't see this putty used in boats is for reasons you or others have already explained. It is expensive to process, form, work with etc. It is also heavy. Again the purpose of the discussion was to just talk materials. If potential materials can first be identified then procession can be evaluated afterward, and more than likely the conclusions that you have made will hold true. But conclusions can be made. I.e. If recycled plastics drop below $x.xx then it is feasible. Or if the weight was not a concern then these are feasible. Or if a method for manufacture can be engineered to cost less than $x.xx / ton then it is feasible. Or is the government is will to infest $X million of equipment then it's possible. Labor cost would have to be less than $x.xx. Etc.

 

[ondarvr]

At the cored panel manufacturing plant we disposed of dumpsters full of waste every day from trimming and cutting panels to size. This was only a mix of fiberglass with wood or foam as the core.

There were many discussions in meetings to see if there was some affordable way to reuse the materials.

Even with the material being onsite, free, and it would have eliminated the cost of having it hauled away, the cost to process the waste into a usable product was just too high. Even if the cost was low, we couldn’t produce enough to do much with it.

Wood was the most used product, the second place material was foam. We used various brands and densities as needed. We used Carbon Core products too, but they were down the list a ways.

 

[gonzo]

↑

Also, an analogy of a deck of cards to a foam core is completely wrong. It could be used as comparison to a laminated wooden beam though. Remember that you are dealing with a lot of engineers and designers, so take the time to use terminology and analogies correctly. Otherwise, you will be called on your errors.
Can you explain why it is a bad analogy? Is the force breaking the glue between the layers not shear?

Yes, a foam core is homogeneous not a stack of laminations.

 

[fpjeepy05]

↑

Yes, a foam core is homogeneous not a stack of laminations.

Honeycomb, balsa, solid wood, and plywood are not homogeneous and are used as core. I've laminated scraps of foam together to make a thicker part. When glued properly they function the same.

At the cored panel manufacturing plant we disposed of dumpsters full of waste every day from trimming and cutting panels to size. This was only a mix of fiberglass with wood or foam as the core.

There were many discussions in meetings to see if there was some affordable way to reuse the materials.

Even with the material being onsite, free, and it would have eliminated the cost of having it hauled away, the cost to process the waste into a usable product was just too high. Even if the cost was low, we couldn’t produce enough to do much with it.

Wood was the most used product, the second place material was foam. We used various brands and densities as needed. We used Carbon Core products too, but they were down the list a ways.

So because you guys didn't figure it out, it can't be done?

 

[ondarvr]

So because you guys didn't figure it out, it can't be done?

No, I’m saying that, so far it’s not something that the industry as a whole has been able to do.

That’s why I keep saying that if you thinks it’s possible you need to come up with a new twist on getting it done.

I can only tell you some of what’s been tried and failed.

You seem to think that when someone says, “ here’s everything we’ve done in the past, and it didn’t work as we hoped, and these are the hurdles we couldn’t overcome” that it’s negative speech.

I’m letting you know that to get it to work as you desire, these aren’t the paths to take.

 

[ondarvr]

Also.

Every one of the things proposed can be done, that’s not the problem. The problem is doing it as you requested, better and for less money.

 

[BlueBell]

PAGE 9 OR IS THIS PAGE 10!

 

[gonzo]

Honeycomb, balsa, solid wood, and plywood are not homogeneous and are used as core. I've laminated scraps of foam together to make a thicker part. When glued properly they function the same.

Once more, that is an incorrect statement. The physical characteristics of a foam lamination is different from a homogeneous layer of foam. Regardless of how you glue them, they will not function the same. In application where weight is not critical, they may work adequately, but never the same. Further, honeycomb, balsa, solid wood and plywood are the types of core you refuse to accept as good choices. Therefore, either concede that they are the cheapest choice, or don't bring them into the discussion.

 

[peterjoki]

This had the potential to be a very constructive and interesting thread. It's very disappointing to see what it came to.

I've read all posts, and refrain from getting tangled into this. Don't have much experience with core construction. I do understand the concept though... Two outer skins and a core. Otherwise its just a laminate, no core. My two cents on the stack of cards.

I also frequently mix a little too much. It's brittle as hell (even with a generous amount of cellulose fiber). And there it no adhesion to the plastic bucket once cured. Give the bottom a wack and it releases nicer than from a well waxed mold. Polyester and epoxy.

 

[peterjoki]

You are all extremely knowledgeable, that's why I love this forum. I learn more every time I log on. Let's stay civil and treat eachother with respect.