Quadrex foam grills: how were they made?

[shinola]

Anyone know how the original quadrex grills were made? I was thinking they were sculped with a hot wire, but apparently that's a no no with polyurethane foam. I guess that leaves either some sort of knife or bandsaw type blade?

[Kay Pirinha]

Hi,

maybe the foam was expanded in a negative mould, just like egg crate pattern foam?

Best regards!

[DES-1]

Maybe member sonofagun might be of help to you as he manufactured reproductions: #1 (http://www.audioheritage.org/vbulletin/showthread.php?39801-Foam-Grille-business-for-sale&p=406241&viewfull=1#post406241)

[shinola]

Kay,

Eggcrate foam is actually made with a bandsaw. Its sawed while being squished by two convoluted rollers, see video below.

Foam poured in a mold has a non-porous skin on the outside, so I'm pretty sure it's cut, not molded.

DES-1,

I'm not sure sonofagun would like to share his "trade secrets" unless I buy his foam grill manufacturing business for $12,000! Also he indicated making the grills is labor intensive, so I imagine he is hand cutting the foam with some sort of jig.

As a guess, I would imagine JBL has the foam sawed with some sort of CNC wire bandsaw, but who knows.


https://www.youtube.com/watch?time_continue=68&v=GGJdhwiaLwo

[DES-1]

[QUOTE=shinola;423387]Kay,


DES-1,

I'm not sure sonofagun would like to share his "trade secrets" unless I buy his foam grill manufacturing business for $12,000! Also he indicated making the grills is labor intensive, so I imagine he is hand cutting the foam with some sort of jig.


LOL, trade secrets! I think you are right about the manufacture methods, no doubt the methods used back in the day are stone age compared to the present.

[Don C]

I think I saw the rig for sale once. Some metal plates cut to match the profile needed from the side, and a bow with a hot wire for cutting.

[shinola]

I think I saw the rig for sale once. Some metal plates cut to match the profile needed from the side, and a bow with a hot wire for cutting.

Thanks. I assume this was an aftermarket thing, not jbl factory equipment?

[Don C]

I would assume so as well.

[shinola]

I would assume so as well.

Ok, thanks.

Now I just need to figure out where to buy foam. From what I've read it's 30ppi or so. There's polyester and polyether reticulated foam, not sure which is best.

Unfortunately I don't see any colors other than black for sale. White could be dyed or painted and is common, but I don't see it for sale in 30ppi.

[sonofagun]

you'll need it! :crying:

[shinola]

you'll need it! :crying:

How very kind of you to wish me luck. Perhaps I shall document the process here once I get it all worked out?

[sonofagun]

My post was not intended as any kind of insult or barb, just a kindly warning of the frustration you may have to go thru which is the same path I've been down.

Do I know you? Have we had some contact previously that (apparently) has caused some animosity? Never my intention from the beginning to attack, insult, or start trouble (or "Barney" as per Don Cheadle's hilarious line in Oceans 11) with anyone - just my 40+ year dedication to appreciating and work to restore the legacy of Jim Lansing's products. I feel somewhat of the problems he faced early on in my present situation(s).

Realize there are others already selling the replacement grilles so you already have competitors. Too bad that instead of joining with me to help me in my struggle (from facing unemployment) many years ago to build a prosperous and growing business*, others just choose to oppose (or criticize) and compete with me taking away badly needed revenue. Instead I live alone and in crushing poverty wondering day to day how I can make ends meet.

*I still hope to achieve this (soon, I wish) as I still make and sell grilles for other makes/models. In addition, I have other products both related and not that are unique and highly marketable/profitable (prototyping one right now). Amazes me that for YEARS I have approached virtually ALL the sources in my state that say they want to help small businesses, but instead just put more work and frankly, dead ends in front of me in spite of my expressed goal to expand to provide JOBS (something it seems lip service only is given to)!





Typical vexing problem/frustration just occurred - I hit the preview button and the next page said I had to log in (which I had done 10 minutes earlier) - nearly had a H.A. as I thought I might have lost all that I had composed (thankly it was still there when I went back!). I have posted many times here on this problem with being logged out so readily here with no solution it seems. Another problem trying to work online with little or no computer savvy!!!!


OMG - now get this! So I checked at the top of the page (before hitting preview or post) to see if I was logged in and it indicated I was, so I hit "post" and what happens? Goes to a completely blank/white screen - I hit refresh and it remains blank (after many minutes. So I have to open another tab and go to the site to log in and post this. Even had to copy and paste in my email so I didn't lose this. Now does anyone understand why I commonly post this: :banghead:


Hooray, I made it!!!!!!

[shinola]

My post was not intended as any kind of insult or barb, just a kindly warning of the frustration you may have to go thru which is the same path I've been down.
Regardless, it's rude to wish me "good luck," or "kindly warn of the frustration" I might face when you have the ability to ease that burden by giving advice. If you do not wish to share advice this is probably not the best thread to be posting in.





Do I know you? Have we had some contact previously that (apparently) has caused some animosity? Never my intention from the beginning to attack, insult, or start trouble (or "Barney" as per Don Cheadle's hilarious line in Oceans 11) with anyone - just my 40+ year dedication to appreciating and work to restore the legacy of Jim Lansing's products. I feel somewhat of the problems he faced early on in my present situation(s).

Before I started this thread I exercised due diligence and looked for information in existing threads, so we wouldn't be rehashing what's already been discussed. I found I had to wade though a lot off topic posts made by you, not contributing to the thread, trying to sell your business and/or grills, etc. Hijacking threads to promote your own interests is a form of pollution as far as I'm concerned.

Take this thread for example, no one helped the OP, and there's three pages of you trying to sell your business after the OP left:

http://www.audioheritage.org/vbulletin/showthread.php?37392-JBL-L100-quadrex-grills-foam
(http://www.audioheritage.org/vbulletin/showthread.php?37392-JBL-L100-quadrex-grills-foam)



Realize there are others already selling the replacement grilles so you already have competitors.

I'm not making or selling replacement grills, this is for a student industrial design project.




Instead I live alone and in crushing poverty wondering day to day how I can make ends meet.

I'm sorry to hear that.

[sonofagun]

Have your students search "foam fabricating/ion for lots of info - also much is on youtube. I don't have all the answers myself.

As to that thread of the guy in Poland wanting info - he has turned out to be a competitor, so helping him would have been nonsense.

As far as advertising my business - lots of threads on this site may start off on one subject but then "morph" into others.

This thread can be closed as far as I'm concerned.

[sonofagun]

[QUOTE=shinola;423387]Kay,


DES-1,

I'm not sure sonofagun would like to share his "trade secrets" unless I buy his foam grill manufacturing business for $12,000! Also he indicated making the grills is labor intensive, so I imagine he is hand cutting the foam with some sort of jig.


LOL, trade secrets! I think you are right about the manufacture methods, no doubt the methods used back in the day are stone age compared to the present.


Stone age? Actually, I have found that companies today I have approached have failed miserably at reproducing L100 Quadrex grilles even though they have cnc machines costing many thousands of $$!!!