I love the idea behind these reusable vacuum table set ups.
Will this particular bag system work with a female mold that is
2 inches depth 10 in x 6 in.? The finished surface of my mold/part is female ( how the hell do you say that in composite terms?).
picture one is Carbon Kitty, our shop mascott lol.
Hi Fastrr,
I use homemade “vacuum clamps” as we call them in guitar-making all the time. They work great, and they will easily do what you’re describing as long as you have enough slack in the membrane. My “clamp” uses 1/16" thick latex, but for molds with intricate shapes, I’d try to find some 1/32". You can see that the latex in my picture just starts to bridge where the braces are 90° to the soundboard…
For reference, before applying vacuum the latex would hang just below the plane of the screwheads on the frame.
That’s very cool. How did you fasten the latex sheet to the frame?
Also if anyone is interested i have found all the materials necessary online to build one of these elastomeric vacuum tables. Not cheap though to build. My materials list was $680 for a 36" X 36". That did include a steel stand also.
The thicker the metal base plate the price just skyrockets… i priced the build for one using 1/8" mild steel ($85). Just for a piece of 5/8" 36"x36" aluminum plate - $760. that may be a bit high but i can call local metal supplier for their price on the aluminum.
Anders, we have a guitar project we are starting to work on also. It’s for a local customer who makes/assmebles the guitars. I wish i could post the stuff online but we are have a confidentiality agreement. If you have any info on building composite guitars… and it’s not secret… i would love to hear them.
The latex is pressed against the (wooden) frame by drywall screws passing through the top Lexan sheet and piercing the latex. The latex becomes it’s own gasket…
You project cost seem sky-high to me. Why use metal? You can easily do a very stable laminated base from moisture-resistant MDF, topped by 1/8" acrylic. That would cost $25. The frame (mine) is also laminated MDF, and the latex costs $50. The big square of Lexan, I realized later, is not necessary. I could have used narrow sections of it that only covered the frame and sealed the latex. In my shop the whole work table is the vacuum table base, with one vacuum port in it. Then, I have multiple “clamps” of different depths and sizes to suit my different needs.
The most popular of composite guitars is what called a “double-top”. Some go for as much as $35,000. The typical recipe for the soundboard of a composite guitar is two skins of 0.6 mm spruce or cedar that sandwich a varying-thickness nomex honeycomb core, bonded together with epoxy or polyurethane glue. The weight is reduced by as much as 50 %, making the soundboard much easier to activate. Unfortunately, the drastic change in weight also changes the frequency response drastically, and many sound very “untraditional” to the discerning ear.
That is ridiculous… why don’t you buy aluminum flat bar and weld it together. I think I remember getting a 12"x5"x0.5" 6061 Al bar for like ~$7-8. If my calculations are correct you could piece together a 36"x36"x0.5" plate for ~$150 if you weld up the seams. It would take longer no doubt, but surely cheaper than $760.
I think 5/8" thick is a bit excessive for what you are likely to do. And you sure as hell wouldnt be able to move it without a forklift! I have a 1/2" 8x4 plate in my shop that i layup flat floor panels for race cars and it sits on a table and i cant move it. It spends most of its life as a cutting table with a protective wooden top on it so it isnt dead space because it is soo hard to move. And knowing what that cost i think you may have been over quoted! Remember it doesnt have to be a super structural metal 7075 is not needed for something like this.
you just wrapped your cat with carbon? Fast, I should smack you hard for that one!!!
fleish, yeah aluminum prices are high… i think also plate is more than bar stock, i could be wrong. I did call my metal supplier and for 3/16" X3ft x 5ft they wanted $180. I myself would not go up to 5/8" thick aluminum… as that is probably meant to hold a very heavy steel or aluminum mold weight. Say you had a 400-500lb mold tool. Most all of our small tools wiegh less than 30lbs. For now i would only want to lay up small tools using this type of system. 3/16 steel or aluminum would work for me. I just want one about 3ft x 3ft on a rolling table so i could move it around as needed.
What i thought was expensive is the silicone rubber sheet material. 3ft x 4ft x 1/16" is around $200 or so. I’m not sure how the latex will hold up but if it can produce 30 or more lay ups before changing out the latex… that would be good.
Where did you buy your latex sheet?
yes guys where do you buy latex sheet?
I dont want to know how many carbon micro fibers stayed on that cat… Poor cat. Thats not really nice of you…