catapult said:
This becomes problematic for sealing the last side during assembly, especially with short arms and a tall cabinet.
It is pretty obvious that one needs to seal the inside of the cabinet before attaching the final side, but how do people like to seal that last piece?
I guess you can coat it with sealer before gluing it on, then how critical is it to keep your sealer away from the glue line?
I think you did miss the fact that what Shin experienced was exceptional. Fair enough.
Water and water vapor behave very differently. Look at Gore Tex for a good example of what I'm talking about. And this statement of yours about waterproof finishes is contrary to your mission of dispelling myths and half-truths and whatever. It is a critical distinction that is not difficult too understand but is actually the core of the issue.
Complete submersion in water with minimal harm.
OK. How much harm? Is there any evidence of swelling? How much measured weight gain?
How long did you submerge your test samples?
Did you submerge any constructed examples (not just a slab of MDF)? Water submersion tests are only an approximation of what moisture vapor will do.
As to the technical merit of your approach, it is about 80% effective at stopping moisture. That' it. The resin used in your chosen finish will not allow it to be more effective than that. And it will do fine for most people under most conditions.
If I'm not mistaken Shin started the thread because he found that many methods were ineffective for him and his construction techniques in his environment. He found one that worked and wanted to share. You are in a different environment, your construction method differs and the appearance of your finish differs. Who made the correct decisions? No one. He wants a look. (verrry nice, Shin <s>). It differs from yours. If he wanted the enameled look he might not be having problems. The little extra gained from using an enamel might put him out of trouble. But the boxes wouldn't look the same.
He had used methods and techniques that are at least close to mathematicaly equal to that which you claim is infallible. His choice of finish is within about 5% of yours at stopping moisture transfer. Yet he still experienced problems. I'll call that an exceptional case.
Your construction differs from his substantially. Your example will behave differently given identical surface treatment in the same environment. Shin's is a radical design with radical construction that exposes the worst of what MDF has to offer. I'll call that exceptional as compared to a butt joined rectangle.
I doubt any new builder will be building anything like what Shin has done. Yet, the basic finishing method he outlined will be at least be very effective for most people and most designs. It will also be overkill for many. It's a viable option for those who want to try it. As is your method.
This is all about details that have an impact. It's all about the little fraction of a percent that makes a difference, when problems arise.
I think that point was made in the opening paragraph of the opening post in this thread.
Water and water vapor behave very differently. Look at Gore Tex for a good example of what I'm talking about. And this statement of yours about waterproof finishes is contrary to your mission of dispelling myths and half-truths and whatever. It is a critical distinction that is not difficult too understand but is actually the core of the issue.
Complete submersion in water with minimal harm.
OK. How much harm? Is there any evidence of swelling? How much measured weight gain?
How long did you submerge your test samples?
Did you submerge any constructed examples (not just a slab of MDF)? Water submersion tests are only an approximation of what moisture vapor will do.
As to the technical merit of your approach, it is about 80% effective at stopping moisture. That' it. The resin used in your chosen finish will not allow it to be more effective than that. And it will do fine for most people under most conditions.
If I'm not mistaken Shin started the thread because he found that many methods were ineffective for him and his construction techniques in his environment. He found one that worked and wanted to share. You are in a different environment, your construction method differs and the appearance of your finish differs. Who made the correct decisions? No one. He wants a look. (verrry nice, Shin <s>). It differs from yours. If he wanted the enameled look he might not be having problems. The little extra gained from using an enamel might put him out of trouble. But the boxes wouldn't look the same.
He had used methods and techniques that are at least close to mathematicaly equal to that which you claim is infallible. His choice of finish is within about 5% of yours at stopping moisture transfer. Yet he still experienced problems. I'll call that an exceptional case.
Your construction differs from his substantially. Your example will behave differently given identical surface treatment in the same environment. Shin's is a radical design with radical construction that exposes the worst of what MDF has to offer. I'll call that exceptional as compared to a butt joined rectangle.
I doubt any new builder will be building anything like what Shin has done. Yet, the basic finishing method he outlined will be at least be very effective for most people and most designs. It will also be overkill for many. It's a viable option for those who want to try it. As is your method.
This is all about details that have an impact. It's all about the little fraction of a percent that makes a difference, when problems arise.
I think that point was made in the opening paragraph of the opening post in this thread.
MJL21193 said:
Very true.
There are some compromises that can be made and some construction methods employed.
For example, The backside is rather uninteresting and seldom seen in most designs. Build the box the way you want but treat the back separately. Design so that any effects of swelling will be visually hidden, like recess the back panel a mm or so.
You can mask just this glue area which is relatively small. Or you can use an alternate adhesive that adheres to finished surfaces and augment the joint with hardware. Also a good place to use a rabbeted joint for more surface area if using a weaker adhesive.
There are some compromises that can be made and some construction methods employed.
For example, The backside is rather uninteresting and seldom seen in most designs. Build the box the way you want but treat the back separately. Design so that any effects of swelling will be visually hidden, like recess the back panel a mm or so.
You can mask just this glue area which is relatively small. Or you can use an alternate adhesive that adheres to finished surfaces and augment the joint with hardware. Also a good place to use a rabbeted joint for more surface area if using a weaker adhesive.
Shoebacca said:
Bob Barkto said:
The finish I use is compleyely waterproof, and moisture / vapor proof when applied in an unbroken layer.
I meant my entire speaker cabinet submerged in water. I have that much confidence in the consistancy of the finish. Minimal harm where there might be a place on the inside that has not been completely coated, or at the endgrain of an interior panel.
I'd be thinking more along the lines of 99.9% effective.
Enamal high gloss and lacquer high gloss look the same, but do they sound the same?
My construction is not "a butt joined rectangle". Look closer at the posted picture. It's quite complex, with curved sides and front with laminated panels plus a whole internal folded T-line. There are more than enough factors at play in it to prove an exceptional case.
It makes sence not to doubt the ability of a person that you don't know. A beginner here might know volumes about all of the releavent details involved in box construction. I prefer to give people the benefit of the doubt, assessing thier knowledge before determining ability.
Can I call you MJL?
I never meant to offend you or to make this personal.
I didn't doubt your ability, I acknowledged it. I only doubted your conclusions. And I still do.
If it appeared personal perhaps it's because we're discussing something I've been passionate about for practically my whole life and I also tend to get a little bit wordy. No harm intended.
Back to the topic.
Lacquer sounds brighter.
I never meant to offend you or to make this personal.
I didn't doubt your ability, I acknowledged it. I only doubted your conclusions. And I still do.
If it appeared personal perhaps it's because we're discussing something I've been passionate about for practically my whole life and I also tend to get a little bit wordy. No harm intended.
Back to the topic.
Lacquer sounds brighter.
MJL21193 said:
The finish I use is compleyely waterproof, and moisture / vapor proof when applied in an unbroken layer.
I meant my entire speaker cabinet submerged in water. I have that much confidence in the consistancy of the finish. Minimal harm where there might be a place on the inside that has not been completely coated, or at the endgrain of an interior panel.
I'd be thinking more along the lines of 99.9% effective.
Enamal high gloss and lacquer high gloss look the same, but do they sound the same?
My construction is not "a butt joined rectangle". Look closer at the posted picture. It's quite complex, with curved sides and front with laminated panels plus a whole internal folded T-line. There are more than enough factors at play in it to prove an exceptional case.
It makes sence not to doubt the ability of a person that you don't know. A beginner here might know volumes about all of the releavent details involved in box construction. I prefer to give people the benefit of the doubt, assessing thier knowledge before determining ability.
Shoebacca said:
A good solution (if the final finish is paint) is to put a coat of urethane (clear or otherwise) on the inside face of the panels after cutting. Then use urethane glue to glue it together. This will be the ultimate for MDF, as every internal surface and edge will be sealed. Also, urethane glue is unbeatable for box construction with any wood or wood based material.
You'll still have to store it in a dry space to let the moisture content equalize before priming.
Bob Barkto said:
Hello Bob, I'm John.
It's ok if you have doubts about my choice of finishing, that's your choice; I'm not here to convince anyone of anything.
Sploo asked me to elaborate on the steps I take to solve the joint problem, and I provided them. It's there for everyone to see, comment on and criticize. I try to answer any comment with a reasonable answer, but like I said, it's not really mine to defend - just a bunch of rules and methods from very reliable sources that I've strung together for painting my speakers.
My real passion is building the speakers, and it did bother me somewhat when you refered to my speaker as a butt joined rectangle.
I have, in a much earlier post, given credit to Shin for his fine work. I recognize talent and skill and most of all the effort it takes to build and finish a complex speaker cabinet.
Enamel sounds drier
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.