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Quoted from gac:There is definitely no play in the channel. I even removed it from the back box and tried to push it onto the panel and I can't get it to fit.
Sorry about that, I will take care of and send you a PM. Long explanation below. If you want short version of explanation, go to last paragraph
I will tell you why it happened and what we are doing now to make sure it does not happen again. I know some of you guys like the details. I go through long explanations to demonstrate issues are resolved in a consistent system.
First problem, warpage. This can make it hard to fit in the metal H-channel:
We have been working on these panel for about 1 1/2 years. For most of that time we were using 3/4" MDF and placing rows on LED strips facing towards the player. It worked, but left hot and cold spots and had many, many solders. It took us a long time to figure out the board the we do now, which is a hybrid resin and wood board and looks great.
We used to use 3/4"MDF but now it is 3/8" resin and 3/8" wood. We did not have local supplier of 3/8" MDF, so we used the top of the line 3/8" plywood and made many boards. There were a few reasons that we used MDF instead of plywood when we started, and we learned those lessons again. One problem is plywood can splinter, but that was not a big problem, because those splinters got filled in with resin. The big problem is plywood likes to warp, and depending on which way you cut it, it can warp more than if cut in the other direction. Also, if you stack them at different angles, that can add to the wrap.
Warpage is one of the problems that Mr. Thompson had on his Creature boards a few years ago. Not to knock his product, it was a great product, warpage is just a challenge with this kind of product.
Now we use cabinet grade 3/8" MDF and that took care of most problems. Another great thing about MDF is that the resin soaks into it about .05" and that section of the board is like concrete. The fibers from the MDF with the resin, super strong.
The next surprise problem, curing of the resin. We do a lot of work with resin and my main guy has been in the resin industry for over 8 years. We have a room here that is temperature controlled to have only a 1 degree variance, and that is set to the temperature that resin likes the best.
On resin, you mix and have about 20 minutes to pour, once poured it has a solid shape and can be removed form a mold after about 3 to 4 hours, but this is not advisable, because the item is a bit flexible. For this reason, we let the lighted speaker panels cure for 24 hours and they come out solid. What we found out is even of you take them out in 24 hours, they still bend slightly and this puts a bit of a memory in the resin, even though they look perfectly straight.
We were very surprised that after a day, in the mold that could still happen. We now keep them in the mold for 3 days after pouring. They come out straight as an arrow and as strong as a brick. I will included a picture of the molds on their boxes on the drying shelves, and they don’t get moved for 3 days. Each one of the molds costs about $500.
We have done everything possible to remove any chance of warpage. If somehow your board gets a slight warp to it, just place it in the sun for 10 minutes and it should go back to normal, or put a slight pressure on it to straighten. The odds of this being needed is very, very, very low and will not damage the board in anyway.
Next problem, the finish:
The lights we use are .38 inches wide. The U channel is .52 inches wide. The thickest speaker plastic is .08 inches wide. In light placement, we lose .02 inches. .38 inches plus .08 inches plus .02 inches is .50 inches if everything is perfect, and that fits in a .52 inch channel. That leaves 2/100th of an inch to do our finishing work over the length of the board, which is 27”.
When a board comes out of the mold it is crystal clear, which is good for light transmission, but light will not exit a clear finish well. For this reason, we must sand the top coat to get good light distribution. When we started, we were hand sanding the boards using many different sanding methods to get the proper finish. Lost many, many boards.
I identified that problem, and we made a sanding jig. Still many problems, tool selection, grit and finishes. But we still had issues. Then I found out my guy was not using the sanding jig, and it is hard to stay within .02” over 27 inches with a power sander. Another problem was they did not have a good method of measuring thickness.
We were having close to a 60% failure rate at that time.
I revisited the sanding jig with my shop guy. Walked through the entire finishing process and it is being used properly, and out of the last 40 boards, no failures, all fit in U channel.
There was also a problem with consistent thickness. The solution for this was very simple. I tracked down a metal U channel and the thickest plastic I could find (I have over 100 speaker panels here, and they are not the same thickness). The thickest plastic we could find was .077 inches. We tracked down a piece of plexiglass that is .085 inches. Now every board that is made we place in a U channel with plexiglass slightly thicker than the thickest plastic.
On the attached pictures are our last batch of boards, all fit in H-channel properly and ZERO failures or defects. Picture of the molds that we pour the boards in and they cure for 3 days. Sanding jig for the boards, the metal keeps the sanding level the same and keep the sanding from dipping, the U-channel we measure is in the back or the picture. Picture of lighted speaker panel in the U-channel with a thicker then board plastic that all boards fit in before shipping.
Summation:
The problem with the board not fitting was a potential problem on some of the earlier boards and is no longer an issue. The problem was either from a warped board or not sanding to fit. The warpage problem was resolved by using proper MDF base board and letting resin cure for 3 days. The not sanding enough problem was from not using a system that gave a consistent result. We now are using a sanding jig that only allows a consistent depth of sanding, and ALL boards are checked for sizing with a U-channel and a plastic that is slightly thicker then what is in your game.
Dan
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